Numerical Modeling of Ice Deposition

Abstract

A method of computing the rate of growth of ice crystals by deposition is described. Predictions of growth characteristics over the temperature range of ?1 through ?35C are shown and compared with meager experimental data available within this temperature range. The growth rate equations are based on Fick's law of diffusion. In applying this law to nonspherical ice crystals, the analogy between an electrostatic potential field surrounding a charged body and the vapor-density field surrounding a similarly shaped ice crystal is utilized. Allowances are made for effects of forced convection caused by the movement of the crystal through the air and the change in shape and bulk density of the ice crystal; these effects are predicted to be of significant importance. A simple, empirical equation using two temperature-dependent parameters was found to describe the crystal growth rate as a, function of mass. For many cases where only the rate of mass conversion from vapor to solid is required, the simple equation is believed satisfactory.