Thermodynamics Analysis For Thermal Shroud Of Small-size Thermal Vacuum Environment Simulator

Space environment simulator can artificially simulate the special environment including vacuum, the cold black, space radiation and other environment which spacecraft suffer in the universe. Reasonableness of Spacecraft design will be verified, insufficient of Spacecraft design and the latent defects in the materials and manufacturing processes will be found through the tests. The tests can reduce or avoid the fault or failure of spacecraft, prolong the working life of the spacecraft, improve the reliability of spacecraft. The thermal shroud is used to simulate the cold dark environment, is the core structure of the environment simulator. The temperature uniformity of the thermal shroud is one of the most important technical specifications. Analyze the thermodynamic of the thermal shroud in small-size thermal vacuum simulator by using the method of numerical simulation,。The result has practical significance for optimizing the structure of thermal shroud, improving the uniformity of temperature, reducing refrigerant.The thermal shroud is mainly divided into tube-plate structure composed of fins and pipes and stainless steel plate-style structure. This paper analyzes the thermal uniformity of single pipe-fin. Analyze the influence on the temperature uniformity at different fin length, fin thickness, branch pipe diameter and refrigerant velocity. Then use the CFD method to research flow and heat transfer of the whole cylinder thermal shroud. Analyze steady-state heat transfer condition and temperature distribution of the refrigerant in thermal shroud. Research the influence on temperature uniformity of the thermal shroud at different outlet form, branch pipe distance, main pipe diameter, and branch pipe diameter and refrigerant velocity. At last, use the CFD method to research the temperature uniformity of the new type stainless steel plat-style thermal shroud, and compares it with the traditional structure. Research the influence on temperature uniformity of the thermal shroud at different outlet form, distance between two stainless steel plates, main pipe diameter, and branch pipe diameter and refrigerant velocity. Obtain the suggestions of the thermal shroud structure improvement.Results show that reducing fin length or increase thickness can improve the thermal uniformity of the thermal shroud, the refrigerant flow rate and branch pipe diameter changes have little impact on the temperature uniformity. Temperature uniformity of cylinder thermal shroud which is U-type is better than that is Z-type. Increasing the number of inlets and outlets and increasing total flow, increasing the ratio of main pipe diameter and branch pipe diameter, can make refrigerant flows more uniformly, and improve the temperature uniformity of the thermal shroud. Reducing the distance of the branch pipe can also improve the temperature uniformity, but the refrigerant flow distribution is uneven. Under the same conditions, thermal conduction efficiency of the stainless steel plate-style thermal shroud is higher, temperature uniformity significantly is better than that of pipe-plate thermal shroud. Increasing total flow or reducing the distance between the two pieces of steel plate can improve the temperature uniformity of the thermal shroud. Different forms of outlet have little impact on temperature uniformity. This paper analyzes the various factors affecting the temperature uniformity of thermal shroud, is important for the design and improvement of the thermal shroud structure...