斯特林制冷机混合填料回热器性能优化及试验研究

针对旋转整体式斯特林制冷机的回热器性能优化,讨论了回热器丝网填料选型的原则,分析了不同温区采用不同丝网参数的回热器模型,并利用REGEN软件对混合丝网模型进行了优化分析。通过实验数据对模拟优化的结果进行了分析和讨论,验证了混合丝网模型优化结果的正确性,为旋转整体式斯特林制冷机回热器性能优化提供依据。     

小型斯特林制冷机回热器热损分析

对斯特林制冷机回热器的各项热损失进行分析研究,表明回热器的尺寸以及填料的选取对于小型斯特林制冷机的性能影响较大.对于给定尺寸各个参数以及循环参数的回热器,要想获得最大净制冷量,存在一个最佳当量直径.当当量直径的取值小于最佳值时,回热器的性能主要由压降损失决定;当取值大于该值时,系统性能主要由回热损失决定.     

大功率脉管制冷机回热器填料优化研究北大核心CSCD

对一台液氮温区百瓦级制冷量的大功率斯特林型脉管制冷机的回热器填料进行了理论优化和实验研究。实验结果发现,在回热器冷端适当组合不同目数的丝网后,会把回热器分成两个部分,这在一定程度上能抑制大功率脉管制冷机回热器中的二次流动,降低回热器中部的温度非均匀性。通过实验得出该脉管制冷机中回热器填料的最优组合为300目不锈钢丝网搭配250目不锈钢丝网,组合比例为10∶1,最终在80 K获得了381.3 W的制冷量。回热器中部最大温差为30.3 K,相较于在回热器中填充单一300目不锈钢丝网的情况,降低了25.6 K。     

低温冰箱自由活塞式斯特林制冷机模拟与优化

自由活塞斯特林制冷机具有高效紧凑,适合中低温制冷等优点。对用于低温冰箱自由活塞式斯特林制冷机进行了一维建模,并实现整机性能的模拟与优化。在考虑各种空体积的情况下,模拟分析了压缩活塞PV功和相位角的变化对整机性能的影响,获得了制冷机运行的最佳相位。对比了环形回热器的填料及填充方式对自由活塞式斯特林制冷机的性能影响,及对应材料下回热器的轴向导热损失情况。模拟了制冷机性能随回热器空隙率和制冷温度的变化情况,计算分析了回热器内部的不可逆损失随空隙率的变化情况,并且获得了不同温度下的最佳空隙率。最后,为了获得好的制冷性能,优化不同制冷温度的回热器设计参数及膨胀活塞与气缸壁的密封间隙宽度。     

微型热声斯特林制冷机填料多孔频率研究

介绍了通过直接测量微型热声斯特林制冷机(MMTASR)填料等效流阻进而辨识MMTASR回热器的特征频率的办法.测量结果与实际的MMTASR系统的流放大因子和传送损失系数的最优频率范围进行了对比.结果显示一定结构的回热器填料的特征频率与系统的最优频率范围吻合较好,因此这种填料特征频率的辨识方法可以应用于实际MMTASR系统回热器填料的生产过程中的质量控制.     

2 W@80 K星载斯特林制冷机丝网的优化选型设计

介绍了丝网的种类,考虑丝网质量对回热器性能的影响,给出了优质丝网的判据.详细分析了丝网目数对空隙率、比传热面积和当量直径的影响,以回热器回热损失与压降损失之和最小,尽可能减小回热器空容积为原则进行计算分析,得出2 W@80 K制冷机回热器的最佳填料为丝径0.036 mm、276目×276目的平纹方孔网.试验结果表明选用该规格丝网的制冷机在制冷温度80 K、压缩机输入功率46.2 W时,获得的制冷量为2 W.     

20 K低温制冷机回热器结构设计

20 K温区高效制冷是目前空间探测任务制冷的关键需求之一,斯特林/脉管复合制冷机是实现20 K温区高效制冷的重要技术手段.回热器作为复合制冷机的核心部件,其性能对制冷机的整机性能有决定性的影响.合理的设计方法和流程可以保证回热器的性能.20 K温区时回热器工质氦气和填料的物性与较高温区,如80 K温区,相比有很大区别,...     

