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About this book

This book comprises select proceedings of the International Conference on Future Learning Aspects of Mechanical Engineering (FLAME 2018). The book gives an overview of recent developments in the field of thermal and fluid engineering, and covers theoretical and experimental fluid dynamics, numerical methods in heat transfer and fluid mechanics, different modes of heat transfer, multiphase transport and phase change, fluid machinery, turbo machinery, and fluid power. The book is primarily intended for researchers and professionals working in the field of fluid dynamics and thermal engineering.

Table of Contents

Frontmatter

Simple Analytical Method for Performance of an Absorber Plate in Flat-Plate Solar Collectors for Two-Dimensional Heat Flow

In this paper, two-dimensional temperature distributions in the absorber plate of a flat-plate solar collector have been determined by an approximate analytical technique. In case of two-dimensional heat flow in the absorber plate under actual boundary conditions, the determination of temperature field using an exact analytical method might not be possible. Alternatively, this temperature field can be evaluated using numerical methods. In the present study, finite difference method has been employed as a numerical tool. However, it is well known that the numerical calculations increase the computational cost. For the ease of calculations, an approximate analytical model has been proposed in the present study and the accuracy of the present analytical method has been checked with the comparison of results obtained between the present analytical and numerical techniques. It can be demonstrated that there is an excellent agreement between two results and the deviation between these two have never exceeded by 5%. Therefore, the present analytical method might have a significant importance for analyzing the performance of an absorber plate in order to avoid difficulties of the numerical solution.

Jayanarayan Mahakud, Balaram Kundu

Energetic and Exergetic Analyses of a Solid Oxide Fuel Cell (SOFC) Module Coupled with an Organic Rankine Cycle

In this article, energetic and exergetic analyses of a natural gas-fueled solid oxide fuel cell (SOFC) and organic Rankine cycle (ORC)-integrated power generation system are presented. In the topping, SOFC cycle of the proposed power generation system, anode channel as well as cathode channel recirculation has been done. Toluene has been used as a working fluid in the ORC. Influence of major operating and design parameters, viz. current density of SOFC, cell temperature on the performance of the proposed system has been examined. Results show that maximum energetic and exergetic efficiencies of the proposed power generation are found to be 67.06 and 58.17%, respectively.

Dibyendu Roy, Samiran Samanta, Sudip Ghosh

Numerical Investigation of Single Gas Bubble Rising in Liquid Column

Analysis of bubble fluid dynamics forms the primary step to evaluate heat/mass transport phenomena encountered from rising bubble in liquid pool. Bubble rise in pools of fast reactor (FR) finds important applications in source term evaluation, purification of cover gas, and air cleaning efficiency of submerged wet scrubbers. In this study, interFoam module available in OpenFOAM numerically investigates bubble rise in liquid pool. The FVM solver solves transient conservation equations, and phase interface is bounded using MULES. Verification of interFoam module is done for 2- and 3-D benchmarks available in the literature. Bubble behavior has been simulated for 5 mm bubble rise in sodium for both 2- and 3-D cases. The 3-D bubble case is validated with data available from the literature for velocity. The study shows that terminal velocity changes with domain dimension and 3-D case predicts realistic velocity values. The bubble rise investigation is useful for safety studies related to FRs.

Arjun Pradeep, Anil Kumar Sharma, D. Ponraju, B. K. Nashine, P. Selvaraj

Natural Convection Heat Transfer Enhancement Using Cooling Pipes in the Heat Generating Debris Bed

The whole core meltdown scenario is considered as a beyond design basis accident with a probability of occurrence less than 10−6 per reactor year. To prevent and mitigate such a hypothetical severe accident, in fast breeder reactors, research has been focused on accommodating the destroyed core debris within the primary containment boundary. An in-vessel core catcher is provided to receive the fuel debris arising out of core meltdown and disperses it uniformly, thus enabling safe and adequate heat transfer by natural convection. The present study is focused on the thermal hydraulic analysis of in-vessel core catcher. A 3-D numerical analysis has been carried out in the lower plenum of the fast reactor. Turbulence is modeled using the standard k-ε turbulent model. The Boussinesq approximation is assumed for liquid sodium. The heat source is assumed to have spread on the heat shield plate and has a total volume of 5.12 m3 with inbuilt decay heat source. The mathematical model is validated with the available benchmark experimental results in the literature. The existing design of core catcher plate is modified by providing cooling pipes in the top collection plate with different configurations to assess the cooling capability of the debris by natural convection. The temperature and velocity contour are obtained to observe the flow field established above the heat source in the sodium pool. It has been found that new design of core catcher improves the natural circulation of sodium toward the center of CC and more than 50 °C temperature decrement is observed in upper heat shield plate.

Vidhyasagar Jhade, Anil Kumar Sharma, D. Ponraju, B. K. Nashine, P. Selvaraj

Effect of Flow Maldistribution on Thermal Performance of Water-Cooled Minichannel Heat Sink

Flow maldistribution affects the cooling capacity of a water-cooled minichannel heat sink and cooling capacity of heat sink can be improved by minimizing flow maldistribution. Flow maldistribution depends upon the number of parameters such as flow rate, inlet/outlet position, and number of channels. This computational study has been performed using ANSYS Fluent 16.0 to investigate the effect of inlet/outlet positions and flow rate to delineate the flow maldistribution in minichannel heat sink. In this study, a minichannel heat sink with 28 numbers of rectangular parallel minichannels having hydraulic diameter 1.5 mm has been considered. Water and aluminum have been selected as a working fluid and heat sink material, respectively. In order to see the effect of inlet/outlet positions on flow maldistribution, four different types of inlet/outlet flow arrangements such as I-Type, Z-Type, C-Type, and U-Type have been considered. Effect of flow rate on flow maldistribution has been observed for the flow rate ranged from 0.5 to 1 LPM. Based on the results, it is found that flow maldistribution is strongly dependent on inlet/outlet positions and flow rate. Among all the arrangement, U-Type arrangement has small flow maldistribution which implies more uniformity in flow distribution in parallel minichannels and Z-Type arrangement has non-uniform flow distribution in parallel minichannels. It is also found that flow maldistribution affects the thermal performance of minichannel heat sink. A heat sink with U-Type flow arrangement has better thermal performance as compared to others arrangement.

Sanjeev Kumar, Ritesh Dwivedi, Pawan Kumar Singh

Mixed Convection Heat Transfer in a Cavity with Rotating Cylinder Under the Influence of Magnetic Field

The present study investigates the influence of magnetic field on the heat transfer phenomena of rotating cylinder kept in the center of the square cavity. The numerical code for mixed convective flow with Magnetohydrodynamics is developed on the open-source CFD platform OpenFOAM. The developed solver is capable of simulating steady and unsteady flows on any arbitrary geometry. The center of the cylinder is fixed at the center of the cavity with varying blockage ratio (L/d = 2 and 4). The surface of the cylinder is kept as hot, and the two opposite vertical sides are kept cold, while the top and bottom surface are maintained as thermally insulated. The cylinder is rotated clockwise (ω = 50) and anticlockwise (ω = −50) about its center. The fluid is assumed to be incompressible and electric conducting in nature and the all walls of the cavity is also maintained as electrically insulated. The intensity of magnetic field is varied in terms of Hartmann number (Ha) in the range of Ha = 0 and 100 for the fixed Rayleigh number of Ra = 105. The flow and thermal field are analyzed through streamlines, isotherm contours for various Ha and ω (angular rotation). Furthermore, pertinent transport quantities as the Nusselt number is also determined to analyze the influence of magnetic field and angular rotation of the cylinder on the heat transfer. It is observed that the heat transfer and fluid flow behavior is significantly affected by the magnetic field and rotation of the cylinder.

Ranjit J. Singh, Trushar B. Gohil

Numerical Simulation of Fluid Flow Inside Nozzle Check Valve

The check valve and non-return valve are specially designed valves for permitting only unidirectional fluid flow and are employed as a measure of safety for the protection of expensive equipment such as compressor, rotating parts, feed pump, and discharge reservoir. This crucial significance of nozzle check valve gives rise to its exhaustive and thorough study to meet safety standards and ISA valve specifications. The valve design primarily comprises of generating a converging and diverging fluid flow across the valve’s inner geometrical surface by keeping least surface area around the valve disc at fully opened position. To better predict the valve’s performance, this paper manifests the numerical simulation of fluid flow in a twelve-inch nozzle check valve and calculates its flow coefficient (Cq). The steady-state 3D Navier-Stokes equations with appropriate boundary conditions are numerically solved using FVM method. The computational domain consists of a 10-D and 7-D length of pipe attached to the inlet and outlet section of the valve, respectively, to capture flow development where D is the diameter of pipe. The simulation is carried for incompressible fluid (water) at numerous Reynolds numbers (3.1E4–9.3E5). Consequently, the velocity and pressure contours are plotted at corresponding Reynolds numbers, and the analysis of flow through the valve for estimating flow coefficient of the valve (Cq) is 2863 ± 5%. It is found that the flow coefficient remained constant for various Reynolds numbers. Hence, the flow coefficient is only a strong function of the shape of valve.

Anshul Bhardwaj, Basant Singh Sikarwar

Design and Simulation of Isolation Room for a Hospital

Heating, ventilation and air conditioning (HVAC) of hospitals is a highly specialized field and critical care units like isolation rooms and operation theatres deserve special attention, as infected patients must be isolated from ambient environment in order to prevent the infection from spreading and to save the life of the patient. This manuscript aims to optimize the ventilation strategy towards contaminant suppression in the isolation room. 3D Navier-Stokes and energy equation using finite volume method (FVM) with a domain of isolation room is solved for appropriate boundary conditions. The patient’s body is approximated as a semi-cylindrical shape resting on a bed and is treated as a constant heat source. Velocity and temperature profile inside the isolation room for various configurations are simulated. Our results suggest that immune-suppressed patients should be kept near the air supply and infectious patients near the exhaust.

Simeon Jacob, Siddharth Singh Yadav, Basant Singh Sikarwar

CFD Analysis of GM Pulse Tube with Functional Gradient Regenerator

The present research aims to establish a stable and reliable simulation of GM pulse tube using commercially available CFD software. In line with aforementioned objective, three major tasks have been addressed in detail. First, a GM pulse tube has been taken from the literature for analysis. Unlike the present state of the art, the present analysis has been carried out using multi-component models in 3D environment. Various components involved in a pulse tube have been modelled, and the corresponding assembly model has been analysed. The proposed approach introduces tremendous amount of numerical complexities which have been addressed in detail. The numerical result agrees to lowest temperature achieved experimentally with 95% accuracy. In second, the thermoacoustic phenomena have been analysed regarding work done at various locations, which re-establishes the fact and phenomena which takes place in a double inlet GM pulse tube. At last, functionally gradient regenerator (FGR) has been proposed to enhance the performance of pulse tube. This particular task has two major sections. The first section enlightens the modelling of functionally gradient porous material (FGPM) for analysis, and the second section focuses on the realistic modelling from manufacturing point of view. Summarizing, the contribution establishes a practice to investigate a GM pulse tube in 3D component level together with an approach to the model functionally gradient regenerator.

