EXPERIMENTAL STUDY ON FREE-CONVECTION CONDENSATION HEAT TRANSFER FROM MOIST AIR

摘要

Characteristics of free-convection condensation heat transfer from moist air under atmospheric pressure were experimentally investigated, for further improvement of physical modeling on heat and mass transfer of solar distillation device. The cooled metal surface was 50mm width x 100mm height. The experimental conditions were as follows. Moist air temperature range was 40～100℃ for saturated moist air, and 50～70℃ for non-saturated moist air. Relative humidity range was 50～90%. Inclination angle of cooled surface was 0° (downward facing) ～180° (upward facing). All experimental results of heat transfer characteristics for vertical surface (angle 90°) were well correlated into a single equation with partial air pressure ratio using classical Nusselt's liquid-film theory. The experimental results for the effects of inclination angle show that heat transfer coefficients for angle 0°～105° were almost constant with slight peak value at angle 45°, followed by rapid decreasing of heat transfer coefficient over angle 120°.