Velocity and Temperature Fields of Laminar Free Convection Film Condensation of Pure Vapour

Abstract

The work is dealt with for solutions of velocity and temperature fields on laminar free film condensation of superheated vapor on a vertical flat plate at atmospheric pressure with consideration of various factors including variable physical properties. The film condensation of saturated vapor is only its special case. The system of ordinary differential equations is computed by a successively iterative procedure and an iterative method is adopted for the numerical solutions of the three-point boundary value problem. With increasing the wall subcooled grades, the maximum of velocity field of liquid film will increase and shift far away from the plate. In addition, the velocity of liquid film will decrease with increasing the vapor superheated grade. Compared with the effect of wall subcooled grades on the velocity of liquid film, the related effect of the vapor superheated grade is obviously weak. With increasing the wall subcooled grades, the thickness of liquid film will increase. With increasing the vapor superheated grade, the thickness of liquid film will decrease. The temperature grade of liquid film on the wall will decrease with increase in wall subcooled grade, and increase with increasing vapor superheated grade. Compared with the effect of wall subcooled grades on the temperature of liquid film, the related effect of the vapor superheated grade is obviously weak. The velocity of vapor film will increase with increasing the wall superheated grades, and decrease with increasing vapor superheated grade. With increasing wall subcooled grade, the velocity of vapor film will decrease slightly. With increasing the vapor superheated grade, the velocity of vapor film will decrease obviously.