| With the developments of High Temperature Superconductor(HTS), high-power pulse tube cryocoolers (PTC) are now in urgent demand and attracting more and more attention. Pulse tube cryocooler has the advantages of compact structure, high reliability, low vibration and long lifetime. High power Stirling-type pulse tube cryocoolers (HSPTC) driven by linear compressors can be an ideal alternative for HTS applications if its performance is comparable with or even better than GM-type cryocoolers in liquid nitrogen temperatures. Therefore, the research of HSPTC attracts more and more attention in recent years. However, there are great theoretical and technological challenges for HSPTCs, including temperature inhomogeneity in the regenerator. The main progresses made in the thesis are listed as follows:1. The enthalpy flow and the entropy flow in the ideal regenerator are analyzed by one-dimensional theory. The loss in the actual regenerator is also analyzed. REGEN3.2, a professional software for regenerator design, is introduced and the mathematical model is analyzed.2. The two parallel regenerator model is proposed based on the fluid network theory. The mechanism leading to the temperature inhomogeneity is explained. The mathematical model is proposed to forecast the maximum radial temperature difference in regenerator by calculating the mass of the inner circulating streaming firstly. Finally, this study analyses the energy loss caused by the radial temperature difference, and proposes some ways to eliminate the inner circulating streaming. The check calculation of the regenerator is taken. The mass flow in the cold end of the regenerator should be controlled less than70g/s.3. The performance parameters of the high-power pulse tube cryocooler are obtained by experiments. The cryocooler reached a bottom temperature of56.2K with a net cooling power of41.2W at77K. The results of the experiments are analyzed by one-dimensional theory and the two parallel regenerator model. |
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