Numerical Investigation of the Thermo-Hydraulic Performance of Water-Ethanol Mixture in A Manifold Microchannel Heat Sink

Abstract

Effective dissipation of localized heat generated in modern electronic assemblies requires cooling systems that operate efficiently within severely constrained dimensions. Micro-scale channel heat sinks are well suited for such applications, yet their performance is governed by the interaction between flow configuration and coolant transport behavior. In this numerical investigation, a composition-controlled water–ethanol working fluid is assessed within manifold-distributed microchannel networks to examine its impact on heat transfer and flow resistance. For laminar flow at equal Reynolds numbers, the mixed coolant demonstrates improved convective response relative to single-component fluids, arising from a favorable coupling of momentum and thermal diffusion effects. This improvement is accompanied by elevated hydrodynamic losses, motivating the implementation of manifold-based flow routing. Several inlet–outlet distribution strategies, including single, dual, and multi-pass U-type arrangements, are evaluated against a conventional linear channel layout. The analysis considers square microchannels with sub-millimeter hydraulic dimensions subjected to uniform bottom heating, while accounting for variable thermophysical properties derived from established correlations. The study illustrates how simultaneous modification of coolant composition and flow architecture can be leveraged to enhance overall thermal–hydraulic effectiveness.