Film condensations of flowing mixtures of steam and air on an inclined flat plate

A programme of condensation experiments was carried out at atmospheric pressure using a water-cooled flat plate varying the air concentrations, the plate inclination and its orientation (upward or downward facing). Rates of heat transfer have been measured on a single face of the condensing plate suspended in a cylindrical test section as steam and mixtures of steam and air flowed over it. The rate of heat transfer decreased as the angle of the plate to the horizontal was reduced and as the concentration of air was increased. A notable observation was that comparison of results for the upward and downward facing cases showed that the heat transfer rates with pure steam are higher for an upward facing plate than for a downward facing one. However, with air present in the steam, this trend is reversed. The effects of plate orientation, mixture flows and buoyancy are discussed.