Pankaj Kumar, Manoj Kumar, Ranjit Kumar Sahoo

Thermodynamic Analysis of Biomass Gasification-Based Power Generation System Through Indirectly Heated GT and S–CO2 Cycle

The study emphasizes on the modeling and thermodynamic performance prediction of a novel biomass gasification-based combined cycle plant. It consists of a topping indirectly heated topping gas turbine (GT) cycle and a bottoming supercritical CO2 (S–CO2) cycle for combined power generation. Sawdust is considered as the driving fuel of the plant, which is gasified in a downdraft gasifier and thus the derived producer gas is further burnt in a combustor-heat exchanger combined (CHX) unit. The CHX unit indirectly heat-up the working medium (air) of the topping GT cycle and the CHX exhaust is further utilized in the bottoming S–CO2 cycle to produce electricity in a combined manner. Simulated performance of the plant is judged over wide ranges of considered pressure ratio (rp) and the gas turbine inlet temperature (TIT). The rp value is varied between 4–16 and the TIT is varied between 900 and 1100 °C. Overall electrical efficiency of the plant is about 46% at rp = 4 and TIT = 1000 °C. At the same thermodynamic state points, calculated value of required biomass input is 0.017 kg/s and also the combined net output from the plant is about 140 kW. Overall electrical efficiency value increases with increase in rp value, for all GT TITs as well as hot end temperature difference (HETD) of the CHX unit.

Samiran Samanta, Pradip Mondal

Experimental Investigation of Forced Convection on Square Micro-Pin Fins

An investigation is to be conducted to determine whether micro-pin fin can increase heat transfer under forced convection or not. This would be accomplished by performing an experimental investigation. In the present analysis, thermal effectiveness of square micro-pin fin arrays under forced convection conditions in air was studied. Square micro-pin fins of different sizes are tested for three different heat loads, and it was observed that heat transfer performance of stainless steel micro-pin fins was enhanced 5–15% compared with flat plate fins. Further, increase in the overall Nusselt number of the surface was found due to boundary layer regeneration and enhanced flow mixing. In addition, heat transfer effectivity and thermal resistance were decreases with the increase of Reynolds numbers.

Ramendra Singh Niranjan, Onkar Singh, J. Ramkumar

Highly Confined Flow Past a Stationary Square Cylinder

Present work explores a numerical study based on Finite-Element Method for fluid flow past a stationary square cylinder placed symmetrically in the channel with high Blockage, B = 0.9. Reynolds Number (Re) progressively varied from 5 to 150 in the laminar region. An attention has been paid to capture the exact point of laminar flow separation on the surface of the cylinder and the separation Re for high blockage flow. The steady to unsteady flow transition is observed at a Re (Rec) of 62. A very high drag coefficient, order of magnitude = 103 is reported for the computation. Inconsistency with unbounded flow solutions, the wake bubble for 90% blockage cylinder shows nonlinear variation with Re in the steady flow regime. In a very narrow regime near the beginning of unsteadiness, the flow is found to be quasi-periodic whereas, for all remaining Reynolds number values considered for the present study, periodic flow is observed.

Shravan Kumar Mishra, Deepak Kumar, Kumar Sourav, Pavan Kumar Yadav, Subhankar Sen

Transport Phenomenon Improvement Using Induce Draught in Cold Storage

Air is heat transport medium in cold storage operation and its distribution plays a vital role in preservation of agricultural products like fruits and vegetables with desired quality. Thermal behaviours of cold storage system are based on air transport arrangements. Convective heat transfer from stored perishable stuff to cooling system within the chamber is subjected to airflow and its distribution. Transport characteristics can handle with axillary arrangements such as induce draught system. Experimental investigation for impact of induce draught on air transportation is carried out in a 1/4th reduced scaled model of the cold storage [size 6 m (l) × 4 m (w) × 4 m (h)] at HT Laboratory, MANIT, Bhopal. Air transport velocity was measured at 96 stations in the chamber with hot wire anemometer. Measurements indicate supply air approaches rear section of the chamber comparatively at higher velocity with induce draught. Markable improvement noticed with slotted duct wall which boosts airflow velocity by three times at mid-sections compare without induces draught. Overall 1.5 times to three times better supply airflow velocity observed in the chamber, as compare to general configuration, while return air velocity measured almost double during the experiment. Experimental results suggests shift of turbulence mixing of air from evaporator side to central zone of the chamber. Better mixing of air can help in a fast setting of thermodynamic equilibrium in the chamber. It will lead to homogenous thermal environment which can extend the life of perishable goods with maintaining their quality.

Pankaj Mishra, K. R. Aharwal

Thermal Performance of Solar Air Heater Having Triangular-Shaped Hollow Bodies Inside

Today, solar energy has emerged as an alternate to the conventional source of energy. Solar air heater (SAH) is one of the significant devices to convert solar energy into heat energy of fluid. Lower efficiency of SAHs is one of the major drawbacks. Hence, researcher in the recent past tried to increase efficiency of SAHs by putting different shapes and arrangement of roughness and baffles on the absorber plate. In this work, triangular-shaped hollow bodies are putted inside the solar air heater to improve its efficiency. Turbulence is produced locally due to existence of these bodies. Here, these bodies will act as fins also. This results in increase of heat transfer area and heat transfer coefficient between absorber and air. Loss of pressure is also less. Maximum enhancement obtained in efficiency is 8.34% for the mass flow rate at 0.012 kg/s. Maximum rise in temperature for Case-I (without triangular bodies) was recorded as 10.2 °C, whereas for Case-II (with triangular bodies) 13.1 °C achieved. CFD simulation results and experimental results obtained have good agreement.

Ambreesh Prasad Shukla, Bhupendra Gupta, Rakesh Kushwaha, P. K. Jhinge

Heat Transfer Enhancement in Oblique Finned Channel

In the modernistic day, cooling is one of the predominant challenges of electronic and automobile industry. The demand for faster and smaller devices increases the thermal load, and at the same time, conventional cooling techniques that use extended surfaces (fins, microchannel, heat sink, heat pipe, etc.) reached their limits. Recently, oblique fin heat sink has been found as an alternative to conventional heat sink because of their improved heat transfer performance and a marginal increase in pressure drop. The reason behind this improved heat transfer is the breakage of the continuous fin into oblique fin which keeps the flow in developing condition. Also, the secondary flow through oblique channel diverts a small fraction of flow and enhances mixing. The present paper tries to capitalize the advantage of the oblique fin with the benefits of nanofluid by carrying out a detailed numerical simulation. Alumina–water nanofluid has been used for numerical analysis using single-phase and discrete phase modeling approaches through oblique fin microchannel. Conjugate heat transfer between the oblique fin heat sink and nanofluid is computed numerically. Approximately, 115 and 145% heat transfer enhancement has been observed in oblique channel compared to rectangular microchannel in single-phase modeling and discrete phase modeling, respectively.

Badyanath Tiwary, Ritesh Kumar, Pawan Kumar Singh

Augmenting Distillate Output of Single-Basin Solar Still Using Cement Blocks as Sensible Heat Energy Storage

Solar still is a green energy product. It uses heat energy of the sun to purify muddy or salty water. Single-basin passive solar still is the best choice for drinking water-prone remote areas. Investigations show its limitation because of its lower performance in terms of distillate output. Several attempts were made by different researchers for improving the performance of conventional solar still. One of the proven methods to improve the output of solar still is to incorporate sensible heat energy storage material. In this experimental work, prime focus is to enhance the output of the single-basin conventional solar still by putting cylindrical cement blocks as a heat storage material in basin water. A comparative study between the modified still (with cement blocks) and conventional still (without cement blocks) of the same size was carried out for the same experimental condition of Jabalpur, India (23° 10′ N, 79° 59′E), with different depth of water ranging from 2 to 5 cm. Result recorded indicates that the output depends on the water depth and mass of sensible energy storage material. The maximum yield was obtained for least water depth of 2 cm. The daylight yield was found enhanced up to 67% in the modified still as compared to conventional still, while decreased performance is observed in overnight productivity. The overall yield increased by 17% considering 24 h. of output. Uncertainty and error analysis have also been carried out.

Jyoti Bhalavi, Bhupendra Gupta, P. K. Jhinge, Mukesh Pandey

Design and Numerical Analysis to Visualize the Fluid Flow Pattern Inside Cryogenic Radial Turbine

In this paper, the mean-line design and numerical analysis to visualize the flow field characteristics of the cryogenic radial turbine for the liquefaction of nitrogen are reported. The three-dimensional design of blade profile and a fluid passage is created using Blade-Gen©. The meridional plane, hub, and shroud layers are optimized to increase the efficiency, minimize the vortex formation, and losses in the fluid passage. Turbo Grid has been used to create the computational grid. Numerical simulations are carried out using shear stress transport turbulence model using CFX© to visualize the fluid flow behavior, high-pressure zone, heat transfer characteristics, vortex formation, pressure, velocity, Mach number, temperature, entropy generation, etc., using nitrogen as a working fluid. The blade-loading characteristics, blade thickness, and blade angle variation at leading and trailing edge are also being discussed.

Manoj Kumar, Pankaj Kumar, Ranjit Kumar Sahoo

Evaluation of Heat Recovery Steam Generator for Gas/Steam Combined Cycle Power Plants

The combined cycle power plant consists of topping cycle, bottoming cycles and heat recovery steam generators (HRSGs) as the integral systems. The main focus of this work is to predict and analyse fluid flow behaviour in HRSG. The heat transfer and pressure drop analysis are performed by using computational fluid dynamics (CFD) model. The CFD model capability for predicting heat transfer and pressure drop performance of finned tube in cross-flow is analysed. The HRSGs having serrated tube and steady-state approach, with a two-equation turbulence model, is employed to examine fluid flow having Reynolds numbers variation from 5000 to 30,000. The external flow Nusselt number and overall pressure drop predicted by the CFD model are compared with those predicted by published empirical correlations.

