Simulation Of Multi-physics Coupling For The Two-axis Precision Turntable Working In Cryogenic Environment

Cryogenic two-axis turntable is a precision position control device, working incryogenic cabin, mainly used for ground testing and calibration of space optics devices.Compared with the turntable at normal temperature, it differs greatly in many aspects,.When turntable being cooled, the dropping temperature and the uneven distribution oftemperature field will result in thermal deformation and thermal stress. So, the analysisis more than static analysis, and should consider the influence of cold cabinenvironment. Therefore，this paper adopts the finite element method to carry outmulti-physics coupling thermal-structural analysis for turntable.Firstly, this paper establishes the scheme of turntable, including the structure,materials, cryogenic technology. The performance characteristics, selection principles，design and process approach of the key components of the turntable are described. Then,the thermal environment and heat transfer path to turntable are analyzed.Secondly, this paper establishes a simulation model of cryogenic two-axis turntable.And the "face to face radiation" heat load is applied to the surface of the turntable, thengetting temperature curve and the earliest work time. The temperature field at keymoment are analyzed, and then explained.Thirdly, taking the thermal analysis results of each moment in the cooling processas initial condition, this article obtains the thermal deformation, the thermal stress ofturntable at each time，and draws two key curve. Then, the deformation and stress ofinitial operating time, and the relationship between the deformation and precision areanalyzed. At last, the thermal fatigue life of the turntable is checked.Finally, this paper establishes two turntable models with different emissivity. Theindicators analysis includes the maximum temperature, minimum temperature,temperature field etc. The comparison indicates that the increasing effectiveness of theemission rate improves the cooling efficiency of the turntable.