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About this book

This book presents selected and peer-reviewed proceedings of the International Conference on Thermofluids (KIIT Thermo 2020). It focuses on the latest studies and findings in the areas of fluid dynamics, heat transfer, thermodynamics, and combustion. Some of the topics covered in the book include electronic cooling, HVAC system analysis, inverse heat transfer, combustion, nano-fluids, multiphase flow, high-speed flow, and shock waves. The book includes both experimental and numerical studies along with a few review chapters from experienced researchers, and is expected to lead to new research in this important area. This book is of interest to students, researchers as well as practitioners working in the areas of fluid dynamics, thermodynamics, and combustion.

Table of Contents

Frontmatter

Fluid Dynamics

Frontmatter

Large Eddy Simulation Modeling in 2D Lid-Driven Cavity

Primitive variable formulation of Navier–Stokes equation is solved in a lid-driven cavity using SIMPLE algorithm. The equations are discretized using finite volume method in a staggered grid mesh. The turbulence flow phenomena are observed in a 2D lid-driven cavity using large eddy simulation modeling of flow. Smagorinsky model is applied for the formulation of eddy viscosity. The solution is obtained upto maximum Reynolds number 4500 using grid sizes 66 × 66, 81 × 81, 101 × 101 and 121 × 121. A comparison has been drawn between turbulence model and without turbulence model. The study of comparison between two models consists of velocity profiles along the center of the cavity, location of primary and secondary eddies, velocity vector plot and pressure contours.

Banamali Dalai, Manas Kumar Laha

Numerical Study on Flow Over Two Inline Triangular Cylinders—Influence of Gap Ratio on Vortex Shedding

In the present study, numerical simulation was carried out for the flow around the two inline equilateral triangular cylinders at different gap ratios (G/D) for various Reynolds numbers (Re). The numerical investigations are carried out for 75 ≤ Re ≤ 200 and 0 ≤ G/D ≤ 2.5. The governing differential equations for laminar incompressible flow are discretized using finite volume method and PISO algorithm is employed to convert PDE to algebraic equation using the open-source software package. The effect of G/D ratio and Re on the non-dimensional shedding frequency Strouhal number (St) is investigated with the aid of vorticity plot and velocity profiles.

Manu Sivan, S. Ajith Kumar

Fluid–Structure Interaction Modelling of Physiological Loading-Induced Canalicular Fluid Motion in Osteocyte Network

The present study develops a fluid–structure Interaction (FSI) model to characterize the physiological loading-induced canalicular fluid motion in an osteocyte network within the bone. The effect of poromechanical properties on the canalicular fluid motion is also studied. The outcomes indicate that fluid motion in the network varies with gait events and fluid motion occurs from compressive to tensile strain environment. This work will provide a better understanding of osteocyte mechanical environment and biochemical communication regulating the bone’s adaptation which is although tedious to be explored using experimental techniques.

Rakesh Kumar, Abhishek Kumar Tiwari, Dharmendra Tripathi, Niti Nipun Sharma, Milan Khadiya

Generation of Temperature Profile by Artificial Neural Network in Flow of Non-Newtonian Third Grade Fluid Through Two Parallel Plates

Generation of temperature profile of third grade fluid in flow through parallel plates maintained at uniform heat flux is reported. Exact solution of heat transfer problem with third grade fluid is very difficult due to high level of nonlinearity. Viscous dissipation considerations make it even more difficult. In the present problem, least square method (LSM) has been employed to solve the governing equations. The velocity and temperature profile computed by LSM is used to train the artificial neural network (ANN). Once ANN is trained, it is able to give temperature profile corresponding to any velocity profile fed into the ANN. This work demonstrates the scope of ANN use to solve these types of complicated and problem of practical use. Artificial neural network (ANN) is employed in the solving of the problem with scaled conjugate gradient (SCG) as training algorithm.

Vijay Kumar Mishra, Sumanta Chaudhuri, Jitendra K. Patel, Arnab Sengupta

Fluid Flow and Heat Transfer

Frontmatter

Fluid Flow and Heat Transfer Characteristics for an Impinging Jet with Various Angles of Inclination of Impingement Surface

Present study involves the thermofluidic characteristics of a two-dimensional impinging isothermal jet for various angles of inclination of impinging surface. The RANS (Reynolds-averaged Navier–Stokes) equations based on the standard k– $$\varepsilon$$ ε turbulence model has been used to predict the turbulent flow and heat transfer fields. The angle of inclination of the impinging surface is varied in the range $$\alpha = 0^\circ$$ α = 0 ∘ – $$10^\circ$$ 10 ∘ , the Reynolds number is considered to be Re = 11,500 and the impinging surface is subjected to the constant wall heat flux. According to the present computational results, the impingement point, a location where the jet strikes on the bottom wall after issuing from the nozzle, gradually shifts towards the right side of the jet centerline with the increase of angle of inclination. The skin friction coefficient decreases but the pressure coefficient increases with increasing the angle of inclination. The Nusselt number, a measure of rate of convective heat transfer, decreases drastically as the angle of inclination increases from $$\alpha = 0^\circ$$ α = 0 ∘ to $$\alpha = 10^\circ$$ α = 10 ∘ .

Jublee John Mili, Tanmoy Mondal, Akshoy Ranjan Paul

Implementation of Improved Wall Function for Buffer Sub-layer in OpenFOAM

In computational fluid dynamics the value of y+ is a defining parameter in the accuracy of the result. In most of the available CFD tools, the computation near the wall has been done based on the concept of two zonal equation (viscous and log-law region). In this study, a new wall function has been implemented in the open-source CFD tool OpenFOAM for obtaining the result of near-wall properties. This newly implemented wall function is based on three-zonal equations compared to the two zonal equations used in standard wall function. A comparative analysis of the newly implemented wall function with the standard wall function has been conducted and the results are discussed. The analysis is conducted for the fluid flow over the backward-facing step. Comparative analysis was also conducted by keeping the value of y+ in viscous as well as in buffer region.

R. Lakshman, Jha Rahul Binod, Ranjan Basak

Numerical Simulation of Low Reynolds Number Gusty Flow Past Two Side-By-Side Circular Cylinders

The fluid flow past circular cylinders is still being investigated to understand the complex phenomenon involved. There are several applications in the area of structural and mechanical designs where cylinders in the side-by-side arrangement are being used. In some of the applications, cylinder array has to experience flow with different gust frequencies naturally while some of the applications may have advantages by introducing artificial gust frequencies in the flow. The proposed work represents simulation results of low Reynolds number (Re = 100) gusty flow past two circular cylinders in a side-by-side arrangement with three different cases of different gust frequencies and with three different gaps between cylinders. Extended flux reconstruction-based two-dimensional fully explicit Navier–Stokes solver is used for the numerical computation with a collocated grid comprising triangular mesh which solves the complete Navier–Stokes equation in the physical plane itself. To clearly understand the flow features associated with wake pattern streamlines and vorticity contours are evaluated. The Strouhal number is computed to derive the vortex shedding frequency. The variations in flow properties for three gusty flow cases with three different values of transverse gap are investigated and concluded.

Yagneshkumar A. Joshi, Deep Pandya, Rameshkumar Bhoraniya, Atal Bihari Harichandan

Comparative Analysis of Inlet Boundary Conditions for Atmospheric Boundary Layer Simulation Using OpenFOAM

The atmospheric boundary layer has been extensively studied by using computational fluid dynamics. The simulation of the atmospheric boundary layer has been conducted either by solving RANS equation or by LES simulation. LES simulation provides higher accuracy in the result but with a very high computational cost. Due to this higher cost in computational effort, RANS turbulence modelling has been preferred by most of the researchers. In Computational fluid dynamics, the role of inlet conditions is more important for any simulation problem. In this study, a comparative analysis has been conducted using open source CFD tool OpenFoam for different inlet boundary conditions for the atmospheric boundary layer. Horizontal homogeneity is a very keen factor while simulating the atmospheric boundary layer. The analysis has been conducted by taking the inlet and outlet profiles of velocity, turbulent dissipation rate, and turbulent kinetic energy. Analysis with different turbulence model constants was also conducted and the results are discussed.

