Experimental study on dynamic behavior of vapor bubbles in an electric field

To investigate the basic mechanism of EHD nucleate boiling heat transfer enhancement, a fundamental study on the dynamic behavior of vapor bubbles on a horizontal wire in a nonuniform DC electric field is experimentally performed. The averaged bubble frequency, diameter and velocity are taken from a frame-by-frame analysis of high speed film images. From the present experimental results, it is found that the dynamic behavior of vapor bubbles can be significantly affected when a nonuniform electric field is applied. With increasing applied voltage, the bubble size decreases and the bubble frequency and velocity increase dramatically. The experimental results and the calculation of the bubble diameter show generally good agreement. Observations show that vapor bubbles depart from the surface of the heated wire in radial directions due to the effect of the electric field. Under higher electric field, the dispersion of vapor bubbles is noticeable in the vicinity of the heated wire.