Advances in Fluid and Thermal Engineering

Inhaltsverzeichnis

1. Frontmatter

2. Plasma Functionalized Wettability Gradient Surfaces for Electronic Cooling

   Vishakha Baghel, Vivek Pachchigar, Mukesh Ranjan, Basant Singh Sikarwar

   Abstract

   In recent era, the growing requirements of miniaturization and weight reduction leads to remarkable thermal loads on small and sensitive electronic devices. This in turn inevitably necessitates the thermal management of electronic devices to enhance the energy efficiency and reliability of the complete systems. Several techniques are implemented for cooling of electronic devices; however, these methods have the drawback of lower heat transfer rates. In contrast, thermal management via spontaneous drop motion is an efficient passive cooling method. Recent progresses in surface technologies and material science facilitates fabricating wettability gradient on the surfaces. These surfaces enable self-propelled motion of liquid droplets at surprisingly high velocities, which also enhances the self-cleaning properties. However, drop dynamics on wettability gradient surface is yet not well understood and is of substantial scientific interest worldwide. Drop motion on wettability gradient surface is a complex phenomenon which involves asymmetric spreading on surface, directional retraction followed by detachment from a less wettable region and migration towards a more wettable region. In this background, the present work aims in the fabrication of wettability gradient surface for drop-based thermal management of electronic device using plasma-based coating method. In addition, experiments are performed on the graded surfaces to investigate the drop velocity on the wettability-graded surfaces.

3. Effect of Porous Plug Shape and Permeability on Convective Heat Transfer Characteristics of Flow Through a Mini Channel

   Surendra Singh Rathore, Balkrishna Mehta, Pradeep Kumar, Mohammad Asfer

   Abstract

   When a porous media is introduced into a flow path, it significantly alters the flow path's hydrodynamic and thermal characteristics. Due to the complex structure of the solid matrix in the flow route, the fluid particles encounter a significant amount of resistance in the form of viscous and inertial momentum loss, resulting in a proportionally considerable pressure drop along the channel. This results in a higher input power required to pump the fluid through the channel, although flow through porous media has been demonstrated to improve heat transfer performance. In electronic cooling applications, the lack of available space lowers the size of channels, making pumping more difficult. While partially porous channels have been found to meet this requirement, their pressure drop is many orders of magnitude more than that of non-porous channels under similar conditions (Hadim in Forced convection in a porous channel with localized heat sources, 1994; Hadim and Bethancourt in Numerical study of forced convection in a partially porous channel with discrete heat sources, 1995; Ahmed et al. in Int Commun Heat Mass Transf 108:104336, 2019; Perng et al. in Int J Therm Sci 50(10):2006–2015, 2011; Zimbeck et al., Loop heat pipe technology for cooling computer servers, pp 19–25, 2008). As a result, it is critical to seek out strategies for optimizing the pressure drop in these channels while maintaining their thermal performance. This parametric analysis considers a partially porous channel with alternate combinations of porous and non-porous zones separated uniformly along the flow direction. The 2D planer and 3D channel are investigated numerically for laminar, steady, incompressible, forced flow subjected to asymmetrical bottom wall heating utilizing discrete heat sources. Additionally, these heat sources are positioned beneath the porous zones. Forchheimer-tenure Brinkman's was extended The Darcy equations are solved for momentum conservation, taking into consideration viscous and inertial losses, as well as the boundary impact. Due to the assumption of local thermal equilibrium between the solid matrix and saturated fluid, an energy conservation single equation model is solved (Carbonell and Whitaker in Fundamentals of transport phenomena in porous media. Springer, pp 121–198, 1984; Straughan in Convection in porous media 165, 2008). The overall pressure drop and heat transfer coefficient are investigated parametrically in two distinctive conditions in a mini-scale channel. In the first scenario, a two-dimensional numerical analysis was conducted to investigate the effect of substituting oblique porous plugs for normal porous plugs with the intent of enhancing the thermomechanical performance of the plug. The obliqueness of the porous plug was changed in both forward and reverse directions for this study. It was observed that forward oblique porous plugs degraded overall performance by reducing heat transfer and increasing the pressure drop in the channel, whereas backward oblique porous plugs augmented the overall performance of the channel by significantly reducing the pressure drop at higher angles of obliquity without impacting the heat transfer coefficient. In the second scenario, a three-dimensional analysis was conducted to determine the effect of introducing solid and porous ribs on the pressure distribution and heat transfer coefficient of flow through a mini-channel subjected to a constant heat flux boundary condition at the bottom wall. The solid block and porous blocks with varying permeabilities were compared to the channel without any blocks under identical flow and heating conditions. It was discovered that solid and porous blocks functioned almost identically at lower permeability values, with the overall effect of increasing the pressure drop in the channel while maintaining the heat transfer coefficient. However, using porous blocks with a higher permeability resulted in a massive improvement in heat transfer performance without affecting the pressure drop.

