Experimental study on the transient heat transfer performance of spray cooling during swing excitation

Abstract

The experimental study examines the transient heat transfer performance of spray cooling when subjected to swing excitation, utilizing a swinging spray cooling apparatus. The findings suggest that the transient heat transfer process of spray cooling can be divided into two stages: rapid cooling and slow cooling. The major heat dissipation primarily occurs during the rapid cooling stage.

In transient heat transfer processes, applying swinging excitation to the spray chamber also leads to liquid accumulation inside. Increasing the swing amplitude(0° to ±135°) and reducing the swing frequency (1.5–0 Hz) both result in greater liquid accumulation depth, although this depth is significantly lower compared to the amount of liquid accumulation under steady heat transfer conditions at the same operating conditions. A moderate level of liquid accumulation can enhance heat transfer during the rapid cooling phase. However, during the slow cooling phase, when there is a higher level of liquid accumulation, it leads to an increase in convective heat transfer resistance, exacerbating the fluctuations in the cooling curve during this period. Increasing the flow rate (0.46–1.16 L/min) and decreasing the spray height (54.7–14.7 mm) prove beneficial in enhancing the heat transfer performance of spray cooling.