Achintya Sharma, Meeta Sharma, Anoop Kumar Shukla, Nitin Negi

Two-Phase Spray Impingement Density Determination in Microchannel Cooling: Measurement and Optimization Results

Within the past few years, electronic industry has developed vastly. Emerging technologies tend to increase demand for higher power densities in small dimensions. Hence, performance of the equipments used for military or electronic industry needs high heat removal from small areas which directly increase its performance. Hybrid cooling which takes advantage of both microchannel and spray impingement cooling is considered as one of the best technologies for critical heat removal so far. Among all controlling parameters of spray, mass impingement density (MID) is considered as the most influencing parameter for high heat removal. This paper describes an experimental study to evaluate and optimize MID for different values of air and water pressure and nozzle-to-surface height during spray-on microchannel. A mechanical patternator was used for collecting water during spray of base dimension 27 mm × 25 mm which was like the microchannel for which MID was calculated. The air and water pressures were varied from 1 bar to 3 bar for nozzle-to-surface height 10–20 mm. Optimal solution was found through response surface methodology (RSM) which concludes at air pressure 1 bar, water pressure 2.87 bar and nozzle tip to surface distance 17.52 mm maximum MID is achieved.

Sasmita Bal, Purna Chandra Mishra, Ashok Kumar Satapathy

Experimental Investigations into Performance Evaluation of Thermosyphon Solar Heating System Using Modified PCM Modules

The demand for effective and efficient use of solar heating arrangement is increasing in domestic and industrial applications. The existing renewable energy resources are intermittent and fluctuate depending upon the meteorological conditions. So, the main aim of this present work is to develop thermosyphon solar heating system for improving the performance using modified phase change material (PCM) modules. Paraffin wax material is used as PCM for holding the heat energy to attain an effective solar fraction. A detailed stratification experimental analysis for heat energy accumulation tank has been carried out on without PCM, PCM without fins, PCM with ring type fins and spiral fins. An hourly based charging and discharging efficiency are also calculated for the above cases and compared. All the experiments are carried out three times and average values are taken for the analysis. From the results measured experimentally, it is inferred that the discharging time of solar water heating system with cylindrical PCM ring type fins is 3 h more than without PCM. The discharging time of solar water heating system with cylindrical PCM took 7 h more than without PCM. The charging energy efficiency of heat energy accumulation tank with cylindrical PCM ring type and PCM in spiral module fins confers better results than cylindrical PCM and without PCM. This shows that the PCM get better stratification time and increases the overall performance of solar water heating system.

T. K. Naveen, T. Jagadesh

Ultra-Fast Cooling of Flat Metal Pate in a Modified Runout Table

Cooling of metal components at the end of the steel production process is a highly critical step in production. The cooling process rate is time critical, and it helps determine various crucial steel properties. There is continuing research which is being done to help improve the process to boost the quality of steel produced as well as reduce the overall cost of production. Ultra-fast cooling involves the use of varied water and air pressures as the cooling media. Surface heat flux at each experimental condition was computed from the transient temperature history measured by K-type thermocouples embedded at the bottom surface of the plate. Peak heat flux on the surface of 2.954 MW/m2 was obtained using an inlet pressure of water 5 bar, pressure of air 3 bar, strip velocity of 5 cm/s, and nozzle to plate height of 100 mm for a starting temperature of 1123 K of the 4-mm-thick steel plate.

Sudhansu Mohan Padhy, Purna Chandra Mishra, Ruby Mishra, Achintya Kambli

A Novel System for Exhaust Emission Reduction of Diesel Engine by Using Electrochemical Technique

In this research, an experimental setup was fabricated, and the new device was designed in conjugation with the catalytic converter. This paper is concerned to enhance the efficiency of the exhaust control system by using electrochemical principle. It relates to the use of a solid electrolyte to convert the NOx into N2O and O2. A freezer gel pack along with the thermocouple is used on the exhaust pipe to maintain the temperature of the reaction. At a temperature range of 200–300 °C, N2O is further reduced to N2 and O2 while the oxidation of HC, CO, and elemental carbon is done in the catalytic converter. Carbon dioxide (CO2) produced is allowed to pass through normal water in an aluminum alloy chamber. Also, particulate matter is treated in a meshed filter downstream to the aluminum chamber. The result shows a significant reduction in NOx emission.

Priyanka Sharma, Prem Pal, Ashutosh Mishra, Mohit Bhandwal, Ajay Sharma

Effect of Shallow Dimple on Cylindrical Surface for Heat Transfer and Pressure Penalty

Effect of shallow dimples on convective heat transfer from cylinder surface is investigated numerically. Relative assessment of circular cylinder and cylinder with shallow dimple on full surface of the cylinder and shallow dimple only on downstream surface of the cylinder are done for heat transfer and pressure penalty. Two-dimensional numerical investigations are performed for air with velocity in the range of 1–5 m/s. Turbulence is modeled using RSTM closer model. The comparison of heat transfer rate for all the reported cases reveals that inclusion of shallow dimple on circular cylinder enhances heat transfer rate. Heat transfer rate augments by 20% in case of full shallow dimple surface compared to plain cylindrical surface. In case of dimple on downstream surface of the cylinder, heat transfer is 10% more than plain surface. Cylinder with shallow dimple downstream outperforms in terms of heat transfer rate and pressure penalty.

Mayank Shah, Rupesh Shah

Numerical Investigation of Two-Dimensional Laminar Flow Past Various Oscillating Cylinder

Two-dimensional laminar flow over oscillating cylinder is analyzed numerically. Three different cylinder shapes namely circular, square, and ellipse are considered for analysis. Cylinder shapes are set to oscillate at frequency ranged such that frequency ratio (oscillating frequency/natural vortex shedding frequency, fr) varies between 0.8 and 1.2. The oscillation amplitude is varied between 30 and 50% of the cylinder diameter at fixed Reynolds number of 185. Numerical study is carried out using dynamic mesh features of commercial code FLUENT. Simple harmonic motion to the cylinder is applied using user-defined function (UDF) facility of FLUENT. The formation of anticlockwise or clockwise motion vortices from surface of cylinder depends upon geometrical shape of the cylinder as well as frequency ratio of oscillation at extreme positive displacement of the cylinder. Wake pattern mode behind the surface of the cylinder is 2S mode or 2P mode. Elliptical cylinder outperforms square and circular cylinder in terms of drag and lift characteristics. The range of time-averaged drag coefficient is lowest. Drag and lift increase linearly for all amplitude and frequency ratio in elliptical cylinder compared to square and circular cylinder.

Ankit Dekhatawala, Rupesh Shah

Compact Solar Air Heater: A Review

In this review work, a theoretical study of solar air heater is carried out by considering compact heat exchanger criteria into account. The present investigation comprises different performance parameters for a compact solar air heater. In this review work, Reynolds number is the only variable parameter which varies from 4000 to 18000. Stanton number (St), Stanton number ratio (St/St0), Colburn factor (j), and area goodness factor (j/f) are considered as performance parameters. Stanton number ratio (St/St0) is maximum for multi-V-shaped ribs with gaps. Colburn factor (j) value is highest for multi-V-shaped ribs with gaps. In the present investigation, goodness factor (j/f) is highest for circular protrusions organized in angular arc form. This study is beneficial for the researchers to conduct the experimental and theoretical investigation in order to search out the new roughness geometries to design compact solar air heater.

Vijay Singh Bisht, Anil Kumar Patil, Anirudh Gupta

Conventional and Advanced Exergy Analysis of Air-Film Blade Cooled Gas Turbine Cycle

Air-film blade cooling is widely used gas turbine blade cooling technique. The present paper carries out conventional as well as advanced exergy analysis of air-film blade cooled gas turbine cycle based on a film cooling model which takes into account the effect of radiative heat transfer from hot combustion gases to gas turbine blade surface. From the basic concept of thermodynamics, it is well known that the rise in temperature at which heat is added in a cycle results in an increase in thermal efficiency. This could be possible by increasing turbine inlet temperature (TIT) for a fixed maximum allowable blade temperature. The study further analyses air-film blade cooled gas turbine cycle thermodynamically and further carries out conventional and advanced exergy analysis. The study shows that component-wise exergetic efficiency has been observed as 97.5, 80.2, and 91.4% for AC, CC, and GT, respectively, while exergy efficiency for gas turbine cycle is observed to be 37.43%. The maximum exergy destruction has been observed for CC ~ 251.5 kW. The results of advanced exergy analysis show that most of the exergy destruction within cycle components is endogenous. This is indicative of weak mutual interactions between cycle components. The study further shows that ~81.2% of exergy destruction for cycle is unavoidable which indicates the least improvement potential for cycle.

Shivam Mishra, Yasin Sohret, Sanjay, Anoop Kumar Shukla

Effect of Area Ratio on Flow Separation in Annular Diffuser

Annular diffusers are integral component of the axial flow compressor, combustion chambers and inlet portion of jet engine. In present study flow behavior inside the parallel hub and diverging casing annular diffuser having area ratio 2 to 4 with help of FLUENT has been predicted. The effect of different inlet swirl angles 0°, 7.5°, 12°, 17° and 25° has been studied to predict the reversal of flow and separation of flow from the wall. The result analysis shows that swirl enhances the pressure recovery up to a particular swirl angle and falls thereafter. It also helps in suppressing the flow separation. The effect of inlet swirl on the pressure recovery coefficient has also been figured out.

Hardial Singh, B. B. Arora

Identification and Inquisition of Thermoelectric Generator Unit for Efficient Waste Heat Recovery

A Peltier device or thermoelectric generator is a solid-state semiconductor device which works on the principle of thermoelectric effect or Seebeck effect and has an inherent capability to convert heat flux directly into an EMF. Thermoelectric effect which is a result of having a physical contact between two dissimilar conductors with the presence of temperature difference across its ends is further enhanced by effective use of semiconductor materials for its fabrication. Its potential to harness low-grade waste has attracted a lot of attention of various researchers worldwide. Thermoelectric effect is difficult to maintain for longer period of time because of its continuous and consistent dependence on temperature difference across its surfaces. Early experiments indicated possibility of heat leakages within the module itself, which could have been causing drop in temperature difference along with working efficiency. The objective of this experimentation is to identify possibility of heat leakages and its possible effects (if any) on its efficiency. Two different positions were used, for the first one heat input surface was upside (hot side up) and second with heat input from below (Hot side down). This change in position will affect the convective motion of trapped air molecules and effect (if any) could be noticed. Results showed that heat transfer rate was more for hot side down with 0.22% more voltage output, 0.44% more power output, and 0.521% increment in Seebeck coefficient.

