Research on the effect of Reynolds correlation in natural convection film condensation

Abstract

Film condensation is a vital phenomenon in the nuclear engineering applications, such as the gas–steam pressurizer design, and heat removing on containment in the case of postulated accident. Reynolds number in film condensation can be calculated from either the mass relation or the energy relation, but few researches have distinguished the difference between them at present. This paper studies the effect of Reynolds correlation in the natural convection film condensation on the outer tube. The general forms of the heat transfer coefficient correlation of film condensation are developed in different flow regimes. By simultaneously solving a set of the heat transfer coefficient correlations with Re mass and Re energy, the general expressions for Re mass and Re energy and the relation between the corresponding heat transfer coefficients are obtained. In the laminar and wave-free flow regime, Re mass and Re energy are equivalent, while in the laminar and wavy flow regime, Re mass is much smaller than Re energy, and the deviation of the corresponding average heat transfer coefficients is about 30% at the maximum. In the turbulent flow regime, the relation of Re mass and Re energy is greatly influenced by Prandtl number. The relative deviation of their average heat transfer coefficients is the nonlinear function of Reynolds number and Prandtl number. Compared with experimental results, the heat transfer coefficient calculated from Re energy is more accurate.