Modeling Forced Convection in Finned Metal Foam Heat Sinks

Abstract

A numerical study has been undertaken to explore the details of forced convection heat transfer in finned aluminum foam heat sinks. Calculations are made using a finite-volume computational fluid dynamics (CFD) code that solves for the flow and heat transfer in conjugate fluid/porous/solid domains. The results indicate that using unfinned blocks of porous aluminum results in low convective heat transfer due to the relatively low effective thermal conductivity of the porous aluminum. The addition of aluminum fins to the heat sink significantly enhances the heat transfer with only a moderate pressure drop penalty. The convective enhancement is maximized when thermal boundary layers between adjacent fins merge together and become nearly developed for much of the length of the heat sink. It is found that the heat transfer enhancement is due to increased heat entrainment into the aluminum foam by conduction. A model for the equivalent conductivity of the finned/foam heat sinks is developed using extended surface theory. This model is used to explain the heat transfer enhancement as an increase in equivalent conductivity of the device. The model is also shown to predict the heat transfer for various heat sink geometries based on a single CFD calculation to find the equivalent conductivity of the device. This model will find utility in characterizing heat sinks and in allowing for quick assessments of the effect of varying heat sink properties.

Pore-scale and volume-averaged numerical simulations of melting phase change heat transfer in finned metal foam

“…However, the interstitial heat transfer coefficients which are necessary in the two-temperature model are difficult to determine accurately, particularly at present there is no available models for the interstitial heat transfer between the metal foam and the static PCM (such as solid PCM or liquid PCM without motion). Further, the implementation of the two-temperature model is more difficult than the one-temperature model, especially if one should tackle with the heat flux continuity boundary condition between metal foam and a solid wall [10,29]. In comparison, the one-temperature model needs no interstitial heat transfer coefficients for closure and it is easier to implement numerically.…”

Analytical solution of forced convective heat transfer in tubes partially filled with metallic foam using the two-equation model

“…Dukhan and Chen [5] conducted analytical and experimental study on forced convective heat transfer in a parallel-plate channel fully filled with metallic foams. DeGroot et al [6] undertaken a numerical study to explore details of forced convection in finned aluminum foam heat sinks. Du et al [7] performed numerical study on heat transfer in metal-foam double-pipe heat exchangers with parallel-flow arrangement.…”

“…Flow and heat transfer in a duct fully filled with metallic foams have been extensively investigated [1][2][3][4][5][6][7][8]. Calmidi and Mahajan [1] and Zhao et al [2] presented experimental and numerical studies on forced convection in metallic foams.…”

Flow and heat transfer characteristics of nanofluid flowing through metal foams

“…Recent applications include micro-channel condensers with metal-foam in the air side [10][11][12], flat-plate solar water collector with metal-foam block [13], finned metal-foam heat sinks [14], metal-foam catalyst support [15,16], and so on. The main scientific problem in these applications is related with transport phenomena in metal foams.…”