Abhishek Khanchi, Harkirat Sandhu, Mani Kanwar Singh, Satbir S. Sehgal, Bharat Bajaj

Performance Evaluation of Thermoelectric Refrigerator Based on Natural and Forced Mode of Cooling Processes

The aim of this work is to evaluate the performance of portable thermoelectric refrigerator for vehicles (cars, trucks and buses). Thermoelectric refrigerator is based on the principle of a Peltier effect. TES-12704 thermoelectric module has been used in fabrication and tested. The cooling temperature of fin attached with thermoelectric module inside the refrigerator is measured and compared in natural and forced mode. The thermoelectric refrigerator is advantageous to keep perishable items at low temperature during travelling of the people. The results show that forced mode of producing cooling effect inside the thermoelectric refrigerator gave better performance as compared to natural mode-based thermoelectric refrigerator.

Jatin Batra, Vishal Dabra, Pardeep Sharma, Vijay Saini

Pool Boiling Using Nanofluids: A Review

Nanofluids have found their applications in various fields of heat transfer and their demand in various industries in ever growing. Pool boiling of nanofluids has always been a topic of great interest and research. In past years, a lot of experimental works have been done on various nanofluids and base fluid solutions to study about the influence of nanofluids on critical heat flux and heat transfer coefficient. Through these works, various factors such as surface roughness, wettability, contact angle, and particle deposition have also been studied as how these factors influence CHF. This paper also focuses on the past work and studies done on nanofluid pool boiling comprising of the very existing data.

Sumit Krishn, Mukund Goyal, Gopal Nandan, Satish Kumar, P. Kumar, Anoop Kumar Shukla

CFD Modelling and Experimental Investigation of Bimodal Slurry Flow in Horizontal Pipeline and Bends

The effect of flow velocity in straight pipelines with horizontal bends having a pipe diameter 53 mm was experimentally investigated over silica sand and fly ash comprised bimodal slurry. Silica sand and fly ash at 80:20 ratios with solid concentration 8.82% by volume were taken for extensive experiments at flow velocity up to 3.56 m/s. Concentration samples are collected from mid-vertical plane at different cross sections in the downstream side of slurry pipe bend. The effect of the presence of fine particles in narrow sized coarse silica slurry through a 90° horizontal bend has been investigated. It is also observed that with increase in flow velocity, the pressure drop decreases. Uniform distribution of solid particles is observed just at the downstream flow of the bend except at bend outlet in case of higher flow velocity. CFD modelling is done using Eulerian two-phase model with realizable standard k–epsilon approach in ANSYS FLUENT 15 software. The predicted results for pressure drop and concentration distribution using CFD modelling have fairly correct resemblance with experimental data collected from pilot plant test loop.

Kanwar Pal Singh, Arvind Kumar, Deo Raj Kaushal

An Experimental Study On Solar Water Heater Integrated With Phase Change Material

This paper shows the experimental investigation of the thermal performance of solar water heater coupled with phase change material (PCM) cylinder. The cylinder contains PCM and spiral copper tubes and is properly insulated using glass wool on the outer surface. The PCM in the cylinder gets charged through hot water during the day, due to the availability of solar radiation. When there is no solar radiation (during the night or during cloudy weather), the PCM discharges and transfers its thermal energy to the cold water and hence raises its temperature. Therefore, this system ensures supply of hot water when there is no solar radiation, without using any conventional form of energy. The testing is done in the laboratory, and the thermal performance of the solar water heater integrated with PCM cylinder is determined. The thermal performance of the solar water heater at different flow rates, i.e., 0.017, 0.030, and 0.050 kg/s with PCM cylinder and without PCM cylinder was determined, and a comparative analysis is done over a period of time. It was found that heat storing capacity and thermal performance of the solar water heater will be enhanced if it is integrated with latent heat thermal energy storage PCM cylinder and hence ensures energy savings.

Pushpendra Kumar Singh Rathore

Numerical Analysis on Variations of Thermal and Hydrological Properties During Water Flow Through Unsaturated Soil

The flow of water through unsaturated soil is based on extension of Darcy’s law. The finite difference techniques are used to solve the model for evaluation of variations of hydrological and thermal variation due to flow of water into the soil. The pedotransfer function for estimating the soil properties is further used as input to simulate the problem domain. The validation of simulated result, based on transient heat conduction equation, is carried out. Further, the second-order upwind and QUICK methods are used to compare the thermal simulated results. The simulation results for variation of moisture content, the matric potential, and hydraulic conductivity with respect to rig linear dimension variation are further presented.

Manjit Singh, Chanpreet Singh, D. Gangacharyulu

Spray Impingement Heat Transfer Using Nanofluid—Experimental Study

Spray impingement plays a vital role in the cooling process. Spray impingement acts as a cooling media for high heat flux applications. As nanofluids have enhanced thermal properties than base fluids, CuO, ZnO, and hybridized CuO and ZnO nanofluids at different volume concentrations were used in this experiment. The nanoparticles were synthesized using high-energy ball milling (HEBM) technique at 300 rpm with the ball-to-powder ratio (BPR) of 10:1. These nanoparticles were characterized by using XRD, SEM, and TEM and were found to be in the range of 30 nm. The densities, viscosity, thermal conductivity, and the specific heat of the nanofluids were calculated using different models. It was observed that increase in the volume concentration, density, and viscosity of the nanofluid increased. The heat transfer study was carried out on an electrically preheated iron plate of dimensions 100 mm × 100 mm × 8 mm at different temperatures of 200, 150, and 100 °C. The cooling rate and the effect of air pressure on cone angle were analyzed. The main sources of uncertainty in the measured data were due to the temperature fluctuations and thermocouple locations. It was observed that the time taken to reach the steady state was faster in nanofluids than normal water.

Bikash Pattanayak, Abhishek Mund, J. S. Jayakumar, Kajal Parashar, S. K. S. Parashar

Experimental Design-Based Analysis on Process Parameters for Head Loss in Pipe Bend

In the present, the parameters responsible for head loss have been optimized by using Taguchi approach. The head loss characteristics in transportation of slurry are function of various parameters like solid concentration, flow velocity and additive proportion. Present investigation is focused to recognize the most influencing parameter for the head loss in 90° pipe bend. Several influencing parameters of head loss are optimized with the help of the Taguchi method. L16 array is used for experimental design of process parameters. The S/N ratio for head loss is characterized by using smaller-is-better rule. The solid concentration of slurry was varied from 30 to 60% (by weight) for flow velocity range of 2–5 m/s. Series of experiments are performed on pilot plant test loop to obtain head loss in pipe bend. Results obtained from experimental design reveal that flow velocity is found as a dominating parameter as compared to solid concentration and proportion of additive. Probability plot reveals that the experimental data follows the 95% level of confidence.

Jatinder Pal Singh, Satish Kumar, S. K. Mohapatra, Gopal Nandan

Novel Dryer cum Grinding Unit: A Thermal Analysis of Herbs Drying

The herbs are being extensively used in Indian families as medical purpose in dried state. Many a time, it is open sun dried or control oven dried. But, open sun drying is unhygienic and inefficient process for herb drying. Further, the aroma of the herbs is get compromised at times in control oven drying. The present work discusses the herb drying process cum grinding in controlled sun drying with persevering the aroma and quality of the herb to be dried. The study shows the effect of collector area exposed to sunshine and the useful heat gain at collector end, and in the drying chamber, further the instantaneous thermal efficiency is evaluated. The various heat losses in the cabinet and their effect on the system efficiency are calculated. The area of collector is exposed to sunshine (Ac) (ranging from 0.6 to 1 m2) for the study. The maximum thermal efficiency obtained is around 85.22%. It is observed that at lower temperature difference, i.e. at 5 °C, the instantaneous thermal efficiency is higher as compared to the 7 °C. Further, total 246 W-h is sufficient for grinding 20 kg dried herbs leaves. This study helps to find out the optimum conditions at which the drying process needs to be performed which would result in improved dryer performance.

Avinash Kamble, Pritam Bakal, Kashinath Patil

Investigating the Effect of Geometry on Micro-Channel Heat Exchangers Using CFD Analysis

Micro-channel heat exchangers (MCHEs) are compact and robust heat exchangers with high surface area per unit volume facilitating closer temperature of approach. MCHE is conventionally fabricated using photochemical etching followed by diffusion bonding (PCED). Though PCED allows various flow path designs for improved heat exchange, it is not deployed for MCHE with cross sections other than semi-circular. Laser additive manufacturing (LAM) can overcome this limitation. The present study is focused on thermo-hydraulic simulation of LAM built MCHE with various cross sections. A 3D steady-state computational fluid dynamics (CFD)-based analysis is performed using CFD code ANSYS CFX to estimate the temperature, pressure drop and velocity distribution across the length of channel and variation of friction factor with Reynolds number. The working fluid is supercritical helium and material of construction of MCHE is Inconel 617 (IN 617). The temperature-dependent thermo-physical properties of helium and IN 617 are taken into account for the above simulation. To validate the simulation output, the results for conventionally fabricated PCHE are compared with that of previously published results and are found to be within 5%. The study of MCHE with cross sections other than semi-circular (i.e. square and circular) is also done using the same CFD code. From this numerical analysis, it is found that the heat transfer is maximum in square geometry while pressure drop, velocity across the channel and friction factor are the least for square geometry.

J. Derek, A. N. Jinoop, C. P. Paul, S. L. Nidhin, N. G. Rasu, K. S. Bindra

Development of Air Intake Manifold Using Alternate Materials by CFD Analysis

Vehicle with high speed is in demand these days. This results in various types of high stresses in multiple vehicular components which may ultimately lead to engine failure and loss in fuel economy. Following the demand, the main objective of the present paper is to increase the performance and volumetric efficiency of the engine by using the lightweight alternate material. However, in order to bring the advantages of alternate material into play, many issues including static burst, noise, and vibration need to be settled in its design and development phase itself. The temperature mapping is carried out for air intake manifold and air duct to ensure that they withstand the temperature. Moreover, the flow analysis with respect to the mass flow rate of exhaust gas recirculation (EGR) is done followed by vibration measurement for alternate material polyamide 6 with glass fiber of 30%. Of all the above, the greatest challenge the paper investigates vests with achieving the volumetric efficiency of the engine similar or better to that of the aluminum manifold. To maintain or improve the volumetric efficiency, the plenum and runner volume are to be considered in such a way that the actual charge of air entering the cylinder through manifold is more effective and smooth.