4. Condition Monitoring of Reciprocating Compressor Using ANN

   Suvandan Saraswat, Kuldeep Ojha, Ruchi Saraswat

   Abstract

   The reciprocating compressor plays a significant role in industries like chemical industries, fertilizer plants, oil and gas refineries etc. where the availability of this machine is very much required to ensure the working of the plant without any failure and safety operation. The timely prediction of failure of the compressor or detection of performance degradation can avoid many failure consequences like reduction in down time, improved safety, reduction in maintenance cost and improved efficiency of plant. Thus to have a safe operation and effective control on maintenance activities the condition monitoring is better tool to diagnose the health of machine. In the present work these faults are investigated at different levels of safety, cost and effectiveness of the compressor.

5. Novel Supercritical Carbon Dioxide Cycle for a Waste Recovery Application

   Syed J. Hoque, Pramod Kumar

   Abstract

   Superior performance, quick response to variable load, and compactness make supercritical CO₂ (sCO₂) power cycles suitable for waste heat recovery (WHR) applications. This paper proposes a novel sCO₂ WHR cycle for high-temperature (>300 °C) applications. The proposed cycle incorporates two recovery heat exchangers, two recuperators, two turbines, and a single compressor. A comprehensive thermodynamic analysis of the novel sCO₂ WHR cycle is presented for utilizing the waste heat of gas turbine exhaust. The influence of cycle parameters on cycle performance in the context of a WHR cycle is discussed. The low side, high side pressures, and the mass flow split ratio between the high-temperature and low-temperature turbines are optimized for maximum power rather than thermodynamic cycle efficiency. The performance of the proposed cycle is compared with other sCO₂ cycles operating under similar conditions. The analysis shows that the proposed cycle produces high performance while significantly reducing heat exchanger sizes. Additionally, the cycle exhibits significantly stable performance under off-design conditions and offers a more comprehensive operating range than the standard sCO₂ WHR cycles cited in the literature.

6. Cross-Recurrence Analysis of Pressure Signals in Air-Water Two-Phase Flow

   K. Sowndarya, Sunny Saini, Jyotirmay Banerjee

   Abstract

   The present research is focused on analyzing the pressure fluctuations associated with two-phase flow. Different flow structures in the pipe are generated by varying the flow rates of air and water phases. For different regimes of two-phase flow, pressure signals are measured with pressure transmitter. A methodology based on cross-recurrence analysis of pressure signals recorded from two different locations in the pipe is proposed in this study to identify the stability of the two-phase flow pattern. Distribution of recurrent points in the cross-recurrence plot reveals identical characteristics of two dynamic signals. Similitude between the signals obtained from two pressure transmitters is observed to be low when two-phase flow passes through the transmitter. Such low similitude implies the instability of two-phase flow patterns. Cross-Recurrence plot of stratified flow, wavy stratified flow and intermittent flow regimes are analyzed. Presence of slug is indicated by a rectangular black patch in cross-recurrence plot. Less attunement between stratified and slug flow is revealed by white spaces without a single black dot in the cross-recurrence plot. Such unadulterated white band implies the existence of dissimilar characteristics between two signals.

7. Effect of Linearly Varying Diameter on Thermo-Hydrodynamics of Two-Phase Closed Thermosyphon

   Shubham Jain, Rahul Joshi, Basant Singh Sikarwar

   Abstract

   A two-phase closed thermosyphon is a passive two-phase heat transfer device. Its thermo-hydrodynamic performance depends on the operating conditions, working fluid, filling ratio, inclination angle, and geometry. This work focuses on geometry and analyzes the effect of diameter variation of a thermosyphon with filling ratio unity, the average pipe diameter of 22 mm, pipe length of 500 mm, and water as the working fluid. Thermo-hydrodynamic simulations are carried out for an equivalent constant diameter thermosyphon, and linearly varying diameter thermosyphon whose average diameter is equal to the equivalent constant diameter thermosyphon. It is found that the linearly varying diameter thermosyphon is more effective than the equivalent constant diameter thermosyphon because the linearly varying diameter adds a favorable pressure difference along with buoyance force. Hence, the thermal and hydrodynamic resistance of the linearly varying diameter thermosyphon is lower as compared to the equivalent constant diameter thermosyphon.

