Free Convective Heat Transfer from Humid Air to a Vertical Plate under Frosting Conditions

Abstract

Heat and mass transfer by free convection from humid air to a vertical plate of different heights(4, 8.5, 17cm) under frosting conditions was investigated experimentally.It is found that the conception based on steady boundary layer theory can be applied on the whole though the frost surface conditions (temperature, roughness etc.) vary with time and that there is a little influence of surface roughness on heat and mass transfer. To establish a method to estimate surface temperature, time dependency of specific weight of a thin frost layer near the surface and the relation between thermal conductivity and mean specific weight of the frost layer are assumed. The estimation agrees with experimental results within engineering accuracy.