AN EXPERIMENTAL STUDY OF THE FROST FORMATION ON A COLD SURFACE IN FREE CONVECTIVE FLOW

The frost growth on a vertical cold plate exposed to a free convective flow has been experimentally investigated. The plate is placed in a vertical channel open at the top and bottom in order to permit the natural circulation of ambient air. The cold surface temperature has been varied in the-13 to –4 °C range, while the ambient air relative humidity resulted in the range 31-58 percent at the temperature of 26-28°C. The measured quantities during the frost formation included the frost thickness (in three different spots), the frost surface temperature and the mass of frost deposited. The frost thickness was found to depend mainly on time and on the frost to plate temperature difference. The frost mass increased linearly with time and was mainly affected by the difference between the air humidity ratio and the saturated humidity ratio of the frost surface