Experimental study on the condensation of ethanol–water mixtures on vertical tube.

Abstract  The condensation heat transfer of the ethanol–water mixtures on the vertical tube over a wide range of ethanol concentrations was investigated. The condensation curves of the heat flux and the heat transfer coefficients revealed nonlinear characteristics and had peak values, with respect to the change of the vapor-to-surface temperature difference. This characteristic applies to all ethanol concentrations under all experimental conditions. With the decrease of the ethanol concentrations, the condensation heat transfer coefficient increased notably, especially when the ethanol concentration was very low. The maximum heat transfer coefficient of the vapor mixtures increased to 9 times as compared with that of pure steam at ethanol vapor mass concentration of 1%. With the increase of the ethanol concentrations, the condensation heat transfer coefficient decreased accordingly. When the ethanol concentration reached 50%, the heat transfer coefficient was smaller than that of the pure steam. [ABSTRACT FROM AUTHOR]