8. Investigation of Performance and Smoke Characteristics of Diesel Engine Powered by Various Blends of Biodiesels Extracted from Disposed Edible Oil

   Mayank Chhabra, Anoop Kumar Shukla, Sachin Singh Parihar, Gaurav Dwivedi

   Abstract

   The worldwide utilization of fuels is evidently unsteady, causing a worldwide financial instability; consequently, all countries, have been encouraged to track down different choices to supplant the utilization of oil. Hence, the issue could be tended to by utilizing biodiesel as another option; consequently, an experimental examination was directed on an automotive compression ignition engine broadly utilized in India's transportation area, fuelled with different mixes of bio-diesel synthesized from discarded edible oil (Soybean). Engine execution is likewise assessed utilizing the diesel fuel in a current automotive compression ignition engine without any hardware changes in the engine. A single stage process of biodiesel synthesis known as transesterification was performed for the synthesis of the biodiesel from disposed edible oil. The methanol to oil proportion was kept steady all through the experimentation (6:1). The basic properties of the disposed edible oil biodiesel were also examined in accordance with protocols associated with biodiesel. Engine tests were performed utilizing different biodiesel and diesel mixes like B₁₅, B₂₅, B₃₅ and B₄₅ in order to investigate the engine execution and exhaust characteristics such as fuel utilization, specific fuel utilization (SFC), break thermal efficiency, and smoke density etc. The performance and exhaust characteristics of the engine on B₁₅ blend was found comparable to the conventional diesel fuel.

9. Effect of Inverting Heat Source Direction on the Melting of Phase Change Material Under the Influence of Microgravity Environment

   Keyur Kansara, Shobhana Singh

   Abstract

   The electronic components, instruments, sensors, and other satellite payload subsystems generate a significant amount of heat during repeated transient duty cycles. The thermal management of such subsystems of the satellite payload becomes more challenging under the influence of the microgravity environment. The rapid temperature fluctuations caused due to stringent space environment may lead to the overheating/failure of the electronic devices. The phase change materials (PCM) are the natural fit for the thermal control of such satellite subsystems where the heat dissipation is non-continuous. A three-dimensional PCM-based thermal control unit (TCU) having extended fins as heat transfer enhancers is designed to control the undesirable temperature fluctuations and maintain the temperature of the satellite subsystems in the operating range. However, the absence of convection and characteristics of the microgravity environment may adversely affect the melting of PCM in the TCU. Additionally, the rigorous structural requirements and spatial demand of the satellite subsystems offer additional challenges to spacecraft thermal control management. The present work investigates the effect of inverting the heat source direction on the melting process of PCM under the influence of a microgravity environment. The energy storage process of the selected PCM is numerically examined at different gravitational acceleration values, changing the heat source's direction. A three-dimensional CFD model is developed using the enthalpy porosity technique to simulate the heat transfer and flow characteristics of PCM-based TCU. The governing equations are non-dimensionalized, and the results are presented in terms of dimensionless numbers.

10. Study of Operating Parameters for a Controllable Water Flash Evaporation

    Sarvjeet Singh, Prodyut Chakraborty, Hardik Kothadia

    Abstract

    Rapid cooling can be obtained by a very innovative technique of depressurizing liquid in a controlled volume. This feature of attaining the possible minimum temperature within a few minutes led this technology to be used for several essential applications such as waste-heat recovery, desalination, drying of nuclear waste, and thermal management of aerospace equipment. The present study intends to develop a flashing experimental system to obtain insights into the mechanisms and the influential parameters to establish a controllable flash technology. The operating parameters such as the initial temperature of water present in a flash chamber and depressurized liquid through a connected vacuum tank are shown to play a vital role in controlling the flashing conditions. A rigorous number of experiments were performed ranging from 45° C to 85° C with varying pressurizing effects to obtain the optimum flashing conditions as per the applications. The drop in the water temperature due to the sudden pressure drop created inside the flash chamber connected with a large vacuum tank is measured by connected K-type thermocouples. A comparison of flash evaporation with normal evaporation/cooling is also presented, which confirmed the high efficiency of 90% of cooling obtained through flash evaporation.