P. Arjunraj, M. Subramanian

Optimization of Electrical Power of Solar Cell of Photovoltaic Module for a Given Peak Power and Photovoltaic Module Area

In this communication, an attempt has been made to optimize maximum electrical power (i) for a given number of solar cells by varying area of photovoltaic (PV) module and (ii) for a given PV module area by varying number of solar cell. Analytical expressions for solar cell temperature and electrical efficiency of solar cell have also been derived for opaque and semi-transparent PV module. Numerical computations have been made for New Delhi climatic conditions with the help of MATLAB R2015a. Based on numerical computation, it has been observed that (i) an electrical efficiency is maximum for higher PV module area with lower packing factor for a given peak power of PV module (75 Wp) and (ii) an electrical efficiency is lower with maximum packing factor for a given PV module area (2.1 m2). Further, an effect of different solar cell materials (i.e., m-Si, p-Si, a-Si, CdTe, CIGS, and HIT) on electrical power has also been investigated. It is found that electrical power output for m-Si and HIT is better than other solar cell material PV module.

Md. Meraj, M. Emran Khan, G. N. Tiwari, Osama Khan

Fluid–Structure Interaction Simulation: Effect of Endovascular Coiling in Cerebral Aneurysms Considering Anisotropically Deformable Walls

In the present research, we use fluid–structure interaction to study the effect of endovascular coiling in brain aneurysms. We simulate pulsatile flow of blood through a tubular hypothetical bulge filled with a homogenous porous medium; however, the wall mechanical properties of the aneurysm wall are different from that of the non-aneurysmal vascular vessel wall. The numerical simulations were carried out using Open FOAM. The FSI technique has a nonlinear material model to represent the ICA tissue. Fully implicit method of coupling employed ensured that the solid and the fluid domain attained convergence at each of the time steps. The results from the FSI simulations show that the presence of a coil in an aneurysm sac reduces fluid loading within the sac, and hence, the velocity of blood flow becomes negligible within the aneurysm. The von Mises stresses and the wall shear stress values on the wall of the aneurysm decrease to a great extent after the coil is inserted. Consequently, the displacement of the blood vessel’s wall also decreases, and hence, the risk of rupture of the aneurysm reduces. In conclusion, treatment using endovascular coiling technique delays further disintegration of the blood vessel and hence proves to be an effective treatment technique for cerebral aneurysm.

Vidhya Vijayakumar, J. S. Jayakumar

Numerical Investigation of Solar Air Heater Duct with Square Transverse and Inclined Ribs

A numerical investigation has been carried out in order to investigate the effect of artificial roughness on heat transfer coefficient and pressure loss of air flow through an asymmetrically heated rectangular solar air heater duct with constant heat flux condition on absorber plate. Reynolds number is varied from 3000 to 15000. Artificial roughness in the form of transverse and inclined ribs is applied to the surface of the absorber plate. Heat transfer coefficient, friction factor and thermo-hydraulic performance parameter (THPP) are calculated for the range of roughness parameters; relative roughness pitch (P/e) from 11 to 25 at constant relative roughness height (e/D) of 0.8. RNG k- ε turbulence model has been selected for CFD simulation. Artificially roughened surface increased heat transfer coefficient at the expense of increased pressure loss of air flow through the duct.

Gaurav Lad, Nikhil Raghuvanshi, Pranshu Mehrotra, Ankur Srivastava

Thermodynamic Investigation of Solar Energy-Driven Diffusion Absorption Refrigeration Cycle

The increasing demand of refrigeration and air conditioning with associated consequence of global warming across the world has made it inevitable for scientific community to look for an alternative of conventional energy sources and to minimize effects of CFC’s and HCFC’s on global warming and ozone layer depletion while facilitating the requirements of refrigeration and air conditioning. It is evident that the geographical locations on the earth having ample sunshine have more refrigeration requirements; however, these locations also offer potential opportunity for utilizing solar radiations for solar energy-driven refrigeration systems. This study focuses on the thermodynamic modelling and analysis of solar energy-driven ammonia–water diffusion absorption refrigeration cycle with helium as pressure equalizing inert gas. It is seen that the loss percentage in the coefficient of performance (WPL and WHPL) is 2.8% higher than cooling capacity percentage loss at low generator temperature while there is no marginal drops at higher temperature. It is also found that the generator temperature in the range of 110–150 °C is best suited to produce maximum refrigerating effect.

Kishan Pal Singh, Onkar Singh

Flow Characteristics of Crude Oil with Additive

In the present work, flow characteristics of high sulfur crude oil (HSCO) with the addition of low sulfur crude oil (LSCO) were studied. LSCO was mixed in high sulfur crude oil in concentration of 10–15% by volume. The rheological characteristics of the heavy crude oil suspension were determined using ISO-certified Rheometer for the range of shear rate varying from 0 to 500 s−1, and temperature range varies from 25 to 45 °C. The rheological characteristics of the HSCO include steady-state flow behavior, yield stress, and thixotropic characteristic, etc. Optical microscopy and dynamic light scattering were used to analyze the size of wax crystals and crystal size distribution, respectively. The average size of wax crystals was 2550 nm for 100% HSCO which further reduced to 350 nm after adding 15% LSCO. HSCO shows the non-Newtonian flow characteristics at low temperature and decreases with increase in temperature. Rheological results of HSCO show that there is a reduction in viscosity with the addition of LSCO. The LSCO as an additive in HSCO can be beneficial for design of crude oil transportation pipeline.

Praveen Kumar, Chetan Badgujar

Refrigerating Effect Produced by Engine Exhaust Heat

Many new technologies appear and developing in automobile field helpful for humanity. Vapour compression refrigeration technique is used in automobile vehicle that acquires cooling effect inside the vehicle. Due to riding obtain well comfortable and keep them in an optimal temperature range by refrigerating effect. Currently, the fuel consumption rate increases due to the external load on the engine. The ambition of ‘refrigerating effect production’ by the engine exhaust heat system is used in the vehicle cabin to reduce the fuel consumption of the casual traveller using air conditioning. The compressor replaces by the heat exchanger and heating coil. Heat exchanger using as energy source of refrigerating effect, and “REPEEH” is few mechanical power being done by engine running of air-condition. After using this technology through obtain refrigeration effect and also increase the engine life due to reducing load on automobile engine. Increases the pollution level of our country due to consumption of more fuel is major parts.

Raman Kumar Sahu, Vinay, Aniket Das

Thermal Design and Numerical Analysis of Transportable Bitumen Storage Tank for Improved Liquefied Bitumen Supply

Asphalt plant manufactures the hot black mix required for road construction. Bitumen is used as a binding agent that binds the aggregates (stones) together. Liquid bitumen ranging between 150 to 160 °C is sprayed on aggregates in a twin shaft mixer having mixer pads mounted on both shafts rotating in opposite direction with respect to each other (inward direction). Hence, asphalt plant needs the supply of hot and liquid bitumen, which is stored in storage tanks and is used as and when required. In this paper, the thermal design and simulation-based numerical analysis of 42,000 and 50,000 L capacity of transportable bitumen storage tank are presented. Usually, bitumen in the storage tank is heated by a thermal fluid called Therminol, having an inlet temperature of 180 °C, flows through tube bank present inside the storage tank. Therminol is heated by the fire-tube boiler. Thus, an effective heat exchanging system in the bitumen storage tank is crucial. In the existing storage tank, the solid bitumen rocks need 12 h of heating to obtain liquid bitumen ranging between 150 to 160 °C. Here, computational fluid dynamics (CFD)-based simulations are carried out to design the effective heat transferring system. Various flow conditions of Therminol, as well as different tube bank configuration, are been simulated and presented. The CFD analysis shows that with proper and modified distribution of tube bank inside the storage vessel helps to improve the heat transfer by a factor 2–3 and hence is capable to liquefy bitumen within 6 h.

Pankaj V. Sirsikar, Chandrakant R. Sonawane, Ashok Tanna, Manoj Yadav

Steady-State Modelling and Validation of a Thermal Power Plant

In the present work, steady-state modelling and validation of a 210-MW sub-critical thermal power plant located in North India using mass, energy, and exergy balance equations. The first and second law efficiencies have analysed for each component. MATLAB calculation tool and Engineering Equation Solver (EES) software have used for performing analyses. The results conclude that 277.2 MW (72.50%) of the total energy lost in the condenser as the main equipment wasting energy to the environment followed by boiler with 101.4 MW (26.52%) in the cycle. On the other hand, the maximum exergy destruction is seen to be in the boiler system 274.48 MW (85.64%) followed by the other components. The calculated thermal efficiency and the exergy efficiency of the overall plant are found to be 36.60 and 35%.

Ravinder Kumar, Ravindra Jilte, B. Mayank, Manujender Singh

Cooling of Solar Photovoltaic Cell: Using Novel Technique

Over the past few decades, the world has started moving towards renewable resources of energy from non-renewable resources for meeting today’s energy demand. The solar energy is available abundant in nature and easy to harvest it, and provides a natural solution to move ahead in fulfilling the energy requirement. The solar photovoltaic cells convert solar energy to electrical energy. In general, the regular PV module cell converts nearly about 5–18% of the incidental solar radiation into electricity, and in order to maintain energy balance nearly 60% of incidental radiations are converted in the form of heat energy and with scientific and experimental analysis; it is already pre-determined that with increase in internal PV cell temperature there is an exponential decrease in electrical efficiency of the solar cell gradually with this alternate cooling and superheating process over a time period thermal stresses are formed in solar cell which eventually degrades the cell. A practical way of marginally increasing the output efficiency of solar PV cell is to decrease the operating and surrounding temperature of solar PV, which can be achieved by maintaining a stipulated temperature when solar photovoltaic cell is in operation. Therefore, in the following work, a novel passive technique of cooling has been introduced by basic principles of evaporation using sand dunes concept of cooling and will be investigated experimentally.

Rajat Satender Rathour, Vishal Chauhan, Kartik Agarwal, Shubham Sharma, Gopal Nandan

Experimental and Numerical Study of Heat Transfer in Double-Pipe Heat Exchanger Using Al2O3, and TiO2 Water Nanofluid

Nanofluid is a two-phase fluid of solid-liquid mixture. Nanofluid provides higher effective thermal conductivity when compared with the base fluid. Thermal properties of heat transfer fluid are one of the important topics of concern for research in heat transfer analysis. In recent years, there are stances about the study of agglomeration of two or more nanoparticles in base fluid, i.e., hybrid or composite nanofluid, and they also have good heat transfer characteristics. In this experiment, Al2O3 and TiO2 and hybridized Al2O3, TiO2 nanoparticles were prepared by using high-energy ball milling technique. These nanoparticles were characterized by using XRD, SEM, and TEM. It was found that crystalline size is 30 nm. Polyvinyl alcohol of 3% was used in 1:10 ratio of the mass of the nanoparticle for preparing stable nanofluid. The stability was observed for 32 h which was good to conduct an experiment. The densities, viscosity, thermal conductivity, and the specific heat of the nanofluid were calculated. The overall heat transfer coefficient, logarithmic mean temperature difference, friction factor, and effectiveness of the hybrid double-pipe heat exchanger using the nanofluid were calculated by NTU method. The data obtained using ANSYS (FLUENT) 18.2 were compared with the experimental result. An optimized volume concentration of the nanofluid was found out to be used as an effective cooling fluid in the hybrid heat exchanger.

