Condensation on downward-facing surfaces subjected to upstream flow of air–vapor mixture

This paper reports experimental results for film condensation on vertical and downward inclined smooth and grooved surfaces subjected to ascending streams of a vapor–air mixture. An experimental facility was built in order to evaluate the heat fluxes for different surface inclinations, surface sub-cooling temperatures and air to vapor ratios in the mixture. Two experimental procedures were employed to evaluate the heat absorption rate during the condensation process. The employment of grooved surfaces resulted in a 10% enhancement of the condensation rate in the case of the pure vapor condensation and a negligible effect when noncondensable gases (NCGs) were present in the mixture.

► Film condensation on downward-facing surface under upstream flow was analyzed.
► Grooved and smooth surfaces were tested and compared.
► Surface inclinations, sub-cooling and air to vapor ratios effects were evaluated.
► Grooved surface showed negligible effect when noncondensable a gas was present.