PRESSURE DRIVEN FLOW OF PURE VAPOR UNDERGOING LAMINAR-FILM CONDENSATION BETWEEN PARALLEL PLATES

The flow of pure saturated vapor between horizontal parallel plates, with film condensation on the bottom plate, is considered and an approximate solution of the non-linear free boundary problem is obtained. The mixed differential-integral approach of this paper predicts film-thickness profile, condensation rate, wall heat transfer rate, pressure variations and other quantities of interest. The solutions for freon-113 show that an increase in mass flow rate (Reynolds number), with other control parameters being constant, leads to a thinner condensate, increased pressure drops, and increased heat removal rates. At a fixed mass flow rate, a drop in temperature difference between the vapor and the wall leads to smaller heat removal rates and, at the same time, thinner condensates. It is verified that the computed results satisfy balance laws and are self consistent. Furthermore, we find excellent qualitative and acceptable quantitative agreements with a related experiment.