Study On Coupled Radiation-Phase Change Heat Transfer In Semi-Transparent Materials

In recent years, with the development of the aeronautical and astronautical technology , the optoelectronic technology and the new energy technology, the demand of the optical material, the functional materials, phase change energy storge material has been increased, but the production and application of many material related to high temperature phase change in the semi-transparent medium. The process of the high temperature phase change in the semi-transparent medium involves complex thermal physical phenomena. The temperature field and the velocity field are decided by the high-temperature solid-liquid phase change, the radiation heat transfer, the heat convection and so on. While the radiative transfer is a key factor affecting the temperature distribution. Currently, there are many ways to study coupled high-temperature phase change and radiation heat transfer, such as the finite volume method, the finite element method, the enthalpy method and the entropy methods, which can solve the problem of coupled phase change and radiation heat transfer. The enthalpy method is a relatively good way, because it can simplify the calculation equation. By solving enthalpy, temperature, phase change, we can control the forming process of the material.In this paper, we mainly study on the heat transfer of the semi-transparent material in the course of the phase change. A mathematical model can be established according to coupled the phase change and conduction heat transfer, the process involved in the location change of the contact surface position. The application of the enthalpy method, the movement of the contact surface and simplify calculations can not be considered. According to this method, the melting process of paraffin is studied. During the phase change process, the coupled phase change and radiation heat transfer will occur. Considering the non-gray characteristic of the semi-transparent material and the different phase of the different thermal physical parameters, the isothermal mushy– zone model is adopted to analysis the solidification process of the plate non-gray semi-transparent material in the condition of radiation and convection Cooling, i.e. use the finite volume method to calculate the energy equation basing on the enthalpy method and use the finite volume method combining band model to calculate the interior non-gray radiation heat change item. Application of this method to simulate coupled radiation and phase change heat transfer, research the influence of optical thickness, albedo, and heat transfer boundary condition on BaF2 ,SiO2 solidification.