Various Trade-Off Scenarios in Thermo-Hydrodynamic Performance of Metal Foams Due to Variations in Their Thickness and Structural Conditions

The long standing issue of increased heat transfer, always accompanied by increased pressure drop using metal foams, is addressed in the present work. Heat transfer and pressure drop, both of various magnitudes, can be observed in respect to various flow and heat transfer influencing aspects of considered metal foams. In this regard, for the first time, orderly varying pore density (characterized by visible pores per inch, i.e., PPI) and porosity (characterized by ratio of void volume to total volume) along with varied thickness are considered to comprehensively analyze variation in the trade-off scenario between flow resistance minimization and heat transfer augmentation behavior of metal foams with the help of numerical simulations and TOPSIS (Technique for Order of Preference by Similarity to Ideal Solution) which is a multi-criteria decision-making tool to address the considered multi-objective problem. A numerical domain of vertical channel is modelled with zone of metal foam porous media at the channel center by invoking LTNE and Darcy–Forchheimer models. Metal foams of four thickness ratios are considered (1, 0.75, 0.5 and 0.25), along with varied pore density (5, 10, 15, 20 and 25 PPI), each at various porosity conditions of 0.8, 0.85, 0.9 and 0.95 porosity. Numerically obtained pressure and temperature field data are critically analyzed for various trade-off scenarios exhibited under the abovementioned variable conditions. A type of metal foam based on its morphological (pore density and porosity) and configurational (thickness) aspects, which can participate in a desired trade-off scenario between flow resistance and heat transfer, is illustrated.

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Microtomography-Based Analysis of Pressure Drop and Heat Transfer Through Open Cell Metal Foams

Volume 4: Heat and Mass Transfer Under Extreme Conditions; Environmental Heat Transfer; Computational Heat Transfer; Visualization of Heat Transfer; Heat Transfer Education and Future Directions in Heat Transfer; Nuclear Energy ◽

10.1115/ht2013-17237 ◽

2013 ◽

Author(s):

M. Oliviero ◽

S. Cunsolo ◽

W. M. Harris ◽

M. Iasiello ◽

W. K. S. Chiu ◽

...

Keyword(s):

Heat Transfer ◽

Pressure Drop ◽

Metal Foam ◽

High Surface ◽

Thermal Characteristics ◽

Industrial Applications ◽

Metal Foams ◽

Surface Evolver ◽

Periodic Cell ◽

Numerical Predictions

Their light weight, open porosity, high surface area per unit volume and thermal characteristics make metal foams a promising material for many industrial applications involving fluid flow and heat transfer. Pressure drop and heat transfer of porous media have inspired a number of experimental and numerical studies. Many models have been proposed in the literature that correlate the pressure gradient and the heat transfer coefficient with the mean cell size and porosity. However, large differences exist among results predicted by different models. Most studies are based on idealized periodic cell structures. In this study, the true 3-D micro-structure of the metal foam is obtained by employing x-ray computed microtomography (XCT). For comparison, ideal Kelvin foam structures are developed in the free-to-use software “Surface Evolver” surface energy minimization program. Pressure drop and heat transfer are then investigated using the CFD Module of COMSOL® Multiphysics code. A comparison between the numerical predictions from the real and ideal geometries is carried out.

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Effect of thickness and thermal conductivity of metal foams filled in a vertical channel – a numerical study

International Journal of Numerical Methods for Heat &amp Fluid Flow ◽

10.1108/hff-11-2017-0465 ◽

2019 ◽

Vol 29 (1) ◽

pp. 184-203 ◽

Cited By ~ 2

Author(s):

Banjara Kotresha ◽

N. Gnanasekaran

Keyword(s):

Heat Transfer ◽

Thermal Conductivity ◽

Metal Foam ◽

Numerical Study ◽

Flow Characteristics ◽

Vertical Channel ◽

Metal Foams ◽

Heat Transfer Analysis ◽

Transfer Model ◽

Content Type

PurposeThis 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/approachThe 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.FindingsResults 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 implicationsThis 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/valueThe 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.

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Numerical Analysis of Heat Transfer and Pressure Drop in Metal Foams for Different Morphological Models

Journal of Heat Transfer ◽

10.1115/1.4028113 ◽

2014 ◽

Vol 136 (11) ◽

Cited By ~ 27

Author(s):

Marcello Iasiello ◽

Salvatore Cunsolo ◽

Maria Oliviero ◽

William M. Harris ◽

Nicola Bianco ◽

...

