Augmentation of nucleate boiling heat transfer by applying electric fields

This paper reports that in order to investigate the augmentation mechanism of boiling heat transfer utilizing the EHD effects of electric fields, basic experiments and numerical analyses were performed on the breakup of bubbles in the electric field. In the experiments, the mixture of silicone oil and ethylalcohol was used as the working fluid and filled in the space between the parallel conductive glass plates. Single air bubble was injected in the fluid on the condition that an electric field was applied between the conductive glasses, one of which was heated and the other was cooled. The experimental results were as follows: a bubble began to deform at the applied electric field of more than 2kV/mm and the shape of the bubble became conical with the spread cross section of the bottom on the heating surface. The breakup of the bubble occurred at the electric field more than 3kV/mm. From the experiments and numerical analyses, it was clarified that the analytically obtained shape of the bubble in the electric field agreed well with that obtained by the experiment, and the bubble- breakup was brought about due to the EHD coupled Taylor instability of the vapor-liquid interface