Reducing instability and enhancing critical heat flux using integrated micropillars in two-phase microchannel heat sinks

We present a novel design of two-phase microchannel heat sink with integrated micropillars on the bottom heated surface. The microchannel can achieve significantly reduced flow boiling instability, and an enhanced heat transfer coefficient (40%) and critical heat flux (17%) compared to that without micropillars. In this design, the liquid film on the heated surface is sustained due to the capillary force within the micropillars and thin film evaporation dominates the heat transfer. The experimental results indicate that the capillary pressure can be maximized without introducing large viscous drag when the microstructure geometry is optimized. The insights gained from this work guide the design of stable, high performance two-phase microchannel heat sinks.