Effect of Electric Fields on Maximum and Minimum Boiling Heat Flux Levels

Unlike in nucleate boiling, during film boiling a vapor layer completely surrounds a heater. An electric field can be applied to destabilize such a vapor film. High voltage (~2kV) electric fields were applied between a 127 µm heater wire and a screen electrode that is concentrically placed at a radius of 25 mm. The maximum and minimum heat fluxes were measured for the various subcooling and electric field strengths. Up to 50% increase in the heat fluxes were observed when using the electric fields in this range of experimental parameters. It is shown how electric fields can be employed a) for enhancing heat transfer and b) as a safety feature to actively destabilize the vapor film by continuously driving the liquid to the heater surface.