Boundary Effect on Temperature Gradients in Microchannels

The effect of boundary conditions on heat transfer in rectangular microchannels is investigated. Of primary interest in this study is the influence of the boundary conditions on the temperature gradients in such geometries. The top of the microchannel under consideration is exposed to a uniform heat flux, which simulates the energy dissipated from electronic chips. Cooling fluid is allowed to flow through channels underneath the heat source. The physical configuration is subjected to various boundary conditions (e.g., first, second, and third kinds) and any combination of convection and radiation energy exchanges between the exposed surfaces and the external environment. The current configuration covers typical situations as found in most electronic cooling systems. The influences of the heat source strength, the external environment, and the aspect ratio are studied. The effects of varying these factors in a range typical of electronics thermal management applications are investigated. Temperature gradients along the fluid flow direction and their effect on the fluid resistance are presented.