Electric-field-induced enhancement of vapour condensation heat transfer in the presence of a non-condensable gas

Abstract

This paper presents the results of an experimental investigation of heat transfer in film vapour condensation from a vapour-gas mixture on a vertical plate under the influence of an electric field. It is shown that with a gas concentration in vapour below 10% a uniform electric field should be applied, and at higher concentrations a corona discharge should be used. The heat transfer augmentation is found to be determined by the electric hydrodynamic processes just as on the surface of a condensate film in the form of a rearranging wave structure and condensate splashing, that decrease the condensate film thickness, so over the volume of the vapour-gas mixture which is stirred by condensate droplets and, to a greater extent, by the corona discharge electric wind. The effects of gas concentration in vapour, of medium pressure, temperature difference between a vapour-gas mixture and a wall, difference of potentials, electric current strength, physical properties of a liquid phase and of a vapour-gas mixture on the degree of heat transfer enhancement are investigated. A seven-fold increase of the relative heat transfer coefficient in the conditions of corona discharge effect is obtained the development of which is favoured by the maximum gas concentration and minimum temperature differences.