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2024 | Book

Advances in Heat Transfer and Fluid Dynamics

Select Proceedings of AHTFD 2022

Editors: Mohammad Altamush Siddiqui, Nadeem Hasan, Andallib Tariq

Publisher: Springer Nature Singapore

Book Series : Lecture Notes in Mechanical Engineering


About this book

This book comprises select proceedings of the 1st International Conference on Heat Transfer and Fluid Dynamics (AHTFD 22). It covers latest research trends and development in diverse areas like, aerodynamics, complex fluid phenomenon, turbulence, flow control, thermal management, green buildings, micro-scale transport phenomena in biological systems, renewable energy, power generation, combustion and related applications in heat transfer and fluid dynamics, among others. The book is a valuable resource for researchers and professionals working in the various areas of mechanical engineering.

Table of Contents


Flow Phenomenon and Computational Fluid Dynamics

Control of Suddenly Expanded Flow with Cavity at Sonic Mach Number

This study focuses on the control of the pressure in the base corner as well as flow quality in the duct during a numerical simulation of sonic airflow from a convergent nozzle exhausted into the circular duct with annular rectangular cavities. Three variables were found to significantly affect the base pressure: expansion level, area ratio, and duct size. For a lower area ratio, the passive control with cavities increases the pressure in the wake corner. Wake pressure also depends critically on the geometry and dimension of the cavity. In this investigation, we took into account the flow and geometrical factors of nozzle pressure ratio (NPR), cavity aspect ratio (ASR), and cavity location (CL). At sonic Mach numbers with the sudden enhancement of the flow area, the computational fluid dynamics method employs flow from a convergent nozzle. The Mach number of the study was M = 1.0 and an exit area ratio of 2.25 was found between the duct and the nozzle. The duct length considered was L = (1D, 2D, 3D, 4D, and 6D), and NPRs considered (1.5, 2, 3, 4, and 5) were used for simulations. The ASR 1 cavities are annular rectangles, 3 mm wide and 3 mm high. The outcomes of the base pressure are compared for ASR 2 with dimensions of 3 mm in width and 6 mm in height. In this study, a turbulence model based on the K-standard wall function was used to simulate and examine the nozzle. The results demonstrate that pressure in wake was considerably inspired by NPR and the cavity positioning from the base.

Muhammad Ikhwan Fiqri, Khizar Ahmed Pathan, Sher Afghan Khan
Numerical Study of Large-Scale Control in Compressible Turbulent Channel Flows

Direct numerical simulations in a fully developed compressible turbulent channel flows have been carried out using the large-scale control of large vortical structures along streamwise direction. Effectiveness of the control at Mach number, $$Ma = 1.5$$ M a = 1.5 and Reynolds number $$Re_b = 3000$$ R e b = 3000 is studied for different amplitudes and wavelengths of forcing. The large-scale control concentrates the turbulent kinetic energy in certain regions near the walls and it can be observed in $$y-z$$ y - z plane of the channel. These high turbulent kinetic energy regions are also the regions of high streamwise vorticity as well. The control reduces the wall-normal velocity fluctuations near the walls for all the cases but, on the other hand, Reynolds shear stresses are reduced for drag reduction cases and are increased for the case where drag increases. The skin-friction drag reduction(DR) of around $$7\%$$ 7 % is achieved in the present study while, for the case with high strength vortical structures, the skin-friction drag increases.

Moghees Ahmad, M. F. Baig, S. F. Anwer
Drag Reduction in Turbulent Compressible Channel Flows Using Spanwise Velocity Waves

Numerical simulations in compressible turbulent channel flows are carried out by applying the active control technique of spanwise velocity waves traveling in streamwise direction. The sinusoidal waves traveling in upstream direction are selected for the present study. For Mach number $$Ma = 1.5$$ M a = 1.5 and bulk Reynolds number $$Re_b = 3000$$ R e b = 3000 , the effects of varying the amplitude of control velocity while keeping other parameters constant are analyzed with the aim to achieve maximum turbulent drag reduction. The application of this active control technique for all the amplitudes studied successfully modifies the near-wall structures by reducing high-speed streaks and vortical structures. The maximum turbulent drag reduction, $$\texttt {DR = 37.01}$$ DR = 37.01 % is observed at threshold amplitude $$Amp = 1.5$$ A m p = 1.5 for a selected wave number $$\kappa $$ κ and oscillation frequency $$\omega $$ ω . The spanwise vorticity near the walls is suppressed and hence, the turbulent drag produced by eddies is reduced as well.