Abhishek Mund, Bikash Pattanayak, J. S. Jayakumar, Kajal Parashar, S. K. S. Parashar

Improving Thermal Efficiency by Varying Input Parameters of a Four Stroke Single Cylinder S.I Engine

The use of automobiles is growing day by day and so does the need to improve efficiency in all stages. Thermal efficiency is a factor that is measured by work done by the heat supplied to it. For improving the efficiency of an S.I engine, the inlet air conditions were altered to support various parameters. Kirloskar TV1 variable compression engine was used to run the tests. Using a variable compression engine helps us to alter the compression ratio without stopping the engine by using the tilted cylinder arrangement. The engine can be run easily at variable load as well as rpm. The orifice was modified to equip the alterations and to run the tests. Atmospheric air contains moisture, and since this air gets inside the engine, initial test was based on to reduce this moisture content and alter the temperature of the air. Various conditions were taken into consideration on how to vary the inlet air parameters. Various modes were sequenced to test out the efficiency. Test 1 involved humidifying the inlet air. Test 2 involved cooling the inlet air. Test 3 involved dehumidifying the inlet air. Test 4 involved altering oxygen content in an inlet air, and test 5 involved a combination of cooling the inlet air and dehumidifying it. The engine was run at constant load and at variable rpm, and test 5 gave optimum results.

Rahul Ajitkumar, Sumit Sharma, Vipin Kaushik

Calibrating the Performance of Pelton Turbine by Using Helical Penstock

This paper presents a study on the comparative analysis of the penstock used in the micro-hydropower plants with the aim of inventing a new design of penstock with the efficiency benefits in the future. The Pelton wheel is designed for 0.000143 m3/s flow rate with a diameter of penstock 0.75 in., and detailed study is done on the benefits of the new penstock which is helical in shape, so the helical penstock can also be considered as a replacement of the old conventional penstock which is straight and its design strategies are discussed. It was found that the helical penstock was approximately 22–23% more efficient in the voltage generation with the additional benefits such as saving in the material cost, less land acquisition, and less wear and tear of the penstock line due to cavitation. This is thus more economical, more viable as it produces more with the same input of water, and thus helps in generating more power.

Punj Lata Singh, Akash Chaudhary, Devansh Rautela

To Reduce Pollution Due to Burning of Coal in Thermal Power Plant

Over the past decades, many techniques or resources are used in order to generate electricity or to produce power and many more. To generate electricity or power, some substance needs to be burned those sources include fuels and coals. Coals are the major sources which are used in thermal power industries. And due to the burning of such fuel or coal, the production of harmful gases arises. These gases include CO2, sulphur, nitrogen, and soot particles. According to various researches, the production of CO2 is much larger than the production of other elements which mostly affects the global warming. This project has a new concept which aims to reduce most of those gases which comes out of the thermal power plant. An experimental study has been conducted to check the amount of pollutants coming out from our prototype, and on the basis of the results, the amount of pollutants reduction will be calculated. This project mainly focuses to reduce the particulate matter coming out of the power plant. Since by burning of a coal, the production of particulate matter is much higher that’s why this paper aims to reduce that CO2 from entering into the atmosphere and hence reducing pollution as well as the ozone layer depletion.

Ankush Agrawal, Harshit Ahuja, R. K. Tyagi

Experimental Investigation of the Performance of a Double-Pass Unglazed Transpired Solar Air Heater

This study presents an experimental investigation of the performance of a double-pass unglazed transpired solar air heater. The performance of the solar air heater was evaluated from the experimental data by energy and exergy analyses. The average thermal efficiency of the solar air heater was found to be 16.9 and 20.6% at the air flow rate of 0.015 and 0.019 kg/s, respectively. The average exergy efficiency was found to be 0.49 and 0.57% at the air flow rate of 0.015 and 0.019 kg/s, respectively. The thermal effectiveness of the heater was 66.6 and 67.1% at the air flow rate of 0.015 and 0.019 kg/s, respectively. The energy and exergy efficiencies and the thermal effectiveness increased with increase in the mass flow rate of air. The performance of this solar air heater is comparable to the conventional glazed solar air heater although it does not have any cover plate.

D. K. Rabha, D. Pathak, R. Baruah, T. Kalita, A. Sharma

Power Management and Energy Optimization in Hybrid Electric Vehicle—A Review

The continuous depleting reserves of fossil fuel triggered the requirement of vehicles equipped or semi-equipped with alternative fuel resources. The dependence on fossil fuels could be reduced using an alternative method. The technology used in the hybrid electric vehicle might play an important role in preserving fossil fuel reserves and the environment simultaneously. A hybrid powertrain transmission utilizes an integrated assembly of renewable and non-renewable energy resources for power generation. It requires an accurate and flexible control system to achieve the required output. Typically, hybrid electric vehicles are furnished with IC engine and electrical storage devices like ultra-capacitors or batteries for power supply. The entire vehicle framework is preoccupied with one comprising of two power sources. This paper gives an overview of hybrid powertrain transmission along with a systematic review of energy optimization (EO) and power management (PM) strategies in terms of fuel consumption and emissions.

Ravi Dutt Sharma, Dheeraj Sharma, Kartik Awasthi, Nazish Ahmad Shamsi

Computational Analysis of Active and Passive Evacuated Tube Solar Collector

A computational study on active and passive evacuated tube solar collector system is examined in this paper. The paper gives us an understanding of the performance of the ETC system under natural flow as well as forced circulation. Major parameters for useful solar thermal energy gain by evacuated tube solar collector are tilt angle, mass flow rate and specific heat capacity of working fluid. To make sure that the system receives maximum useful heat gain, the optimum mass flow rate has been analyzed using ANSYS Fluent CFD. Thermal efficiency of active evacuated tube solar collector at optimum mass flow rate is compared with thermal efficiency of passive evacuated tube solar collector. It is observed from the numerical modeling of the evacuated tube solar collector that passive system is more efficient than active system.

Harender, Dhruv Mittal, Deepank Deo, S. Aditya, Arvind Kumar

Thermal and Resistance Analysis of Perforated Fin Using CFD

The present paper deals with the study of the heat transfer and friction characteristics under turbulent flow within a perforated fin. Standard computational methods using CFD have been used for creating the flow and heat transfer environment similar to that of experiments done by various researchers. To simulate the turbulent flow regime, k–Ɛ turbulence model is selected during the CFD simulation. The results obtained from the simulation for both solid and perforated fin is compared on the basis of fin geometries and effectiveness. The results clearly indicate that the perforation in fin increases heat transfer rate as compared to the solid fin.

Kuldeep Panwar, Etkaf Hasan, Renu Singh, Vijay Chaudhary, Kuldeep Rawat

Heat Transfer and Friction Characteristics of an Artificially Roughened Solar Air Heater

In the present work improvement of warmth conveying rate by creating harshness underside of onlooker surface in sun-powered air warmer has been explored. CFD examine has been done, to appraise warm course through convection and grinding factor in SAH pipe in which symmetrical triangular formed transverse rib unpleasantness is utilized. Computational outcomes are accomplished utilizing CFD apparatus Ansys-Fluent. The computational area has a width five times of stature (W/H = 5), relative unpleasantness tallness (e/D) of 0.042, and vertical projection (e) is 1.4 mm. The separation between two back to back ribs (P/e) and Reynolds numbers (Re) are in the scope of 7.14–17.86 and 3800–18,000 separately. The powerful scope of working parameters unpleasantness on Nusselt no. (Nu) and Friction factor (f) is watched and the result is exhibited to make an examination with the smooth pipe of a sun-based air radiator. The most extreme value of Nu and f in this present work are accomplished s 2.94 and 3.27 individually.

Rakesh Prasad, Anil Singh Yadav, Nishant K. Singh, Dilip Johari

Attic Space Convection Analysis with Full-Blown Heat Condition with Different Possible Geometries

An issue with the design optimization of building attic space has been addressed in this paper in an artistic manner with the consideration of full-blown condition. Different values for the ratio (0–1) of the roof and the floor length in the rectangular cavity has been considered. It includes triangular-, rectangular-, and trapezoidal-shaped enclosure. For finding the optimized shape, the study has included the consideration of different values for the Rayleigh number 104–106. The assumption of uniform temperature over the wall and no-slip condition is considered. Isotherm and streamlines are computed to observe the temperature distribution and fluidity of laminar air at Prandtl number 0.71. With the use of ANSYS 18.1, the present study finds the ratio of roof and floor of an attic space to be in between 0.8 and 0.9 for best thermal performance.

Anuj Gupta, Harishchandra Thakur

An Analysis of a Duct with Different Vortex Generators for Performance Enhancement of a Solar Air Heater: Computational Fluid Dynamics (CFD)

A two-dimensional computational fluid dynamics (CFD) analysis of the artificially roughened solar air heater rectangular duct with three different types of vortex generators (rectangular, triangular, and circular) on the absorber plate is conducted in order to increase the transfer of heat in the flow. ANSYS FLUENT 16.0 is used as a solver to determine the nature of flow in the solar air heater duct having vortex generators using finite element method with the SIMPLE algorithm as a base. The variation of average Nusselt number was investigated with the change in Reynolds number ranging from 3800–18,000 and with the constant heat flux of 1100 W/m2. The research has found that the average Nusselt number was considerably increased with every range of Reynolds number in all the geometries but most significantly increased in triangular vortex generator with negligible pressure drop. The value of average Nusselt number found in triangular vortex generator at Reynolds number 18,000 was 3.848 times to that of average Nusselt number of the smooth duct at same Reynolds number. The thermo-hydraulic performance and enhancement ratio of Nusselt number is also studied and found to be the best for the duct with triangular vortex generator at Reynolds number 3800.

