An experimental investigation was conducted to determine the secondary breakup morphology of electrically charged drops. Movies of drop breakup in a high speed air stream were recorded for drops charged between 0 and 60% of the Rayleigh charge limit. The conventional Weber number was found to be insufficient to classify the breakup morphology of charged drops. Rather an electrostatic Weber number was defined to account for the presence of the electrostatic surface stress. When the electrostatic Weber number was used in place of the classical Weber number, the observed breakup morphology was found to be similar to that proposed by previous researchers for uncharged drops. It is therefore concluded that secondary breakup of electrically charged drops can be characterized using the wealth of available literature on uncharged Newtonian drops, provided the electrostatic Weber number is used, and that the charge relaxation time is much smaller than the breakup time.
Experimental study on drop breakup time and breakup rate with drop swarm in a stirred tank
