Design Of A High-power Stirling-type Pulse Tube Cryocooler

With the developments of High Temperature Superconductor (HTS) and gas liquefaction technology, 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 alternate for HTS applications and small-scale liquefication plant if its performance is comparable with or even better than that of well-developed GM-type cryocooler in the temperature region of 30-80 K. However, there are great challenges in theory and technology for HSPTCs, mailnly including the loss mechanism of large scale regenerator, temperature inhomogeneity, and design of compact heat exchangers with high cooling power. The main contribution of the thesis are listed as follows:1. The regenerator of a single-stage high-power Stirling-type pulse tube cryocooler was designed based on a well-known regenerator model of REGEN3.3, which was developed by National Institute of Standards and Technologies (NIST). The effect of geometry, mesh screens and cold-end pressure ratio on the performance of the regenerator was analyzed.2. The efficiency coefficient method was first introduced to optimize the coefficient of performance (COP) and cooling power (Qc) of a PTC simultaneously. Multi-objectives optimization can be realized with the method such as COP, Qc,Mass and lifetime of the cryocoolers, while traditional design method can only optimize one single objective.3. Based on 1 and 2, a HSPTC which can provide 300 W at 77 K driven by a CFIC linear compressor was designed and constructed, the input PV power is 3.47 kW. The assembly of the HSPTC and experimental preparations have been completed, and the performance test is to start.4 Due to the fact that the cost of linear compressor with high input power is high and still depending on import, the scheme of converting the exsiting relatively mature Philips Stirling cryocooler into the high power pulse tube cryocooler was proposed. Priliminary theoretical and experimental investigation was carried out.