Moghees Ahmad, M. F. Baig, S. F. Anwer
Passive Control of Base Flow at Supersonic Mach Number for Area Ratio 4

This paper presents simulation results to assess a cavity's impact on base pressure at a supersonic Mach number of 1.4. The flow field in a sudden expansion flow is disrupted due to the presence of a cavity to control the base pressure and reduce base drag. This study also focuses on understanding the recirculation region's flow pattern and the flow's behavior through a converging–diverging nozzle. C-D nozzles are used in many aerospace industries. This research is carried out by the numerical approach using Computational Fluid Dynamics (CFD) Analysis. The simulation part, considering the Mach number, area ratio of 4, and the nozzle pressure ratio in the range of 2 to 10, was gathered at various length-to-diameter (L/D) ratios and cavity aspect ratios when conducting this analysis. The cavity aspect ratio used in this research is 3:3, 3:6, 6:3, and 6:6, which will show the results of the base pressure. Throughout this investigation, the cavity is located at 1D. The work applied the K-standard wall function turbulence model with the commercial computational fluid dynamics (CFD) and verified it. The C-D nozzle was created and modeled. The results demonstrate that the expansion level (Nozzle Pressure Ratio), the cavity aspect ratio, and the cavity's location significantly influenced the base pressure.

Nur Aqilah, Khizar Ahmed Pathan, Sher Afghan Khan
Numerical Analysis on the Effect of Constriction on the Mixing of Fluids in Serpentine Microchannels

Fluid mixing at micro level is a key function in microfluidic systems for the homogenization of fluid samples. Extensive work has been done by many researchers in the designing of micromixers for achieving efficient mixing. The impact of constrictions on fluid flow and mixing caused by the rectangular bend microchannel is numerically analyzed in this work. The micromixer has two aligned inlet channels and a main mixing channel which has constrictions in its rectangular bend section. Numerical analysis of mixing has been carried out for three different Reynolds number viz. 10, 30 and 60 and at two constriction values (s = 0 µm and s = 50 µm). The findings suggest that the blending efficiency of the micromixer having constriction is much better than the mixing performance exhibited by the channel having no constriction (s = 0 µm).

Kamran Rasheed, Sameen Mustafa, Mubashshir Ahmad Ansari, Shahnawaz Alam
Investigation on Fluid Flow in Biomimetic Microchannel

In this work, a numerical investigation on fluid flow and mixing has been performed on split and recombined microchannels based on Murray’s law. Murray’s law is derived from nature-inspired tree-like structures that are commonly found in living and non-living things. The human cardiovascular system and plant water transport systems are the most famous and investigated examples of such a type of structure. The same concept is introduced to design a micromixer having asymmetric bifurcation in order to solve the mixing problem at the microscale. Mixing at a small scale is a very complicated phenomenon, and due to its integration with bioengineering and chemical investigations, homogeneous and quick mixing has long been a prerequisite for microfluidic devices. In this paper, asymmetric and symmetric bifurcation micromixers were investigated with Reynold’s number ranging from 0.01 to 300. The results demonstrate that almost all the Reynolds number ranging from 0.01 to 300 are better handled by the symmetric bifurcated micromixer. However, for the asymmetric bifurcated micromixer, the increase in mixing index is only seen at Reynold number 300; below that, its efficiency is consistently lower than that of the symmetric micromixer. This is due to the larger daughter vessel dominating the smaller daughter vessel. The ability to take part in the mixing of smaller daughter vessel was obstructed by the bulk flow of the larger daughter vessel. This seems to be the main cause of inadequate mixing. The research reveals that symmetric bifurcated micromixers with ratio $${d}_{1}/{d}_{2}=1.0$$ d 1 / d 2 = 1.0 channels are much more effective in design than asymmetric bifurcated micromixers with ratio $${d}_{1}/{d}_{2}=0.6$$ d 1 / d 2 = 0.6 channels.

Mohd Amir Khan, Arees Qamreen, Mubashshir Ahmad Ansari
Numerical Analysis of Transient Induced Flow Through Open Ended Tall Vertical Concentric Annulus

In this work, thermally induced water flow behavior in an open, tall, vertical annulus is carefully characterized using numerical analysis. The annuli in this study had aspect ratios of 1.184 and 352 (length to annular gap) (outer radius to inner radius). When constructing the machinery for nuclear reactor systems, the circular test sections with such a high aspect ratio are essential. The proprietary code employs a tried-and-true semi-implicit finite difference method as the numerical approach, which is based on the SMAC technique. The induced flow is brought on by a step change in the inner wall heat flux even while the exterior wall is assumed to be adiabatic. The Raleigh number (Ra) ranges from 1.1 × 104 to 6.6 × 105, although the Prandtl number (Pr) is 6.43. The research examines the impact of heating on the mass flow rate, pressure drop, and heat transfer coefficient among other design parameters. Along with the outcomes, a time- and location-based temperature and velocity profile is given. Additionally taken into account are the temporal fluctuations in induced flow and pressure distribution along the annulus.

