Velocity and Temperature Fields of Laminar Free Convection Film Boiling of Liquid

Abstract

Physical property factors coupled with the theoretical and mathematical models of the laminar free convection film boiling of liquids are treated into the functions of dimensionless temperature, for simultaneous solutions with the three-point boundary values conditions of the two-phase film flow. Then, the numerical solutions of momentum and temperature fields at different wall superheated grades and liquid bulk subcooled grades are theoretically reliable, because the variable physical properties are treated rigorously. On this basis, a system of rigorous numerical solutions for momentum and temperature fields of the two-phase film flows are calculated with taking the film of boiling water as the example, in which the related boiling of saturated water is only the special case. The numerical procedure presented here is reliable for rigorous solutions of the theoretical models of three-point boundary value problem with the two-phase flow. The dimensionless velocity components have definite physical meanings; then, the corresponding solutions of the models can be easily understood. With increasing the wall superheated grades, the maximum of velocity field of vapor film will increase and shift far away from the plate. The velocity of vapor film will decrease with increasing the liquid subcooled grade. With increasing the liquid subcooled degree, the thickness of liquid film will increase, and the velocity profile level of liquid film will decrease slower and slower. Furthermore, with increasing wall superheated grade, the effect of wall superheated grade on the velocity field of liquid film will decrease.