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 wavefree 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. 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 有时候 一个 共同 heat transfer coefficients are obtained in the heat transfer coefficient correlations with Re_ (mass) and Re_ (energy), the general expressions for Re_ (mass) and Re_ (energy) laminar and wavefree 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.