Direct contact condensation of an immiscible vapor on a thin film of water

Experiments involving direct contact condensation of immiscible organic vapors on water were carried out at atmospheric pressure for the determination of the heat-transfer coefficients of the interface. The system used consisted of a thin film with a spherical geometry on which condensation occurs. The flow is laminar and the atmosphere of the condensing vapor is saturated and stagnant. Results of the average heat-transfer coefficients of the interface, h ̄_i, in cal/cm²s°C were: 0.072 for N-pentane, 0.066 for methylenechloride, 0.035 for freon-113 and 0.02 for 1-1 dichloroethane. These results were correlated as a function of the normal boiling point temperature of the vapors by a relationship suggested from nucleation theory. It was found that the relative magnitude of the surface resistance, 1 h ̄_i, as compared to the total resistance, is appreciable and is in the order of 50 per cent.