R. Lakshman, Nitin Pal, Ranjan Basak

Parametric Analysis of Coupled Thermal Hydraulic Instabilities in Forced Flow Channel Using Reduced-Order Three-Zone Model

One of the significant issues of supercritical water reactor (SCWR) is the variation of coolant density along its axial direction of flow, which further creates a stability issue in the reactor. This causes the dynamic instability in the coolant channel. Present work is focused to study the parametric effects on the stability of the system using a simplified three-zone lumped parameter model by considering the neutronics coupled with thermal hydraulics. The coolant channel is divided into three zones, namely heavy fluid region, light fluid region, and intermediate heavy and light mixture fluid region. The interface of these hypothetical regions is separated by time dependence boundaries. A set of governing equations are solved for the individual zones that provide another set of algebraic and ODEs, which has coolant enthalpy and the length of each boundary as a primary variable. The US reference design of SCWR has been considered at 25 MPa as the operating pressure. Increasing the length of the coolant channel and hydraulic diameter can destabilize the system. Increasing inlet orifice and decreasing in the exit orifice coefficient have a stabilizing effect on the system.

Daya Shankar, Harabindu Debnath, Indira Kar

Numerical Simulation of a Single-Pass Parallel Flow Solar Air Heater with Circular Fins Using S2S Radiation Model

Solar air heater (SAH) is a heat exchanger device that converts solar radiation into thermal energy, using solar thermal technology (energy from the sun is trapped and absorbed to heat the air). The conventional SAH is inefficient due to poor heat transfer characteristics from the absorber. In this present study, a parallel flow SAH consisting of circular fins attached to the absorber is designed to enhance the heat transfer rate. Computational fluid dynamics (CFD)-based numerical simulation is carried out in ANSYS Fluent using the k–ɛ turbulence model with enhanced wall treatment for different mass flow rates and different solar radiation intensities. The simulation output is validated using experimental results which are available in the literature. The heat transfer characteristics, absorber, and outlet air temperature are shown using contours. The mean deviation in the outlet air temperature predicted by the simulation is found to be ~7%. The simulation and experimental results conclude that surface-to-surface radiation model can accurately predict the fluid flow behavior inside the SAH.

Praveen Alok, Sai Charan Teja Javvadi, Pavan Kumar Konchada, G. Raam Dheep

High-Speed Flow

Frontmatter

Parametric Study of Blast Wave Formation in a Shock Tube

Blast waves are formed when there is a sudden release of energy from a point in space, like, from an explosion. These waves propagate through air, come into contact with structures or human beings, and proceed to cause fatal or irreversible damage. Many methods have been developed to attenuate blast waves. However, to conduct physical experiments, the use of real explosives is for the risk of collateral damage. Thus, shock tubes are utilized to create blast waves within a confined region so that they can be studied safely. When the diaphragm bursts, a shock wave is formed in the driven section of the tube and, eventually, the pressure profile of the wave changes to that of a blast wave. The paper focuses on a parametric study of the variation of driver section length and pressure in the formation of blast waves in a shock tube. The distance at which the blast wave forms increases with increasing driver section pressure and length. The experimental results show that the pressure wave closely matches with that of Friedlander waveform at higher driver pressures.

Sachin Pullil, N. Vaibhav, R. Sanjay, S. R. Nagaraja

Intermittent Afterburner Engagement Leading to Single Engine Landing in a Typical Bypass Military Aero Engine

Thrust of an aero engine is augmented with the help of afterburners which are useful during takeoff and tactical maneuvers. It provides higher thrust without increase in engine size and helps to take off with maximum weapon load. Failure of afterburner engagement influences takeoff and/or abandon mission requirements. The current case studies are deliberated with respect to a low bypass turbofan engine having a thrust to weight ratio of 8:1 with afterburner on. The ignition of afterburner is by hot streak method where fuel is supplied for a short duration of time into the gas stream of the core engine just upstream of the turbine. The paper highlights the ignition system and its problem during afterburner engagement leading to single engine landings in twin engine aircraft configuration. It also highlights importance of various systems during afterburning ignition and the deficiencies in fuel nozzles in its manufacturing and assembly configurations leading to intermittent afterburner engagement thus affecting the reliability of aircraft/aero engine operation.

Saroj Kumar Muduli, Subrata Kumar Rout, Benudhar Sahoo, P. C. Mishra

Numerical Simulation of Interaction of Blast Wave Generated from Cannon with Wall at Different Pressure Ratio

A computational fluid dynamic method has been applied to simulate the pressure blast from a cannon and to investigate the pressure distribution on a wall located in front of the cannon. By solving this problem, peak value of pressure on wall has been calculated for different pressure ratio of driver and driven section in the cannon. By taking the maximum value of pressure at a particular pressure ratio as factor of safety, we have to invent a blast wave resisting jacket which will be helpful for blast wave explosion. The Advection Upstream Splitting Method (AUSM) scheme with third-order Monotone Upstream centered Scheme for Conservation Laws (MUSCL) approach were used for solving the unsteady, axisymmetric Navier–Stokes equation. Density-based solver was selected for present simulation due to its high-speed compressibility. The standard K-epsilon model with standard wall function is used for this simulation which is highly suitable for wall phenomenon problems. At the initial condition of this problem, the driver section of cannon is given to high pressure and driven section is at atmospheric pressure. After firing from cannon, flow of air take place from driver section to driven section and at advance time air flows out from the cannon. At exit of the cannon blast wave formation takes place which move in forward direction and after some time it strikes to the wall and move in backward direction. The computational result indicated that on increasing the pressure ratio in cannon causes the multiple fluctuations in pressure on the wall. The increase in pressure ratio also increases the peak pressure on wall.

Ansab Khan, Abhishek Kundu, Akshoy Ranjan Paul

Review on Hypersonic SSTO Engine (HSE) with Variable Diffusers, Double Annular Combustors and N2O-Oxygen Enhancer

This paper details a novel concept of an engine capable of flying on a single-sage-to-orbit (SSTO) aircraft. Leveraging the positive facets of existing technologies of extremely high-speed flight regime, and in an attempt to improve on the deficiencies of the same, the proposed engine will be made to operate in an envelope of vastly varying flight parameters. All factors will be optimized for the continuously changing free stream conditions. In the study, it is found that the fixed geometries of diffusers and nozzles lead to unwanted results which are addressed by the HSE. Another novelty introduced is of having an oxygen enhancer (not oxidizer) in the form of N2O which will be used to increase level of O2 in the flowing mass. Subsequently, an enhanced version of a generic nitrogen generating system (NGS) is employed to cut emissions. The resulting engine will be capable of reaching high hypersonic Mach numbers from ground up using it radical concentric annuli, inner one of which will house an afterburning turbojet and outer one a scramjet with its own combustion section.

Vedant Gupta, S. S. Godara, B. Tripathi

Modified Method of Characteristics for Analysing Cold Flow in Bell-Type Rocket Nozzle

To achieve higher thrust force, numerical investigation of flow behaviour of bell-type rocket nozzle has been carried out in the present research work. Analysis of thermodynamic properties is performed by using ANSYS Fluent software. K-ω shear stress transport model has been used to study the turbulent components of thermodynamic properties. Overall performance gain of a bell-type nozzle and nozzle geometric modifications are discussed. The nozzle geometric modifications are highlighted by executing a C-code with concepts of the method of characteristics (MOC) and modified method of characteristics (MMOC). With modified geometry as per the modified method of characteristics (MMOC), the present numerical study has ensured the fully expanded cold flow in nozzle. The results obtained by the method of characteristics (MOC) are compared with the calculations of the thrust force for the modified geometry.

