Experimental study of flow boiling in a compact hierarchical manifold microchannel heat sink array

This work focuses on the fabrication and experimental characterization of a two-phase hierarchical manifold microchannel heat sink array for intrachip high-heat-flux dissipation. A test device with a 5 mm × 5 mm heated area and 9 × 9 array of heat sinks, each with 18 parallel channels (19 μm × 155 μm), is fabricated in silicon. A multi-layer hierarchical manifold fabricated in silicon is bonded to the heat sink array. Flow boiling experiments are conducted using HFE-7100 as the working fluid at mass fluxes of 200 kg/m²s and 300 kg/m²s. The test device is able to dissipate heat fluxes up to 445 W/cm² at a chip temperature of less than 40 °C above the fluid and at a pressure drop less than 80 kPa. A maximum heat transfer coefficient of 31,900 W/m²K occurred at a mass flux of 300 kg/m²s and a heat flux of 301 W/cm². The effects of heat flux on chip temperature, heat transfer coefficient, and pressure drop are investigated.