Abstract:The present paper investigates turbulent film boiling on a sphere with external flowing liquid. An isothermal wall surface of the sphere is assumed. For calculation, the liquid nitrogen, flowing upward, is used as the working fluid. The high velocity of the flowing liquid at the boundary layer is determined by the potential flow theory. In addition, the present paper addresses a new model to predict the vapor−liquid interfacial shear on a sphere by using the Colburn analogy. Substituting the shear into the force balanced equation and combining the energy and thermal energy balance equations, film thickness and Nusselt number can be obtained under different Froude numbers. Finally, a comparison between the results of the present study and those reported in previous theoretical and experimental studies is provided.