Optimization and experiment of supercritical helium flow in cryopump

Large built-in cryopumps are widely used in nuclear fusion devices, the cryopumps studied in the paper are mainly used to provide a vacuum environment for beam generation and transmission. The cryopump is cooled by forced flow, so the supercritical helium flow heat transfer of the cryopump is investigated, the thermal load of the crysorbent panels of the unit pumping structure is calculated and analyzed by ANSYS Steady Thermal State software, meanwhile the supercritical helium flow heat transfer is simulated by ANSYS Fluent software, then the pressure drop of the fluid, temperature and flow uniformity are analyzed in different flow channels. The results show that the parallel structure with a tube diameter of 17.2 mm can reduce the pressure drop of the flow channel to 4.9E4 Pa, and the inlet velocity of the left and right branches are 1.96 m/s and 2.02 m/s, respectively, and the flow distribution is uniform, while the temperature field meets the requirements of the cryogenic pump. Finally, the model and calculation method are verified by using the laboratory cryopump, the simulation results coincide with the experimental results, which verifies the reliability of the simulation.