Jawed Mustafa, Saeed Alqaed, Shahid Husain, M. Altamush Siddiqui
Numerical Solutions of 2D Riemann Problems of Gas Dynamics Using a Hybrid PVU-M+ Scheme

The present work consists of numerical solution of two-dimensional Riemann problems for gas dynamics using PVU-M+ scheme (Hasan et al. Comput Fluid 119:58–86 2015 [1]). The test cases and their initial data are taken from Lax and Liu (SIAM J Sci Comput 19:319–340, 1998 [2]). The flow domain consists of a square geometry divided in 4 quadrants such that there exists only one planar wave (shock, rarefaction or slip line) between each two quadrants. The solutions are analyzed through density contours and line plots at a suitable location in X–Y plane. Although the PVU-M+ scheme resolved most flow features, it showed difficulty in capturing pressure field in a weak velocity field behind a discontinuity (rarefaction/shock). To overcome this, pressure field at cell interface is calculated based on acoustic speeds and a pressure gradient at cell center is obtained using this pressure field which is then blended with forward/backward approximation of pressure gradient using a mean hybrid weight function, $${\overline{W} }_{h}=\frac{1}{3}{\sum }_{k=1}^{3}{\left({W}_{h}\right)}_{i+2-k}$$ W ¯ h = 1 3 ∑ k = 1 3 W h i + 2 - k , where the hybrid weight function defined as, $${W}_{h}=A{e}^{-{\left(\frac{M}{B}\right)}^{2}}$$ W h = A e - M B 2 has two adjustable constants (“A” and “B”) which can be adjusted according to the flow problems and ‘M’ being the local Mach number based on convective flux velocity (u or v). This modified PVU-M+ scheme is named “PVU-M+H” where “H” stands for hybrid. Recommended values of “A” and “B” are 0.2 and 0.12, respectively, for all type of flow problems. All test cases were solved keeping these values of “A” and “B”.

Altaf Ahmed, Nadeem Hasan
Long Time Evolution of Optimally Perturbed Wing-Tip Vortices

We numerically investigate the effectiveness of optimal perturbations in exciting instabilities in the wake of flow past a finite aspect ratio wing at Re=1000. Analysis of the long-term evolution of perturbed wing-tip vortices is done in a frame of reference that moves roughly at the speed of the perturbation ( $$\sim U_\infty $$ ∼ U ∞ ; free stream speed). We simulate the scenarios in which the optimal perturbation is periodically injected into the wake. The wing-tip vortices displacement in response to the perturbation serves as a model for the actual perturbation. The maximum displacement experienced by perturbed wing-tip vortices as a function of time is analysed. The maximum displacement displays short time growth (up to 10-time units) after initial decay for the scenario where a single perturbation is present over a length of $$\sim $$ ∼ 8b (where ‘b’ is the separation between the wing-tip vortices at $$x=50c$$ x = 50 c (c: chord length) from the leading edge of the finite wing in the wake) along the wing-tip vortices. Additionally, the impact of altering the spacing between the wing-tip vortices has been investigated. When the separation is reduced to $$\sim $$ ∼ 0.37b, the initial rate of decay of maximum displacement slows down by $$\sim 40\%$$ ∼ 40 % . Increased perturbations and further narrowing of the space between the wing-tip vortices are predicted to produce intriguing findings.

Mohd Suhail Naim, Navrose
Comparison of Various RANS Turbulence Models for Dry Bed Simulation of Rotating Packed Bed (RPB)

The potential of rotating packed beds (RPB) is currently being explored by researchers to intensify heat transfer in thermal systems, primarily in cooling towers. The RPB has originally been implemented in chemical industries as a replacement for giant columns for carrying processes like distillation, separation, and absorption. In a rotating packed bed, the water flows radially outwards by the centrifugal force (100–1000 times the gravitational force in conventional columns) generated by a spinning porous cylindrical rotor, and the air is directed to flow radially inwards in a counter-current direction by a blower. To close the gap in fundamental knowledge of RPB and promote research further to achieve process intensification in heat transfer systems, deeper comprehension of fluid dynamics is essential. In the present work, the dry bed flow of air was simulated in ANSYS Fluent software and various RANS turbulence models have been explored and compared. The CFD simulation has been performed for a wide range of gas flow rates and two rotational speeds 800 rpm and 1600 rpm. The simulation results have been validated with the results from experiments.

Gaurav Kumar, Dheeraj Singh, Shweta Gole, D. S. Murthy
Effect of Buoyancy on Three-Dimensional Flow Around a Heated Square Cylinder in Mixed Convection

