Experimental investigation on flow boiling characteristics of a radial micro pin–fin heat sink for hotspot heat dissipation

The rapid development of integrated circuit technology has led to an increasing chip-level heat flux, which poses a difficult challenge to cooling techniques. A radial micro pin–fin heat sink that combines the merits of micro pin–fin structure and central inlet jet configuration is proposed in this study for heat dissipation of high-heat-flux hotspot. Flow boiling experiments with ammonia are conducted for mass fluxes of 34–182 kg/m²s, heat fluxes of 752–1397 W/cm², saturation temperatures of 26 and 30 °C, and inlet conditions of near-saturated and two-phase inlet. The rectangular parallel microchannel structure is also tested for comparison. The effects of heat flux, mass flux, saturation temperature, and inlet condition on the heat transfer and pressure drop characteristics are investigated. The governing heat transfer mechanisms of microchannel flow boiling are identified for different experimental conditions. Experimental results indicate that the radial micro pin–fin heat sink can maintain stable and outstanding heat transfer performance over a wide range of experimental conditions, which verifies its application prospect in the heat dissipation of high-heat-flux hotspot.