Effects of high electric field on low-velocity gas-solid two-phase flow movement

Abstract

It is of significance to study the movement of solid - gas mixed flow of small particle size in the high electric field region for explaining such insulation accidents as contamination deposition, gap breakdown, unknown flashovers, and the like occurring on power line insulators surface. Based on artificial simulation experiments, we applied the particle image velocimetry (PIV) technology to investigate the flow-electric field coupling movement of low-speed mixed flow, comprehensively compare the effects of electric field uniformity, voltage levels, wind speed and other factors on the distribution of flow field. The results show that the effect of non-uniform electric field on the flow field is apparently stronger than that of uniform electric field. It increases with the applied electric field increasing, and decreases a little with the wind speed increasing. In the uniform electric field, the particles have a trend to move to the cathode plate, while in the non-uniform electric field, they are evidently charged under the action of corona and prone to moving toward the anode plate. In contrast, the effect of the AC electric field on the flow field is weaker than that of the DC electric field. However, it still has obvious manifestation. These relevant conclusions play an active role for in-depth research on the external insulation characteristics of HV power grid in sand dust environments such as pollution deposition and distribution on the surface of insulation string, breakdown of the air gap, etc., especially the charged mechanism of small sized dust and sand particles.