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

Kotresha, Banjara; Gnanasekaran, N.

doi:10.1108/hff-11-2017-0465

Cited by 13 publications

(11 citation statements)

References 31 publications

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“…The assumptions made in the present numerical examination are as follows: The flow is steady and incompressible. The gravitational impact on the fluid flow is assumed to be negligible (Huang et al , 2010). The experimental and numerical investigation (Calmidi and Mahajan, 2000) shows the insignificant effect of thermal dispersion in foam-air combination because of high heat conducting capacity of metal foams, hence thermal dispersion is neglected in the presented study. In the investigations (Garrity et al , 2010; Baragh et al , 2018; Boules et al , 2021), the influence of thermal radiation was found to be negligible, hence the same condition is adopted in the current study. The flow mixing due to the tortuous path of the metal foam is not considered (Kotresha and Gnanasekaran, 2018a). Metal foam region is assumed as isotropic homogeneous porous media (Kotresha et al , 2019; Kotresha and Gnanasekaran, 2018b; Garrity et al , 2010).…”

Section: Methodsmentioning

confidence: 93%

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Minimization of exergy destruction with discrete metal foam filling in a pipe under turbulent flow condition

Kotresha²,

Naik

2023

HFF

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Purpose This study aims to present the numerical analysis of exergy transfer and irreversibility through the discrete filling of high-porosity aluminum metal foams inside the horizontal pipe. Design/methodology/approach In this study, the heater is embedded on the pipe’s circumference and is assigned with known heat input. To enhance the heat transfer, metal foam of 10 pores per inch with porosity 0.95 is filled into the pipe. In filling, two kinds of arrangements are made, in the first arrangement, the metal foam is filled adjacent to the inner wall of the pipe [Model (1)–(3)], and in the second arrangement, the foam is located at the center of the pipe [Models (4)–(6)]. So, six different models are examined in this research for a fluid velocity ranging from 0.7 to7 m/s under turbulent flow conditions. Darcy Extended Forchheimer is combined with local thermal non-equilibrium models for forecasting the flow and heat transfer features via metal foams. Findings The numerical methodology implemented in this study is confirmed by comparing the outcomes with the experimental outcomes accessible in the literature and found a fairly good agreement between them. The application of the second law of thermodynamics via metal foams is the novelty of current investigation. The evaluation of thermodynamic performance includes the parameters such as mean exergy-based Nusselt number (Nue), rate of irreversibility, irreversibility distribution ratio (IDR), merit function (MF) and non-dimensional exergy destruction (I*). In all the phases, Models (1)–(3) exhibit better performance than Models (4)–(6). Practical implications The present study helps to enhance the heat transfer performance with the introduction of metal foams and reveals the importance of available energy (exergy) in the system which helps in arriving at optimum design criteria for the thermal system. Originality/value The uniqueness of this study is to analyze the impact of discrete metal foam filling on exergy and irreversibility in a pipe under turbulent flow conditions.

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Section: Methodsmentioning

confidence: 93%

“…The flow mixing due to the tortuous path of the metal foam is not considered (Kotresha and Gnanasekaran, 2018a).…”

Section: Methodsmentioning

confidence: 99%

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Minimization of exergy destruction with discrete metal foam filling in a pipe under turbulent flow condition

Kotresha²,

Naik

2023

HFF

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“…Hence, it is crucial to analyze the thermo-hydraulic behavior of metal foams with both flow resistance and heat transfer enhancement. Several factors that influence flow and heat transfer through metal foam include material aspects (thermal conductivity [11]), structural aspects (porosity and pore density [12]), configurational aspects (thickness [11,13] and partial filling [14,15]), the foam geometrical aspect (shape [16]), and the arrangement aspect (foam multi-layer [17]), etc. It is interesting to note that different combinations of these aspects result in varied pressure drop and heat transfer, thus allowing a better trade-off between enhanced heat transfer with the accompanied increased pressure drop.…”

Section: Introductionmentioning

confidence: 99%

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

Gnanasekaran

Mobedi

2021

Energies

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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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“…From the point of view of the numerical modeling, finding an adequate representation of clusters of obstacles that captures the relevant features of the flow effectual for design purposes at reasonable computational cost is not a trivial task (Kotresha and Gnanasekaran, 2019). Homogenization is an elegant and efficient method in pursuing this goal (Jumah et al, 2001;Blanco et al, 2017;Hayat et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

A multiscale method for producing homogenized drag laws of a permeable medium by conflating experimental data with Lattice-Boltzmann simulations

Clausse

Silin

Boroni

2019

HFF

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Purpose The purpose of this paper is to obtain a permeability law of a gas flow through a permeable medium using particle image velocimetry experimental data as primal information, which is conflated with numerical calculations by means of a multi-scale method. Design/methodology/approach The D2Q9 single-relaxation-time Lattice Boltzmann model (LBM) implemented in GPU is used for the numerical calculations. In a first homogenized micro-scale, the drag forces are emulated by means of an effective Darcy law acting only in the close neighborhood of the solid structures. A second mesoscopic level of homogenization makes use of the effective drag forces resulting from the first-scale model. Findings The procedure is applied to an experiment consisting of a regular array of wires. For the first level of homogenization, an effective drag law of the individual elemental obstacles is produced by conflating particle image velocimetry measurements of the flow field around the wires and numerical calculations performed with a GPU implementation of the LBM. In the second homogenization, a Darcy–Forchheimer correlation is produced, which is used in a final homogenized LBM model. Research limitations/implications The numerical simulations at the first level of homogenization require a substantial amount of calculations, which in the present case were performed by means of the computational power of a GPU. Originality/value The homogenization procedure can be extended to other permeable structures. The micro-scale-level model retrieves the fluid-structure forces between the flow and the obstacles, which are difficult to obtain experimentally either from direct measurement or by indirect assessment from velocity measurements.

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

Cited by 13 publications

References 31 publications

Minimization of exergy destruction with discrete metal foam filling in a pipe under turbulent flow condition

Minimization of exergy destruction with discrete metal foam filling in a pipe under turbulent flow condition

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

A multiscale method for producing homogenized drag laws of a permeable medium by conflating experimental data with Lattice-Boltzmann simulations

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