An approximate method for laminar film condensation in nonuniform gravity

The approximate method previously developed for laminar film condensation in a uniform gravity field is extended to the case of arbitrary gravity fields. Calculations are performed on laminar film condensation over a horizontal circular cylinder for a wide range of Prandtl numbers and sensible-latent heat ratios. It is found that straight-forward extension of the approximate method leads to under-prediction of the heat transfer rate for small Prandtl numbers due to overestimation of inertia effects. This problem can be corrected by introducing the parameter associated with the ratio of the gravitational force to the shear force. The corrected level of the heat transfer rate is in excellent agreement with that obtained from full boundary layer equations.