直接达到液氦温度的G—M型制冷机及其应用

随着低温下具有高比热峰值的磁性稀土材料的发现，大幅度提高Ｇ－Ｍ型制冷机的性能具有了可能性。基于磁性稀土填料Ｅｒ３Ｎｉ、ＥｒＮｉ、ＧｄＲｈ等的特性，根据热力过程分析和数值计算结果，对双级Ｇ－Ｍ型制冷机进行了重新设计、加工，使其达到了液氦温度。介绍了我们研制的４．２Ｋ双级Ｇ－Ｍ型制冷机的设计和结构。该制冷机的最低制冷温度为２．５Ｋ，制冷量为５８０ｍＷ／４．２Ｋ、１１００ｍＷ／５．０Ｋ，热工效率高。同时     

空间环境模拟设备用G—M制冷机的研制

介绍了一台以磁性蓄冷材料Ｅｒ３Ｎｉ为第二级蓄冷器填料的大制冷功率两级Ｇ－Ｍ制冷机。该制冷机可作为空间环境模拟设备冷背景冷源，满足了辐射制冷器空间环境热模拟试验的要求。通过优化制冷机结构参数，使制冷机在转速为４０ｒ／ｍｉｎ时，二级最低制冷温度达５．５Ｋ、２０Ｋ时取得１５．４Ｗ的有效制冷量。证明了应用磁性蓄冷材料改善Ｇ－Ｍ制冷机性能的有效性。     

20K温区两级脉冲管制冷机的研究

脉冲管制冷机的实用化是目前脉冲管制冷机的一个主要研究方向。介绍了作者为提高脉冲管效率而研究的一种分离结构的两级脉冲管制冷机。实验获得了１１．７Ｋ的最低温度,制冷量３Ｗ／２０Ｋ。采用名义功率２．２ｋＷＧ－Ｍ压缩机驱动得到了１２．４Ｋ的最低温度,制冷量２Ｗ／１８．５Ｋ,４Ｋ／２４．６Ｋ,实际输入功率约１．５ｋＷ。这一效果已基本达到了实用化应用的要求。该研究表明脉冲管制冷机的效率在２０Ｋ温区已接近类似的     

4K脉管制冷机的实验研究

为研究如何利用脉管制冷机达到４Ｋ温度和最佳多级脉管构型，对几种类型的单级脉管制冷机与Ｇ－Ｍ制冷机组合休进行了实验，当脉管热端温度为室温时采用这种组合体的脉管冷端所获得的最低温度达３．５Ｋ。最后一级回热器的热端大约预冷到１５－２０Ｋ。其最佳工作条件为：压力约１．０－１．５ＭＰａ，频率１－２ＨＺ，热流和热损失分析与相移效应的关系。以及为达到４Ｋ温度的多级脉管制冷机的构型，均作了简要的讨论。     

新型低温高性能G－M制冷机

介绍了美国Ｂｕｔｔｅｒｗｏｒｔｈ－Ｈｅｉｎｅｍａｎｎ低温公司用普通材料和常规技术制作的高性能Ｇ－Ｍ制冷机，描述了该制冷机的设计原理和性能。该制冷机的制冷温度已达到６．５Ｋ以下，１０Ｋ时制冷能力为５Ｗ。     

新型低温高性能G—M制冷机

介绍了美国Ｂｕｔｔｅｒｗｏｒｔｈ－Ｈｅｉｎｅｍａｎｎ低温公司普通材料和常规技术制作的高性能Ｇ－Ｍ制冷机，描述了该制冷机的设计原理和性能。该制冷机的制冷温度已达到６．５Ｋ以下，１０Ｋ时制冷能力为５Ｗ。     

磁性稀土材料在VM制冷机中的应用

介绍用液氮作中间冷却剂产生１０Ｋ低温的ＶＭ制冷机。介绍了磁性回热材料的选择以及磁性稀土材料在制冷机中的应用与发展。在回热器中用低温下比热值较大的磁性稀土材料Ｅｒ（Ｎｉ０．７９Ｃｏ０．２１）２部分代替铅丸进行试验，无负荷温度降低，在２０Ｋ时间测得制冷量增加，证明了回热器的效率有所提高。     

