The Finite Element Analysis Of Temperature Field On The Cryostage In Cryomicroscopes

In order to meet the requirements of the research of cryobiology, a cryostage is designed to achieve accurate temperature control. The physical model of the cryostage based on power compensation in cryomicroscopes is designed by use of the software Ansys. The change regularity of the heat generation in the special cooling rates and isothermal process is discussed in vacuum and air conditions by controlling the electric heating power in the cooling and isothermal process of the samples. The main contents are presented as follows: (1) the configuration of the cryostage is designed, which includes the determination of model size, analysis of thermal physical properties of materials, selection of cooling medium and so on.(2) the temperature field of the cryostage is calculated by the numerical method (Ansys), and the influence of physical parameters of the samples on the heat generation and the uniformity of the temperature distribution is studied and analyzed at different conditions by the method of controlling variables.Conclusions: (1) the density and the specific heat of samples have a significant impact on the heat generation, and a linear relationship exists between the density or the specific heat of samples and the heat generation, while the heat generation is not affected by the thermal conductivity in the cooling process. When the physical properties of samples and cooling rates are constant, the heat generation in nitrogen and helium is higher than that in vacuum at different conditions. The heat generation is not affected by physical properties of the samples, but affected by cooling rate in the isothermal process. (2) the uniformity of the temperature distribution is not deeply affected by the density and the specific heat, and the influence on the uniformity of the temperature in the condition of vacuum is stronger than that in nitrogen and helium conditions. The uniformity of the temperature field is affected deeply by the thermal conductivity changed in the range of 0-200W/(m?K), but not affected in 200-800W/(m?K) range.The numerical simulation of the temperature filed on the cryostage in cryomicroscopes can provide some explorative conclusions in this thesis. It is of important instructional significance for designing the system of temperature control on the cryostage.