不同电场中细颗粒物的荷电特性研究

Research on the Charging of Fine Particulate in Different Electric Fields

为了研究细颗粒物在直流电晕放电和脉冲电晕放电条件下的不同荷电特性,采用静电低压撞击器分别测试直流电场和脉冲电场中不同电压条件下的单个颗粒平均荷电量,并与理论计算结果进行对比,结果表明:在直流电晕放电中细颗粒物直径小于0.2μm时主要以扩散荷电为主,大于0.2μm时主要以场致荷电为主;在脉冲电晕放电中细颗粒物主要通过自由电子和离子的迁移扩散进行荷电,最终小粒径段颗粒物荷正电且荷电量非常少,大粒径段颗粒物荷负电;在相同的线板式反应器中,脉冲电场可以比直流电场施加更高的峰值电压,加剧带电粒子与颗粒物之间的碰撞荷电,最终提高颗粒物的荷电量。

In the present paper, the charging characteristic of fine particulate trader different applied voltages in both DC and pulsed electric field were investigated using the electrical low-pressure impactor （ELPI）. Experimental data were compared with the simulation results. The results show that in DC electric field, the charging of fine particles with the diameters smaller than 0.2k tin are mainly dominated by diffusion charging, while the larger ones are mainly dominated by field charging. In pulsed electric field, the charging of fine particles are mainly driven by the migration and diffusion of free electrons and ions. Furthermore, the smaller particles are positively charged, while the larger ones are negatively charged in pulsed electric field. Moreover, the amount of charges is much more captured by large particles than smaller ones. To enhance particle charging, the peak voltage of pulsed electric field could be much higher than DC electric field in the same laboratory-scale reactor with wire-plate electrode configuration.