液滴的凝结与蒸发是一种相变过程，它既是一种高效的传热传质过程，又与环境气候变化密切相关。实验表明，静电场对液滴的形成过程有重要的影响，是一种有效的强化传热传质方式，也与雷电雨的形成有关。本文基于相平衡理论，利用电场作用下的热力学方程导出了静电场作用下球形介电液滴内外的压强差、蒸气压以及液滴平衡半径的数学表达式。采用数值计算的方法，利用该数学表达式对液滴的形成过程进行了分析。结果表明，与没有电场作用相比，静电场作用下介电液滴内外的压强差、蒸气压以及平衡半径都有增加。蒸气压和平衡半径增加将加速液滴的蒸发过程，因此静电场作用能够促使液滴的快速蒸发。该结论与实验相符，可为相关的理论研究及工程应用提供参考。

The condensation or evaporation of droplet is a phase change process, which is not only an efficient heat and mass transfer process, but also has a close relation with the change of the environmental climate. Experimental results show that the electrostatic field has a big influence on the formation of droplet, and it is an effective way to enhance heat and mass transfer and it’s also related to the formation of lightning and rain. Based on the phase equilibrium theory, this paper derived the mathematical expressions of pressure difference, vapor pressure and equilibrium radius of spherical dielectric droplet under electrostatic field by using the thermodynamic equations with the effects of electric field. By means of numerical calculations, it analyzed the formation process of droplet with these mathematical expressions. The results show that the pressure difference, vapor pressure and equilibrium radius of dielectric droplet under electrostatic field are increased compared with those without electric field. The increase of vapor pressure and equilibrium radius will accelerate the evaporation process of droplet, so the electrostatic field can promote the evaporation of droplet. This conclusion is consistent with the experiments and can provide reference for related theoretical researches and engineering applications.