The Sublimation of Dry Ice Pellets Used for Cloud Seeding

Abstract

A numerical model has been developed to investigate the sublimation rate of cylindrical dry ice pellets in clear and cloudy air. Experiments conducted in the University of Alberta FROST icing-wind tunnel were used to make comparisons with the model predictions of the sublimation rate. These experiments were carried out in both cold and warm environments. Furthermore, some of the experiments were conducted with the sprays operating in order to determine the effect of a simulated ?cloudy? environment on the sublimation rate. The principal conclusions are: a) despite the use of several simplifying assumptions, the cylindrical model predict the sublimation rates of dry ice pellets to within 20%, when compared with wind tunnel observations, and b) cloudy and saturated conditions at warm temperatures enhance the sublimation rate of dry ice, but cloudy and saturated conditions at cold temperatures do not have an appreciable effect on the sublimation rate of dry ice.