S. Panigrahi, P. S. Maity, Gyan Sagar Sinha, D. Dangi, Atal Bihari Harichandan

Aerodynamics

Frontmatter

Performance Analysis of NACA4412 Airfoil with Gurney Flap

Gurney flap has been used to increase lift in varied types of wings used in aerial vehicles. It is also preferred as it increases pressure on the pressure side of the airfoil thus increasing the lift. Gurney flaps delay the onset of boundary layer separation in fluid flows. In the present research, analysis is performed on NACA4412 airfoil attached with gurney flap of different lengths with respect to chord lengths at 0°, 4° and 8° angles of attack. Ground effect phenomenon is also done at different height regime for different height to chord ratio through computational fluid dynamics (CFD). Analysis is carried out and coefficient of lift, drag, airfoil performance and pressure distribution is studied. In gurney flap, the lift force increases with decreasing ground clearance due to pressure region created under the airfoil. Phenomena of gurney flap are applicable for increase in coefficient of lift during the takeoff of the aircraft.

Ankit Kumar, Pooja Chaubdar, Gyan Sagar Sinha, Atal Bihari Harichandan

Effect of Ground Clearance and Air Temperature on Drag and Lift for NACA 2412 Airfoil

The flow behavior over a NACA 2412 airfoil is studied computationally. The pressure distribution and wall shear stresses over the airfoil were obtained through computational modeling. Total lift and drag forces were calculated by considering both friction and pressure effect over the airfoil. Simulation was carried out by changing the ground clearance from 0.1 to 1.5 m. Along with that the effect of wind temperature and velocity on drag and lift force was also studied at zero angle of attack. It has been observed that both the drag and lift force increases nonlinearly with linear variation of velocity. The air temperature does not affect the drag and lift significantly. It was also observed that a higher lift is obtained on the lower surface when the airfoil is away from the ground. However, if the ground clearance becomes very less, a negative lift has been observed. This is due to the narrow region of flow that increases the air velocity leads to create a lower pressure region at the bottom part of the air flow.

Prakash Ghose, Rishitosh Ranjan

Aerodynamic Characteristics of a Square Cylinder: Effect of Dissimilar Leading Edges

This paper presents the results of flow over square cylinder with dissimilar leading edges such as corner recession and corner arc at a Reynolds number 200. The leading edges are modified in such a way that the dimensions of the bottom leading edge are kept fixed and that of top leading edge is varied in the predefined proportions or cut ratios between 0 and 1 with respect to bottom edge. This study reveals that the flow over square cylinder with dissimilar leading edges shows an inverse relationship between Strouhal number and coefficient of drag for cut ratios less than 0.5 but beyond 0.5, both these parameters register an increasing trend.

Akhil S. Nair, S. Ajith Kumar, K. Arun Kumar, R. Ajith Kumar

Numerical Investigation of Various Wake Patterns in Flow Past Two Side-By-Side Cylinders

In the present research work, an incompressible unsteady viscous two-dimensional finite volume Navier–Stokes solver is developed to investigate flow past two-dimensional geometries. Two-dimensional analysis of flow past any arbitrary body geometry can lead to comprehensive parametric study so that the complete flow details can be captured. In the present solver, the full Navier–Stokes equations have been solved numerically in the physical plane itself by considering “Consistent Flux Reconstruction” technique on a collocated unstructured mesh comprising of triangular cells. A C-code has been developed to estimate the primitive variables and to analyze the flow characteristics. The flow characteristics around a single unconfined circular cylinder along with two circular cylinders in side-by-side arrangement at various gap ratios have been considered for the investigation. Streamlines and vorticity contours are plotted to visualize instantaneous flow field. Lift and drag coefficients and Strouhal number are computed in order to characterize the flow. Different types of wake patterns, like in-phase or anti-phase synchronized wake patterns and deflected wake patterns, are observed based on various gap ratios between cylinders. For a certain Reynolds number, the vortex shedding frequency from either of the cylinders in a side-by-side arrangement has been estimated to be identical.

P. Pandey, D. Singh, P. Das, D. Ghosh, Atal Bihari Harichandan

Multiphase Flow and Phase Change Material

Frontmatter

Effects of Joules Heating and Soret Number on Double-Diffusive Mixed Convection Flow in an Enclosed Square Cavity

In this paper, a double-diffusive mixed convection flow in an enclosed cavity with the effects of Soret number (Sr) and Joule’s heating parameter (J) is presented. Finite volume approach-based differed quadratic upstream interpolation for convective kinematics (QUICK) scheme and central difference scheme are used to resolve the respective convective and diffusive fluxes. The results are presented in terms of temperature, concentration and stream line contours by varying the buoyancy ratio (−100 ≤ N ≤ 100), Soret number (Sr = 0 and 1) and Joules number (J = 0 and 1). The present results are validated with the reported literature. Results show that the temperature is uniformly distributed with the absence of Soret number and a bulk fluid diffusion takes place inside the cavity once the Soret effect is induced. The effects of Joules heating on average Nu and Sh are negligible for Sr = 0, and it has a significant variation with Soret number.

A. Satheesh, C. G. Mohan, P. Padmanathan, Agarwal Anmol Pallav Kumar

Dimethyl Adipate-Based Microencapsulated Phase Change Material with Silica Shell for Cool Thermal Energy Storage

Phase change materials (PCM) have the ability to store and release thermal energy. Encapsulation of these energy storage materials overcomes the difficulties that can enable them for a broad range of applications. In the present study, microencapsulation of dimethyl adipate into silica shell was carried through interfacial hydrolysis and polycondensation method. The prepared microencapsulated phase change materials (MPCM) were characterised using a field emission scanning electron microscope, have shown good sphericity with an average particle size of 596 nm. The chemical structure of MPCM obtained using Fourier transform infrared spectroscopy has exhibited good chemical stability between shell and core materials. Latent heat of enthalpy measured using differential scanning calorimetry was around 24 kJ/kg with onset melting and end set melting as 7.33 °C and 11.97 °C, respectively. Furthermore, thermo-gravimetric analysis studies have shown that MPCM exhibited end set temperatures as 180 °C. Due to the inorganic shell coating over the PCM droplets, MPCM has shown an increase in thermal stability. These properties make MPCM as a viable candidate for cool thermal energy storage applications.

Vedanth Narayan Kuchibhotla, G. V. N. Trivedi, R. Parameshwaran

Estimation of Parameter in Non-Newtonian Third-Grade Fluid Problem by Artificial Neural Network Under Noisy Data

Estimation of a parameter of third-grade fluid problem by using artificial neural network is reported. The fluid is allowed to flow through two parallel plates and supplied with a constant and uniform heat flux. Inverse analysis is employed by using artificial neural network (ANN) to estimate third-grade fluid parameter. The direct problem is solved by semi-analytical method and least square method (LSM) to compute the temperature profile. The temperature profile and the corresponding parameter of third-grade fluid are perturbed to mimic error in measurement and then used in ANN for training the neurons with error in data. An unknown temperature profile is fed into the trained ANN, and ANN gives the corresponding parameter as output. In the ANN, Levenberg–Marquardt algorithm (LMA) is used to train the ANN. Five different levels of error in measurement are analyzed in the estimation of the parameter.

Vijay Kumar Mishra, Sumanta Chaudhuri, Jitendra K. Patel, Arnab Sengupta

Role of PCM in Solar Photovoltaic Cooling: An Overview

The present article put forth a comprehensive review of the latest research works carried out on the cooling techniques for maintaining the required temperature of photovoltaic modules for achieving greater efficiency. The conventional cooling technologies such as water cooling, air cooling and water spray are little discussed in this article as these are not preferred in the present scenario due to their power requirement and complicated arrangement. The phase change materials (PCM) have evolved as a better alternative for the cooling of photovoltaic modules due to their advantageous thermo-physical properties. The recent research investigations on using phase change materials as heat absorbing material are critically reviewed in the present article. The investigations include experimental and numerical studies on single PCM, combined PCM (PCM with nanoparticles, graphite powders), PCM as secondary thermal energy storage. The critical review suggests that further research works are necessary for developing a passive design (not using external power) for obtaining optimum temperature of the solar photovoltaic modules.

