Design And Analysis Of The Cryogenic System For QWR Superconducting Cavity

The dissertation focuses on study on the QWR cryogenic system, which is the key component of the Tandem Superconducting Device(TDS) in HI-13 Upgrade in China Institute of Atomic Energy. The study will serve as the guideline for the engineering design of the TDS QWR cryogenic system.Detailed calculations of the radiant heat loads to 4.2K cold mass and 77K heat shield were carried out based on the structure of the QWR cryostat. The conductive heat loads from the supports inside the cryostat were given with variable physical properties of materials. The total static loads and dynamic loads are summed as 4.692W and 38.4W, respectively. And comparison between the double-wall cooling method and the cooling tube method for the 77 heat shield has been discussed to provide the thermal parameters for flow process simulation.The critical thermal parameters of the main components of the QWR cooling system were determined for parallel arranged QWR cryostats. The mass flow and time for cool-down of the QWR to 4.2K was also estimated. Numerical model for the cooling process has been developed in case that the QWR cryostats are connected in parallel. Temperature at the outlet of QWR cooling channel and its pressure fluctuation were calculated with the change of the mass flow of He by the large-scale process software. The optimized mass flow of He and the allowed fluctuation range were also obtained according to the temperature and pressure required by the QWR superconducting cavity. And the influence on the system when the mass flow of He is far from normal has been discussed.The temperature distribution of QWR has been numerically simulated by FLUENT and the maximal temperature difference has been obtained. The detailed simulation and comparison of the heat shield has been carried out for the spiral cooling method and the flexible cooling method. The temperature distribution of the support for the 4.2K cold mass has been simulated by ANSYS, and its heat flux has been simulated and compared with the theoretical results presented preciously.