Optimization of Micro Channel Morphology

An increasing demand for a higher heat flux removal capability within a smaller volume for high power electronics led us to focus on micro channels in contrast to the classical heat fin design. A micro channel can have various shapes to enhance heat transfer, but the shape that will lead to a higher heat flux removal with a moderate pumping power needs to be determined. The standard micro-channel terminology is usually used for channels with a simple cross section, e.g. square, round, triangle, etc., but here the micro channel cross section is going to be expanded to describe more complicated and interconnected micro scale channel cross sections. The micro channel geometries explored are pin fins (in-line and staggered), parallel plates and sintered porous micro channels (see Fig.1). The problem solved here is a conjugate problem involving two heat transfer mechanisms; 1) porous media effective conductivity and 2) internal convective heat transfer coefficient. Volume averaging theory (VAT) is used to rigorously cast the point wise conservation of energy, momentum and mass equations into a form that represents the thermal and hydraulic properties of the micro channel (porous media) morphology. Using the resulting VAT based field equations, optimization of a micro channel heated from one side is used to determine the optimum micro channel morphology. A small square of 1 cm ² is chosen as an example and the thermal resistance, ⁰C/W, and pressure drop are shown as a function of Reynolds number.