Frost growth parameters in a forced air stream

Abstract The formation of frost on parallel horizontal plates facing a forced air stream is studied at varying temperatures, relative humidities and air velocities. Both the surface temperature of the plates and the relative humidity of the air stream are found to have important effects for the frost thickness. The density of frost is found to increase with relative humidity and especially air velocity. A dynamic one strip method is applied to determine the thermal conductivity, which is used in order to study internal changes in the frost layer. Two categories of frost formation are observed—monotonie and cyclic growth. In the former it is found that the condensed water vapour contributes in equal amounts to increases in the thickness and the density while in the latter melting at the frost surface results in abrupt internal densification.