新型磁性蓄冷材料G—M制冷机的研制

对应用磁性蓄冷材料作为二级蓄冷器填料而研制的大制冷功率两级Ｇ－ Ｗ 制冷机的研究工作进行了总结,给出了理论分析及结构设计。并在一台样机进行了实验研究,通过优化制冷机结构参数和运行参数,使制冷机二级最低制冷温度达７．８ Ｋ、２０ Ｋ 时取得１４．５ Ｗ 的有效制冷量,从理论和试验上对应用磁性蓄冷材料改善Ｇ－ Ｍ 制冷机性能的有效性进行了有益的探索。     

用4.2 K制冷机为冷源的磁性材料比热测量

设计了一套用４．２Ｋ制冷机为冷源的磁性材料比热测量装置。由于采用了Ｇ－Ｍ制冷机对试件进行冷却,从而使得实验操作简单方便,测试费用也较低,本试验过程完全实现了测试系统自动化,样品冷却温度,比热测量过程的监控以及比热测量数据的处理都由计算机自动完成,实验表明,该装置达到了预期的设计目标,可用于磁性蓄冷性能的研究工作。     

G—M制冷机填料型冷头换热器的实验研究

冷头换热器的不完全换热损失是Ｇ－Ｍ制冷机的主要冷量损失之一，制冷机的蓄冷器性能愈好，就要求冷头换热器的换热效率愈高。为了获得较高换热效率的冷头换热器，本文根据外置式Ｇ－Ｍ制冷机的特点，采用烧结工艺，设计和加工了一种填料型冷头换热器。测试了该换热器阻力性能，流动阻力比相应的间隙换热器小。初步的实验结果表明，采用该换热器的单级Ｇ－Ｍ制冷机无负荷温度达到１５Ｋ，在２０Ｋ可提供４．４Ｗ的冷量。     

液氦温区脉管制冷机的频率特性

着重研究了操作频率对液氦温区脉管制冷机性能的影响,在实验和分析的基础上,明确了制冷温度、制冷量、制冷效率与工作效率之间的关系,并与4K G－M制冷机的情况进行比较,得出了一些有益的结论。通过频率优化,脉管制冷性能得以较大提高。在初步试验中,分别在1．2Hz和1．1Hz获得了30W@70K,500mW@4.2K以及20W@65K,590mW@4.2K的制冷量。同时还给出了脉管制冷湿度稳定性的测试结果。试验结果表明,研制的脉管制冷机温度波动均小于同类商品型4K GM制冷机及脉管制冷机。     

On the numerical design of a new type of 4 K GM/PT hybrid refrigerators

In this paper we developed and designed, based on theoretical considerations, a new type of 4 K GM/PT hybrid refrigerators. The upper warm stage of the hybrid refrigerator is a typical GM refrigeration cycle, and the cold stage is a pulse tube refrigerator (PTR), on which is thermodynamically coupled the upper warm stage. Four different types of phase shifting assembly: (1) a cold auxiliary piston that is connected to the displacer of the upper GM refrigerator stage, (2) an orifice with reservoir encircled the cold head of the upper stage, (3) an orifice with double-inlet, and (4) in combination with the cold auxiliary piston, orifice and double-inlet, has been proposed and analyzed for the adjustment of the phase shift between the gas mass flow and pressure in the pulse tube. Numerical simulation is performed to understand the unique thermo-physical features, to reveal the time-dependent dynamic parameters and to quantify the overall cooling performance of the hybrid refrigerator. We rely on a one-dimensional, unsteady compressible flow numerical model that is based on a mixed Eulerian-Lagrangian method developed by the present author. The model will be first applied to analyze the cooling performance of the hybrid refrigerator with different types of phase shifting assembly. In what following, it is used to simulate the dynamic parameters in the cold stage of the pulse tube cycle. Next, optimization of the structure parameters and geometrical configuration of the new refrigerator will be presented. Finally, the influences of different hybrid regenerative materials on the cooling capacity of the new hybrid GM/PTR will be also discussed.     

室温磁制冷机的实验性能研究

介绍了利用1.5 T永磁体提供磁场、选取氦气作为换热流体、采用主动式磁回热器的室温磁制冷机的实验性能研究情况.应用现有实验装置,通过调节气体压力与循环频率,最大达到了30.93 K的高低温端温差,在高低温端温差为10.97 K达到了25.20 W制冷量.研究结果表明室温磁制冷机的制冷能力显著,并且为室温磁制冷机的设计以及进一步的发展提供了有益的参考.     

