Experimental study of deformation characteristics of ice-melting droplets at voltages less than and greater than the critical discharge voltage

Abstract

The deformation of water droplets produced by melting icicles before and after electric discharge is studied through dynamic deformation experiments on an icicle–flat-plate electrode model. The maximum droplet deformation length, the critical growth rate of the deformation length, and the changes in droplet shape parameters at different applied voltages before and after the generation of discharge arcs are investigated. When no discharge occurs, the maximum droplet deformation length increases with increasing applied voltage, then decreases (primarily because of an opposing force exerted by the ionic wind generated by corona discharge), and then increases again. The critical growth rate of the droplet deformation length increases with increasing applied voltage. When discharge occurs, the maximum droplet deformation length exhibits a monotonically decreasing trend with increasing applied voltage, whereas the critical growth rate of the deformation length decreases, then increases, and then decreases again with increasing applied voltage. The falling pattern of droplets changes from a dripping faucet mode to a jet-like mode at sufficiently high applied voltage, and this is responsible for the sudden increase in the critical growth rate of droplet deformation. Both before and after discharge occurs, the shape parameter of the droplet shows an increasing trend with increasing applied voltage, and the evolution of droplet shape progresses from spherical to pear-like to bar-like.