SIMULATION OF ICE ACCRETION ON A CYLINDER DUE TO FREEZING RAIN

A hybrid analytical and random-walk model has been developed to predic t the shape of ice accreted on a horizontal cylindrical insulator due to freezing rain. The freezing rain occurs with the temperature of the vertically falling raindrops above the freezing point and the air tem perature below freezing. The analytical model calculates the angular d istribution of the water-film temperature and the location where freez ing begins. The random-walk model predicts the accretion shape. The tw o random-walk model parameters, the freezing probability and the shedd ing parameter, are expressed as functions of the atmospheric condition s. The model predicts a variety of realistic accretion shapes from cyl indrical to icicle-like. Model verification based on comparisons with other models and with experimental results demonstrates quantitatively and qualitatively the credibility of this new modelling approach.