Heat transfer during film condensation of a liquid metal vapor

Abstract

The object of this investigation is to resolve the discrepancy between theory and experiment for the case of heat transfer durirnfilm condensation of liquid metal vapors. Experiments by previous investigators have yielded data which are extremely scattered and markedly below the predictions of both the classical IUusselt theory and more recent modifications to it. All theoretical treatments so far have taken account only of the thermal resistance presented by the condensed film. However, calculations from kinetic theory show that with liquid metals a significant thermal resistance can exist at the liquid-vapor interface. This resistance increases with decreasing vapor pressure and is dependent on the value of the "condensation coefficient." Experimental work to back up this hypothesis of a liquid-vapor interfacial resistance is presented. The working fluid for the experiments is mercury condensing at low pressures in the absence of non-condensable gases on a vertical nickel surface. Data of previous investigators are analyzed, and possible reasons for being unable to interpret these results meaningfully are cited.