A new time- and space-dependent model for predicting frost formation

In this paper, a new CFD (Computational Fluid Dynamics) model is proposed to predict frost formation and growth with the benefit of the nucleation theory. This model can be applied to describe the initial and growth period of frost formation and also to reflect the influence of surface structure on frost development. Both spatial and temporal variation of the frost configuration and its properties can be predicted. The phenomena of frost formation on a cold surface placed in a stream of humid air are simulated using this model. The proposed model is validated in comparison with data arising from one experiment and two accepted numerical models. The results show that the frost grows faster in the upstream region. In the initial period, the mass transfer, from water vapor to frost layer, mainly contributes to the increase of frost thickness. In contrast, it mainly contributes to the increase of density in the fully developed period. The effects of inlet air velocity are discussed as well.