Mixed-convection film condensation along outside surface of vertical tube in saturated vapor with forced flow

This study employs the nonsimilar transformation method to perform a comprehensive investigation into the steady-state mixed convection of a condensate film on an isothermal vertical tube in dry saturated vapor with a forced flow. The analysis takes account of the inertia and convection effects in the condensate layer and the resistance at the liquid–vapor interface. The numerical results indicate that the effect of the forced-flow parameter increases as the thickness of the liquid condensate layer increases. Moreover, it is found that a higher forced-flow intensity increases the condensate flow rate, but has no more than a marginal effect on the temperature profile in the condensate layer. In the extreme case of a tube with an infinite radius, the results show that neglecting the inertia term induces a significant error. Accordingly, inertia effects must be taken into account in condensation problems characterized by higher values of the forced-flow parameter (ξ) and Jakob number (Ja).