ABSTRAKT

A comprehensive model predicting the deformation, growth and detachment of a vapour bubble in the nucleate boiling regime with an applied electric field is described in this paper. The model takes into account the full electrohydrodynamics of the phenomenon including the influence of local temperature on the generation of free charges in the liquid. Solution of the model by the level set method has been successfully implemented with a commercial CFD code. Aspects of the code and the graphical software requiring further development are noted.
Sample results are presented to demonstrate the effect of the electric field on the growth and detachment of the bubble, for a bubble initially protruding through a thermal boundary layer on a horizontal wall. The bubble is elongated under the influence of electric forces, the effect being more pronounced for stronger electric fields. The electric field is found to promote earlier detachment of the bubble at a smaller volume, thus increasing the bubble frequency. The wall heat flux during the process of detachment is not much affected by the electric field.