Heat transfer during film condensation of potassium vapor

Abstract

The object of this work is to investigate theoretically and experimentally the following two phases of heat transfer during condensation of potassium vapore, a. Heat transfer during film condensation of pure saturated potassium vapor on a vertical surface. b. Heat transfer during film condensation of potassium vapor in the presence of a small quantity of non-condensable gas. Investigators have until recently been unable to explain the large discrepancy between theory and experiment for the case of heat transfer during film condensation of pure liquid metal vapors. Calculations from kinetic theory and irreversible thermodynamics suggest that this difference may be due to a significant thermal resistance at the liquid-vapor interface in addition to that of the condensate film. This interfacial resistance becomes especially noticeable at low vapor pressures and is dependent on a "condensation" coefficient to be determined experimentally. The presence of a trace of non-condensable gas during condensation may greatly reduce the heat transfer rate. An analysis predicting the heat transfer rate during condensation of potassium vapor in the presence of a non-condensable gas is presented,and experiments are performed to test the validity thereof.