Pragati Priyadarshini Sahu, Abhilas Swain, Radha Kanta Sarangi

Second Law and Cycle Analysis

Frontmatter

Enhancement of Boiling Heat Transfer Using Surfactant Over Surface with Mini-Channels

The present article focuses on experimentally investigating the saturated pool boiling performance of isopropanol and its solution with surfactant sodium lauryl sulphate (SLS) over modified surfaces intended towards application in small heat transfer equipment. A comprehensive review on enhancement of pool boiling heat transfer using different surfactants is also presented. Three types of surfaces such as plain surface, a surface having macro-channels, surface with mini-channels are tested for pool boiling. The best performing surface, the surfaces with mini-channel is tested with three solutions of isopropanol with the above-mentioned surfactant with 200, 600 and 1000 PPM concentration. The highest heat transfer coefficient is observed for the 600 PPM solution with the surface with mini-channels.

Abhilas Swain, Radha Kanta Sarangi, Satya Prakash Kar, P. C. Sekhar, Sandeep Swain

An Analytical Investigation of Pressure-Driven Transport and Heat Transfer of Non-Newtonian Third-Grade Fluid Flowing Through Parallel Plates

Flow of a third-grade fluid induced by the difference in pressure, thorough rectangular parallel plates, having different wall temperatures, is revisited considering the effect of viscous dissipation. The governing equations, describing the physical phenomenon, are nonlinear. The non-Newtonian third-grade fluid parameter is considered to be small, and the governing equations are reduced to weakly nonlinear equations. The nonlinear momentum and energy conservation equations, thus obtained, are solved employing perturbation method. Analytical solutions for the velocity and temperature distributions are obtained. Results generated by the perturbation method are compared with that of Danish et al. (Commun Nonlinear Sci Numer Simul 17:1089–1097, 2012 [1]) and an excellent agreement is exhibited within the small range of perturbation parameter (third-grade fluid parameter). Effects of various parameters such as Brinkmann number, non-Newtonian third-grade fluid parameter, temperature ratio of the upper plate and lower plate on the variation of velocity and temperature are discussed. Results indicate that an increase the third-grade fluid parameter results in a decrease in the velocity. Temperature of the fluid decreases with an increase in third-grade fluid parameter and displays an increasing trend with an increase in Brinkman number. The peak temperature is observed to occur not at the upper plate, at a region which is near the upper plate. Results are useful for designing thermal systems applied in the fields of polymer melt flows, food processing, flow of slurry, etc.

Sumanta Chaudhuri, Paromita Chakraborty, Rajen Das, Amitesh Ranjan, Vijay Kumar Mishra

Design and Analysis of a Naturally Ventilated Fog Cooled Greenhouse Integrated with Solar Desalination System

This paper presents the design and performance of a naturally ventilated fog cooled greenhouse coupled with solar still. The greenhouse is East–West oriented, and its microclimate is maintained using evaporative cooling through foggers. The canopy-mounted solar still produces freshwater from brackish or saline water. The analysis is performed on a representative day for the month of May and December for Kolkata located in the state of West Bengal and representing hot and humid climatic conditions. Computer codes are developed in-house to develop thermodynamic model for analysing the performance of the integrated system. The study reveals that the solar still can produce maximum 26.39 kg of fresh water on a typical summer day. It is also found that the greenhouse temperature can be maintained at a level 6 °C below the ambient during peak sunshine hours on a typical summer day.

Md Iftikar Ahmed, Sk Arafat Zaman, Sudip Ghosh

Performance Assessment of a Steam Gasification-Based Hybrid Cogeneration System

In this article, a hybrid cogeneration scheme based on a solid oxide fuel cell (SOFC)—gas turbine system and utilizing syngas derived from municipal solid wastes (MSW)—has been investigated thermodynamically. Steam gasification of municipal solid wastes produces hydrogen-rich gas that is consumed by the SOFC stack as fuel. An externally fired air turbine (EFAT) draws the heat of combustion of the SOFC exhaust via a heat exchanger, while the clean turbine exhaust air itself is fed to the cathode of the SOFC. A bottoming heat recovery steam generator (HRSG) further recovers waste heat to produce process steam required for the gasifier as well as for process heater. Results of the study for base case parameters show that the integrated system can have a maximum electrical efficiency of about 50%, while substantial fuel saving (more than 51% when compared with separate power and steam plants) because of cogeneration of steam required for gasification system.

Sk Arafat Zaman, Dibyendu Roy, Sudip Ghosh

Heat and Mass Transfer

Frontmatter

Experimental Study of Thermal Contact Conductance for Selected Interstitial Materials

Enhancement of thermal contact conductance (TCC) has found numerous scopes in a variety of thermal systems such as nuclear power reactor, microelectronics, heat exchangers, dry sliding contacts, etc. Better heat dissipation is the main objective in all such applications where a higher value of TCC is the prime concern at the contact of heat source and sink. In the present investigation, axial heat flow experiments have been carried out on bare metallic joints as well as for the contacts with interface materials for the improvement of TCC. Steady state methodology is employed for the estimation of TCC at the interface of two materials under atmospheric conditions. Stainless steel (304) has been chosen as the specimens’ material due to its low thermal contact conductance value and extensive range of applications. Silicone-based thermal grease and graphene pastes are employed as thermal interface materials between the specimens. The thickness of paste is an important factor since large thickness will further reduce the thermal contact conductance. Therefore, TCC is estimated and studied with the varying thickness of thermal paste. Moreover, the thermal pastes have also been tested for varying contact pressures (0–5 MPa) and interface temperatures (30–100 °C). Eventually, the results of thermal contact conductance with thermal interface materials have been compared with those for bare metallic contacts. Results demonstrate the applicability and suitability of two types of thermal pastes for their application in the present range of operating parameters.

Mohammad Asif, Alok Kumar

Boiling Front and Boiling Temperature in Microchannels Under Non-uniform Heat Flux Distribution

Boiling front, onset boiling temperature, and pressure drop for microchannel in non-uniform heat flux condition have been investigated in this paper. Homogeneous flow model has been assumed with constant heat flux boundary condition. Model, results have been shown for water as working fluid. Unlike most of the models from literature, fixed outlet pressure and inlet temperature have been assumed making the model analysis more realistic. The governing equations have been solved to predict the effects of boiling front, onset boiling temperature, and pressure drop on various parameters like outlet pressure, mass flow rate, and inlet temperature.

Radha Kanta Sarangi, Abhilas Swain, Satya Prakash Kar, P. C. Sekhar

Natural Convection Heat Transfer on the Strip Heaters Flushed on the Vertical Flat Plate: A Numerical Study

In the present study, a CFD analysis of a vertical plate with heat generating sources subjected to natural convection phenomenon is performed. The effect of each individual strip heater over the flat plate assembly which mimics the cooling of the electronic systems is studied. The geometry, the grid generation and the simulations with appropriate boundary conditions are carried out using COMSOL Multiphysics. Mesh independence test has been carried out. Prior to the actual simulations, the numerical code is validated. A test case of constant temperature vertical plate is simulated and the obtained results, i.e., the average heat transfer coefficient is compared with the standard empirical correlation results. Influence of the strip heaters on the vertical plate is elucidated in terms of temperature, velocity and heat transfer coefficient variations.

Akurathi Rupendra Siva Prasad, Medisetti Venkata Krishna, Pradeep S. Jakkareddy

Pool Boiling Heat Transfer Using Isopropyl Alcohol and Ammonium Chloride Surfactant

This research article mainly focuses on the enhancement of pool boiling heat transfer using isopropyl alcohol and its solution with the surfactant ammonium chloride on a heating surface, which can be used in heat transfer device. A review on the effect surfactant (ammonium chloride) with different solvent on the heat transfer process also given. The solution is used as the working fluid to measure the heat transfer performance. After conducting the experiment, the result shows that in case of 200 PPM concentration, heat transfer coefficient is more than in case of 400 and 600 PPM, and it is due to the high viscosity and critical micelle concentration (CMC). The experimental data are modeled through the radial basis neural network (RBN) for the prediction of wall superheat, and heat transfer coefficient was given. The RBN model is able to predict the experimental data with a good accuracy level in comparison with the empirical and semiempirical correlations.

