100-140 Hz脉冲管制冷机耦合特性的实验研究

为研究惯性管长度变化对压缩机输出效率和压缩机与冷指之间的耦合特性的影响,对100-140 Hz的2 kg级的高频脉冲管制冷机的整机效率进行了理论分析,通过实验研究了不同惯性管长度对压缩机活塞位移、相位、压力波的影响,并得出了压缩机输出PV功.实验结果表明不同惯性管长度组合,对应不同频率压缩机的效率最高;制冷机整机效率最...     

冷指尺寸对超高频微型脉冲管制冷机性能的影响分析

冷指是脉冲管制冷机的重要部件,其尺寸大小决定压缩机乃至制冷机整机的尺寸,其内部的功热转换效率和损失等会对制冷机的性能产生显著的影响.为满足脉冲管制冷机微型化的需求,必须提高制冷机频率、减小冷指尺寸,而冷指尺寸的缩小又会影响制冷机的性能.为了掌握冷指尺寸对制冷机性能的影响规律,利用SAGE软件对运行频率为130 Hz,直...     

U型脉管制冷机冷端连管对压缩机输出特性影响

实验研究了U型脉冲管制冷机中冷端连管直径、长度对线性压缩机输出特性及制冷机性能的影响。结果表明,管径过小的连管导致压缩机出口压力波与速度波相位差增大,压缩机效率下降,制冷机性能下降;冷端连管长度对压缩机效率影响不大,但随着冷端连管增长,制冷机整机性能下降。     

超高频脉冲管双冷指与压缩机的耦合匹配及优化

对一台压缩机分别驱动单个冷指和双冷指脉冲管制冷机进行了实验研究。实验发现双冷指脉冲管制冷机制冷性能和效率都不如单冷指脉冲管制冷机,导致性能下降的原因是由于双冷指制冷机的总阻抗与压缩机不匹配。从阻抗的角度研究双冷指制冷机与压缩机的耦合匹配特性,根据压缩机理论PV功转化效率,对与双冷指耦合的线性压缩机进行了参数优化。优化后的双冷指脉冲管制冷机可获得和单冷指脉冲管制冷机几乎一致的理论PV功转化效率。     

脉冲管制冷机内部交变流动过程实验研究第二部分 实验结果分析与讨论

对一台小孔型脉冲管制冷机内部动态流动过程进行了系统的实验研究.在准确测量脉冲管制冷机蓄冷器热端和脉冲管热端的压力波和速度波曲线的基础上,对其进行傅里叶分析,得到波动曲线的基本参数,包括幅值和相位等.系统研究了各种条件和工况(包括运行频率、充气压力、小孔开度、压缩机出口压比等)对脉冲管制冷机内部压力波和速度波的幅值与相位的影响规律.实验结果对于脉冲管制冷机的机理理解、设计和调试有着重要的意义.     

脉冲管制冷机惯性管调相能力的实验研究

为了验证脉冲管制冷机惯性管理论模型的准确性,通过修正压缩机活塞表面质量流的方法间接测量了惯性管入口质量流幅值及质量流与压力波之间的夹角.对目前脉冲管制冷机中应用较为广泛的单段惯性管加气库及双段惯性管加气库的调相能力进行了测量,并将测量值与简化湍流热声模型计算结果进行了比较.所测单段和双段惯性管阻抗幅值及相位角随内径及长...     

斯特林型高频脉冲管制冷机的实验研究

介绍了一台单级U型高频脉冲管制冷机的实验装置和实验结果.制冷机冷端无负荷最低温度达到了38.31 K,此结果为目前国内单级斯特林型高频脉冲管制冷机所达到的最低温度.当输入电功率200 W时,在50 K有0.6 W制冷量;当输入电功率为250 W时,在80 K有4.25 W的制冷量.这为40 K以下深低温,大冷量的斯特林型脉冲管制冷机的研制做出了有益的探索.通过分析压缩机运行频率对制冷机的最低温度和制冷量的影响,得出了在液氮温区针对特定的制冷温度,压缩机存在的一个最佳工作频率.在此工作频率下,压缩机和脉冲管耦合后,制冷机能够获得较高的效率.     

同轴型脉冲管制冷机中蓄冷器与脉冲管热耦合对性能影响的研究

同轴型脉冲管制冷机的特点是蓄冷器和脉冲管共用一个不锈钢壁面形成同轴结构,这样使其在结构上最为紧凑,但同轴结构会不可避免地形成蓄冷器和脉冲管内部气体之间的热耦合。借助一台U型脉冲管制冷机对脉冲管制冷机中蓄冷器和脉冲管热耦合的形成及其影响进行了初步的实验研究和分析。通过实验研究得到了蓄冷器和脉冲管壁面轴向温度变化曲线。在此基础上进行了热耦合的实验研究,以此来考察热耦合对整机性能的影响。初步的整机性能实验结果显示这种热耦合对改善制冷机性能是有益的。     

13.5K两级气耦合型高频脉冲管制冷机实验研究

高频脉冲管制冷机由于冷端无运动部件、振动小、寿命长等优点,广泛运用于低温物理实验、航空航天等领域。通过介绍一种两级气耦合高频脉冲管制冷机,在该脉冲管的第一级中,采用了双向进气和多路旁通作为调相机构,为获取更好的调相效果,第二级脉冲管的惯性管和气库被置于第一级的冷头处。为了进一步调节第二级脉冲管中压力波质量流的相位差,将压缩机的气流引入二级脉冲管热端作为第二级脉冲管的双向进气。该制冷机在充气压力1.7 MPa,输入电功250 W的工况下,可以获得13.5 K的无负荷制冷温度,0.6 W@30 K的制冷量。文章对该制冷机实验结果进行了总结。     

热端温度对直线型脉冲管制冷机的影响分析

基于一台单级直线型脉冲管制冷机,研究分析了热端温度变化对制冷机性能的影响关系.建立了一维数值模型,分析了高频脉冲管制冷机内部相关热力学参数随热端温度变化的关系,从而揭示了热端温度变化影响整机性能的作用机理.最后通过实验数据和模拟值的比较研究,验证了模型的准确性.     

