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This paper reports the results of an experimental investigation on the heat transfer performance of metal foam as a heat sink subjected to oscillating flow. The measured pressure drops, velocities, and surface temperatures of oscillating flow through aluminum 40 PPI foam are presented in detail. The calculated cycle-averaged local temperatures and Nusselt numbers for different kinetic Reynolds numbers were analyzed. The variation of total heat transfer rate with a kinetic Reynolds number suggests that oscillating flow at relative low frequency has a substantial effect on heat transfer enhancement in a metal foam heat sink. A comparison of the length-averaged Nusselt numbers between oscillating and steady flows indicates that higher heat transfer rates can be obtained in metal foams subjected to oscillating flow. The relation between pumping power and total heat transfer rates for the oscillating flow cooling system was also analyzed with a view to designing a novel heat sink using metal foam. The results show that high heat transfer performance of metal foam heat sinks subject to oscillating flow can be obtained with moderate pumping power. [ABSTRACT FROM AUTHOR]

Open-cell metal foams exhibit distinctive advantages in fluid control and heat transfer enhancement in thermal and chemical engineering. The thermofluidic transport characteristics at pore scale such as topological microstructure and morphological appearance significantly affect fluid flow and conjugated heat transfer in open-cell metal foams, important for practically designed applications. The present study employed an idealized tetrakaidecahedron unit cell (UC) model to numerically investigate the transport properties and conjugated heat transfer in highly porous open-cell metal foams (porosity--0.95). The effects of foam ligaments and nodes (size and cross-sectional shape) on thermal conduction, fluid flow, and conjugated heat transfer were particularly studied. Good agreement was found between the present predictions and the results in open literature. The effective thermal conductivity was found to decrease with increasing node-size-to-ligament ratio, while the permeability and volume-averaged Nusselt number were increased. This indicated that the effects of node size and shape upon thermofluidic transport need to be considered for open-cell metal foams having high porosities. [ABSTRACT FROM AUTHOR]

Open-cell metal foams exhibit distinctive advantages in fluid control and heat transfer enhancement in thermal and chemical engineering. The thermofluidic transport characteristics at pore scale such as topological microstructure and morphological appearance significantly affect fluid flow and conjugated heat transfer in open-cell metal foams, important for practically designed applications. The present study employed an idealized tetrakaidecahedron unit cell (UC) model to numerically investigate the transport properties and conjugated heat transfer in highly porous open-cell metal foams (porosity--0.95). The effects of foam ligaments and nodes (size and cross-sectional shape) on thermal conduction, fluid flow, and conjugated heat transfer were particularly studied. Good agreement was found between the present predictions and the results in open literature. The effective thermal conductivity was found to decrease with increasing node-size-to-ligament ratio, while the permeability and volume-averaged Nusselt number were increased. This indicated that the effects of node size and shape upon thermofluidic transport need to be considered for open-cell metal foams having high porosities. [ABSTRACT FROM AUTHOR]