Analysis of Air Bubble Deformation Subjected to Uniform Electric Field in Liquid Dielectric

A new numerical analysis has been carried out in order to determine the electrostatic pressure acting on the liquid-air interface. Also by aid of photographic recording the surface tension at the equator and poles is determined, the internal pressure is calculated and the relationship with the voltage square is enlightened. The analysis of the unstable bubble ejected or compressed against the sphere electrode with sharp edge protrusion, is explained and the values of charge under an applied electrical field at ejection condition are given. The breakdown electric field of the transformer oil is calculated, and a new breakdown voltage equation linking the compressed conducting bubble to the breakdown field is proposed. A new ratio of calculated electric charge at ejection mode relative to the value of ejected electric field is achieved. Also the breakdown voltage can be estimated by knowing the value of the voltage at compressed mode, using a new addressed space charge formation factor which is equal to 1.1. The results have been assessed through comparison with available analytical and experimental data.