Pure steam condensation model with laminar film in a vertical tube

► A new physical model for laminar film condensation is proposed. ► The liquid was assumed to be in Couette flow forced by the interfacial velocity at the liquid–vapor interface. ► To estimate the interfacial velocity, an empirical power-law velocity profile was introduced. ► The proposed model predicted the condensation heat transfer coefficient from experiments reasonably well. A new physical model for calculating the liquid film thickness and condensation heat transfer coefficient in a vertical condenser tube is proposed by considering the effects of gravity, liquid viscosity, and vapor flow in the core region of the flow. To estimate the velocity profile in the liquid film, the liquid film was assumed to be in Couette flow forced by the interfacial velocity at the liquid–vapor interface. For simplifying the calculation procedures, the interfacial velocity was estimated by introducing an empirical power-law velocity profile. The resulting film thickness and heat transfer coefficient from the model were compared with the experimental data and the results obtained from the other condensation models. The results demonstrated that the proposed model described the liquid film thinning effect by the vapor shear flow and predicted the condensation heat transfer coefficient from experiments reasonably well.