【作者】 李卓裴；

【导师】 邱利民； 甘智华；

【作者基本信息】 浙江大学 ， 制冷及低温工程， 2010， 博士

【摘要】 液氦温区低温制冷机在低温超导、航天深空探测、国防军事、医疗以及低温物理等研究领域有着重要应用。斯特林型脉管制冷机具有可靠性高、寿命长、重量轻及潜在的高效性高效率等优点,因此研制开发液氦温区斯特林型脉管制冷机具有重要的研究与应用价值。然而,相比于发展日趋成熟的80 K温区斯特林型脉管制冷机,4K温区斯特林型脉管制冷机理论和实验研究尚处于起步阶段,限制了其在相关领域的应用。鉴于此,本文以探索液氦温区回热器高频损失机理和寻找高频下采用氦-4工质获得液氦温区的有效途径为目标,开展了以下工作：1.脉管制冷机的热力学分析及液氦温区高频回热器损失机理研究基于热力学定律,分析了脉管制冷机内部各部件的热力学特性,并给出了脉管制冷机的各种损失。研究了制冷温度、工质种类、平均压力、压比等参数对液氦温区回热器在高频下损失的影响,对进一步了解液氦温区回热器的损失机理具有重要的指导意义。2.系统编制了液氦温区斯特林型脉管制冷机的结构图谱脉管制冷机的级间结构对脉管制冷机的性能有着重要影响。本文探索了液氦温区斯特林型脉管制冷机可采用的级间布置方式,并首次编制了液氦温区斯特林型脉管制冷机的结构图谱。为了进一步明确级联方式不当而导致的多级脉管制冷机损失,研究了不同声功下脉管热端温度布置方式对制冷机整机性能的影响,为液氦温区斯特林型脉管制冷机级联方式的优化指明了方向。3.低温惯性管调相的理论研究针对4K斯特林型脉管制冷机声功较小,运行频率较低而导致采用常规的室温惯性管调相能力不足的问题,本文研究了脉管热端温度对惯性管调相能力的影响,并提出采用低温惯性管作为4K斯特林型脉管制冷机调相装置的方案。对低温下实际气体性质进行了修正,并计算了压比、平均压力、气库容积对惯性管调相角度的影响。4.两级G-M型脉管制冷机预冷的单级斯特林型脉管制冷机的设计、制作本文基于回热器模拟软件REGEN3.3设计了带预冷的单级斯特林型脉管制冷机,重点研究了高频回热器在液氦温区的性能。给出了斯特林型脉管制冷机到达液氦温区所需要的预冷温度和预冷量,并设计了单级斯特林型脉管制冷机和两级G-M型脉管制冷机热耦合部件。搭建了整机和动态参数测试实验台,为脉管制冷机的实验研究打下了基础。5.带预冷的4K斯特林型脉管制冷机的实验研究为了验证理论计算结果并探索斯特林型脉管制冷机采用氦-4工质进入液氦温区的可行性,本文开展了运行参数(包括工作频率、平均压力、输入功率、预冷温度等)、回热器填料以及回热器结构等对4K斯特林高频脉管制冷机性能影响以及对预冷级制冷机预冷要求的实验研究。采用氦-4作为工质的斯特林型脉管制冷机首次进入液氦温区。更多还原

【Abstract】 Cryocoolers working at liquid helium have important applications in the field of low temperature superconductivity (LTS), space exploration, military detection, medical examination and low temperature physics. Stirling type pulse tube cryocoolers have the advantage of high reliability, long life, light weight and have potentially high efficiency which makes them very appealing for 4 K applications. However, compared with the relatively efficient 80 K Stirling type pulse tube cryocoolers, both theoretical and experimental investigation on 4 K Stirling type pulse tube cryocoolers is only at the preliminary stage which limits their application in the liquid helium temperatures. In order to further understand the loss mechanism of 4 K regenerators at high frequency and explore the effective way of reaching 4 K with helium-4 as the working fluid, research work is carried out which focuses on the following sections:1. Thermodynamic analysis of pulse tube cryocooler and investigation on the loss mechanism of 4 K regenerator at high frequencyBased on the first law and second law of thermodynamics, analysis is carried out on the thermodynamic characteristic of the components of a pulse tube cryocooler and the various losses in a pulse tube cryocooler are given. Effect of temperature region, working fluid, average pressure and pressure ratio on the losses of 4 K regenerator at high frequency is studied which can provide guidance for better understanding the loss mechanism of high frequency 4 K regenerators.2. Staging configuration diagram of multi-stage Stirling type pulse tube cryocooler working at liquid helium temperatures is drawn.The staging configuration of pulse tube cryocoolers has great influence both on the performance of the cryocooler and the compactness of the system. The possible staging configuration of 4 K Stirling type pulse tube cryocoolers is explored and the configuration diagram is drawn for the first time. In order to determine the loss caused by staging configuration, effect of warm end temperature of pulse tube on the performance of the cryocooler with different acoustic power is investigated which is helpful for the optimization of multi-stage 4 K Stirling type pulse tube cryocooler.3. Theoretical investigation on cold inertance tubeThe conventional inertance tube located at the ambient temperature as the phase shifter for 4 K Stirling type pulse tube cryocooler with small acoustic power and relatively low operating frequency is not able to shift the mass flow and pressure to the ideal phase angle efficiently. As a result, the effect of temperature on the phase shifting ability of inertance tube is investigated and the use of cold inertance tube as the phase shifter for the precooled 4 K Stirling type pulse tube cryocooler is proposed. Modification of real gas behavior at low temperatures is made and effect of average pressure, pressure ratio and reservoir volume on phase angle of inertance tube is studied.4. Design and fabrication of a 4 K single-stage Stirling type pulse tube cryocooler precooled by a two-stage G-M type pulse tube cryocoolerIn order to focus on the behavior of the high frequency regenerator at liquid helium temperatures, a precooled 4 K Stirling type pulse tube cryocooler is designed based on the regenerator simulation model known as REGEN 3.3. The precooling requirement including the precooling temperature and the precooling power for the Stirling type pulse tube cryocooler to reach 4 K is given. And the thermal coupling component between the G-M type pulse tube cryocooler and the Stirling type pulse tube cryocooler is designed. Experimental setup of the precooled pulse tube cryocooler and the dynamic parameters measuring system was built up which lays the foundation for the experimental investigation of the 4 K Stirling type pulse tube cryocooler.5 Experimental investigation of the 4 K precooled Stirling type pulse tube cryocoolerIn order to verify the theoretical calculation and explore the possibility of reaching 4 K with helium-4 as the working fluid for a Stirling type pulse tube cryocooler, the effect of operating parameters which includes operating frequency, average pressure, input power and precooling temperature, regenerator matrix and regenerator geometry on the performance of the 4 K Stirling type pulse tube cryocooler and the precooling condition for the precooler is carried out. Liquid helium temperature was obtained with helium-4 as the working fluid for a Stirling type pulse tube cryocooler for the first time.更多还原