11. Numerical Study of Heat Transfer Fluid Position on Solidification of PCM in Fin Assisted Thermal Energy Storage System

    S Abhinand, Amrita Sharma, Hardik Kothadia

    Abstract

    The study intends to provide the optimal configuration for the position of Heat Transfer Fluid (HTF) tube under fin assisted thermal energy storage system for the applications of cooling. The aim of the numerical study is to find the effect of different positions for HTF flow on enhancing the phase change process. The HTF can either be passed through the inside of the Phase Change Material (PCM) which is an interior process or through outside of it that is the exterior process. The change has been done such that HTF volume is kept constant. A most economical fluid i.e., water is used as PCM while the refrigeration system is used to convert water into ice. The used PCM for the cooling applications is water as it is having a high latent heat of fusion and the solidification point of water lies in a lower temperature range. A V-shaped fin is incorporated with the respective direction of cooling like external V shaped fins that are employed for exterior cooling and similarly internal fins for interior cooling. The variations in heat transfer parameters such as heat transfer rate and heat transfer coefficient are studied at these different positions of HTF. Due to the increment in the area of contact of PCM with HTF that takes place in the case of exterior cooling, the heat transfer properties are enhanced compared to the interior cooling. Also adding fins provides a larger surface area for the heat transfer to take place and improves the solidification.

12. Linseed Biodiesel—A Review

    Sanjay Mohite, Chandrashekhar K. Patil

    Abstract

    Linseed crop may be produced conveniently in India due to weather and conditions of soils in the country. In this paper, linseed plant and its oil, production of linseed biodiesel, its physiochemical properties, comparative analysis of biodiesel properties, its benefits and limiting factors, comparative study of diesel with biodiesel, energy audit and biofuel certification and findings and its results of authors, relating to this topic have been discussed. Standard energy audit and biofuel performance certification are found as challenges in future. After the transesterification procedure, the viscosity of Linseed oil biodiesel decreased to a large extent. Free fatty acid reduced from 3.5 to 0.75 and the viscosity reduced from 2169 to 362 mm²/s after esterification. There is a reduction in the emission of carbon monoxide, unburned hydrocarbon and smoke emissions as compared to diesel. Metal based, oxygenated, cetane number increasing additives and antioxidant additives are used to mix with the biodiesel to improve fuel quality. The objective of this paper is that linseed biodiesel could be produced and used conveniently in India.

13. Static and Fatigue Analysis of Boiler Shell with Circumferential Riveted Joint

    Sudhir Kumar Singh, Tafhim Eqbal, Vaibhav Gupta

    Abstract

    Boilers and pressure vessels with riveted joints are used to contain pressurized fluids and are subjected to complex loads under static and dynamic situations. Pressure vessel failure happens both circumferentially and longitudinally. Circumferential riveted joints are critical to the design of pressure vessels because the circumferential stress is double the longitudinal stress. Boiler shell with circumferential riveted joints is studied at pressures between 2.5 and 5 MPa for structural analysis. The riveted joint was created using SolidWorks software and analysis performed on Ansys software. The proposed joint is investigated to examine how structural steel, titanium alloy, and nickel-cobalt-chromium alloy affect the vessel's performance. The results are presented, and a comparison is made to determine which material is more suitable. Static results demonstrate that Boiler shell joints of nickel-cobalt-chromium alloy have a smaller total deformation (0.067 mm) and lower Von-misses stress (63.37 MPa) than structural steel and titanium alloy at an internal pressure (2.5 MPa). The Maximum shear stress of titanium alloy (30.63 MPa) shows better result as compared to Structural steel (33.52 MPa) and Nickel-cobalt-Chromium alloy (34.11 MPa). Data for fatigue life, damage, safety factor and sensitivity for candidate materials are taken from Ansys software. The findings demonstrate that the boiler shell with circumferential riveted joint of Titanium alloy has a good fatigue life, low fatigue damage, and a high safety factor at high internal pressure when compared to the circumferential riveted joint of structural steel, Nickel-cobalt-chromium alloy. The final result shows that the selected materials will survive and function well, while titanium alloy and nickel-cobalt-chromium alloy surpass structural steel.

14. Quantifying the Dynamics of Fluid Flow in a Hydraulic Jump Using Imaging Techniques

    Abdul Rahim Farhatnuha, Kizhakkelan Sudhakaran Siddharth

    Abstract

    Imaging techniques have gathered attention in the recent past owing to it non-intrusive nature and superior results in quantifying the dynamics of fluid flows. The current study is an attempt to use imaging techniques in determining the velocity values across different regimes of a hydraulic jump. Two techniques, Feature Correlation Velocimetry (FCV, which depends on the advection on naturally formed corrugations on liquid surfaces) and Particle Tracking Velocimetry (PTV, which depends the on tracking of externally seeded tracer particles across successive images), have been employed in this study to quantify the dynamics of fluid flow over a hydraulic jump across its different spatial regions. Results show that both FCV and PTV are successful in quantifying the flow nature in all regimes (involving both laminar and turbulent nature of flow) of a hydraulic jump. In addition, FCV proves to me more efficient in providing the temporal fluctuations of a flow compared to PTV owing to the use of cross correlation algorithms used for the same.

