Preventing snow accumulating upon inclined substrates using falling water film

This paper has concerned preventing snow accumulating upon inclined substrates using falling water film. A cluster of physical models for a gas–water–snow system was developed and solved with a control-volume finite-difference procedure. The effects of various parameters on heat transfer and water film temperature decrease were investigated. The results revealed that it is feasible to use falling water film to prevent snow accumulation upon inclined substrates as long as the suitable initial film flow rate and temperature are adopted. It was clarified that among the influential factors of water film temperature decrease, the snowfall intensity, initial water film thickness and the substrate inclination play an important role. The intensity of the film temperature decrease mainly depends on the snowfall intensity and the initial heat capacity of the water film flow, which is a function of temperature and mass flow rate. An intensive heat transfer occurs in a very thin layer near the free surface of the water film. The numerical results were correlated in terms of effective Nusselt number, and Reynolds, Prandtl and Gukhman numbers. The maximum deviation of the numerical data from the correlation is approximately 15.6%, which only causes an uncertainty less than 3% in the simple prediction. Received on 26 April 1999