Thermal-hydraulic performance of various designs of microchannel heat sink with internal bifurcations

Abstract

Microchannel Heat Sinks (MCHS) can dissipate large amounts of heat in a compact area making them a main choice for managing heat in space-limited applications. Recently, with the help of 3D metal printing, it became easy to fabricate various designs of MCHS with internal complex designs. This study, compare the thermo-hydraulic performance of three bifurcation based MCHS designs, with the traditional straight MCHS. Single-phase cooling of surfaces with high heat fluxes of 200 kW/m2 and 400 kW/m2, was numerically analyzed. The model is validated with the literature. The MCHS designs under study included: a standard smooth microchannel (Case A), a channel with a single extended bifurcation (Case B), multiple inline bifurcations (Case C), and a design employing stepwise bifurcations (Case D). Case A served as the reference case for comparison. Results showed that incorporating bifurcations substantially enhances the MCHS's heat removal efficiency. Specifically, the increment in Nusselt number for Cases B, C, and D compared to case A were 1.78, 1.6, and 1.55, respectively at heat flux of 200 kW/m2 and Reynolds of 200. Moreover, MCHS designs with bifurcations significantly improved temperature uniformity, achieving the best temperature uniformity of 7.7 °C at a Reynolds number of 700 under a 400 kW/m2 heat flux.