Three-dimensional flow around a heated square cylinder is studied using direct numerical simulation (DNS) in a mixed convective flow regime. In this study, an infinite square cylinder is immersed in horizontal free-stream crossflow (air, Prandtl number $$Pr=0.7$$ P r = 0.7 ) at right angles to gravity. Numerical results are shown with different heat levels defined by the over-heat ratio $$\epsilon =(T_w-T_\infty )/T_\infty $$ ϵ = ( T w - T ∞ ) / T ∞ , where $$T_w$$ T w and $$T_\infty $$ T ∞ are equal to the surface and surrounding temperature. At large-scale heating $$\epsilon \thicksim O(1)$$ ϵ ∼ O ( 1 ) , the thermal straining and transport properties of the fluid particles are varied. To capture this variation, an in-house solver of the compressible flow model is employed. The compressible flow governing equations in Cartesian coordinates are transformed into a body-fitted coordinate system and solved using the flux-based particle velocity upwind-modified+ (PVU-M+) scheme. The low Mach number $$M=0.1$$ M = 0.1 is used for all computations. The results obtained using the in-house solver are validated with the values reported in the literature achieved by experimental, DNS, and Floquet methods. The disordered vortical structure of the mode B transition changes its shape and spanwise wavelength with the increase of the heating level from $$\epsilon =0$$ ϵ = 0 to $$\epsilon =1$$ ϵ = 1 at the Reynolds number $$Re=500$$ R e = 500 . In addition, a very significant change in the force coefficient and the vortex shedding frequency is observed upon increasing the heating level. Variations in the frequency spectra of the lift coefficient are observed with varying heating.

Mohd Perwez Ali, Nadeem Hasan, Sanjeev Sanghi

Heat Transfer and Combustion

Effect of Divider Wall Shape on the Flow Development and Heat Transfer Characteristics in a Two-Pass Duct

This paper presents the flow patterns and heat transfer distribution across the bend region in a two-pass rectangular duct for an inlet turbulent flow regime (Re = 6500). The results are presented at various vertical and horizontal planes located at different positions across the bend along the flow progression. Two divider wall configurations (in-between two-pass of the duct) are studied, i.e., (1) sharp-corner turn and (2) smooth curved turn. It has been noticed that flow gets completely modified because of divider wall shape. The numerical results reveal that primary and secondary flow in turn regime displays combined features of a bend-induced, Dean-type circulation. The flow dynamics and local heat transfer vary significantly with different divider wall configurations. For the duct with a sharp divider wall, a pair of counter-rotating Dean vortices induce after 90° near the end-wall of bend region. In contrast, for the duct with a smooth curved divider wall, vortices pair is induced close to the divider wall and stretched across the entire width. The results show that Dean vortices play an important role in enhancing localized heat transfer across the bend regime. Interestingly, the duct with a sharp divider wall exhibits higher localized heat transfer, whereas the duct with a smooth, curved divider wall exhibits lower localized heat transfer but more uniform distribution.

Arun Chand, Nishab Ali, Andallib Tariq
Spot Conductance Measurement Using Infrared Thermography

The estimation of thermal contact conductance (TCC) across any contacting surfaces is required for the efficient design and safety of mechanical systems. The accurate estimation of heat flux and temperature drop across the interface is crucial for the assessment of TCC. In the present experimental investigation, stainless steel (SS304) is selected as it is frequently used in various industrial applications. A high-temperature experimental facility has been built to study interfacial heat transfer and TCC estimation. The contact spot conductance has been estimated using steady-state measurements in vacuum utilizing surface temperature information from infrared thermography. The primary objective is to determine the effect of contact pressure (1.7, 4.7, 7.7 MPa) and surface roughness (0.49 and 1.64 μm) on TCC at interface temperatures of 300 °C. Infrared thermography technique is applied for better thermal visualization and accurate prediction of interfacial temperature drop. The result depicts that at lower surface roughness, TCC increases more rapidly with contact pressure. Moreover, experimental results have been suitably normalized and compared to the available theoretical models.

Khursheed Anwar Khan, T. Altaf Hasan, Andallib Tariq
Thermal Conductivity Measurement of Novel Waste Tire Rubber-Polypropylene Composite

As the manufacturing and use of vehicles are increasing globally, the disposal and recycling of waste tire have become a major environmental issue when they are out of service life. One of the potential recycling processes is turning the waste tire into a useful composite as insulating material. The present work produced a blended composite based on waste tire rubber (425 µm) and virgin polypropylene granules in a 4:1 ratio through a single screw filament extruder under controlled conditions. The thermal conductivity of the newly developed insulating material was measured using an in-house fabricated experimental setup built in accordance with ASTM D5470. Since waste tire rubber has good insulating property, it can be combined with thermoplastic materials and converted into insulating material for various thermal applications.

Khan Zahir Ahmed, Mohammad Faizan, Mohammad Asif
Thermal Fluid Analysis of Different Combinations of Jet Channel and Air Foil Pillars with CuO–Water Nano Fluid

Small-scale thermal devices are very effective and interesting to use for the applications which involve large amount of heat flux. The use of Nano particles in the base fluid like water also augments the various properties which help in the heat dissipation from the components subjected to high temperatures. In the current study, the various combinations of jet-channel and pillars have been investigated comparatively. CuO–water-based Nano fluid is used along with the air foil pillars in a heat sink to augment the heat transfer. Comparative analysis has been executed for the different parameters like temperature, heat exchange coefficient, Nusselt number and thermal resistance. The study has been carried out for a constant value of heat flux at the bottom surface. Minimum temperature is found in case of jet-pillar combination. The channel flow diminished the heat exchange coefficient.

