Dynamics of bubble in dielectric liquid in electric field: Mesoscopic simulation

Abstract

We investigate the dynamics of a gas-vapor bubble in a dielectric liquid placed in strong electric field using the mesoscopic lattice Boltzmann method with possible phase transitions and energy transfer [1]. In the electric field, the bubble is elongated along the field lines under the action of electrostriction forces. This leads to the increase of the field magnitude near the poles of the bubble. Since the electric strength of the gas phase is much lower than the one of the liquid phase, the electric breakdown becomes possible inside the bubble with generation of conducting substance. Electric currents produce heat, and the temperature inside and around the conducting bubble rises leading to the evaporation of liquid and further increase of conductivity. Breakdown in a cavity leads to the increase of electric field magnitude in neighbor ones, which results in the sequence of breakdowns in nearby cavities. This is the relay-race mechanism of breakdown. In very strong electric field, the anisotropic instability is possible leading to the decay of the dielectric fluid into a system of gas-vapor channels in a liquid oriented mostly along the field lines.