Faculty Publications
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Item Prediction of heat transfer with discrete heat sources in a vertical channel filled  ith high porosity metal foam(Dalian University of Technology, 2018) Kotresha, B.; Gnanasekaran, N.This paper discusses about the numerical prediction of isothermal condition with discrete heat sources in a vertical channel filled with high porosity metal foams. The problem considered consists of a vertical channel in which discrete heat source assembly is placed at the centre and high porosity metal foams are placed on either side of the aluminium plates to enhance the heat transfer. The flow through the metal foam porous medium is predicted by using Darcy Extended Forchheimer model and Local thermal non-equilibrium model as well as local thermal equilibrium model is used for heat transfer prediction. The results are presented in terms of temperature excess over the ambient for both empty and metal foam filled channel. Finally, the heat input through the discrete heat sources is varied to obtain an isothermal condition on all the heat sources at a constant inlet velocity. © 2018 by the authors of the abstracts.Item Natural Convection Through High Porosity Metal Foams—A Numerical Study(Springer Science and Business Media Deutschland GmbH, 2021) Kotresha, B.; Jadhav, P.H.; Gnanasekaran, N.Numerical analysis of natural convection through highly porous metal foams attached to the aluminium plates is performed in this study. A heater sandwiched between two aluminium plates attached with aluminium metal foams of different pores per inch (PPI) is considered for the present analysis. Initially, experiments are carried out for aluminium plate-heater assembly for different heat inputs. In the numerical investigation, the aluminium plates are attached with metal foams on either side for further analysis. A well-known Darcy extended Forchheimer flow and LTNE thermal models are considered for the metal foam in the computations. The natural convection is modelled using Boussinesq approximation. Initially, the numerical result for the plate without metal foam is validated with the experimental results for different heat inputs. The results show that the Nusselt number decreases with the increase of metal foam pore density (PPI) and increases with the increase in Rayleigh number. © 2021, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Forced Convection Analysis in a Horizontal Pipe in the Presence of Aluminium Metal Foam—A Numerical Study(Springer Science and Business Media Deutschland GmbH, 2021) Jadhav, P.H.; Kotresha, B.; Gnanasekaran, N.; Arumuga Perumal, D.Numerical exploration of forced convective heat transfer through the aluminium metallic foam filled in a horizontal pipe is done expending a commercially existing software ANSYS FLUENT 15.0. The motive of the ongoing numerical examination is to investigate the effect of fully filled metal foam in a horizontal pipe for different flow regimes. 10 PPI metal foam having 0.85 porosity is filled 60% along the length of pipe in the flow direction. The Darcy-extended Forchheimer (DEF) flow and local thermal non-equilibrium (LTNE) models are considered at the metal foam region to envisage fluid flow and augment in heat transfer. The numerical methodology is validated by comparing the results with available experimental data. The results of pressure loss, variation of wall temperature and Nusselt number are reported and discussed. © 2021, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Thermodynamic analysis of entropy generation in a horizontal pipe filled with high porosity metal foams(Elsevier Ltd, 2022) Jadhav, P.H.; Gnanasekaran, N.; Arumuga Perumal, D.A.In the field of thermal management of electronic equipment, examining entropy generation properties is extremely useful. The entropy production experiments have been expanded to porous media using high porosity metal foams. The entropy production/generation for forced convection heat transfer in a tube is quantified via a numerical research. In the field of air stream direction, the horizontal pipe is entirely filled with nickel metal foam of 0.6 m length. For the isotropic porous metal foam zone, the Darcy-extended Forchheimer (DEF) flow is used to capture the dynamics of flow and local thermal non-equilibrium (LTNE) model is used for analyzing the heat transport phenomenon, while the k-e turbulent model is used for the non-foam porous region of the tube. The effect of fully filled nickel metallic foam with different pore densities of 10, 20, and 30 metal foam with a porosity of 0.85 is being investigated. The computational solutions presented here are supported by experimental results published in the literature. The outlet exergy of the system rises with higher flow rates and falls with higher metal foam pore densities. The results of entropy generation due to thermal and fluid friction and Bejan number conceptions are also shown and discussed. © 2022 Elsevier Ltd.Item Comparison of fluid flow and heat transfer through metal foams and wire mesh by using CFD(Bentham Science Publishers, 2019) Kotresha, B.; Gnanasekaran, N.Background: The unique structural characteristics of the metal foams, such as low density, large surface area, ability to increase turbulence, and increased heat transfer efficiency, are the advantages associated with thermal applications such as electronics cooling, refrigeration air conditioning, etc. The porous metal foam structures are extensively used to enhance heat transfer. Objective: This paper discusses the numerical simulations of a vertical channel filled with metal foam and wire mesh. The fluid flow and heat transfer phenomena of a wire mesh are compared with two different types of metal foams. Metal foams are made of aluminium and copper while the wire mesh is made of brass. The porosity of the metallic porous structures varies from 0.85 to 0.95. Methods: A Darcy extended Forchheirmer model is considered for solving fluid flow through the porous media while the heat transfer through the porous media is predicted using local thermal non-equilibrium model. Results: Initially, the results obtained using the proposed numerical procedures are compared with experimental results available in the literature. The numerical simulations suggest that the pressure drop increases as the velocity of the fluid increases and decreases as the porosity increases. The heat transfer coefficient and Nusselt number are determined for both the metal foams and the wire mesh. Conclusion: The Nusselt number obtained for wire mesh shows almost 90% of the copper metal foam in the same porosity range. The numerical results suggest that the brass wire mesh porous medium can also be used for enhancement of heat transfer. In this article, patents have been