Enhancement of Natural-Convection Boiling Heat Transfer to Saturated Liquid by Electric Field

Abstract

Enhancement of natural-convection boiling heat transfer by electric field is investigated experimentally. Boiling of a refrigerant R113 occurs on a flat surface under the atmospheric pressure, and a D.C. voltage up to 35kV is applied between the heat transfer surface and an electrode made of stainless steel wire mesh 10mm apart. The whole boiling curve is measured under different applied voltages. The orientation of the heat transfer surface can be varied from the horizontal facing up to the horizontal facing down. The results of experiment indicate that boiling heat transfer is enhanced by electric field. The film boiling heat transfer is greatly enhanced, especially when the surface faces horizontally downward. An enhancement ratio of film boiling heat transfer as high as 14 is obtained. The critical heat flux and the minimum heat flux are both increased with increasing electric field. As a result, in an electric field of high intensity, the boiling curve becomes almost independent of the orientation of the surface.