Sandeep Swain, Abhilas Swain, Satya Prakash Kar

Numerical Simulation on Impact of a Liquid Droplet on a Deep Liquid Pool for Low Impact Velocities

Droplet impact finds application in paint industries, spray coating, and aeration and hence becomes problem of engineering value. Velocity of impact, geometry, as well as the medium through which the droplet travels before it impacts the liquid surface plays a key role for the occurrence of droplet coalescence and droplet bouncing. In the present work attention has been given to low impact velocities ranging from 0.2 to 0.6 m/s for a droplet of diameter of 3 mm. Transition from coalescence to bouncing is observed at a velocity of 2 m/s. During the bouncing a secondary droplet forms and detaches from the parent droplet before it coalesces. Volume of fluids (VOF) method has been used to carry out the numerical simulation. VOF model is used for two or more immiscible fluids by solving a single set of momentum equation and it tracks the volume fraction of all the phases throughout the flow domain. Interface calculation has been done using Geometric Reconstruction Scheme using a Commercial software package.

Vineet Kumar Tiwari, Tanmoy Mondal, Akshoy Ranjan Paul

Enhancement of Thermal Performance of Parabolic Trough Collector Using Cavity Receiver

In the present work, the use of rectangular perforated fins in a V cavity absorber tube has been studied for the enhancement of the thermal performance of the solar parabolic trough collector system. Four different cases of fin geometries have been considered, and numerical analysis has been done to study the laminar flow and heat transfer characteristics of the absorber tube. The continuity, momentum, and energy equations have been solved by using commercial software package. The fins with the perforation diameter of 4 mm and pitch ratio of 22.1 show the maximum heat transfer. The optimal case shows the maximum value of thermo-hydraulic performance as 1.049, and the increase in Nusselt number is 1.3 times as compared to a smooth absorber tube.

Bilkan John Hemrom, Uttam Rana, Aritra Ganguly

Laminar Mixed Convection Over a Rotating Vertical Hollow Cylinder Exposed in the Air Medium

The present numerical analysis focuses on the thermo-fluid characteristics of laminar mixed convection from a rotating hollow tube placed vertically with a variation of Rayleigh number (104 ≤ Ra ≤ 108), Reynolds number (ReD < 2100) and cylinder aspect ratio (2.5 ≤ L/D ≤ 20). A comprehensive comparative study has been performed to estimate the augmentation in heat loss rate from the pipe wall due to rotational effect. A series of numerical simulations are conducted to understand the detailed flow behavior around the cylinder for various Reynolds numbers. Thermal plumes and velocity vectors are pictorially presented to have clear understanding of physics of problem.

Basanta Kumar Rana, Jnana Ranjan Senapati

Computational Analysis of Static Flow Instabilities in Supercritical Natural Circulation Loop

The present paper is to study and explore the possibility of static instability, Ledinegg flow excursion, in a rectangular supercritical natural circulation loop (RSCNCL). Due to drastic change of thermo-physical properties of fluid near the pseudo-critical point, various static and dynamic instabilities might occur in the loop. The instability may be either Ledinegg excursion or density wave oscillations (DWOs). Many previous researchers have analyzed dynamic instability, DWO, in SCNCL, whereas the Ledinegg excursive instability is not studied in depth. In the present research work, a mathematical model will be implemented to predict the Ledinegg instability in SCNCL. The numerical investigation is successful to find whether there would be any Ledinegg instability in the case of SCNCL or not.

Santosh Kumar Rai, Pardeep Kumar, Vinay Panwar

Effect of Loop Geometry on the Flow Dynamics of a Single-Phase Natural Circulation Loop

In thermal reactors, like PWR and PHWR, single-phase natural circulation loop (NCL) is used to remove heat from the reactors in the absence of forced circulation. Different types of flow patterns (like steady, oscillatory and chaotic flow) are observed in an NCL depending on the geometrical configuration and operating conditions. In the present study, a square geometry is considered as the basic design of the loop. The changes in flow pattern are observed due to a change in the aspect ratio of the loop geometry and the tube diameter of the loop. Numerical simulations are carried out using MATLAB-based Simulink model, and a comparative assessment is made between various loop configurations for different heater powers. The initial transient part of the time-series data is neglected for the proper investigation of the flow dynamics. In this work, the phase change of the working fluid is not considered. This limits the maximum heater power to 800 W. From the results, we found that with the change in the aspect ratio or tube diameter flow behaviour changes. Accordingly, its effect the heat transfer from the source to sink.

Ritabrata Saha, Koushik Ghosh, Achintya Mukhopadhyay, Swarnendu Sen

Refrigeration and Air Conditioning

Frontmatter

A Comparative Analysis Between Indoor and Outdoor Thermal Comfort Parameters of Railway Pantry Car

Indian railway pantry car kitchen plays a vital contribution to the catering system, which provides the meal to every onboard passenger. It is an integral part of every “long and short distance train.” The objective of this study was to compare the indoor and outdoor thermal comfort parameters of the Indian railway pantry car kitchen. Data were collected on 14 railway pantry car coaches for field measurements during summer and winter season. Descriptive analysis and Mann–Whitney test were performed in this study. A descriptive analysis result of this study revealed that the measured indoor thermal comfort parameters found more as compare to outdoor conditions except for air velocity cases. The statistical analysis result shows that there is a significant difference between air temperature (p < 0.05) and globe temperature (p < 0.05) values in indoor and outdoor conditions. There is no significant difference found in the case of relative humidity (p > 0.05) in both conditions. However, in the case of air velocity (p > 0.05), outdoor condition exceeds than indoor condition. Further, the design intervention of workplace would be suggested to improve the thermal comfort of the chef.

Md. Sarfaraz Alam, Arunachalam Muthiah, Urmi Salve

Performance Optimization of an Air Conditioning System at Different Mass Flow Rates and Temperatures

The objective of this paper is to find out the optimum flow rate to achieve optimum COP. In order to achieve the objective, the duct was fabricated, and a blower was attached at inlet of the duct. The vapour compression refrigeration system and duct were combined together. Different flow rate were measured for different ambient temperatures. The flow rates (cfm) were selected as 173.97, 212.45, 260.67, 287.09 and 337.52 for ambient temperatures 30, 32, 34, 36 and 38 °C. The outlet temperature and specific humidity were also monitored. The optimum COP was found to be 2.83 at flow rate (cfm) 287.09 and at 36 °C.

Taliv Hussain, Adnan Hafiz, Sameer Raza, Abdur Rahman, Tabrez Ahmed, Pragati Agarwal

Thermo-physical Investigation of Vegetable Oil-Based Nano-lubricant

This work aims to study thermo-physical properties, including thermal conductivity, viscosity, viscosity index, and rheology of vegetable oil-based nano-lubricant. Synthesis of nano-lubricant was done using vegetable seed oil (castor oil) and copper oxide (CuO) nano-particles using a magnetic stirrer and probe-type sonicator for breaking agglomerate. The thermal conductivity of samples was measured using transient hot-wire liquid thermal conductivity meter, and the effect of nano-particles was analyzed. Viscosity and viscosity index (VI) of the nano-lubricants thus prepared have been analyzed by Stabinger viscometer. The variation of viscosity of nano-lubricant with the shear rate was reported using an advanced air bearing rheometric system. The viscosity variation with respect to shear rate showed a decreasing trend, whereas the viscosity variation with respect to concentration showed an increasing trend. The results show that it is possible to increase the stability of samples in terms of viscosity variation with temperature and shear rate using nano-particles, hence makes it suitable for lubricant applications.

