气流中荷电液滴破碎数值模拟

Numerical simulation on charged droplets breakup in high velocity gas flow

荷电液滴破碎过程十分复杂,影响因素繁多,并且破碎时间短暂,难以进行试验研究。对荷电液滴的破碎过程进行了分析,根据荷电后液体表面张力的变化,得出荷电液滴We数的表达式,得出破碎过程的主要影响因素有气液相对速度、气液物性参数以及静电场。在此基础上,选用VOF多相流模型、四边形网格和SIMPLE算法,设定不同的气液相对速度、液滴初始粒径等参数,对液滴破碎过程进行了数值模拟。模拟结果发现We数不同,液滴有可能出现袋形破碎、剪切破碎或爆炸破碎。对于低粘度液体,We数可以作为破碎类型的主要判别依据。气液参数相同的情况下,荷电液滴We数大,液滴更容易发生变形破碎。

It is very difficult to do experiment because the process of and instantaneous. In this paper, several factors that influence the c charged droplet breakup is complex harged droplet breakup process are analyzed by deducing the ression of Weber, which are gas-liquid relative velocity, gas-liquid parameters and electrostatic field. Then, the breakup process is simulated by choosing VOF multi-phase model, quadrangle grid and SIMPLE method. The simulation of droplet breakup shows breakup model may be bag breakup, shear breakup or explosion breakup. For low viscosity liquid, the Weber number can be the main criterion of breakup model. With the same parameter, charged droplet is easier to breakup than uncharged droplet, because the Weber number of charged droplet is larger.