排针-辊式电晕放电特性

Characteristics of Needle-roller Corona Discharge

为提高高压静电分选效率,寻求产生最佳电场的新型排针电极结构,采用自制新型排针–辊式高压放电装置,探究了放电针直径对电晕放电性能的影响;设计了一种新的测量装置,实现了对单根及多根放电针上放电电流的测量,为了在相同电压下得到更好的放电效果,对35根放电针中的偶数序号放电针缩进5次、每次5 mm,进行比较研究;在MATLAB平台上,利用电磁场理论,对不同缩进条件下排针型电极的空间电场分布仿真模拟。结果表明:其他条件一定,放电针的直径越小,排针总的放电电流(排针电流)及每根针放电电流(针电流)越大;随着偶数序号放电针缩进长度的增加,排针电流呈先增大后减小的趋势,在缩进长度为15 mm时,排针电流达到最大值,空间电场强度最强,此时为最佳电场的新型长短针的排针结构。电场模拟结果与实验相一致,印证了排针中缩进的偶数序号放电针对突出的奇数序号放电针的放电有加强作用。

In order to explore the best structure of needles to generate electric field that improves the efficiency of high-voltage electrostatic separation, we investigated the influence of the diameter of discharge needle on the performances of corona discharge by using a self-made novel needle-roller discharge device. A new measuring apparatus was used to measure the current on single discharge needle or multiple discharge needles. In order to get a better effect of discharge at the same voltage, discharge needles with even number among 35 needles were indented with five times in the experiment. The simulation of space electric field distribution of needle electrode based on the platform of MATLAB was realized by using the theory of electromagnetic field. The results show that when other conditions remain unchanged, the smaller the diameter of discharge needles is, the greater the total discharge current and the current on single needle will be The discharge current increases first then decreases with the indent of discharge needle. When the length of indent is 15 mm, the discharge current and spatial electric field intensity reach the maximum. Thus the optimal structure of needle electrode is obtained. The simulation of electric field is consistent with the experimental results, which confirms the elec- tric field enhancement of needles with even number to needles with odd number.