Numerical Modeling of the Frosting Process on a Cold Finned Surface With Variable Fin Spacing

Frost formation can incur damage to agricultural crops, roads, railways, electrical transmission lines, transport of oil and natural gas in cold climates, as well as refrigeration and air-conditioning equipment. Modeling of the frost formation process involves coupled heat and mass transport phenomena which are not only function of time but also of space. To model such complex interactions, a transient two dimensional mathematical model has been developed using a control volume approach, discretizing Navier-Stokes equations over a fixed Cartesian staggered grid coupling the pressure and velocity via the SIMPLE algorithm. To identify the interface between the air and the frost sub-domains, a cut cell approach has been used. The validated numerical model is used to investigate the impact of the heat exchanger configuration on the frost layer distribution. Specifically, a variable fin spacing (converging channel) is compared to the regular configuration (with straight fins) and is shown to have a positive impact on the frost layer distribution.