高压电场内细颗粒堆积机理研究

细颗粒的堆积既是电厂尾部除尘系统的核心问题,也是航天领域空间环境内限制动力或光学元件性能的关键问题。电场力因具有长程有效性和强可操作性成为控制细颗粒堆积的主要手段。本文通过微观实验研究了高压平行板电场间细颗粒堆积的机理,观察到颗粒在预极化、预荷电、变外电场电压等工况下的堆积形貌,并发展了图像处理的方法统计堆积颗粒数。研究表明,偶极力是外电场下颗粒成链的主因,而颗粒的倒伏则是来自曳力的作用,颗粒链的极限高度主要受外电场场强和颗粒堆积结构的影响。

Investigation on the Packing of Fine Particles in Presence of High-Voltage Electric Field

The packing of fine particles plays a crucial role in determining the capture efficiency of dust removal devices in power plants,as well as in understanding the performance reduction of optical or power devices in aerospace engineering.Electrostatic forces,for its long-range characteristics and feasible manipulation,are widely used to control the packing of fine particles.In this paper,the packing structure of fine particles on collecting plate under high electric field is investigated by digital microscopy technology.The effects of pre-charging,pre-polarization,and external electric field on packing morphologies are discussed.It is found that the dipole-dipole force between particles causes the formation of long particle chains.The maximum length of particle dendrites during the packing is dependent on both the density of external field and deposit structure.