Faculty Publications
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Item Investigation of Mixed Convection Heat Transfer Through Metal Foams Partially Filled in a Vertical Channel by Using Computational Fluid Dynamics(American Society of Mechanical Engineers (ASME) infocentral@asme.org, 2018) Kotresha, B.; Gnanasekaran, N.Two-dimensional computational fluid dynamics simulations of mixed convection heat transfer through aluminum metal foams partially filled in a vertical channel are carried out numerically. The objective of the present study is to quantify the effect of metal foam thickness on the fluid flow characteristics and the thermal performance in a partially filled vertical channel with metal foams for a fluid velocity range of 0.05-3 m/s. The numerical computations are performed for metal foam filled with 40%, 70%, and 100% by volume in the vertical channel for four different pores per inch (PPIs) of 10, 20, 30, and 45 with porosity values varying from 0.90 to 0.95. To envisage the characteristics of fluid flow and heat transfer, two different models, namely, Darcy Extended Forchheirmer (DEF) and Local thermal non-equilibrium, have been incorporated for the metal foam region. The numerical results are compared with experimental and analytical results available in the literature for the purpose of validation. The results of the parametric studies on vertical channel show that the Nusselt number increases with the increase of partial filling of metal foams. The thermal performance of the metal foams is reported in terms of Colburn j and performance factors. © Copyright 2018 by ASME.Item A Synergistic Combination of Thermal Models for Optimal Temperature Distribution of Discrete Sources Through Metal Foams in a Vertical Channel(American Society of Mechanical Engineers (ASME) infocentral@asme.org, 2019) Kotresha, B.; Gnanasekaran, N.This paper discusses about the numerical prediction of forced convection heat transfer through high-porosity metal foams with discrete heat sources in a vertical channel. The physical geometry consists of a discrete heat source assembly placed at the center of the channel along with high thermal conductivity porous metal foams in order to enhance the heat transfer. The novelty of the present work is the use of combination of local thermal equilibrium (LTE) model and local thermal nonequilibrium (LTNE) model for the metal foam region to investigate the temperature distribution of the heat sources and to obtain an optimal heat distribution so as to achieve isothermal condition. Aluminum and copper metal foams of 10 PPI having a thickness of 20 mm are considered for the numerical simulations. The metal foam region is considered as homogeneous porous media and numerically modeled using Darcy Extended Forchheimer model. The proposed methodology is validated using the experimental results available in literature. The results of the present numerical solution indicate that the excess temperature of the bottom heat source reduces by 100 °C with the use of aluminum metal foam. The overall temperature of the vertical channel reduces based on the combination of LTE and LTNE models compared to only LTNE model. The results of excess temperature for both the empty and the metal foam filled vertical channels are presented in this work. © 2019 by ASME.Item A Parametric Study on Mixed Convection in a Vertical Channel in the Presence of Wire Mesh(Taylor and Francis Ltd., 2021) Kotresha, B.; Gnanasekaran, N.A numerical study on mixed convection is carried out through a partially filled brass wire mesh in a vertical channel. A heater embedded with aluminum plates is placed at the center of the vertical channel. The aluminum heater assembly is wrapped with brass wire mesh to facilitate more heat transfer. The vertical channel that consists of aluminum heater assembly with the brass wire mesh is considered as the numerical model. Local thermal non-equilibrium and Darcy extended Forchheimer models are used to accomplish the numerical simulations for thermal and flow characteristics of the considered domain. The aim of the study is to find out the optimum filling of the brass wire mesh in the channel which gives a higher heat transfer rate with low pumping power of the fluid. In the present analysis, three different filling conditions of wire mesh are considered: (i) fully filled channel, (ii) 70% filled channel, and (iii) 40% filled channel. From the results, it is inferred that the vertical channel partially filled with 70% of wire mesh porous medium predicts 89% of heat transfer of the completely filled channel with 41% reduced pressure loss. As a result, the proposed parametric study is good enough to prove that the partly filled wire mesh can be used in the thermal applications where augmentation of heat transfer is required with less pressure drop. © 2020 Taylor & Francis Group, LLC.