Keyword(s):

Heat Transfer ◽

Reynolds Number ◽

Pressure Drop ◽

Metal Foam ◽

High Surface ◽

Industrial Applications ◽

Metal Foams ◽

The Real ◽

Numerical Predictions ◽

The Ideal

Because of their light weight, open porosity, high surface area per unit volume, and thermal characteristics, metal foams are a promising material for many industrial applications involving fluid flow and heat transfer. The pressure drop and heat transfer in porous media have inspired a number of experimental and numerical studies, and many models have been proposed in the literature that correlate the pressure gradient and the heat transfer coefficient with the mean cell size and porosity. However, large differences exist among results predicted by different models, and most studies are based on idealized periodic cell structures. In this study, the true three-dimensional microstructure of the metal foam is obtained by employing x-ray computed microtomography (XCT). This is the “real” structure. For comparison, ideal Kelvin foam structures are developed in the free-to-use software “surface evolver” surface energy minimization program. These are “ideal” structures. Pressure drop and heat transfer are then investigated in each structure using the CFD module of COMSOL® Multiphysics code. A comparison between the numerical predictions from the real and ideal geometries is carried out. The predictions showed that heat transfer characteristics are very close for low values of Reynolds number, but larger Reynolds numbers create larger differences between the results of the ideal and real structures. Conversely, the differences in pressure drop at any Reynolds number are nearly 100%. Results from the models are then validated by comparing them with experimental results taken from the literature. The validation suggests that the ideal structure poorly predicts the heat transfer and pressure drops.

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Influence of pore density on heat transfer and pressure drop characteristics of wet air in hydrophilic metal foams

Applied Thermal Engineering ◽

10.1016/j.applthermaleng.2019.113897 ◽

2019 ◽

Vol 159 ◽

pp. 113897 ◽

Cited By ~ 1

Author(s):

Zhancheng Lai ◽

Haitao Hu ◽

Guoliang Ding

Keyword(s):

Heat Transfer ◽

Pressure Drop ◽

Metal Foams ◽

Pore Density

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A Synergistic Combination of Thermal Models for Optimal Temperature Distribution of Discrete Sources Through Metal Foams in a Vertical Channel

Journal of Heat Transfer ◽

10.1115/1.4041955 ◽

2018 ◽

Vol 141 (2) ◽

Cited By ~ 1

Author(s):

Banjara Kotresha ◽

N. Gnanasekaran

Keyword(s):

Heat Transfer ◽

Temperature Distribution ◽

Heat Source ◽

Metal Foam ◽

Vertical Channel ◽

Metal Foams ◽

Local Thermal Equilibrium ◽

High Porosity ◽

Heat Sources ◽

Excess Temperature

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.

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EXPERIMENTAL STUDY OF FREE CONVECTION HEAT TRANSFER IN THE POROUS METAL-FOAM HEAT SINK

Transactions of the Canadian Society for Mechanical Engineering ◽

10.1139/tcsme-2013-0071 ◽

2013 ◽

Vol 37 (3) ◽

pp. 841-850 ◽

Cited By ~ 1

Author(s):

Tzer-Ming Jeng ◽

Sheng-Chung Tzeng ◽

Zhi-Ting Yeh

Keyword(s):

Heat Transfer ◽

Free Convection ◽

Metal Foam ◽

Convection Heat Transfer ◽

Porous Metal ◽

Metal Foams ◽

Heat Sinks ◽

Convection Heat ◽

Pore Density ◽

Free Convection Heat

This study experimentally investigated the free convection heat transfer characteristics of the annular metal-foam heat sinks. The results showed that the heat transfer coefficient (h) decreased as the pore density of metal foams increased when the thickness (tc) of the annular metal foams equaled 5 mm, but the (h) increased as the pore density increased when tc = 11 and 14.5 mm. Besides, the (h) increased firstly and then decreased as (tc) increased. There was better heat transfer effect when tc = 11 mm in the present study.

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Investigation of Mixed Convection Heat Transfer Through Metal Foams Partially Filled in a Vertical Channel by Using Computational Fluid Dynamics

Journal of Heat Transfer ◽

10.1115/1.4040614 ◽

2018 ◽

Vol 140 (11) ◽

Cited By ~ 2

Author(s):

Banjara Kotresha ◽

N Gnanasekaran

Keyword(s):

Heat Transfer ◽

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Fluid Flow ◽

Metal Foam ◽

Convection Heat Transfer ◽

Vertical Channel ◽

Metal Foams ◽

Convection Heat ◽

Mixed Convection Heat Transfer

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.

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Enhanced Heat Transfer and Thermal Performance of Metal Foam Microchannel Heat Sinks With Internal Y-Shaped Bifurcation

Volume 8: Heat Transfer and Thermal Engineering ◽

10.1115/imece2016-66449 ◽

2016 ◽

Author(s):

Han Shen ◽

Xueting Liu ◽

Bengt Sunden ◽

Gongnan Xie

Keyword(s):

Heat Transfer ◽

Thermal Management ◽

Thermal Performance ◽

Metal Foam ◽

Electronic Devices ◽

Metal Foams ◽

Heat Sinks ◽

Pore Density ◽

Transfer Enhancement ◽

Microchannel Heat Sinks

Internal Y-shaped bifurcation has been proved to be an advantageous way on improving thermal performance of microchannel heat sinks according to the previous research. Metal foams are known due to their predominate performance such as low-density, large surface area and high thermal conductivity. In this paper, different parameters of metal foams in Y-shaped bifurcation microchannel heat sinks are designed and investigated numerically. The effects of Reynolds number, porosity of metal foam, and the pore density (PPI) of the metal foam on the microchannel heat sinks are analyzed in detail. It is found that the internal Y-shaped bifurcation microchannel heat sinks with metal foam exhibit better heat transfer enhancement and overall thermal performance. This research provides broad application prospects for heat sinks with metal foam in the thermal management of high power density electronic devices.

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