Deepak Kumar, Mohammad Zunaid, Samsher Gautam
CFD Study of Winged Pin–Fin Heat Sink

The present study numerically investigates the forced convection from the pin–fin type of the heat sink with an inline and a staggered arrangement of fins for varying Reynolds numbers. It further investigates the effect of attaching wings along the length of the fins on flow and heat transfer characteristics. It has been observed that the Nusselt numbers increase and friction factor decreases with increase in Reynolds numbers irrespective of the shape of the fins as well as the way the fins are arranged. The staggered arrangement of pin fins provided better thermo-hydraulic performance than the inline arrangement and the performance is further improved when the wings are embedded on the downstream side of the fins.

Krishna Veera Kumar, Md. Shaukat Ali
Development, Characterization and Performance Evaluation of Graphene Oxide Nanofluid in EG:Water-Based PV/Thermal System

The advanced nanofluid with good stability is demand of industry as well as solar thermal systems. In industrial application, Graphene Oxide (GO) nanofluid formulated with Ethylene Glycol (EG): water (W) is usually known well for good stability along with high thermal conductivity. In this research, GO nanofluid is characterized for exploring thermal, optical, and suspension stability under certain conditions and then utilized as working fluid in photovoltaic thermal (PV/T) system. SEM, UV–vis, FTIR and TGA analysis are performed for morphology, optical and thermal stability characterization respectively. Thermal conductivity measurements of the GO/EG:W nanofluid revealed an enhancement of 9.5% at 40 °C compared to water. It also displayed good long-term stability, with a zeta potential of 30.3 mV. The long-term stability with time as well as stability at high temperature of GO nanofluid give a good room for future researchers to use it as coolant in solar PV panel. Because large increment in thermal conductivity of EG:W nanofluid of GO may act very amazing media for heat transport which resulted in enhancement of performance of PV solar panels. Therefore the electrical as well as thermal efficiencies of the PV/Thermal system improved.

Ajiv Alam Khan, Syed Mohd Yahya
Experimental Studies on Pool Boiling of Water-Based Al2O3, CuO and Hybrid Nanofluids

Experiments on pool boiling of distilled water and nanofluids: Al2O3-water, CuO-water and Hybrid (Al2O3-water and CuO-water, mixed in equal volume) have been performed on a heated nichrome wire that is submerged in distilled water and the nanofluids. This study aims to find increase in the critical heat flux (CHF) due to hybrid nanofluids mixed in equal volumes of Al2O3-water and CuO-water nanoparticles. The volume concentrations of nanoparticles were varied from 0.01 to 0.05%. The heat flux to the test heater was impressed and the corresponding current and voltage supply were recorded using a data logger until the wire started becoming red hot and then broke which is referred to as the critical heat flux. Experiments show that there is an enhancement of critical heat flux (CHF) on varying the vol. %age concentration. It is found that the CHF is quite high in case of the hybrid nanofluids as compared to the base fluid that is distilled water and single particle nanofluids. Enhancement of CHF to around 91.06% in the hybrid nanofluids has been estimated when compared with the distilled water. The heat flux versus excess temperature has been plotted for different concentrations of the nanoparticles in the Al2O3-water, CuO-water and hybrid nanofluids (Al2O3 + CuO/water). The heat transfer coefficient (HTC) has also been shown for different concentrations of the nanoparticles in the three nanofluids under study with heat flux for the nucleate boiling region.

Mohammad Saalim, M. Altamush Siddiqui, Suhail Ahmad Khan
Numerical Analysis of an HVAC System Incorporated with Latent Heat Energy Storage System

Owing to India's climatic conditions, India’s energy outlook has predicted a three-fold increase in ownership and growth in energy consumed for cooling to 650 TWh by 2040. Further, due to airborne viruses like COVID-19, the health and air-conditioning societies modified guidelines and suggested incorporating air from the ambient to dilute the indoor air and reduce contaminant levels. However, mixing ambient air with recirculating air results in an additional cooling load in the heating, ventilation, and air-conditioning system (HVAC). The study aims to design a shell and tube heat exchanger to reduce the HVAC load by cooling the fresh air from ambient temperature and subsequently mixing it with the recirculated air. The fresh air at 315 K flows through the heat exchanger with calcium chloride hexahydrate as a phase change material (PCM). Further, two configurations of heat exchangers are examined. In one, air flows through the inner tube, and PCM is in the annulus, while in the second, the air flows in the annulus, and the PCM is in six radially equidistant tubes. The designed heat exchanger with PCM in annulus and PCM in tubes led to an average energy saving of 3 and 2.7%, respectively, for 3600 s of operation.

