基于不同湿度条件下离子流场数据的颗粒物场致–扩散荷电分离测量方法及其特性分析

Separating Measurement Method and Analysis of Particle Charging Characteristics Based on Ion Flow Field Data Under Different Humidity Conditions

为了分析不同湿度条件下离子流场中悬浮颗粒物的荷电特性,提出基于离子流场数据的颗粒物场致–扩散荷电分离测量方法。基于平行平板电极,搭建颗粒物荷电特性测量平台,获得用于表征颗粒物荷电特性的荷电参数。通过对离子流场数据进行处理,实现场致、扩散荷电参数的分离,进而分析湿度对颗粒物荷电特性的影响机理。针对该文使用的燃香颗粒物,实验测量结果表明:相对湿度小于或等于60%时,场致荷电参数和扩散荷电第一参数基本不随湿度发生变化,扩散荷电第二参数随湿度增大逐渐减小;相对湿度大于或等于70%时,场致荷电参数随湿度逐渐增大,扩散荷电参数几乎为0。由于场致、扩散荷电参数随湿度变化规律不同,使得场致荷电、扩散荷电和总空间电荷密度随湿度增大呈现不同的变化规律。颗粒物吸湿性和离子水合反应是导致荷电特性随湿度变化的主要原因。该文提出的场致–扩散分离测量方法可以用于确定颗粒物荷电特性,可为高污染、高湿环境下高压直流输电线路离子流场建模提供理论支撑。

In order to analyze the charging characteristics of suspended particles in the ion flow field under different humidity,a method for measuring the field and diffusion charging of particles based on the ion flow field is proposed in this paper.A device for measuring the charging characteristics of particles is built using parallel plate electrodes,and the charging parameters used to characterize the charging characteristics of particles are proposed.The field and diffusion charging parameters are measured by processing the ion flow field data,respectively.Then the influence of relative humidity on particle charging characteristics is analyzed.The results show that when the relative humidity is less than 60%,the field charging parameter and the first diffusion charging parameter are changeless with relative humidity;the second diffusion charging parameter decreases with the relative humidity.When the relative humidity is more than 70%,the field charging parameter increases gradually with relative humidity,and diffusion charging parameters are almost zero.Due to the different variation laws of field and diffusion charging parameters with humidity,the field charge,diffusion charge,and total space charge density show different variation laws with the increase of humidity.The hygroscopicity of particles and ionic hydration are the main reasons for the change of charging characteristics with humidity.The separating measurement method proposed in this paper can be used to measure the charging characteristics of particles under different humidity,and provide theoretical support for the modeling of ion flow field of HVDC transmission line in complex environments such as high pollution and high humidity.