Thermal Performance Enhancement of Microchannel Heat Sinks with Sintered Porous Media

Abstract

Heat-transfer enhancement of a microchannel heat sink (MCHS) with a sintered porous medium was performed numerically in detail. The three-dimensional Brinkman–Darcy–Forchheimer equations and energy equation were solved using the finite-volume method. Emphasis was placed on the effects of pumping power, geometric parameters, and properties of a porous metallic medium on the temperature distribution, pressure drop, and thermal resistance of the MCHS. The results show improved heat-transfer performance of an MCHS with a porous metallic medium compared to the performance of that without this medium. However, a significant pressure drop was induced along the channel. The results also indicate that the overall thermal resistance of the MCHS was reduced significantly when the pumping power was increased. However, the effectiveness declined considerably under high pumping power and the thermal resistance of the porous channel was not necessarily smaller than that without porous media; this suggests that if the pumping power is not large enough to overcome the pressure loss, the system will fail. We also found that for the same porous conditions (porosity and permeability), an appropriate number of channels, channel aspect ratio, or width ratio gives a porous MCHS a low thermal resistance and that for the same geometric dimensions, and a porous MCHS with higher porosity and permeability has a lower thermal resistance and a maximum 76.6% improvement in thermal resistance in the range of parameters considered in this study.

Acknowledgments

Financial support by the National Science Council, R. O. C., through the contract NSC 101-2221-E145-003 and NSC 101-2221-E-024 -007 is highly appreciated.