Design of non-flammable mixed refrigerant Joule-Thomson refrigerator for precooling stage of high temperature superconducting power cable

A cryogenic Joule-Thomson (JT) refrigerator has many advantages for large industrial applications, including easy cooling power adjustability and high reliability because there are no moving parts at low temperature. In this paper, a single stage and a cascade type of non-flammable (NF) mixed refrigerant (MR) JT refrigerators have been proposed for the precooling process of a neon/nitrogen mixed refrigerant JT refrigerator. The neon/nitrogen MR JT refrigerator is used to maintain a subcooled state of liquid nitrogen coolant for an HTS (high temperature superconductor) cable.Both selected MRs for the 1st stage (low temperature cycle) of the cascade MR JT refrigerator and the single MR JT refrigerator are composed of Nitrogen (N₂), Argon (Ar), Tetrafluoromethane (CF₄, R14) and Octafluoropropane (C₃F₈, R218). R410A is selected as the refrigerant for the 2nd stage (high temperature cycle) of the cascade MR JT refrigerator, of which the cooling temperature is approximately 240 K. A commercial software with Peng-Robinson equation of state (EOS) is utilized to design the non-flammable MR JT refrigerator. The optimal design is discussed with consideration for various parameters such as the temperature staging, the operating pressure of the compressor and the mass flow rate of the working fluid. The maximum coefficient of performance (COP) and Carnot efficiency of the cascade MR JT refrigerator are obtained as 0.216 and 40%, respectively at 105 K. Exergy analysis is also carried out in this paper to reveal the irreversibility of the refrigeration cycle.     

空调压缩机驱动高效同轴脉冲管制冷系统

介绍了为实际应用而开发的低成本、高效率、长寿命的制冷系统：空调压缩机驱动的单级同轴脉冲管制冷机。实验获得了３８．４Ｋ的最低温度，制冷量３Ｗ／５０Ｋ，大于６Ｗ／８０Ｋ，输入功率约６２０Ｗ，启动过程操作简单、降温快、运行稳定。     

Progress on a novel VM-type pulse tube cryocooler for 4 K

VM type pulse tube cryocooler is a new type pulse tube cryocooler driven by the thermal-compressor. This paper presented the recent experimental results on a novel single-stage VM type pulse tube cryocooler with multi-bypass. The low temperature double-inlet, orifice and gas reservoir, and multi-bypass were used as phase shifters. With the optimal operating frequency of 1.6 Hz and optimal average pressure of 1.4 MPa, a no-load temperature of 4.9 K has been obtained and 30 mW@5.6 K cooling power has been achieved. It was the first time for the single-stage VM-PTC obtaining liquid helium temperature reported so far. Moreover, it was also the first time for the multi-bypass being used in the low-frequency Stirling type pulse tube cryocooler.     

GM/PT混合式制冷机二级蓄冷器的实验研究

二级脉冲管蓄冷器对GM／PT混合式制同制冷性能有较大影响。蓄冷器与脉冲管结构的布置形式对GM／PT混合式制冷机性能有着较大影响,蓄冷器体积与脉冲管体积之间存在着最佳比较,介绍了GM／PT混合式制冷机的结构和实验装置,分析了整机性能的影响因素,给出了不同结构与体积比下的实验降温曲线,并对实验结果进行了分析讨论。     

冷却高温超导磁体的大冷量单级G-M制冷机

随着高温超导磁体在电工技术方面日益广泛的应用，如高温超导限流器、高温超导变压器、高温超导储能系统等。对工作在30K～40K、并可提供50W～100W制冷量的低温制冷机提出了需求。常规的单、双级G-M制冷机产品不能满足高温超导磁体的冷却要求，本文初步得到了提高单级G-M制冷机性能、增大40K温度以下制冷量的方法，并在一台常规单级G-M制冷机上验证，获得了30W/40K制冷量的好结果，指明了研制这种大冷量G-M制冷机的方向，为成功研制冷却高温超导磁体的大冷量单级G-M制冷机走出了第一步。     

一种采用迷宫密封的10 K G-M型制冷机研究

提出了一种采用迷宫密封的10K G-M型制冷机,对迷宫密封的机理进行了简要的理论分析,给出了这种新型10K制冷机的结构参数,建立了实验平台,给出实验降温曲线和制冷量曲线。研究证明,这种采用迷宫密封的10K G-M型制冷机是一种技术上较为完善并且更具实用性的10K温度范围的新型G-M制冷机。