Investigation on visualization and heat transfer performance study of the mini-channel flow boiling

Abstract

In recent years, mini-channel water flow boiling has been proven to have favorable cooling capability, especially for electronic component heat dissipation. Nevertheless, the fundamental principles related to flow boiling in mini-channel water lack clear comprehension, and the relevant experimental data on heat transfer performance and CHF visualization need to be supplemented. The behavior of vapor bubbles was explored in detail through visualization experiments to elucidate the mechanism of flow boiling and heat transfer in mini-channels. Meanwhile, the effects of mass flux, heat flux and tilt angle on the flow boiling of water and the CHF characteristics were revealed clearly though a series of crossover experiments. The results showed that in mini-channel water flow boiling, mass flux and heat flux will have effects on vapor bubble behavior, especially the merging of vapor bubbles, and then modify the heat transfer coefficient, and the mass flux in the optimal range exists. The tilt angle has less effect on the heat transfer coefficient, but affects the rate of vapor bubble growth. After local dryness the heat transfer mechanism transitions directly to film boiling instead of transition boiling, the boiling curve grows linearly with the wall superheat, and the CHF increases with increased mass flux. The research content of this paper helps to fill the gap in the experimental study of flow boiling in mini-channel and provides guidance for related practical applications.