Rahul Kumar Sharma, Ashish Kumar, Dibakar Rakshit
Optimisation for Optimum Nozzle Design of the Hybrid Jet-Pillar-Microchannel Heat Sink

The present study conducted an optimisation study for geometric variables of the jet nozzle of the multi-jet impingement and pillar-integrated microchannel heat sink for best performance. Nozzle diameter, nozzle angle, and nozzle diameter decreasing factor are the three design variables and minimisation of the thermal resistance is considered as the objective function. A regression model is developed using Minitab software and optimised using response surface methodology and further contribution of each variable is observed by performing analysis of variance. Nozzle angle exhibited the maximum contribution in varying the objective function that is 47.84% and thus thermal resistance was reduced by 15.8% by changing the nozzle angle from optimum conditions.

Jyoti Pandey, Mohd. Zahid Ansari
Investigation of Laminar and Turbulent Natural Convection Combined with Radiation in a Square Enclosure with a Vertical Partition

The present research work focuses on numerical simulation of combined natural convection and radiation inside a square enclosure with a vertical partition having different heights. The distance of the partition is varied from the hot wall for establishing the results. The left wall is considered to be the hot, the right wall as the cold and the horizontal top and bottom walls are considered to be adiabatic. The analysis is done in both the laminar and in the turbulent range for the Rayleigh number in range of 103 to 1010. The partition is considered to have a fixed thickness which is taken to be L/20. Also, it is assumed to be adiabatic. Air is taken as the working medium. It has been concluded from the results that an increase in radiative Nusselt number is much higher than that of convective Nusselt number for turbulent flow regime. It was found to be 379% as the Rayleigh number increases from 108 to 1010. Also, the increase in NuT is almost 352% when Ra is increased from 108 to 1010. However, as the partition height is increased the value of NuT decreases to 15 and 28% for Ra 105 and 1010 respectively.

Mariyam Ali, Anil Kumar Sharma
Effect of Fuel Spray Geometries on Diesel Combustion Characteristics for Developed Combustion Chamber

This study investigates the effect of geometries of fuel spray on diesel combustion characteristics, i.e., ignition lag (IL) for diesel engines. The IL is measured for two nozzle spray designs, i.e., hollow conical spray (HCS) and solid conical spray (SCS). Various cylinder air pressures (CAP), hot surface temperatures (HST), and injection pressures (IP) are considered operating parameters. An experimental setup is fabricated for testing and analysis to reduce IL. The IL for the fuel sprays is recorded through an oscilloscope based on the time lag between the incidents of injection and the presence of flame inside the combustion chamber. The results show that the IL for HCS is (4.9 ms) lesser than SCS (5.2 ms), corresponding to minimum IP, maximum AP and HST. The IL decreases by changing the IP from 100 to 200 bar for HCS and SCS. The increasing HST from 350 to 550 °C and CAP from 15 to 25 bar provide reduced IL. The IL with HCS is 6.12% lower than the SCS. However, the maximum IL of 36.6 ms is obtained by solid conical spray whereas 32.6 ms by HCS corresponds to same parameters i.e. minimum values of HCS, IP, and CAP. The findings show that the hollow conical spray design is more suitable for the diesel engine considering the fuel saving, smooth functioning, and other combustion characteristics.

Inayat Hussain, Ajit K. Dubey, Sanaur Rehman, Saty Dev, Pushpendra Yadav, Md. Nazeem Khan
An Estimation of Various Performance Parameters of CI Engine Fueled with Diesel and Biodiesel Blends

A series of test experimental analyses have been performed to analyze the performance parameters of CI engine fueled with diesel and biodiesel blends. The various biodiesel blends have been prepared as K0L20D80, K5L15D80, K10L10D80, K15L5D80, and K20L0D80 with the combination of Karanja and Linseed biodiesel along with diesel. The results indicate that the performance parameters of blends have been given adjacent results to diesel. A higher concentration of Karanja oil as compared to linseed oil in diesel blends has given better results for performance parameters. The results demonstrated that K15L5D80 gives better results compared to all other blends and is close to diesel for the performance parameters of CI engine.

Brahma Nand Agrawal, Charan Singh, Shailendra Sinha
Combustion and Performance Analysis of a CI Engine Fuelled with Soybean Oil Biodiesel Blends

In the present experimental investigation, comparative analysis of combustion and performance characteristics of a DI diesel engine fuelled with diesel and soybean biodiesel blends was done. Biodiesel was produced through catalytic transesterification method and its blends with diesel were prepared in various concentrations (B10, B20 and B30) by volume. In BX blend, X indicates percentage concentration of the biodiesel in the diesel fuel. Analysis of various combustion and performance parameters such as in-cylinder pressure, rate of pressure rise, net heat release, ignition delay period, brake thermal efficiency and brake specific fuel consumption were performed at different engine loads (20, 40, 60, 80 and 100%) keeping constant the engine speed. Combustion parameters obtained are the averages of five engine cycles. It is observed that with increasing loads, higher values of various combustion parameters are found for all fuels. Results indicated better combustion and performance parameters at full engine load for all fuels. Increase in biodiesel concentrations result in higher in-cylinder pressure, net heat release, rate of pressure rise and lower ignition delay periods at full load. It is found that at full load condition, S30 and S20 blend have shown improved combustion over S10 blend. There has been a marginal improvement in performance parameters for S10 blend at full load.