Noel Vinsent Chand, Vineet Kumar, Anuj Kumar Sehgal

Experimental Investigation on a Solar Thermal Energy Packed Bed Sensible Heat Storage Combined with Latent Heat Storage

The thermal energy storage is required to store the solar energy, which can be stored by using sensible, latent and thermo-chemical heat storage energy systems. The sensible heat storage is more reliable and full-fledged technology, but it is low efficient due to low heat storage density. In the present study, experimental setup is developed by combining the sensible heat storage with a latent heat storage unit in order to store the solar energy. The developed thermal energy storage unit contains an insulated cylindrical tank having hollow spherical capsules of HDPE (filled with fatty acid which has phase-change property). The water and oil liquid transport medium is used as a heat-carrying substance which works as a transporting heat energy from high-temperature container to TES tank and act as SHS materials. The temperature of the transport medium is maintained constant at inlet of the tank during charging and discharging processes. The effect of flow rate and inlet temperature of HTF is analyzed on charging time with the help of charging experiments. The performance parameters viz. cumulative heat stored and efficiency are analyzed during charging and discharging processes. The result shows that efficiency of the system with water as HTF is more than that of oil.

Vineet Kumar, Anuj Kumar Sehgal, Abhishek Gupta

Numerical Simulation of Cold Flow Analysis of Internal Combustion Engine with Double-Lobed Piston Head

The demand for cost-effective eco-friendly automobiles is increasing day by day because of its impact on reducing air pollution. We cannot compromise with the usage of automobiles and its advancements as it is inevitable for the development. The only way to combat the problem of air pollution is the reduction of the harmful emissions, and it can be achieved by introducing new innovative engine designs which can give a complete combustion. This paper proposes a new double-lobed piston head design which can give better in-cylinder air flow patterns (Tumble and Swirl), turbulence and air–fuel mixing for an IC engine and thereby result in complete combustion. The in-cylinder airflow patterns developed during the intake stroke and the compression stroke of this newly designed IC engine were analyzed and compared with that of conventional flat piston head engine using the numerical simulation of cold flow analysis. No change in tumble was observed which means the piston head configuration has a negligible effect on the tumble. But there is a 66.67% increase in swirl during intake stroke and 91.47% increase during the compression stroke. This increased swirl creates high turbulence and thereby increasing the engine’s combustion efficiency. These results proved the efficiency of the double-lobed piston head configuration in providing better engine performance and thereby reducing the air pollution.

B. Bibu, Vikas Rajan

Vortexing Behaviour During Draining of a Liquid Through Two Unequally Eccentric Drain Ports in Cylindrical Tanks

This paper presents the results of an experimental study on the vortexing behaviour during draining of a liquid (water at room temperature) from a cylindrical tank of inner diameter D = 96 mm through two circular drain ports (d1 and d2) placed at unequal eccentricities (e1 and e2) from the tank center. e2 is fixed as 42 mm, whereas e1 is varied giving e1/e2 ratios of 0, 0.25, 0.5, and 0.75. After imparting an initial rotation (N rpm), the liquid is drained from the cylindrical tank. The critical height of vortex formation ‘Hc’ and the corresponding time of draining were recorded. The results of the present study show that vortex formation gets completely suppressed at all diameters d1 when e1/e2 = 0.5 and 0.75. Furthermore through flow visualization experiments, an upward axial flow (above the drain port) establishment is observed in this study which is thought to influence the dynamics and characteristics of the vortex air-core formation. The phenomenon of vortex intermittency is also observed in the cases where vortex formation occurs. This attempt is the first of its kind in the research history of vortex dynamics.

S. Kiran, Rajeev Warrier, Batchu Sai Naga Vinay Mouli, S. Harisankar, R. Ajith Kumar

Effect of Temperature and Pressure on the Leakage Flow Characteristics of the Bent Axis Hydro-Motors—An Experimental Study

This article investigates the steady-state leakage flow (hydraulic oil) characteristics of the bent axis hydro-motor fitted in an in-house fabricated hydrostatic transmission (HST) system. In this respect, two different classifications of the bent axis hydro-motors, fixed displacement and variable displacement types, are taken into consideration, which is generally used in heavy earth moving vehicles. The leakage flow paths in these two selected hydro-motors are studied considering their constructional detail. A mathematical model is established to estimate the leakage flow of the said hydro-motors that accounts the change in viscosity with respect to the operating state variable, i.e., absolute temperature and operating pressure, where the coefficient model is obtained from the test data. Using the established model, the leakage flow characteristics of the hydro-motors are obtained at different operating conditions and are verified experimentally. From the study, it is concluded that with the increase in load pressure and temperature of the working system, the leakage flow of the hydro-motors used in the heavy earth moving vehicles also increases.

Ajit Kumar Pandey, Alok Vardhan, Yash Kumar, K. Dasgupta

Experimental Analysis of Thermal Conductive Properties on Aerogel-Filled Composite Structure

Aerogels are well known for its ultimate thermal resistive characteristics and its low density, i.e., several times less than air. Because of these favorable properties, aerogels are mostly used in thermal insulations. The main drawbacks of these insulations are poor strength and limited operating temperatures. In this paper, an attempt has been made to enhance the strength and broaden the range of operating temperature of the insulation made of silicon aerogel. To acquire these properties, a composite structure filled with silicon aerogel has been proposed and experimentally investigated to evaluate its thermal conductivity at different temperatures and heat flow rates. Results have been compared with empty structure and glass wool-filled structure by using plots. From the plots, it was concluded that the structure filled with the aerogel has less thermal conductivity than the other structures and also the percentage change of thermal conductivity was determined at different temperatures with different heat transfer rates.

Bommidi Atcharao, P. Poorna Mohan, P. N. E. Naveen

Effect of Selectively Applied Surface Roughness and Wake Splitter Plate on the Aerodynamic Characteristics of a Circular Cylinder

This paper investigates flow over a stationary circular cylinder (diameter, D) with locally applied roughness height, ‘k’ applied at certain circumferential locations of the cylinder in the presence of a detached wake splitter plate with varying length, L. The numerical simulations are done by using commercial software ANSYS Fluent. This numerical study is conducted at a Reynolds number value of 25,000, k/δ = 1.1 (δ is the boundary layer thickness at a given circumferential location) and L/D = 0.5, 1, 1.5, 2.0 at different roughness locations α = 0°, 9°, 31°, 65°, and 75°. The results indicate that lift coefficient, drag coefficient, and Strouhal number are significantly affected as the L/D ratio increases, whereas with the change in the roughness location, the aerodynamic/hydrodynamic characteristics are not notably affected. Longer splitter plate along with roughness application is found to cause two effects: (a) considerable reduction in drag coefficient and Strouhal number and (b) considerable increase in the lift coefficient.

Shruthi Sivadas, K. Arun Kumar, R. Ajith Kumar

Mixing Studies in Turbulent Oxy-Methane Jets with and Without Reaction

Interactions of multiple jets have several industrial applications like jet mixing in rocket engine and in combustion chambers. Non-premixed (diffusion) flame is used in many applications owing to its stability. The present study considers three-dimensional simulation of three separated oxy-methane jets which shows that combustion has a prominent impact on their velocity distribution. The radial distributions of longitudinal velocity at different axial locations have been examined. Comparison has been done on reactive and non-reactive jets. Velocity decay for reactive jets is found to be slower relative to non-reactive jets. Turbulent intensity is higher in non-reactive jets which causes faster spreading. The temperature profile shows that the peak temperature does not exist on the centerline plane but at some offset height from the oxy-fuel centerline plane. The study has been carried out for different jet inlet temperatures. Increase in inlet temperature of reactant leads to a faster velocity decay.

Jana Tamal, A. R. Srikrishnan, B. Deependran, R. Ajith Kumar

Combustion Simulation of a Four Stroke Single Cylinder S.I Engine for Reducing Emissions

The requirement to reduce the pollutants from the atmosphere is currently needed and the major part of it is caused by IC engine, so as to reduce such emissions, an analysis is being carried out in Ansys IC engine Fluent model. A design of basic combustion engine with a bowl type piston is modeled and a simulation is carried out in Ansys 17.1 Workbench. Simulation of combustion cycle from IVC to EVO is being simulated and the pollutants evolved during this process is being calculated and tabulated by varying the pressure and temperature accordingly and obtaining the best outcome possible from it. The design of valves, inlet, and outlet manifolds and a piston is created which would be further decomposed in the simulation software and chamber is created inside which the pollutants data are collected from. By providing the fuel composition that needs to be injected at 4.5° CA bTDC up to 35.5° CA aBDC as it is a gasoline direct injection engine. Spark at 11° CA bTDC is introduced to make sure whole of the fuel is burnt without any unburnt fuel which may produce soot in the system. The results show a variation when the pressure and the temperature of the intake is varied when compared to that of the intake parameter which has high pressure and temperature. The experimental value of pressure 101,325 Pa (1 atm) and temperature 300 K is taken as the initial condition values and is being used as ideal value for comparison and determining the best among the results obtained.

Akshay Kumar Vijayendernath, Sumit Sharma

Applying ECFM Combustion Model to Spark Ignition Engine, Comparison with Experimental Data

In order to increase the efficiency of the engine and reduce emissions, right sizing plays a predominant role. Validation of turbulent combustion in engine environment using numerical tools is even more challenging. For better understanding of the thermodynamic and chemical behaviour of gas, a proper CFD models set-up should be used to represent turbulence, heat model, ignition, flame propagation and knock. This paper presents an application of ECFM (Extended Coherent Flame Model) as a combustion model coupled with ISSIM (Imposed Stretch Spark Ignition Model) to create the flame kernel due to spark. Two mechanisms named stretching and wrinkling affect the development of the flame front. Stretching is a result from turbulent velocity, and wrinkling is a result from turbulent length scale. The effect of the ECFM model constant addressing stretching and wrinkling, and the process to fix those parameters are briefed in this paper. The simulation results have showed a very good agreement with the combustion test results of RENAULT Engine in terms of pressure, heat release rate and combustion duration.

A. Jeevan Sai, R. Balamurugan, Cedric Servant, Frederic Ravet, S. Ajith Kumar

Numerical Investigation of Scheffler Concentrator Receiver for Steam Generation Using Phase Change Material

This study is about the numerical modelling of concentrated solar power (CSP) system using a Scheffler dish solar concentrator which can be used for steam generation and its applications. Water is used for direct steam generation from the receiver. In the proposed model, phase change material (PCM) is present in between the inner and the outer cylinder of the copper receiver. A binary mixture commonly known as solar salt (60% NaNO3-40% KNO3) is used as PCM for analysis. It helps to get rid of fluctuations due to sudden weather changes. Scheffler solar concentrator of 16 m2 area with fixed focus is used to concentrate the solar radiations to the receiver. The purpose of this study is to see the effects of temperature distribution with and without the PCM and also the rate of steam generation for the system numerically using Finite Element Method. Numerical analysis was performed using Transient thermal analysis module in ANSYS Workbench. Results showed that the proposed design of the cylindrical receiver containing the solar salt enhances the performance of the system.

