Electrohydrodynamic (EHD) enhancement of water droplet evaporation by non-uniform electric field and the subsequent dynamic characteristics were experimentally investigated in this paper. A pin-to-plate electric field was produced by a needle connected to a high-voltage power supply and the grounded heated surface coated by thin Teflon film with a contact angle of about 100°. The droplet was generated onto the hot surface by a micro-syringe with a constant initial volume of 4 μl, and a high-speed camera was used to capture the droplet morphology. Effects of electric field and surface temperature on the contact angle, droplet height, evaporation stage, volume variation, and evaporation rate were studied. The results showed that both the increase in external electric field strength and surface temperature enhance droplet evaporation with a maximum enhancement ratio of 6.8 times in the present work. In addition, a special extra constant contact angle (CCA) stage was found in droplet evaporation under electric field, while only constant contact radium (CCR) and Mixed stages existed in neutral (no voltage) evaporation. In particular, the evaporation enhancing mechanism of no-uniform electric field considering corona wind blowing, surface tension weakening and molecular orientational alignment was also presented.

本文通过实验研究了非均匀电场对水滴蒸发的电液动力学（EHD）增强作用以及随后的动态特性。针到板的电场是通过与高压电源相连的针产生的，接地的加热表面被铁氟龙薄膜覆盖，接触角约为100°。液滴通过恒定初始体积为4μl的微注射器在热表面上生成，并使用高速相机捕获液滴形态。研究了电场和表面温度对接触角，液滴高度，蒸发阶段，体积变化和蒸发速率的影响。结果表明，外部电场强度和表面温度的增加均增强了液滴的蒸发，目前的最大增强比为6.8倍。此外，在电场作用下的液滴蒸发中发现了一个特殊的超恒定接触角（CCA）阶段，而在中性（无电压）蒸发中仅存在恒定接触镭（CCR）阶段和混合阶段。特别地，还提出了考虑电晕风吹，表面张力减弱和分子取向排列的不均匀电场的蒸发增强机理。而在中性（无电压）蒸发中仅存在恒定接触镭（CCR）和混合阶段。特别地，还提出了考虑电晕风吹，表面张力减弱和分子取向排列的不均匀电场的蒸发增强机理。而在中性（无电压）蒸发中仅存在恒定接触镭（CCR）和混合阶段。特别地，还提出了考虑电晕风吹，表面张力减弱和分子取向排列的不均匀电场的蒸发增强机理。