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

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 thermohydraulic performance of three bifurcation based MCHS designs, with the traditional straight MCHS. Singlephase cooling of surfaces with high heat fluxes of 200 kW/m 2 and 400 kW/m 2 , 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/m 2 and Reynolds of 200. Moreover, MCHS designs with bifurcations significantly improved temperature uniformity, achieving the best temperature uniformity of 7.7 degrees C at a Reynolds number of 700 under a 400 kW/m 2 heat flux.