Thermal and hydraulic performance analysis of fractal microchannel heat sinks

The increasing power density of electronic devices demands efficient cooling solutions. Fractal microchannel heat sinks (MCHSs) are promising due to their ability to distribute coolant uniformly through branching networks. The novelty of this work lies in the comparative numerical and experimental evaluation of three modified Y-fractal MCHS configurations, Y-fractal heat sink (Y-FHS-SC), Y-fractal bottom cavities heat sink (Y-FBCHS-SC), and Y-fractal wavy heat sink (Y-FWHS-SC) with secondary connections, under identical operating conditions to clarify the trade-off between heat transfer enhancement and hydraulic resistance. Three-dimensional simulations were performed and validated experimentally for flow rates ranging from 150–300 ml min −1 with a constant heat flux of 20 W cm −2 . The results show that the Y-FWHS-SC significantly enhances convective heat transfer due to contraction–expansion effects and improved fluid mixing, producing a maximum average Nusselt number enhancement of 62.8% and 49.0% compared with Y-FBCHS-SC and Y-FHS-SC, respectively. However, this design introduces a substantial hydraulic penalty, with pressure drop increasing by approximately 9 times. Overall thermo-hydraulic evaluation indicates that Y-FHS-SC provides the most balanced performance for practical electronic cooling applications.