15. Failure Modes and Effect Analysis of a Gas Compressor in a Gas Processing Complex: A Case Study Based Approach

    Kumar Ratendra, Narula Virender

    Abstract

    Gas compressors are used to compress gas from an initial intake to higher exhaust pressure through a reduction in volume. Higher-pressure reciprocating compressors are used to dispatch the gas for long distance. Reciprocating gas compressors are important to oil and gas industry. Major objective of this study is to explore about failure analysis of reciprocating gas compressors so that failures can be reduced and performance can be improved. Here changes in maintenance practices are followed to run the compressors smoothly. Despite of best practices failures are observed due to different reasons. The early detection of defects is necessary so Failure mode and effect analysis (FMEA) method is adapted to analysis failures. Data is collected from the Oil and Natural Gas Industry and suggestions/experience of experts is also considered. Risk priority number (RPN) is calculated. Several steps are applied to reduce risk priority number (RPN). After that it is observed that failures are reduced and performance is improved. Major findings are that valves are the weakest part of compressor, being the most frequent failure and consume big share of maintenance cost. The highest RPN score is 135 for valves and after implementation of recommendations revised RPN score comes to 30 that is approximately 78% less. To reduce RPN for valves, several steps are recommended i.e. use poppet type valves to handle liquid better in place of plate type valves, use of non-metallic valves, predictive periodic maintenance to be followed. This will increase the availability of compressor and reduce maintenance cost.

16. Heat Transmission and Friction Flow in a Round Tube with Equally Gapped Perverted Tape Element, an Investigation

    Dharmendra Kumar Tiwari, Mohan Gupta, Rajendra Prasad Verma, Abhishek Singh

    Abstract

    “Heat transfer and friction factor” properties of a double pipe heat exchanger furnished with equally gap perverted tape component was investigated tentatively. The diameters of outside and inside tube are 25.8 and 50.6 mm, sequentially, hot and cold water was employed as operating fluids on the tube and shell sides, sequentially. For the construction of perverted tape we are using the stainless steel of length 1500 mm and thickness 1 mm. These perverted tapes were arranged in investigational tube segment in two ways: (i) complete-length typical perverted tape at dissimilar perverted proportions (y = 6 and y = 8) and (ii) perverted tape with varied free space ratios (L = 1, 2 and 3). The findings acquired with the tube with the perverted tape inserts are differentiated to that obtained from the tube with no perverted tape. The outcomes show that as the twist ratio grew, so did the heat transmission coefficient. In contrast, increasing the free space ratio (L) improves both the friction factor and the coefficient of heat transfer. For friction factor and Nusselt number, the findings from every example were connected. The projected friction factor and Nusselt number from the correlations were then shown against the investigational detail. It is discovered that the Nusselt number was within 15percent and the friction factor was within 10%.

17. CFD Based Investigation on the Influence of the Darrieus Rotor Diameter in the Performance of Combined Hydrokinetic Rotor

    Md. Mustafa Kamal, R. P. Saini

    Abstract

    A combined hydrokinetic rotor can outperform the Darrieus and Savonius rotors on their own. The outside diameter of the Darrieus rotor is changed in the present study to alter the combined rotor configurations. In this work, the Darrieus rotor diameter is determined to be between 0.15 and 0.30 m. The study's aims are met through the use of a numerical technique. According to the numerical calculations, the diameter of the Darrieus rotor has a potential to alter the combined rotor's performance. The Darrieus rotor diameter of 0.20 m is found to be the best. The highest power coefficient yields as 0.199. The flow interference is more pronounced when the distance between the two rotors is small, according to flow visualisation. With a bigger Darrieus rotor diameter, the combined rotor's peak torque is found to be higher. The torque pulsation level is highly influenced by the diameter of the rotor (solidity of the rotor).

18. Prediction of Output Generated by a Steam Turbine Using Machine Learning

    Nishigandha Lad, A. Vamsikrishna

    Abstract

    A steam turbine is one of the most widely used equipment to generate electricity. In this data-driven world, the development of predictive models for such equipment has become necessary. In this paper, machine learning models are developed to predict the output generated by the steam turbine. Five predictive models are developed and compared. It is found that a third-degree polynomial regression model with an R-squared value of 87% and Mean square error value of 94.9 is found to be the best-suited model as per the requirement.