Numerical Simulation of Heat Transfer in GraduallyVarying Microchannel Heat Sink

Microchannel heat sink has broad relevance in microelectronics and optical devices. Study in this paper focuses on enhancing the cooling characteristics of microchannel heat sink used in such devices. Instead of conventional, rectangular or circular cross-section channel designs, this study uses microchannels with gradually varying cross-section along the length. Three channels geometries employing entirely diverging or converging designs as well as combined diverging-diverging design are studied. The cooling performance is ascertained by using nanofluid and DI water as coolants flowing at different Reynolds numbers by analysing thermal characteristics such as temperature variation and Nusselt number using commercial software ANSYS^® Fluent. Study demonstrates that the nanofluid is more efficient for the heat sink application irrespective of the channel geometry.