Experimental study on the coupling characteristics of 100 Hz inertance tube pulse tube cryocooler working under optimal frequcency

Miniature pulse tube cryocooler is one of the main developing trends of pulse tube cryocooler. Four pulse tube cold fingers, two compressors and a series of inerance tube assemblies are employed to carry out the experimental investigation of coupling characteristic of miniature pulse tube cryocooler. It is concluded that the cooling performance of miniature pulse tube cryocooler is determined by the match conditions among its compressor, cold finger and inertance tube. If the three parts of cooler match well, the cold finger can achieve nearly same cooling performance under two totally different working conditions.     

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.     

斯特林型两级脉管制冷机的改进

在最近研制的1台直线压缩机驱动的两极脉管制冷机的初步试验的基础上,对直线压缩机的线圈重新进行了设计和制作,解决了由于绕制圈数过多而无法输入足够电功率的问题。对冷头的热端法兰及回热器热端热交换器进行了改进,采用了微槽式水冷却器,解决了压缩热无法得到充分冷却引起的制冷机热端温度过高的问题。改进后制冷机的性能得到了显著的提高,在2.0 MPa充气压力和40 Hz频率的条件下,该制冷机获得了14.2 K的最低制冷温度。并且,第一级和第二级在97.8 K和34.9 K时,分别具有2.5 W和1 W的制冷量。     

基于线性压机驱动的高频同轴脉管制冷机研究

介绍了基于线性压机驱动的高频同轴脉管制冷机的特点及同轴脉管制冷机与线性压机匹配时的设计思路,通过数值计算模拟了同轴脉管制冷机制冷性能和动态参数的关系。搭建了脉管制冷机试验台并介绍了测试系统的组成,最后对所设计的高频同轴脉管制冷机进行了初步试验研究。试验结果对进一步改进脉管制冷机的设计提供了有益的参考。     

基于传输管容抗调节的压缩机与冷头匹配研究

通过在脉管制冷机传输管两侧增加并联气库实现传输管体积的调节,仅通过容抗调节进行压缩机与冷头的阻抗匹配优化,提高脉管制冷机整机效率。实验证明,气库型传输管相比于利用综合阻抗调节的传统细长型传输管具有相同的阻抗匹配优化效果。该方法采用长径比较小的气库型传输管,引入的体积流阻抗很小,可以极大减少声功的传输损失。气库型传输管的阻抗特性与布置方式无关,可充分利用压缩机周边的空间,更易于安装和调试,使整机结构更加紧凑。     

Numerical simulation of a GM-type pulse tube cryocooler system: Part II. Rotary valve and cold head

A simplified model to characterise a rotary valve is proposed. This model is used inside a complete GM-type pulse tube cryocooler (GMPTC) simulation including the compressor, rotary valve and cold head. The verification of the model is presented including the pressure wave, cooling power and COP by comparing the simulation results to the experimental data of an existing GMPTC system. The exergy losses produced by the compressor, rotary valve and cold head are discussed. This paper is aimed to propose a simulation method which can be applied to analyse and optimise a GMPTC cold head by using the characteristics of a specific compressor and rotary valve.     

20K以下温区斯特林型脉管制冷机的最新研究进展与损失机理分析

系统介绍了20 K以下温区斯特林型脉管制冷机的最新研究进展,指出了多级斯特林型脉管制冷机的应用前景与发展趋势.深入分析了多级斯特林型脉管制冷机20 K以下温区的主要损失特性,以及其难以达到更低制冷温度和更高制冷效率的内在原因,着重说明进一步提高高频回热器效率、发展高效线性压缩机技术是实现突破的关键.     

Investigation on a three-cold-finger pulse tube cryocooler

This paper introduces a new type of pulse tube cryocooler, three-cold-finger pulse tube cryocooler (TCFPTC), which consists of one linear compressor and three cold fingers, i.e., CFA, CFB and CFC. Those three cold fingers are driven by the linear compressor simultaneously. This paper investigates two aspects. First, it studies the mass flow distribution among the three cold fingers by varying the input electrical power. The cooling powers of the three cold fingers at constant cooling temperatures and the cooling temperatures of the three cold fingers at constant cooling powers with various input electrical powers are investigated. Secondly, the interaction among the three cold fingers is investigated by varying the heating power of any one cold finger. Generally, if the heating power applied on one cold finger increases, with its cold head temperature rising up, the cold head temperatures of the others will decrease. But, when the cooling power of CFC has been 4 W, the cold head temperature of whichever cold finger increases, the cold head temperature of CFA or CFB will seldom change if its heating power keeps constant.     

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.