Muhammad Aazam Waheed, Mohammad Sufiyan Nafis, Anas Anwar Khan, Sanaur Rehman
Experimental Investigation on Combustion and Performance Characteristics of DI Diesel Engine Using Waste Cooking Oil Biodiesel Blends

The hefty prices of raw materials are the greatest hurdle to biodiesel's adoption as an alternate fuel. While waste cooking oil offers a cost-effective solution, it poses challenges in disposal and the potential for contamination. These factors lead waste cooking oil to a promising alternative. Waste cooking oil biodiesel blends have therefore been developed and employed to evaluate their impact on engine combustion and performance parameters. In the present experimental study, a catalytic transesterification process was used to produce biodiesel (waste cooking oil). Biodiesel was blended with diesel in three proportions (W10–10% waste cooking oil blend 90% diesel, W20–20% waste cooking oil blend 80% diesel, and W30–30% waste cooking oil blend 70% diesel). In-cylinder pressure, rate of pressure rise, net heat release, cumulative heat release, mean gas temperature, ignition delay, brake specific fuel consumption (BSFC), and brake thermal efficiency (BTE) were among the combustion and performance parameters that were analysed on a diesel engine at five engine loads (20%, 40%, 60%, 80%, and 100%). The percentage of biodiesel in the blend was increased, which improved the values of combustion and performance parameters. The optimal blend in terms of combustion and performance parameters was found to be W30. In comparison to diesel, W30 had a 13% shorter ignition delay, 22% lower net heat release, 10% slower rate of pressure rise, 2% higher BTE, and 1% lower BSFC. Therefore, biodiesel blends with a high concentration may prove to be a viable substitute for diesel fuel. 034.

Anas Anwar Khan, Sanaur Rehman, Muhammad Aazam Waheed, S. S. Alam, Mohd Sufiyan Nafis

Solar and Renewable Energy

Internet of Things Connected Hybrid Solar Cooker

The potential of cooking during off sunshine hours is investigated using an energy storage unit in the solar cooker, such as a thermal energy storage material or thermal heating of the absorber plate of solar cooker by photovoltaic (PV) technology. To determine the viability of a solar cooker during the off-sunshine hours, performance experiments on a hybrid solar cooker utilizing phase change materials (PCMs) and PV technology have been carried out. In order to improve user experience, the hybrid solar cooker has also been upgraded with an internet of things-based monitoring interface. The Bureau of Indian Standards are also used to test the thermal characteristics of solar cookers. The duration of cooking in a solar cooker using various PCMs in sunshine and off-sunshine hours being is the main emphasis of the present experimental study.

Pratyush Kukreti, S. S. Bhandari, Govind Verma
Performance Evaluation of Solar Box Cooker with Phase Change Materials

Solar cooker uses solar radiation to cook the food. These are good alternative for cooking as it uses solar radiation which is free and does not cause any environmental pollution. Normally, the box type cooker can cook the food in day time only. On the other hand, the solar box cooker that utilises phase change material (PCM) is able to prepare food both during the day and in the evening. In this study, simulations of box solar cookers with three distinct PCMs have been conducted to compare the performance of the cooker with different PCMs. The 3D model of the box solar cooker has been prepared, grid independence test has been done and the simulations have been performed using ANSYS FLUENT package. In the simulation the maximum temperature achieved by the absorber plate during the charging mode and time to achieve this maximum temperature have been evaluated. Using the maximum temperature achieved the other thermal performance parameters have been calculated. Through the simulation it is found that maximum temperature of the absorber plate is achieved with PCM Erythritol. The drop in temperature of the absorber plate during the discharging mode is more with PCM Quinone. Also, during the discharging mode, the energy provided by Acetanilide and Quinone is less than the energy required for evening cooking, so Acetanilide and Quinone do not support evening cooking. However, the analysis shows that the evening cooking is possible by using Erythritol as the phase change material. All the performance parameters are high with Erythritol as compared to Acetanilide and Quinone. Thus, the performance of the cooker is better with Erythritol.

Md. Riyaz Anwer, Naiem Akhtar, Md. Reyaz Arif
Experimental Investigation of Photovoltaic Panel Cooling by Uniformly Flowing Water on the Top Surface for Efficiency Improvement

The study done in this article furnish the results of an experimental investigation on the cooling of solar photovoltaic (PV) panel with water flowing uniformly over the top surface. An experimental setup was designed, fabricated, and put to testing in real outdoor environment in the geographical region of Chandigarh, India. To overcome non-uniformities in the flow, various trials were made and a cuboidal vessel was designed. About a 50% decrease in temperature was observed. An improvement of about 17% in efficiency was observed by cooling the PV panel, it increased from 11.83% to 13.83%.

