【作者】 孙贺；

【导师】 甘智华； 邱利民；

【作者基本信息】 浙江大学 ， 制冷及低温工程， 2008， 硕士

【摘要】 与传统的低温制冷机相比,如G-M和斯特林制冷机,脉管制冷机在低温端无运动部件,具有结构简单、可靠性高,长寿命等优点。随着液氢无损储存、新型超导体MgB2及低温泵等技术的快速发展,20K温区单级G-M型脉管制冷机有着广泛的应用前景。本文介绍了当前G-M型脉管制冷机实用化现状,并对一台单级G-M型脉管制冷机进行了理论和实验研究,以提高其在20K温区的效率和制冷量并达到实用化要求。主要内容包括以下几方面:1.基于REGEN3.3的单级G-M型脉管制冷机数值计算和分析。计算分析了低频情况下,相位角、回热器长度、质量流量、铅丸直径、充气压力和工作频率对回热器性能的影响,得出了能够指导试验的有益结论。2.单级G-M型脉管制冷机试验研究。对回热器长度、回热器中80K以下温区回热材料布置形式、制冷机工作频率和充气压力进行了优化。经优化,在输入功率7.5kW时,该制冷机最低制冷温度达到10.6K,这是目前国内外公开报道的单级脉管制冷机最低制冷温度。该制冷机在20.6K可提供20W的制冷量。并且该制冷机在长时间运行过程中温度波动为0.4K,性能稳定,可基本满足实用化要求。3.平面旋转阀阀芯的改进。为了进一步提高平面旋转阀的可靠性,本文提出了在阀芯与底盘的接触面上引入四个气室的改进方案,在不影响制冷机性能的情况下,能够降低阀芯的磨损以及阀芯旋转所需要的扭矩,从而有助于提高制冷机的寿命。更多还原

【Abstract】 Compared with the traditional cryocoolers, such as G-M and Stirling cryocooler, pulse tube cooler （PTC） without moving parts at the low temperature range has simpler structure, higher reliability and longer lifetime. With the development of zero boil-off liquid hydrogen storage, high temperature superconductor MgB₂ and cryogenic pumps, the application of cryocoolers working at 20 K becomes more extensive. The research and development of G-M type PTC has been reviewed. Theoretical and experimental investigations on a single-stage G-M type PTC have been carried out. to improve the coefficient of performance （COP）, cooling capacity at 20 K and meet the requirement for practical applications. The present work focuses on the following sections:1. Numerical calculation and analysis of G-M type PTC based on REGEN3.3. The effects of some important parameters on the performance of the regenerator of a single-stage G-M type PTC working at low frequency are calculated and analyzed, including phase angle, regenerator length, mass flow rate, diameter of lead sphere, charging pressure and frequency. Some useful conclusions can provide theoretical foundation for the experimental optimization of the PTC.2. Experimental study on a single-stage G-M type PTC. The effects of regenerator length, regenerative materials below 80K, filling pressure and frequency on the performance of a single-stage G-M type PTC are tested and analyzed. The lowest no-load temperature of 10.6K has been obtained, which is a new record for the single-stage PTC. The cooling capacity of 20W at 20.6K has been obtained with an input power of 7.5kW. Meanwhile, the performance of the PTC in long-time run has been tested. The temperature fluctuation of the cold head of the PTC is less than 0.4K, which can meet the requirement for practical applications.3. Improvement of valve core rotary valve. In order to improve the reliability of rotary valve, four air-chambers on the interface between valve core and chassis have been proposed. The wear and the torque required of the valve core can be significantly reduced by this method. Preliminary experiments have confirmed that the new type of valve structure do not affect the cooling performance of the PTC.更多还原