Abstract: Based on the Brinkman-extended Darcy Equation, both double-equation resolving model and mono-equation resolving model for fluid flow in micro scale are designed. The analytical solutions for the velocity and the temperature profiles of fluid flow in microchannel are obtained and compared by abstracting the microchannel heat sinks as a block of fluid-saturated porous medium. Furthermore, the effects of aspect ratio and the effective thermal conductivity ration on fluid flow and heat transfer in microchannel are analyzed. It is proved that the analytical solutions of both the double-equation and mono-equation resolving models can predict the volume average profiles of the velocity and the temperature in microchannel. Notably, it is focused that the double-equation resolving porous medium model can predict the total thermal resistance and optimize the structure performance of the microchannel heat sinks. The optimized microchannel heat sinks is manufactured on the silicon wafer through multiplex inductively coupled plasma etching. On the condition of local thermal equivalence, the mono-equation resolving porous medium model can be used in practical calculation expediently without depending on the heat transfer coefficients, which can only be obtained in experiments.

Key words: Microchannel, Heat sinks, Heat transfer, Micro scale, Porous medium