航天器制冷机的发展概况

随着空间技术的发展，使得各种遥感仪广泛用于航天器上。如红外探测器、Ｘ射线、γ射线和亚毫米波探测器等须在低温下工作才能提高灵敏度，降低热噪声。因此，制冷系统是空间技术不可缺少的重要组成部分。目前采用的制冷系统有：被动制冷包括辐射制冷和低温制冷剂贮存系统；机械制冷机。主要介绍了空间制冷机分类、特点，在航天器上已经和即将使用的制冷机。     

空间机械制冷机与红外探测器的耦合技术

在空间红外遥感中，红外探测器是通过与制冷机的耦合获取冷量的。着重讨论为满足红外探测的需要，如何最大限度地消除空间的振动、电磁干扰等不利因素的影响。同时介绍降低漏热，提高冷量传输效率，从而保证制冷机与红外探测器良好耦合的技术。     

空间机械制冷机的工程化研究现状

空间制冷技术是制约空间红外遥感技术发展的关键技术之一。随着红外遥感元件所需冷量的大幅提高，空间机械制冷机逐渐成为空间制冷的主力军。首先简单介绍国内外空间机械制冷机的工程化进展状况；并结合美国JPL实验室近十年关于机械制冷机的研究报告，概述在空间机械制冷机研制过程中需要重视和考虑的技术问题，有助于加快我国空间机械制冷技术的应用进程。     

星载制冷机隔振装置的设计与实验研究

制冷机广泛应用于空间红外遥感探测器中,其主要运动部件压缩机在工作过程中产生的微振动,是影响探测器正常工作的主要振源之一.基于松弛型阻尼器,设计制冷机多自由度隔振装置.对隔振装置的隔振性能进行仿真分析,同时,搭建隔振装置实验平台,完成隔振性能的实验研究.结果表明,设计的隔振装置在制冷机工频处的隔振效率达到94％以上,可以...     

制冷机与红外探测器耦合技术中的热分析

在空间红外遥感中,红外探测器通过制冷机获取冷量。由于空间应用对制冷机的输入功率有严格的限制,降低导热、辐射冷损、提高传输效率就成为该耦合系统的一个关键问题。应用有限元工程分析软件做了详细的热力学分析,同时通过对耦合系统各构件的有限元热分析,进一步对其结构进行优化。     

空间机械制冷机降额使用条件分析

空间机械制冷机是红外探测器组件中的关键组成部分,在性能参数满足要求后,可靠性成为制约制冷机在实际任务中应用的关键因素。根据不同的在轨使用寿命要求,对制冷机采取降额使用的策略是提升在轨可靠性的有效途径。在总结制冷机失效模式及分析其失效机理基础上,明确了降额的依据,并确定了降额因子大小。     

航天应用的制冷机系统

介绍冷却４×２２ 元 Ｈｇ Ｃｄ Ｔｅ 红外探测器的集成组件的斯特林制冷系统。这是一种单级的牛津型的斯特林制冷机。其特点是采用膜片弹簧支撑、音圈电机驱动、差动变压器的位移传感器和间隙动密封技术。制冷机的最低制冷温度４３ Ｋ, 降温时间２０ ｍ ｉｎ, 其压缩机功耗约３０ Ｗ。制冷机系统采用双机屏蔽轴向对置排列, 以减小系统机械振动和对探测器的电磁干扰。制冷机通过柔性冷链（汇流排）冷却红外探测器组件。系统在８０ Ｋ 时对探测器提供的冷量大于３０ ｍ Ｗ,制冷机功耗４５ Ｗ。冷链温差为２５ Ｋ, 探测器等效温度灵敏度０２ Ｋ。     

HOT器件用自由活塞斯特林制冷机研究进展

自由活塞斯特林制冷机可用于红外探测器组件的冷却,具有振动小、寿命长等优点。随着红外探测器工作温度的提高(HOT器件),斯特林制冷机进入更小尺寸、更低质量、更高性能、更低功耗和更低成本的发展方向,即超小型斯特林制冷机。文章总结了近10年国内外超小型自由活塞斯特林制冷机的发展概况,并对超小型自由活塞斯特林制冷机的设计理念进行了介绍。     

红外探测器与小型制冷机

小型致冷机可以用来冷却红外探测系统的敏感元件。工作范围为60K到80K。制冷量为0.1瓦到2瓦。这两个指标又取决于冷却的探测器数目和探测器一制冷机接合面的热效率。这类小型制冷机的平均无故障时间应当大于2500小时,而且温度回升要很小。根据菲利浦公司几十年来从事低温工作的经验,在空间红外探测器上,采用斯特林循环的小型制冷机可以     

大面阵红外探测器冷平台仿真设计与试验

随着线列红外探测器面阵规模越来越大,传统的制冷机与红外探测器单点连接的耦合方式已经无法满足红外探测器芯片温度均匀性的要求.本文对某型号大面阵红外探测器冷平台及其辅助支撑、柔性冷链进行了相关的结构设计、仿真分析与试验验证,设计的冷平台在正弦和随机振动时变形量小,温度均匀性不大于0.919 K,可以满足大面阵红外探测器的工...     

