Faculty Publications
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Item Performance evaluation of partially filled high porosity metal foam configurations in a pipe(Elsevier Ltd, 2021) Jadhav, P.H.; Gnanasekaran, N.; Arumuga Perumal, D.A.; Mobedi, M.In this contemporary research, a parametric analysis of partially filled high porosity metallic foams in a horizontal conduit is performed to augment heat transfer with reasonable pressure drop. The investigation includes six different models filled partly with aluminium foam by varying internal diameter of foams from the wall side and external diameter of foam from the core of the tube. The pore density of the foam ranges from 10 to 45 PPI and their porosity varies from 0.90 to 0.95. Flow dynamics are captured using Darcy Extended Forchheimer model for the porous filled region and two-equation turbulence k-? model employed in clear region of the fluid. The local thermal non-equilibrium assumption is incorporated in porous filled region of the conduit to compute the heat transport characteristics. The results showed that the thermal performance factor of 10 PPI aluminium foam performs close to the 10 PPI expensive copper foam. The performance factor is found to be higher for 30 PPI aluminium foam amongst the PPI's of the foam considered. However, the performance factor is found to be 2.93, 2.22 and 1.73 for 30PPI, 45 PPI and 20PPI with their porosities of 0.92, 0.90 and 0.90, respectively for the model 1, model 2 and model 3 at lower Reynolds number of 4500 and then it decreases progressively with increasing flow rates of the fluid. The results of average wall temperature, average Nusselt number and Colburn j factor are also evaluated to obtain best possible performance. © 2021Item Numerical assessment of thermal characteristics of metal foams of orderly varied pore density and porosity under different convection regimes(Elsevier Masson s.r.l., 2022) Trilok, G.; Kumar, K.K.; Gnanasekaran, N.; Mobedi, M.The present study is done to analyze heat transfer and fluid flow in a channel with orderly varied pore density and porosity combination of foam samples. Darcy Forchheimer flow and LTNE thermal models are considered to estimate heat transfer characteristics. Considering the effect of orderly varied combinations of the dual structural properties, forced convection over a range of flow velocities and natural convection phenomenon are studied numerically in the channel housing porous samples. Two limiting solutions for Nusselt number (Nu) i.e., Nun (for natural convection) and Nuf (for forced convection) for Ri→∞ and Ri→0 respectively, as a function of independent variable Richardson number (Ri) with structural properties pore density and porosity are obtained with the help of local thermal non-equilibrium (LTNE) thermal model and Darcy-Forchheimer flow model. Further these asymptotic solutions are blended using technique illustrated in the literature in order to obtain solution for Nusselt number for mixed convection (Num). Correlations for Nusselt number as a function of combination of porosity and pore density are obtained emphasizing on the varied significance of these parameters in different convection regime. The present study not only emphasizes on effect of combination of structural properties of metal foams on heat transfer characteristics, but also illustrates a technique that enables to arrive at suitable correlation for an intermediate phenomenon existing between two other extremes, with zero computational cost. Effect of pore density on heat transfer characteristics at a given porosity, is found to be not much influencing in natural convection dominant regime. However, in mixed and forced convection dominant scenario it is illustrated that, effect of variation in pore density and porosity plays a significant role in expressing distinguishable heat transfer characteristics, along with other well-known independent parameters such as porosity and Reynolds number. © 2021 Elsevier Masson SASItem Numerical Study for Enhancement of Heat Transfer Using Discrete Metal Foam with Varying Thickness and Porosity in Solar Air Heater by LTNE Method(MDPI, 2022) Diganjit, R.; Gnanasekaran, G.; Mobedi, M.A two-dimensional rectangular domain is considered with a discrete arrangement at equal distances from copper metal foam in a solar air heater (SAH). The local thermal non-equilibrium model is used for the analysis of heat transfer in a single-pass rectangular channel of SAH for different mass flow rates ranging from 0.03 to 0.05 kg/s at 850 W/m2 heat flux. Three different pores per inch (PPI) and porosities of copper metal foam with three different discrete thicknesses at equal distances are studied numerically. This paper evaluates the performance of SAH with 10 PPI 0.8769 porosity, 20 PPI 0.8567 porosity, and 30 PPI 0.92 porosity at 22 mm, 44 mm, and 88 mm thicknesses. The Nusselt number for 22 mm, 44 mm, and 88 mm thicknesses is 157.64%, 183.31%, and 218.60%, respectively, higher than the empty channel. The performance factor for 22 mm thick metal foam is 5.02% and 16.61% higher than for 44 mm and 88 mm thick metal foam, respectively. Hence, it is found that metal foam can be an excellent option for heat transfer enhancement in SAH, if it is designed properly. © 2022 by the authors.Item Analysis of functionally graded metal foams for the accomplishment of heat transfer enhancement under partially filled condition in a heat exchanger(Elsevier Ltd, 2023) Jadhav, P.H.; Gnanasekaran, N.; Mobedi, M.The use of partially filled high porosity graded aluminum and copper foams is explored to satisfy both heat transfer and pressure drop in a heat exchanger. Both positive and negative orientations are accomplished for the enhancement of heat transfer with reduction in the pressure drop. The present research includes three different configurations M1, M2 and M3 (porous layer inner diameter = 0.06 m, 0.04 m, and 0.02 m, respectively, while outer diameter = 0.10 m) partially filled with positive (i.e., increasing, 20/45 PPI) negative (i.e., decreasing, 45/20 PPI) and compound (i.e., 45 Cu/20 Al PPI) graded porous layer thickness. Each configuration involves three different graded porous layer to present the optimum graded porous layer thickness. The thermo-hydrodynamic characteristics are apprehended by using Darcy Extended Forchheimer (DEF) flow and local thermal non-equilibrium (LTNE) models for the partially filled graded porous structure and k-ω turbulence model is accomplished in open passage flow of the conduit. The decreasing graded foam located inside the models M1 and M2 performed 1.68%–12.85% and 13.42%–23.32% higher heat transfer rate compared to without graded metal foam of models M2 and M3, respectively accompanied with 55.43%–84.02% and 35.69%–50.31% lesser pumping power. © 2022 Elsevier Ltd