Shubham, Rahul Kumar, Soumen Mandal

Parametric Investigations and Thermodynamic Optimization of Regenerative Brayton Heat Engine

The modified configuration of regenerated Brayton heat engine along with pressure drop losses in its irreversible mode is thermodynamically investigated and optimized. The temperature difference between the system and the reservoirs is considered as the source of external irreversibility. On the other hand, frictional losses in compressor/turbine, regenerative heat and pressure losses induce internal irreversibilities in the system. The output power of the cycle is thermodynamically optimized in context with cycle temperature. It is found that regenerative effectiveness plays a vital role in obtaining maximum possible output power, and first law efficiency predominantly depends on the cold-side effectiveness in the system. It is also observed that the thermodynamic performance of the proposed system/device prominently depends on the efficiency of the turbine and consequently is less dependent on compressor efficiency. Moreover, the model investigated in this study yields lesser output power/first law efficiency and exactly follows the results/outcomes presented in the available literature at α1 = α2 = 1, which are the pressure recovery coefficients at two ends.

Rajesh Arora, Ranjana Arora

Recent Developments in Finding Laminar Burning Velocity by Heat Flux Method: A Review

This paper reviews the recent developments in heat flux method to determine the laminar burning velocity of a liquid or a gaseous fuel. Laminar burning velocity is an elementary property in designing the combustion chamber and turbulent combustion model and to validate kinetic simulation. There are numerous methods to find the laminar burning velocity such as Bunsen burner method, flat flame burner method, counterflow method, soap bubble technique, tube propagating technique, and heat flux method. In this paper, some of these methods are discussed in brief and recent developments of heat flux method have been elaborated, as this method is simple and accurate. To find out laminar adiabatic burning velocity, there are two requirements to be satisfied. First is the flame should be one-dimensional, thus flat and stretchless; second is adiabatic which means net heat exchange with the burner is zero. But, satisfying both these conditions at the same time is very difficult. The other methods have failed in satisfying both the conditions. However, heat flux method proved to satisfy these conditions. Results of laminar burning velocity using heat flux technique for methane–air have been compared with other methods of finding laminar burning velocity.

Ashok Patil Abhishek, G. N. Kumar

Dynamics and Control of Thermally Heat-Integrated Systems

The most crucial objective in a chemical process is to synthesize/design a robust control structure, which can ensure a safe, smooth, and profitable operation within the process, even in case of disturbances. In this work, a plantwide control structure has been synthesized for an example process where tetrahydrofuran (THF)–water mixture is separated using an extractive distillation technique. The process design flow sheet consists of two distillation columns from where THF and water are being recovered at high purities while the entrainer is recovered and recycled as a material recycle stream within the process. Further, two feed-effluent heat exchangers (FEHEs) are used to exchange the heats between the hot and the cold streams within the process to provide the heat integration, thus making the process more energy efficient. An improvement of 20.79% in the overall energy requirements has been observed upon applying the heat integration circuit. A plantwide control structure is later synthesized on the base case design, and its performance is evaluated for ±10% change in throughput change and ±5% change in composition change. The significant feature of this work is the synthesis of control strategy when the control degree of freedom is lost during the implementation of heat integration circuits. To counter this issue, Hi-Select control loop is used along with supervisory composition controllers.

Asma Iqbal, Syed Akhlaq Ahmad

Thermodynamic Analysis of an Integrated Gasification Fuel Cell-Combined Cycle Power Plant Using Indian Coal

In the present study, a detailed thermodynamic analysis of an integrated gasification fuel cell-combined cycle (IGFC-CC) power plant is carried out wherein gasification technology is coupled with solid oxide fuel cell (SOFC) with Brayton and Rankine cycles as bottoming cycles. The proposed power plant is modelled and simulated using a computer flowsheet program called ‘Cycle-Tempo’. The thermodynamic analysis of the cycle with Indian coal as fuel suggests that the steam at higher temperature coming out from the exit of an anode of the SOFC can be used as a potential source for the endothermic gasification reactions in the gasifier. Steam with a flow rate of about 5.43 kg/s extracted from the anode exhaust of SOFC is supplied to the gasifier. The variations of syngas compositions, H2/CO ratios and heating values of syngas with different steam–fuel ratios (SFR) at different gasifier reaction temperatures among three different commercially available gasifiers, viz. fixed bed, fluidized bed and entrained flow gasifiers have been presented in the results. With an increase in SFR, it has been observed that the H2 composition in the syngas increases, whereas the heating value of the syngas decreases. With an increase in SFR from 0.1 to 0.7 at gasifier reaction temperature of 800 °C, H2/CO ratio has increased from 0.613 to 1.707, whereas at 1300 °C, this ratio has increased from 0.46 to 0.95 since lower temperatures favour steam reforming reaction. The net overall plant energy and exergy efficiencies are observed to be maximum in case of entrained flow gasifier with SFR of 0.7 and the values are 46.55% (HHV basis) and 42.65%, respectively. The exergy analysis of the plant indicates that the maximum exergy destruction takes place in the gasifier component with a value of 24.85% suggesting a detailed study for its design optimization.

A. Pruthvi Deep, Ashutosh Jena, Sujit Karmakar

Numerical Study of TiO2 Nanofluid in Multistage-Bifurcated Microchannel Subjected to Hotspots

The present study discusses implementation of multiple passive structures along the flow length using TiO2 nanofluid with 0.1% volume fraction to analyze a multistage-bifurcated microchannel. Fully developed laminar flow for different multistage plate configurations is used for the computational study, and additional investigations were done to evaluate pressure drop for Reynolds Number ranging from 250 to 500. Two different heat fluxes have been used: 4000 W/cm2 given for hotspot area and 1000 W/cm2 for the entire heat sink. Furthermore, the influence of flow rate on bifurcation stages combined with hotspot is highly investigated. Also, the pressure drop, temperature distribution, and flow streamlines are studied to evaluate cooling performance.

Amit Kumar, G. Narendran, D. Arumuga Perumal

Flow of Ferro-Fluid in a Circular Tube Under the Influence of Magnetic Forces

This study deals with the flow of ferro-fluid in a circular tube under the influence of a magnetic field. Ferro-fluid comprises ferromagnetic particles of small size suspended in a liquid. Magnetic force sets a motion of ferro particles that causes fluid to move due to drag between fluid and the particles. Magnetic pumping will be useful in enhancing cooling of electronic devices at the expense of small amount of energy leading to the increased life of such devices. An expression is derived for velocity profile in a circular duct. Magnetic field and magnetic force distributions are presented for a colloidal solution of 50μ iron particles suspended in water. The magnetic pressure induced is found to be significant which causes the drift of the solution.

Achhaibar Singh, P. K. Rohatgi

Flow Around Curved Plates at Low Subcritical Reynolds Number: Investigation of Wake Characteristics

In this paper, numerical simulation results of flow over flat plate and curved plates at a Reynolds number of 8000 are presented. Drag coefficient and Strouhal number trends are reported at different chord length (CL)-to-diameter (D) ratios of 0, 6/13, 3/4, and 1 with varying angle of incidence (ranging from α = 0° to 30° in steps 10°). The curvature of the plate was adjusted by varying the radius of curvature keeping the chord length fixed at 40 mm. The results of this study show that the aerodynamic characteristics, viz., drag force and Strouhal number, are significantly affected by the introduction of curvature and flow angle of incidence (plate orientation). The maximum reduction of drag coefficient obtained is 58% by the introduction of both plate curvature and plate orientation. Further, it is noted that base pressure coefficient complies with the trend of the drag and the maximum flow field vorticity shows an abrupt increase in CL/D beyond 6/13.

Amala Anil, K. ArunKumar, R. Ajith Kumar, C. M. Hariprasad, Thamil Mani

Study on Performance Analysis of Earth-Air-Pipe Heat Exchanger as Passive Cooling and Heating System

The energy demand for the private and business building increases quickly with the population. In the last two decade indicated extreme energy emergency found in creating nations particularly amid summer season. For hot atmosphere nations like India, the use of cooling framework assumes essential part. The Mechanical Vapor Compression (MVC) frameworks toward this path are demonstrating effective however in the present situation when the demand of energy is expanding, and the supply isn’t adequate one should center around the passive cooling techniques or other substitute which can meet necessity at least cost and energy utilization. As the passive cooling not just gives the course of the outside air to keep up the freshness yet in addition keep up the solace at low energy necessity, such a significant number of analysts have been working over these frameworks to discover it as a substitute of MVC units. Earth-air-pipe heat exchanger (EAPHE) can be utilized as a passive cooling and heating framework by using geothermal energy. This paper intends to display the audit on execution ponder and mechanical advancement of EAPHE at various atmosphere conditions. Exploratory outcomes demonstrate that normal temperature drops to 12–20 °C which can be accomplished that relies upon atmosphere conditions. Normal pipe length, measurement, and air speed inside pipe were discovered 10–100 m, 0.05–0.5 m, and air speed 2–5 m/s separately. These papers additionally recognize the purpose behind non-successful working of the EAPHE and proposed strategies to enhance the effectiveness of the framework to improve cooling of heating impact.

Mahendra Kumar Verma, Vikas Bansal, Kunj Bihari Rana

Review of Flows Past Arrays of Elliptic and Square Cylinders

The bodies which create the separation of flow for a certain area of their surface are known as bluff bodies. The bluff bodies can have sharp edges or these can also have a continuous surface. Vortex shedding is important phenomena related to bluff bodies which are present in both laminar and turbulent flows. When more than one cylinder or array of cylinders of the various cross sections is taken, then the results are highly different from the case of flow over one cylinder. Flows past arrays of cylinders of different cross-sectional areas are experienced in numerous engineering relevant. The several cylinders of cross-sectional areas such as of circular, square, ellipse, rectangular, and semi-circular can be organized in side-by-side, tandem or staggered layout. This paper evaluates the prevailing appreciation of the flows past arrays of cylinders with emphasis on the near-wake flow patterns, the transitional wake formation and conduct, Reynolds number influences and aerodynamic force coefficients. A principal attention is on the major numerical and experimental discourse that has noticeably since the last significant review of this issue. In this paper, a vigorous has been made to review the study of the work of various researchers for flows past arrays of elliptic and square cylinders, which will be helpful to perceive the various gaps in the research for conducting further new research work in this field.

Rajesh Kumar, N. K. Singh
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