Abstract:

Electrostatic spray is widely used in industry, such as electrostatic spraying, electrostatic atomizing combustion, electrostatic atomization dust removal, etc. The application effect is closely related to spray charge characteristics. In order to obtain a better charge effect, the influence of the induced current on the true charge current of the droplet during the corona charging process was explored. The changes of spray charge-to-mass ratio, charge decay and droplet size were studied by changing the charge voltage, electrode spacing, electrode ring diameter and liquid flow rate. The results showed that the corona charging process is unstable but can obtain better charge effect. The charge-to-mass ratio of droplet decrease first then increases as the increase of charge voltage. It increases first and then decreases with the increase of the electrode ring diameter, and increases with the increase of the electrode spacing at the same voltage. The best charging effect is that the electrode ring diameter is 80mm and the electrode spacing is 40mm. When the droplet was charged, the charge amount would vary with the transport distance. The corona charge decayed faster than inductive charge at the same distance. Charged droplet could reduce the surface tension and the particle size of the droplet. As the charge capacity of the droplet increases, the droplet size decreases.

Key words: corona charge, electrostatic spray, charge-to-mass ratio, charge decay, size distribution

摘要：

静电喷雾广泛应用于工业各个领域，如静电喷涂、静电雾化燃烧、静电雾化除尘等，其应用效果与喷雾荷电特性密切相关。为获得更佳荷电效果，本文探究了电晕荷电过程中感应电流对液滴真实荷电电流的影响，通过改变荷电电压、电极间距、电极环直径及液体流量等，实验研究了各因素变化对喷雾荷质比、电荷衰减及液滴粒径的影响。结果表明：相比于感应荷电，电晕荷电过程不稳定但能获得更佳的荷电效果，液滴荷质比随荷电电压的增加而先减小后增大，随电极环直径的增加而先增大后减小，随电极间距的增大而增大，电极环直径80mm，电极间距40mm能获得最佳荷电效果；荷电液滴带电量会随输运距离增加而泄漏衰减，相同距离下液滴通过电晕放电带有电荷后衰减更快；液滴带电后能够降低液体表面张力，随着液滴荷电量的增加，雾化液滴粒径有所降低。

关键词: 电晕荷电, 静电喷雾, 荷质比, 电荷衰减, 粒度分布