Om Prakash, Ashwani Kumar, Subrata Kumar Ghosh

Numerical Analysis of Laser-Assisted Cryopreservation of Biological Tissues

Cryopreservation of tissue is an important aspect of bioengineering, and it does not involve any ice formation, rather tissue is solidified by intense increase in viscosity. This can only be brought by applying cooling rates in the order of 105 K/min. An external heating source followed by a sudden cooling is suggested here. The heat source in this study is assumed to be a Gaussian laser, and the cryogen used to cool down the tissue would be liquid nitrogen. This numerical study tries to understand the viability and feasibility of laser-assisted cryopreservation technique while accounting for convective–radiative heat loss and following a dual phase lag conduction equation. The algebraic equations obtained after discretization of the governing equations by finite volume method (FVM) are then solved by the tri-diagonal matrix method. Enthalpy-porosity technique is used to capture the frozen tissues. Cooling rates at various locations are calculated, and the feasibility of this approach is tested.

Saurabh Das, Satya Prakash Kar

Combustion Analysis

Frontmatter

Experimental and Numerical Study of Temperature Distribution on Float Glass Along the Wall

Present work represents the experimental and numerical study of temperature distribution over float glass under different fire conditions. A total of 9 experiments have been carried out, on fully exposed float glass of 300 × 300 × 4 mm3 pin supported along the wall with diesel line burner of 1020 × 150 mm2 with continuous fuel supply to investigate the effect of thermal load and temperature distribution on glass. Pins were fully insulated from glass to avoid heat transfer between the two. Four K-type thermocouples were placed on the exposed surface while one was placed at the center of glass rear surface. Another three K-type thermocouples were mounted at 0.5 mm, 1 mm, and 1.5 mm from the wall surface, respectively, to measure the surrounding air temperature between the glass and fire source. Heat flux sensor was mounted at a parallel distance of 25 mm from the glass to register the incident heat per unit area upon the exposed surface. Parameters measured during the experiments were heat flux, temperature distribution over float glass, i.e., exposed surface temperature, rear surface temperature, air temperature between the glass and fire source. Maximum temperature difference between exposed and rear surface is noted at the time of glass breakage.

Raj Kumar Mishra, Ankit Dasgotra, Mahesh Kumar Tiwari, Akhilesh Gupta, Ravi Kumar, Pavan K. Sharma

Numerical Study on Crude Oil Pool Fire Behavior in an Enclosure

This paper analyzes the experimental results on crude oil pool fire obtained in an enclosure fire experiment, by using FDS software. Experiment is conducted in an enclosure of volume 64 m3. A cylinder pan of diameter 0.5 m is used to burn jatropha oil fuel. Fire dynamics simulator (FDS) is used to perform the numerical simulations in which heat release rate of jatropha oil measured using the mass loss method was inputted. Simulation results show that calculated temperatures are in good agreement with the experimental findings. Overall, simulation using FDS provides an effective way to study the burning behavior of crude oil pool fire.

Avinash Chaudhary, Mahesh Kumar Tiwari, Akhilesh Gupta, Surendra Kumar

Thermal and Emissions Characteristics of Pressurized Kerosene Stoves with Selected Commercial Burners

Kerosene is still an alternative for cleaner cooking than other conventional biomass cooking sources mostly used in rural areas of the developing countries. Kerosene stoves are cheap and easily available. The commercial burners for pressurized kerosene cooking stoves that are available in the Indian market have been the main focus in the present article. This paper also highlights the performances of various kerosene cook-stoves. From available kerosene cook-stoves, venus burner assisted cook-stoves has the highest thermal efficiency of ~58%, whereas cook-stoves with roarer and silencer burner results in thermal efficiency of ~55% and ~54%, respectively. For the input power range of 1.5–3 kW, the CO and NOx emission for venus burner was found in the range of 610–915 ppm and 19–35 ppm, respectively.

Gyan Sagar Sinha, Lav K. Kaushik, P. Muthukumar

Experimental Study on Elevated Methanol Pool Fires in a Compartment

The present paper reports an experimental investigation to explore the effect of fuel pan elevation on fire scenario due to methanol pool fires in a fixed ventilated compartment of size 4 m (height) × 4 m (length) × 4 m (width) having a door opening of 2 m (Hd) × 1 m (W). A reasonably large pool size of diameter 0.8 m is used in experiments so that the results are useful for actual plant fire hazard analysis (FHA) in future. The combustion characteristic of methanol is investigated in 1/32 ratio of fuel surface area to compartment floor area. Fuel pan was kept far toward rear wall center with initial fuel depth of 0.045 m and lip height of 0.055 m, respectively, instead of center (conventionally popular). The three fire source heights ‘h’ for a circular pool fire experiments are 0.3, 0.6, and 0.9 m from the floor. Various parameters like heat release rate (HRR), flame centerline temperature, hot gas temperature, and heat flux are measured. It is noted that no one case flame is impinged to hot gas region. The difference between hot gas layer temperature and upper heat flux is found to be higher in Exp. 3 as comparison of other two experiments (Exp. 1 and Exp. 2). The HRR is also found to be higher for Exp. 3 due to availability of less height between hot region and fire source, which resulted in more evaporation of fuel.

Mahesh Kumar Tiwari, Akhilesh Gupta, Ravi Kumar, Raj Kumar Mishra, Avinash Chaudhary, Pavan K. Sharma

Soot Formation Characteristic of Impinging Diesel and Biodiesel Blended Sprays at Diesel Engine-Like Conditions

In the present experimental work, soot formation characteristics of impinging sprays of two fuels are analyzed at diesel engine-like operating conditions in the constant volume combustion chamber. Comparative study is conducted between diesel fuel and biodiesel blend (50% diesel and 50% biodiesel by v/v) under similar operating conditions in terms of soot formation. Hot surface ignition approach is employed for the combustion of sprays. Biodiesel developed through conventional transesterification process from waste vegetable oil is used. Hot surface temperature and cylinder air pressure are varied from 623 to 723 K and 20 bar to 40 bar respectively. Photo transducer is used for indicating and recording the whole combustion process on-screen of four-channel scopemeters. It is found that soot formation during combustion of impinging sprays of both fuels significantly reduced with increase in hot surface temperature and cylinder air pressure. It is also noted that soot formation during combustion of biodiesel blend sprays (BD50) is appreciably lower than soot formation of diesel fuel sprays at all operating conditions in present study. Biodiesel blend appears to be a better choice with respect to soot formation emissions in high-speed, high-injection pressure, small size, direct injection diesel engines having significant fuel impingement.

Sanaur Rehman, Shah Shahood Alam

Effect of Inlet Swirl and Turbulence Levels on Combustion Performance in a Model Kerosene Spray Gas Turbine Combustor

A computational simulation has been performed for Kerosene (C12H23) fuel through a 3D gas turbine combustor model. This numerical work is conducted to study the effect of temperature distribution pattern with different swirl and initial turbulent quantities. The turbulence effect is solved by the realizable two-equation model, discrete phase model (DPM). Eulerian–Lagrangian approach is used to simulate the interaction between continuous and discrete phase. The pressure-swirl atomizer model is also used here and the reaction was performed by constrained equilibrium chemical reaction model. Turbulent-chemistry interaction has been incorporated with the help of presumed beta probability density function (PDF). The effect of radiation on the temperature field is also incorporated by using discrete ordinate (DO) radiation model. A noticeable change in temperature pattern due to swirl can be proven by this simulation. Results also hint that the inlet turbulent intensity and length scale variation might not affect temperature.

