高占空比颗粒电场荷电的计算

采用包含颗粒间相互作用的等效场强代替原外场,利用点偶极子模型计算出高占空比颗粒表面的最大场强,并与有限元法的计算结果进行比较,结果表明,对于具有不同介电常数的颗粒来说,在颗粒占空比较高时,这种方法仍具有足够的精度.根据颗粒场致荷电的机理,进一步推导出计算高占空比颗粒电场饱和荷电量和随时间变化的荷电量的近似公式.结果表明,颗粒电场荷电量不仅随场强、颗粒粒径和介电常数的增大而增大,还随颗粒占空比的增大而增大;颗粒电场荷电的速率与颗粒占空比相关,占空比越大,荷电速率越大.

Calculation of electrical charge for fraction particles with high volume

On the basis of the assumption that the effects between neighbored particles could be negligible,the electrical charge for fraction particles with low volume was calculated.The assumption was not reasonable for fraction particles with high volume.The equivalent electric field strength,including the effects of particles,was presented to calculate the maximum field strengths on the surfaces of high-volume fraction particles to replace the primary electric field strength in the dipole model.In comparison with those calculated by the finite element method,the results showed that it was accurate for high-volume fraction particles with various dielectric constants.According to the mechanism of electrical charge,the approximate formulas for the saturation charge and the charges to time for the high-volume fraction particles were derived. With the increase of the electric field strength,the particles' radius,the dielectric constant of particles and the volume fraction of particles;the electric charged rose.It showed that there was positive correlation between the velocity of charging and the volume fraction of particles.