Enhancing boiling heat transfer by high-frequency pulsating jet with piezoelectric micropump

Two-phase jet impingement provides a compact cooling solution capable of dissipating high heat flux at a low pressure drop, making it favorable for electronic cooling. However, there is still a limited understanding of the boiling characteristics of high -frequency pulsating jets. To address this knowledge gap, experiments are conducted using a piezoelectric micropump to study the boiling heat transfer characteristics. The frequency of the pulsating jet was controlled by adjusting the applied signal of the piezoelectric micropump, ranging from 10 Hz to 40 Hz. Both steady jet boiling and pulsating jet boiling were investigated using two nozzle configurations, with the flow rate varying from 30 to 120 ml/min. It is found that the high -frequency pulsating jet can significantly improve the critical heat flux (CHF) to 245.2 W/cm2 at the flow rate of 60 ml/min, 84% higher than that of the steady jet. But the high -frequency pulsating jet shows no markable effects on the heat transfer coefficient within the studied parameters. This research also discussed the mechanism behind the CHF enhancement, which provides valuable insight into jet impingement boiling under flow pulsation. Furthermore, the proposed two-phase cooling system is suitable for high -power -density electronics owing to its compactness and high thermal performance.