Experiment Research On Discharge Of Sand Dust Two-phase Mixture In Non-uniform Electric Field

The research of laws and application in discharge of mixture needed innovation in theoretical and more demands in application. The scholars at home and abroad showed great concerns and importance to it. There were few research reports in discharge of sand dust-air two-phase mixture which was a kind of mixture discharge, but it concerned chose with electrostatic precipitate, pollution treated by discharge plasma, even the mine accident victims of transport line in sandstorm. Therefore, the discharge research of sand dust-air two-phase mixture has very important significance in theoretical and practical application.This paper had mainly conducted the experiment study in the corona current discharge and the characteristic under lighting impulse voltage of sand dust-air two-phase mixture. The corona discharge experiment of two-phase mixture mainly studied the influence factor on the shape of corona discharge, the corona profile and the corona current, such as permittivity, the grain size distribution and the gap distance. The experiment result showed: the corona discharge waveform of two-phase mixture was a pulse waveform which had very high frequency; the waveform under positive polarity was irregular, but had some regular under negative polarity; under the same charging voltage, the corona current of two-phase mixture was smaller than that of air, and decreased with the permittivity increased. For the corona profile, the experiment used a UV imaging instrument to observe the discharge phenomenon. The experiment result showed: under positive and negative polarity, the corona discharge intensity of two-phase mixture was weaker than that of air in the same condition; the corona discharge images of two-phase mixture and air was a round spot under negative polarity, but was a round spot with fan shape tail under positive polarity. The standard lightning impulse voltage experiment mainly studied the influence on 50% breakdown voltage, V-T characteristics, breakdown discharge channel. The experiment result showed: the 50% breakdown voltage of two-phase mixture under negative polarity was always bigger than that under positive polarity; at the same time, the 50% breakdown voltage of two-phase mixture decreased with the permittivity increased, especially under the negative polarity; under the same gap and the same permittivity, the 50% breakdown voltage of thick sand-air mixture was slower than that of thin-air mixture; in the V-T characteristics aspect, for the same gap, the V-T characteristics curves of negative impulse voltage were steeper than those of positive impulse voltage, but the time to breakdown under negative impulse voltage was longer and more dispersive than those under positive impulse voltage.