discussed. © 2019 Bentham Science Publishers.Item Effect of thickness and thermal conductivity of metal foams filled in a vertical channel – a numerical study(Emerald Publishing, 2019) Kotresha, B.; Gnanasekaran, N.Purpose: This paper aims to discuss about the two-dimensional numerical simulations of fluid flow and heat transfer through high thermal conductivity metal foams filled in a vertical channel using the commercial software ANSYS FLUENT. Design/methodology/approach: The Darcy Extended Forchheirmer model is considered for the metal foam region to evaluate the flow characteristics and the local thermal non-equilibrium heat transfer model is considered for the heat transfer analysis; thus the resulting problem becomes conjugate heat transfer. Findings: Results obtained based on the present simulations are validated with the experimental results available in literature and the agreement was found to be good. Parametric studies reveal that the Nusselt number increases in the presence of porous medium with increasing thickness but the effect because of the change in thermal conductivity was found to be insignificant. The results of heat transfer for the metal foams filled in the vertical channel are compared with the clear channel in terms of Colburn j factor and performance factor. Practical implications: This paper serves as the current relevance in electronic cooling so as to open up more parametric and optimization studies to develop new class of materials for the enhancement of heat transfer. Originality/value: The novelty of the present study is to quantify the effect of metal foam thermal conductivity and thickness on the performance of heat transfer and hydrodynamics of the vertical channel for an inlet velocity range of 0.03-3 m/s. © 2018, Emerald Publishing Limited.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 Determination of interfacial heat transfer coefficient for the flow assisted mixed convection through brass wire mesh(Elsevier Masson SAS 62 rue Camille Desmoulins Issy les Moulineaux Cedex 92442, 2019) Kotresha, B.; Gnanasekaran, N.In this work, a numerical investigation of Darcy?Forchheimer mixed convection from a heated vertical flat plate embedded in a brass wire mesh porous medium is carried out to determine the coupled effects of flow and thermal diffusion. The numerical model consists of a two dimensional computational domain in which conjugate heat transfer analysis is performed to predict the hydrodynamic and thermal performance of the brass wire mesh in a vertical channel using Local Thermal Non-Equillibrium (LTNE) model. The novelty of the present study is to acquire the interfacial heat transfer coefficient, an as yet another challenging task, of the wire mesh porous medium so as to provide a quick and feasible solution to modeling of fluid flow and heat transfer through brass wire mesh porous media. The results of heat transfer through brass wire mesh are reported in terms of Colburn j factor, performance factor and are compared with other porous mediums available in literature. The present study not only opens up new vistas for more parametric studies but also provides practical and cost effective assessment to design new porous materials. © 2018 Elsevier Masson SASItem Performance score based multi-objective optimization for thermal design of partially filled high porosity metal foam pipes under forced convection(Elsevier Ltd, 2022) Jadhav, P.H.; Trilok, G.; Gnanasekaran, N.; Mobedi, M.Optimization study in flow through metal foams for heat exchanging applications is very much essential as it involves variety of fluid flow and structural properties. Moreover, the identification of best combinations of structural parameters of metal foams for simultaneous improvement of heat transfer and pressure drop is a pressing situation. In this work, six different metal foam configurations are considered for the enhancement of heat transfer in a circular conduit. The foam is aluminum with PPI varying from 10 to 45 and almost the same porosity (0.90-0.95). The aluminum foams are chosen from the available literature and they are partially filled in the conduit to reduce the pressure drop. For a constant heat flux condition, the goal is to find out the efficient metal foam and configurations when air is considered as a working fluid. A special attention is paid to the preference between pressure drop and heat transfer enhancements. That is why TOPSIS optimization techniques with five different criteria (contains the combination of the weightage/priority of heat transfer and pressure drop) is used. Based on the numerical results of heat and fluid flow in conduit, it is found that when an equal importance is given to both heat transfer and friction effect, 30 PPI aluminum foam with 80% filling on the inner lateral of the pipe provides the best score as 0.8197. The best configuration and PPI for different preferences between friction and heat transfer enhancements is discussed in details. The Reynolds number varies from 4500 to 16500. © 2021 Elsevier LtdItem Correlations and Numerical Modeling of Stacked Woven Wire-Mesh Porous Media for Heat Exchange Applications(MDPI, 2022) Trilok, G.; Srinivas, K.E.S.; Harikrishnan, D.; Gnanasekaran, N.; Mobedi, M.Metal foams have gained attention due to their heat transfer augmenting capabilities. In the literature, correlations describing relations among their morphological characteristics have successfully been established and well discussed. However, collective expressions that categorize stacked wire mesh based on their morphology and thermo-hydraulic expressions required for numerical modeling are less explored in the literature. In the present study, cross relations among the morphological characteristics of stacked wire-mesh were arrived at based on mesh-size, wire diameter and stacking type, which are essential for describing the medium and determining key input parameters required for numerical modeling. Furthermore, correlation for specific surface area, a vital parameter that plays a major role in interstitial heat transfer, is provided. With the arrived correlations, properties of stacked wire-mesh samples of orderly varied mesh-size and porosity are obtained for various stacking scenarios, and corresponding thermo-hydraulic parameters appearing in the governing equations are evaluated. A vertical channel housing the categorized wire-mesh porous media is numerically modeled to analyze thermal and flow characteristics of such a medium. The proposed correlations can be used in confidence to evaluate thermo-hydraulic parameters appearing in governing equations in order to numerically model various samples of stacked wire-mesh types of porous media in a variety of heat transfer applications. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.