Experiments Study And Fractal Simulation On Frosting Growth

Describing the inner structure and the thermal properties of frost layer is a very important and difficult project. So, a frosting experiment equipment which can observe the process of initial stages of frosting is firstly designed. Compared with many other frosting experiment equipments, it can give us a very big and clear image of frosting.Base on the experiment equipment, a series of experiments are done for the initial frosting process and many experiment datum are gotten. According to those datum, many discusses and analysis are done for those different kind of frosting phenomenon.With fully understanding of frosting successive growth character, combined with one-dimensional successive nucleation growth model and considering the influence of temperature on cold layer and in atmosphere, a computer simulation model of frosting growth is presented. To compare the simulating image with the real image by use of the computer, coherent result can be gotten. A series of patterns and their fractal dimensions are obtained for different conditions. With the increase of frost layer, the fractal dimensions are increasing either.In order to understand the conduction in the frost, by using finite difference method on a control volume, the frost section is discretized. Combined with the energy equation, the discretization equations are deduced. Owing to the inherent asymmetric property of the frost, the conductivity of the interfaces are processed and selected. The temperature distributions are counted finally. Then, the efficient conductivity is counted with considering the influence of the density and the void rate by using Matlab.Fractal infiltration construction are used to describe the inner construction of initial frosting. The curve which can describe the conductivity change with the density are built. compared with the old model, it has its rationality.