Vikas, Abhishek Pandey, Ankit Yadav
Performance Study of Basin Type Solar Still with Different Concentrations of Water-Al2O3 Nanofluids

In this paper, a comparison of the performance of single basin single slope solar still with water and with water based nanofluid of Aluminium Oxide (Al2O3) has been made. For this, two experimental solar stills of the same basin area have been fabricated and tested for their identical thermal performance. These solar stills have been used to compare the performance with water in one solar still and water-based nanofluid in the other solar still by performing experiments at the same location and time. It is found that the solar still with water based Aluminium Oxide (Al2O3) nanofluid having concentrations 0.05%, 0.1%,0.15% and 0.2% enhances the output of the solar still as compared to the water by 18.54%, 22.26%, 24.37% and 20.38%, respectively, thus giving an optimum value of enhanced output at 0.15% concentration.

Farooque Azam, Naiem Akhtar
Recent Advances in Applications of Solar Dish Stirling Engine Technology

In the face of dangers posed by Climate Change in the World today, a shift to renewable sources is the need of the hour. A healthy mix of different energy sources of both renewable and non-renewable nature is the way to move forward. A Solar Stirling Engine has one of the highest thermal efficiency among Solar Thermals. Its applications can play a vital role in contributing to this energy mix of fuel sources. In this paper, recent advancements in the applications of the Solar Dish Stirling Engine System are reviewed. These include Solar Stirling Electric Power Generation, Off Grid Electrification, Combined Heat and Power, Hybridisation and Storage, Water pumping, Water distillation and desalination. It was found that researchers are assessing several new combinations of energy systems, especially in the case of Combined Heat and Power Systems for Residential and Commercial Buildings. Several Studies have also focused on using Solar Stirling Engines in conjunction with other technologies for Water Pumping in the agriculture sector, Water Distillation and Desalination, which is vital for the shortages of clean water.

Vaibhav Singh, Anil Kumar
Analysis of Evacuated Tube Consisting Parabolic Concentrator with Al2O3-Water Nanofluid

Efficiency enhancement has always been a challenge for scientists and researchers. Although the realization of proposed concepts is necessary for development, it consists of several challenges from fabrication to testing the concept. The present study carried out experiments on parabolic trough collectors with the bare tube and evacuated tube receivers. Further, the performance has been tested for water and Al2O3-water as nanofluid. The parabolic trough and experimental setup were fabricated to carry out experiments outdoors for the daily solar flux and varying flow rates of the working fluid. The nanofluid with an evacuated receiver tube continuously shows better performance over the range of flow rates investigated in this study.

Muntashir Mohammed Razzak, Afzal Husain, Nasser Al-Azri, Nabeel Al-Rawahi
Solar Collector Tilt Angle Optimization for Maximum Solar Irradiation in Lucknow, Uttar Pradesh, India

This study is oriented about providing the cleanest form of energy for the living species on earth. Solar energy is the cleanest form of energy. Solar plate collector’s tilt angle is the main point of interest in this study. This study is about how to find the optimum tilt angle and at the same time the maximum solar energy. This study shows the solar energy falling on the solar plate increased at the optimum tilt angle. For Lucknow (26.87˚ N, 80.95˚ E) India, the optimum tilt angle during winter season is 55˚ (Latitude +28˚) and during summer season it is 0˚ (Latitude −27˚). Solar energy falling on the collector surface during winter is 31.83 MJ/m2 and during summer season 22.38 MJ/m2.

Abdul Qadeer, Shah Alam, Hasan Zakir Jafri, Wasim Akram
Thermal Performance Analysis of a Double-Pass Solar Air Heater with Discontinuous W-Shaped Ribs

Experiments were done on a two-pass solar air heater (SAH) to see the consequence of discontinuous w-shaped ribs on the Thermal characteristics. The absorber plate has discontinuous w-shaped ribs on both sides, with the upper portion painted black to absorb more radiation. Dittus-Boelter and Modified Blasius equations are used to create a rectangular duct and confirm its validity. In this paper, the variation of Thermal and Thermohydraulic/effective efficiency is shown against Reynolds Number. For the analysis, the relative roughness pitch (p/e) ranges from 5 to 20 The relative gap width is taken as 0.5. The angle of attack (α) is taken as 45° and 75°. The Reynolds Number for the experiment was taken from 4900 to 12,000. It has been observed from the experiments that the maximum efficiencies were found out at a relative roughness pitch of 10 with their values a bit higher in the case of 75° than in the case of 45° due to change in its turbulency.

Sudhanshu Dogra, Gaurav Bharadwaj
Advances in Heat Transfer and Fluid Dynamics
Mohammad Altamush Siddiqui
Nadeem Hasan
Andallib Tariq
Copyright Year
Springer Nature Singapore
Electronic ISBN
Print ISBN

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