Prakash Ghose, A. Datta

Performance and Emission Analysis of CI Engine Fueled with Waste Cooking Biodiesel Blends at Different Compression Ratios

Biofuels can be considered as one of the alternative to replace the conventional liquid fuels partially as they can be used as blends in IC engines. Due to continuous use of petroleum sources in automobiles, it causes the depletion of world petroleum reserves, and it is expected to last for few years. Many active researches are in progress in finding the alternative for this conventional fuel. One of the alternative fuels whose use is rapidly growing is biodiesel. In the present work, biodiesel is produced from waste cooking oil which is obtained from local hotels and restaurants by using transesterification process. Various properties of diesel, biodiesel, and its blends are found. Experiments are carried out at various loads to study the performance of a single-cylinder, multi-fuel engine at two different compression ratios. The compression ratios used are 17.5 and 19.0. Different performance and emission parameters are evaluated for different blends and are compared with each other. Among all the results, B20 biodiesel blends show the best performance as compared to other biodiesel blends. And with 30% waste cooking oil biodiesel blend, lowest emissions of oxides of nitrogen (NOx) were observed. For B20 blend, CO was reduced by 35%, CO2 by 29.5%, and fuel consumption was reduced by 10%. Same time, 8.5% more in efficiency was observed. When B30 was used increased by 15.1%, fuel consumption reduced by 10%, and HC reduced by 20% and CO2 was reduced by 16%.

Rahul Mohanty, Vinod Kotebavi

Effect of Compression Ratio on Thermal Efficiency and Cycle-by-Cycle Variation of a Biogas-Fueled SI Engine

In this study, a gasoline-fueled, single-cylinder, variable compression ratio (VCR), spark ignition (SI) engine of rated indicated power 4.5 kW was successfully retrofitted and tested with raw biogas. Further, this study also examine the consequence of operating compression ratio (CR) on the brake thermal efficiency (BTE) and cycle-by-cycle variations of the raw biogas-operated SI engine working in between CR 10 and CR 14. As observed, the developed cylinder pressure profiles are different and unique for each cycle, even though the operating conditions of the engine remain unaltered. The COV of IMEP increases with increasing CR, and the the maximum COVIMEP was found to be 6.51% at CR 14 and is within the acceptable limit. However, the COV of peak cylinder pressure behaves very differently and reduces with rise in CR of the engine. The maximum BTE of the engine was found 30.3% at CR 12 and 1400 rpm.

Santosh Kumar Hotta, Anil Kumar Rout, Niranjan Sahoo

CFD Simulation of Gasoline and Methanol Combustion in a Twin Spark IC Engine

In this current work, the outcome of four sets of spark timings on engine performance parameters is studied. CFD simulations are carried out on a variable compression ratio twin spark SI engine for both methanol and gasoline. Simulations were able to predict performance parameters with high accuracy. To simulate flow physics, combustion in the engine, ANSYS Fluent is employed. A parametric study of the effect of spark timing and compression ratio under methanol operation at 1600 RPM is performed. The results yield a promising strategy in deciding spark advance angle. Both methanol and gasoline show increased mean effective pressure at twin spark of 26°–28° BTDC.

Praveen Alok, Debjyoti Sahu

Thermofluids in Energy Applications

Frontmatter

Performance Study on Flat Plate Solar Water Heater with Copper Nanoparticles

Evaluating the improvement in efficiency and heat transfer rate in heat exchangers using additives has been the centre of attraction for many researchers. In this study, a solar flat plate water heater is modelled using ANSYS Fluent, and the simulated results are compared with experimental data. For the simulation, a single-phase model is used with equivalent correlations for the thermo-physical properties of the nanofluid. Using water as the working fluid, the performance was evaluated for a set flow rate and solar insolation. The study is extended by modelling the same in ANSYS Fluent and using water and CuNP mixture as working fluid to analyse the enhancement of heat transfer in thermal absorbers. The pressure drop in the system is analysed and the data is used to justify the usage of nanoparticles in solar thermal absorbers. The efficiency of the system for various volume fractions of nanoparticles is optimized by introducing an efficiency index.

R. Praveen Bharathwaj, M. B. Varun Pradeep, Joe Jones Raju, A. Satheesh, P. Padmanathan

Experimentation with a Solar Air Heater Coupled with Evacuated Tubes and Heat Pipes

The demand for energy is increasing worldwide and the best way to meet this demand is a clean renewable energy source. Among the various options available, solar energy can be considered as the best renewable energy source. This paper deals with design, fabrication, and performance study of a solar air heater coupled with evacuated tubes and heat pipes. Heat pipes are used to absorb the solar energy and evacuated tubes are used to prevent the convective losses. A selective absorber coating is used to coat the inner side of the evacuated tube. Air is forced in to the duct of size 10 cm × 10 cm by a fan, which is driven by a photovoltaic panel. Six heat pipes and six evacuated tubes are used to absorb the solar radiation. A solar flux meter is used in to measure incoming solar radiation. Experiments are conducted with and without evacuated tubes. For both the configurations, the variations of thermal efficiency with respect to time have been reported. The maximum thermal efficiency obtained is 35% for evacuated tube with heat pipe. The average efficiency of evacuated tube with heat pipe is 1.5 times that of heat pipe alone.

P. Devasena, D. Dimple, A. Varshith, K. Anvesh Reddy, Vinod Kotebavi

Design of Low-Cost Solar Powered E-Rickshaw: A Case Study

Concern has increased over the use of fossil fuels in passenger transport vehicle. In Indian cities, autorickshaws are making a huge quantity of air effluence. There are two types of rickshaw are seen running on the road, first one manual type which is pulled by human being and another one is motorized which is using electricity. Here, the proposed e-Rickshaw is designed with respect to a stable design at optimum ground clearance and its aerodynamics. The functionality, construction and mechanisms of solar power-driven rickshaw are briefly discussed in this paper. This paper shows how this conceptual autorickshaw provides passenger comfortable and safe ride upto a speed of 25–30 km/h.

Daya Shankar, Manisha Biswas, Rupa Datta

Integrated MSW to Energy and Hot Water Generation Plant for Indian Cities: Thermal Performance Prediction

The present study reports the model development and thermodynamic analyses of an integrated municipal solid waste (MSW) fuelled externally fired air turbine (AT) plant and hot water generation plant for Indian cities. Waste generated from a typical Indian municipal town (Kandi) is considered to be the fuel input to the plant. Dry and segregated MSW is burnt in the combustion chamber of dual combustor-air heating (DCAH) unit which then heat-up the working fluid (air) of the topping AT cycle. Exhaust heat from the DCAH unit is utilized to produce hot water to meet the demand of town. Effect of topping compressor’s pressure ratio (rp = 4–16), air turbine inlet temperature (ATIT = 900, 1000 and 1100 °C) and hot end temperature difference (HETD = 70–150 °C) on the energetic, exergetic and environmental (3-E) performance of the plant is analyzed and reported here. It is observed that the plant can deliver 1100 kWe of electricity and about 2450 L of hot water (hourly basis) at the base case scenario. Maximum exergy is destroyed at the DCAH unit and at the WHU, respectively. Sustainability index (environmental parameter) value is found to be 1.56 at the base case. Furthermore, it is observed that these plant operational parameters can be influential for evaluation of 3-E performance of the plant.

Pradip Mondal, Shambhunath Barman, Samiran Samanta

Thermal Performance Evaluation of an Improved Biomass Cookstove for Domestic Applications

Biomass fuels are normally burnt inefficiently using the traditional cookstoves in rural areas. The uncontrolled harmful emissions released due to the combustion of biomass cause various respiratory problems to the users. Thus in order to overcome such problems related to the traditional cookstove, an improved biomass cookstove is proposed in the present study. An effort is made to design and fabricate an improved biomass cookstove to study various heat losses from it and performance parameters. Water boiling test (WBT) was conducted for understanding the overall performance of the improved stove. Results of WBT were compared with a commercially available biomass cookstove. The average thermal efficiency while boiling 7.5 L water was ~33%, whereas the average thermal efficiency in case of the commercial stove was ~23%. While boiling 7.5 L water in this improved stove, the performance was better than the commercial stove with respect to specific fuel consumption. The maximum level of CO was detected around 20 ppm during the start and it reduced to 5 ppm as combustion progressed. Both the values for CO2/CO and indoor air quality were within acceptable limit.

