Effects of micro-slots in fully interconnected microchannels on flow boiling heat transfer

Abstract

This study introduced the experimental work to assess the effect of micro-slots on the flow boiling characteristics of HFE-7100 in a microchannel heat sink. In this work, fully interconnected microchannels with three different slot sizes of 10 μm, 20 μm and 40 μm, are designed as active nucleation sites to enhance flow boiling and thin film evaporation. The different slots sizes are defined the name as 135, 125 and 112 slots per inch (SPI), respectively. This new configuration is developed based on the experimental and theoretical study of half interconnected microchannel design. Results shows that compared to the plain wall microchannels, the heat transfer coefficient and critical heat flux of the fully interconnected microchannels with 135 SPI are significantly improved by up to 5.5 and 1.82 times, respectively. In addition, the transient study indicates that flow boiling in the present design is more stable than that in plain wall microchannels. Moreover, a visualization study was conducted to investigate the mechanism of high-frequency rewetting through micro slots. The study verified the importance of the micro-slots in microchannels with respect to the heat transfer rates and pressure drop.