Spray cooling is a promising approach to efficient removal of heat and has attracted increasing interest with its excellent characteristics, such as strong heat exchange capacity, low flow rate, and uniform temperature distribution. Recently, high voltages have been successfully employed in electrospray (ES) cooling, which has improved cooling performance but has poor heat transfer control. We experimentally investigate heat transfer performance of ES cooling with different spray modes, and we study spray characteristics and droplet impinging behavior of the different modes. The results show that droplet size decreases and spray velocity increases with increasing applied voltage, and droplet formation and subsequent impinging behavior are gradually dominated by electric forces. In addition, the nucleate boiling region is significantly extended, and the critical heat flux (CHF) increases to a higher surface temperature when the spray mode is transformed to cone-jet/multi-jet modes. Under certain conditions, ES cooling achieves a 2.8 times enhancement rate over neutral (no voltage) dropwise cooling. Moreover, the visualization results of the droplet impinging behavior on the hot surface for different spray modes are consistent with their cooling performance. Overall, ES cooling is found to greatly improve the cooling capacity, and the specific mechanisms for enhancement vary with spray mode. Our results contribute to precise control of ES cooling and give a better understanding of the effect of electric fields on spray cooling.

喷雾冷却是有效去除热量的一种有前途的方法，并以其出色的特性（例如强大的热交换能力，低流量和均匀的温度分布）而引起了越来越多的关注。近来，高压已成功地用于电喷雾（ES）冷却中，该技术具有改进的冷却性能，但传热控制较差。我们通过实验研究了不同喷雾方式下ES冷却的传热性能，并研究了不同喷雾方式下的喷雾特性和撞击液滴的行为。结果表明，随着施加电压的增加，液滴尺寸减小，喷雾速度增加，并且液滴的形成和随后的撞击行为逐渐受到电力的支配。此外，核沸腾区域显着延长，当将喷涂模式转换为锥喷/多喷模式时，临界热通量（CHF）增大到较高的表面温度。在某些条件下，与中性（无电压）逐滴冷却相比，ES冷却可获得2.8倍的增强率。而且，对于不同的喷雾模式，液滴在热表面上的撞击行为的可视化结果与其冷却性能一致。总体而言，发现ES冷却可大大提高冷却能力，并且增强的具体机制随喷涂模式而异。我们的结果有助于精确控制ES冷却，并更好地了解电场对喷雾冷却的影响。与中性（无电压）逐滴冷却相比，ES冷却实现了2.8倍的增强率。而且，对于不同的喷雾模式，液滴在热表面上的撞击行为的可视化结果与其冷却性能一致。总体而言，发现ES冷却可大大提高冷却能力，并且增强的具体机制随喷涂模式而异。我们的结果有助于精确控制ES冷却，并更好地了解电场对喷雾冷却的影响。与中性（无电压）逐滴冷却相比，ES冷却实现了2.8倍的增强率。而且，对于不同的喷雾模式，液滴在热表面上的撞击行为的可视化结果与其冷却性能一致。总体而言，发现ES冷却可大大提高冷却能力，并且增强的具体机制随喷涂模式而异。我们的结果有助于精确控制ES冷却，并更好地了解电场对喷雾冷却的影响。增强的具体机制因喷涂模式而异。我们的结果有助于精确控制ES冷却，并更好地了解电场对喷雾冷却的影响。增强的具体机制因喷涂模式而异。我们的结果有助于精确控制ES冷却，并更好地了解电场对喷雾冷却的影响。