Raktimjyoti Barpatragohain, Niyarjyoti Bharali, Partha Pratim Dutta

Experimental Investigation of Paddy Drying in Rotating Fluidized Bed in Static Geometry

The concept of rotating fluidized bed with static geometry (RFB-SG) is highly beneficial in drying operations. The present work is focused on the drying of granular particles (paddy) in the developed RFB-SG dryer. In this RFB-SG, the tangential injection of fluidizing gas via several inlets induces rotary motion to the solid particles and forms a solid-bed. In the entire process of fluidization, the solid particles experience a radially outward centrifugal force, whereas the gas is forced to move inward towards the chimney. The RFB-SG is expected to operate more efficiently at higher gas flow rates as compared to the conventional fluidized bed reactor. Experiments were carried to dry paddy of initial moisture ranging 23–37% (wb) to 14% (wb) with drying air inlet temperature of 55 and 60 °C and mass flow 250 m3/h. A better air utilization decreased the drying time by 20% on increasing the air inlet temperature by 9%. Air inlet temperature of 60°C is better for drying paddy as compared to 55°C.

Rishiraj Purkayastha, Pavitra Singh, Abinash Mahapatro, Alok Kumar, Pinakeswar Mahanta

Conjugate Heat Transfer Analysis of Solar Cooker Cavity Using CFD Approach

Conjugate mode of heat transfer experienced in solar cooker cavity is presented in this paper using computational fluid dynamics (CFD) approach. Trapezoidal-shaped box-type cooker has been used to investigate the heat loss from cooker cavity. Steady laminar natural convection and radiation inside the trapezoidal cavity having hot bottom, cold top isothermal wall and adiabatic sidewalls are considered. Forced convection due to wind flow on the top of the glass top cover and radiation is considered as well. The losses due to convection and radiation are considered from the top glass cover as well. Parameters like bottom plate temperature, emissivity of the plate and wind flow over the top cover are found to be more influencing on the heat losses from the cavity. Based on the results using CFD approach, the suitable parameters may be chosen for design of solar cooker cavity better and optimised performance.

Sudhansu Sekhar Sahoo, Prasanta Kumar Satapathy, Pravat Kumar Parhi, Auroshis Rout, Sanju Thomas

Thermofluids in Materials and Manufacturing

Frontmatter

Experimentation with Thermally Stable Mesoporous Silica Powder and Its CO2 Adsorption

The CO2 coming out of the power plants at higher temperature. Adsorption is considered as a promising technology for the removal of CO2 from flue gas. So, the adsorbent material should have the properties which are applicable in high temperature condition. Silica-based materials are available, and they withstand high temperature. This paper describes the experimentation with the ordered mesoporous silica materials obtained by the acidic route as well as the basic route and compares the thermal stability and the CO2 adsorption capacity. The porosity of OMS materials is characterized by using N2 adsorption–desorption. The CO2 isotherms at 30 °C are measured up to 8 bars for OMS samples to find out CO2 adsorption capacity. CO2 adsorption studies show promising results for OMS materials obtained by the acidic route. TGA analysis confirms the stability of material upto >200 °C.

Sanjib Barma, Bishnupada Mandal

Experimentation with Thermo-mechanically Stable Epoxy Composite Reinforced with Palm Fiber

The aim of this current investigation is to evaluate the influence of bio-filler on developing thermo-mechanically stable composites. A new class of low-cost palm fiber-reinforced epoxy composite was fabricated using 0, 5, 10, and 15 wt% rice husk (RH) powder as bio-filler. The influence of filler addition on thermal, dynamic mechanical is investigated. By using thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA) technique for analysing the thermal stability of the untreated and chemically treated composite materials and find out more stable material. The thermal degradation of palm fiber occurred in the following temperature ranges: hemicelluloses (150–350 °C), cellulose (275–500 °C), and lignin (250–500 °C). Moreover, no significant difference is observed in the thermal degradation of RH filled and unfilled samples beyond 550 °C. However, the storage modulus and loss modulus of the composite are increased with filler addition. A low tan δ value is observed for the unfilled samples. The corrosion property of the composite increased with filler addition.

Jnanaranjan Kar, Arun Kumar Rout, Priyadarshi Tapas Ranjan Swain, Alekha Kumar Sutar

A Review on Materials Used for Combustion in Porous Radiant Burners

This paper reviews different materials that are used in porous media combustion. Porous medium combustion is a novel concept which not only increases the thermal efficiency while it also reduces the pollutant emissions. Different thermal and physical properties of porous materials have been discussed in this paper. Different types of ceramic that dominate porous media combustion have been highlighted, which can guide researchers during material selection.

Gyan Sagar Sinha, Lav K. Kaushik, P. Muthukumar

Thermal Analysis of Al 7075-T651 During High-Speed Machining

In the present study, finite element analysis during machining of Al7075-T651 was conducted and chip–tool interface temperature has been evaluated and validated with the available literature. The design of experiment model based on Taguchi’s orthogonal array (L16) was used to simulate the cutting experiments considering three factors: cutting speed, feed, and depth of cut with 4 levels. %. For optimizing the process and controlling the chip–tool interface temperature, cutting speed and feed need to be optimized appropriately. ANOVA test identified cutting speed and feed were the significant process parameters for the chip–tool interface temperature for which cutting speed contributes 19.44% and feed contributes 65%.

P. Chandrasekhar, Sudipta Chand, Radha Kanta Sarangi, Satya Praksah Kar, Abhilas Swain

Analysis of Heat Transfer Coefficient in Turning Process

Heat development during the metal machining process is a major challenging issue for the machinist. In the turning process, heat is distributed among chip, tool, workpiece, and cutting surrounding. This heat dissemination significantly influenced the complete cutting action. Further, heat transfer directly influenced the cutting attributes like wear growth rate, cutting life of the tool, surface finish, and workpiece dimensional precision achieved. In the current work, the stepwise procedure is deliberated to estimate the convection heat transfer coefficient for the workpiece into the surrounding and tool–workpiece interface into the surrounding. Further, the influence of input cutting terms (axial feed and cutting speed) onto the convection heat transfer coefficient is studied with the help of the main effect plot and surface plot. Highest heat transfer coefficient (hc = 32.2 W/m2 K) value (from workpiece into surrounding) is obtained at highest cutting speed (75 m/min) with the lowest feed (0.25 mm/rev) cutting conditions, while greatest heat transfer coefficient (hin = 3.1 W/m2 K) value (from the interface of tool–workpiece into surrounding) is noticed at a moderate speed (60 m/min) with axial feed (0.30 mm/rev) cutting conditions. Heat transfer coefficient (hc) for workpiece into surrounding is improving with accelerating cutting speed, while it reduces sharply till 0.30 mm/rev of axial feed but further slowly increases. Heat transfer coefficient (hin) for the interface of tool–workpiece into surrounding is retarding with axial feed, whereas it is sharply increasing up to 60 m/min of machining speed beyond this it is almost constant.

Ramanuj Kumar, Amlana Panda, Ashok Kumar Sahoo, Deepak Singhal

Embedded Heat Pipe-Assisted Cooling in Machining Process: A Comprehensive Review

During the machining process, the utilization of minimal cooling application generates difficulties with the cutting fluid. Very minimum quantity of cutting fluid is applied to the machining zone during the process. Considering the correlation amid tool-chip contact and the sources of heat from tool taken into account, the influences of the embedded heat pipe are of prime limelight in the technologically advanced machining sector. Since the quantity of fluid is considered to be low, therefore, some extra supporting internal cooling systems in terms of the heat pipe is the topic of research interest. Notably, this is innovative solution against dry and cooling machining to improve heat dissipation, and thus improving the cutting performance in advanced machining technology. Keeping this in view this innovative procedure with the backdrop of heat generation sources has been focused for the betterment of heat pipe embedded technology. This review study articulates various types of cutting tool and heat pipe materials and explores the relevance of the cutting performance. Considering the future outlook, this review will converge internal cooling strategies particularly embedded heat pipe using industry implemented factors for machining sector to bring the technological changes.

Shailesh Kumar Sharma, Amlana Panda, Ramanuj Kumar, Ashok Kumar Sahoo, Bharat Chandra Routara
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