Heat transfer during film condensation of potassium vapor on a horizontal plate

Abstract

The object of the investigation is to analyze the following two features of heat transfer during condensation of potassium vapor: a. Heat transfer during film condensation of a pure saturated potassium vapor on a horizontal surface. b. Heat transfer during film condensation of potassium vapor in the presence of a small quantity of non-condensable gas. Until now, the discrepancy between theory and experiment concerning the condesnation of pure liquid-metal vapors has been explained by a thermal resistance at the liquid-vapor interface. This interfacial resistance was analyzed by means of the kinetic theory, and the results depended on the use of a condensation (or accommodation) coefficient. This coefficient was found to decrease in value at higher pressures. This work presents a more refined analysis of the interfacial temperature distribution, including the effect of subcooling in the vapor in the region of the liquid-vapor interface. Furthermore, a theory predicting the temperature drop in the condensate film on a horizontal plate is presented. Experiments were performed to verify the theory. In addition, data from previous investigators were analyzed. Experiments with non-condensable gases in the saturated vapor were made using the horizontal plate facing upward. These results supported Kroger's (19) theory.