Pool boiling heat transfer enhancement using sintered particle wick structure

Abstract

There is a high need of two-phase cooling technology for a high heat with a small thermal resistance in various applications including energy, space, and electronic systems. A pool boiling is a simple, efficient, and reliable cooling approach, but a main technical challenge lies in poor Heat Transfer Coefficient (HTC) and limited Critical Heat Flux (CHF) due to excessive vapor in the heated surface at high heat flux. To address this challenge, we perform pool-boiling heat transfer enhancement using sintered particle wick structures consisted of 1 to 3 layers of 200 µm copper particles, to minimize the excessive vapor coverage by capillary-driven liquid supply to the heated surface. The HTC and CHF for the wick structures are measured using water at ambient pressure. Enhancements in the Heat Transfer Coefficient and CHF are found primarily due to a high rate of bubble generation from the sintered wick surface, thermal-hydraulic length modulation and high bubble release frequency. We also found that the gravity/capillary imbibition in the wick structures is important on the liquid supply to the heated surface from the droplet size dependent wettability test, and this may contribute to the HTC and CHF enhancement in wick structure.