新型复合式斯特林/逆布雷顿低温制冷机

未来空间系统需要可靠的长寿命、低温度、小冷量的低温制冷机.采用复合制冷机的技术可以分别强化不同制冷机各自的技术优势并且弱化各自技术的弱势.对国外在斯特林/逆布雷顿复合制冷机的整合研究及多级逆布雷顿制冷机的发展进行了概述及讨论.对未来我国开展逆布雷顿复合制冷机的研究具有一定的现实意义.     

A capacitance based axial position sensor for cryocoolers

The recent development of a Stirling cryocooler designed to operate with a body temperature of less than 220 K required an axial motor position sensor which could operate over this temperature range. Although linear variable differential transformers (LVDTs), have traditionally been used, these are temperature dependent and would have required development due to integrated electronics, which could not be used at these low temperatures. A sensor was therefore developed based on the principle of measuring the capacitance between static and moving concentric rings. The design is presented along with the signal conditioning circuit. Experimental results show that the sensor had suitable bandwidth with a temperature independent gain between room temperature and 220 K. Future developments are described including a similar sensor to measure the radial motion of a motor during operation.     

Experimental study of a cascade pulse tube cryocooler with a displacer

Recovering the expansion power in pulse tube cryocooler is of great utility in improving cooling efficiency. Using a second-stage cooler after a primary cooler to produce extra cooling power is an effective way especially when the cooling temperature is not very low. In the configuration, the two coolers are connected by a displacer which is used as a phase shifter. In this paper, experimental investigations were conducted to study this system. Firstly, the performance of the overall system and separated cooler was respectively presented. To better understand the displacer, phase relation, mechanical resistance and displacement were then clarified. In addition, the power consumption distribution of the cascade cryocooler was discussed. Finally, both numerical and experimental comparisons were made on the displacer-type and tube-type cryocooler. The experimental results show that the displacer-type cryocooler has superior performance due to the better phase-modulation capability and less power loss. With the input electric power of 1.9 kW and cooling temperature of 130 K, the overall system achieved a cooling power of 371 W and a relative Carnot efficiency of 24.5%.     

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.     

High-efficiency 3 W/40 K single-stage pulse tube cryocooler for space application

Temperature is an extremely important parameter for space-borne infrared detectors. To develop a quantum-well infrared photodetector (QWIP), a high-efficiency Stirling-type pulse tube cryocooler (PTC) has been designed, manufactured and experimentally investigated for providing a large cooling power at 40 K cold temperature. Simulated and experimental studies were carried out to analyse the effects of low temperature on different energy flows and losses, and the performance of the PTC was improved by optimizing components and parameters such as regenerator and operating frequency. A no-load lowest temperature of 26.2 K could be reached at a frequency of 51 Hz, and the PTC could efficiently offer cooling power of 3 W at 40 K cold temperature when the input power was 225 W. The efficiency relative to the Carnot efficiency was approximately 8.4%.     

Integrated Resonant Self-Pumped Loop and pulse tube cryocooler for cryogenic cooling distribution

Cooling distribution is a vital technology concerning cryogenic thermal management systems for many future space applications, such as in-space, zero boil-off, long-term propellant storage, cooling infrared sensors at multiple locations or at a distance from the cryocooler, and focal-plane arrays in telescopes. These applications require a cooling distribution technology that is able to efficiently and reliably deliver cooling power (generated by a cryocooler) to remote locations and uniformly distribute it over a large-surface area. On-going efforts by others under this technology development area have not shown any promising results.This paper introduces the concept of using a Resonant Self-Pumped Loop (RSPL) integrated with the proven, highly efficient pulse tube cryocooler. The RSPL and pulse tube cryocooler combination generates cooling power and provides a distributive cooling loop that can be extended long distances, has no moving parts, and is driven by a single linear compressor. The RSPL is fully coupled with the oscillating flow of the pulse tube working fluid and utilizes gas diodes to convert the oscillating flow to one-directional (DC) steady flow that circulates through the cooling loop. The proposed RSPL is extremely simple, lightweight, reliable, and flexible for packaging. There are several requirements for the RSPL to operate efficiently. These requirements will be presented in this paper. Compared to other distributive cooling technologies currently under development, the RSPL technology is unique.     

Advances on a cryogen-free Vuilleumier type pulse tube cryocooler

This paper presents experimental results and numerical evaluation of a Vuilleumier (VM) type pulse tube cryocooler. The cryocooler consists of three main subsystems: a thermal compressor, a low temperature pulse tube cryocooler, and a Stirling type precooler. The thermal compressor, similar to that in a Vuilleumier cryocooler, is used to drive the low temperature stage pulse tube cryocooler. The Stirling type precooler is used to establish a temperature difference for the thermal compressor to generate pressure wave. A lowest no-load temperature of 15.1 K is obtained with a pressure ratio of 1.18, a working frequency of 3 Hz and an average pressure of 2.45 MPa. Numerical simulations have been performed to help the understanding of the system performance. With given experimental conditions, the simulation predicts a lowest temperature in reasonable agreement with the experimental result. Analyses show that there is a large discrepancy in the pre-cooling power between experiments and calculation, which requires further investigation.