空调温区自由活塞斯特林制冷机中回热器的优化设计

根据一台空调温区自由活塞斯特林制冷机(FPSC)的设计要求(300 W@280 K),对其关键部件回热器进行了优化设计。回热器填料选择了流阻损失较小的卷箔式结构和聚酯材料。搭建了Sage整机模型和回热器模型以分析不同回热器长度和孔隙率对回热器换热损失及整机制冷性能的影响,280 K制冷温度下回热器长度和孔隙率的优化结果分别为32 mm和76%。最后分析了FPSC内部换热损失的分布情况,验证了卷箔式结构在空调温区应用中的优势。     

基于并联回热器模型的大功率斯特林脉管制冷机回热器温度不均匀性研究

基于流体网络理论,建立了两个并联的回热器模型来解释回热器内温度不均匀产生机理.通过对回热器内部环流的计算,首次提出了预测回热器最大径向温差的数学模型.最后,还对回热器径向温度不均匀引起的损失进行了定量分析,并提出了抑制大功率斯特林型脉管制冷机回热器内温度不均匀的方法.     

10W@77K自由活塞斯特林制冷机的设计和实验研究

为满足高温超导、红外探测和气体液化等领域对高效率、高可靠性、长寿命低温制冷机的需求,对10W@77K自由活塞斯特林制冷机进行了研究.制冷机设计为整体式结构,由动磁式直线电机驱动.基于Sage建立制冷机整机模型开展了数值求解,并根据数值计算结果对运行频率、工作压力以及回热器填料等对制冷机性能的影响规律进行了分析.计算结果...     

Basic dynamics of split Stirling refrigerators

The basic features of the split Stirling refrigerator, driven by a linear compressor, are described. Friction of the compressor piston and of the regenerator, and the viscous losses due to the gas flow through the regenerator matrix are taken into account. The temperature at the cold end is an input parameter. The general equations are derived which are subsequently treated in the harmonic approximation. Examples are given of application of the relations for describing optimum-performance conditions as well as the interrelationship between cooler and heat-engine operation.     

Study of a coaxial thermoacoustic-Stirling cooler

A coaxial thermoacoustic-Stirling cooler is built and performance measurements are performed. The cooler uses the acoustic power produced by a linear motor to pump heat through a regenerator from a cold heat exchanger to an ambient one. The cooler incorporates a compact acoustic network to create the traveling-wave phasing necessary for the operation in a Stirling cycle. The network has a coaxial geometry instead of the toroidal one usually used in such systems. The design, construction and performance measurements of the cooler are presented. A measured coefficient of performance relative to Carnot of 25% and a low temperature of −54 °C are achieved by the cooler. This efficiency surpasses the performance of the most efficient standing-wave cooler by almost a factor of two.     

热声制冷机

热声制冷是微型低温技术潜在的最佳方法。一台声驱动热声制冷机主要包含一个接在中空管道端部的声波发生器和一个在管道内预选位置处放置的热声器件。声波发生器产生的声波在热声效应作用下可在热声器件两端形成温度梯度。介绍了一种基于高效斯特林循环的热声制冷机的基本原理及主要组成。在此基础之上,可通过对各组成部件结构参数的计算、确认,设计出一台热声制冷机。     

小型斯特林制冷机回热器理论模型与分析

对小型斯特林制冷机回热器建立理论模型,通过对控制方程进行无量纲化处理及合理简化,推导出表征小型斯特林制冷机回热器不可逆性的熵流方程。     

Flow characteristics of a cyclic flow regenerator

The results of experimental investigations on the cyclic flow characteristic of the regenerator of a split cycle Stirling cryocooler is presented. A mathematical model has been proposed to describe the action of regenerator and other main components of the cryocooler system on its dynamic response.     

Improvements of a room-temperature magnetic refrigerator combined with Stirling cycle refrigeration effect

A high pressure hybrid refrigerator that combines the active magnetic refrigeration effect with the Stirling cycle refrigeration effect at room temperature is studied here. In the apparatus, a helium-gas-filled alfa-type Stirling refrigerator uses Gd sheets as the regenerator and the regenerator is put in a magnetic field varying from 0 to 1.4 T, which is provided by a Halbach-type rotary permanent magnet assembly. With an operating pressure of 5.5 MPa and a frequency of 2.5 Hz, a no-load temperature of 273.8 K was reached in 9 minutes, which is lower than that of 277.6 K for pure Stirling cycle. For the hybrid operation, cooling powers of 40.3 W and 56.4 W were achieved over temperature spans of 15 K and 12 K, respectively. For the latter case, the cooling power improves by 28.5% if compared with that exploiting only the Stirling cycle refrigeration effect.     

星载斯特林制冷技术研究进展

介绍了国外星载长寿命斯特林制冷技术的研究进展及其在空间遥感系统和科学探测卫星中应用情况,并对影响斯特林制冷机工程应用的工作寿命和可靠性进行了简要分析.综述了国内星载斯特林制冷技术的发展现状,最后提出在我国开展星载斯特林制冷机研制的几点建议.     

A model for exergy analysis and thermodynamic bounds of Stirling refrigerators

A thermodynamic model based on exergy flow through a Stirling Refrigerator is developed. Important irreversibilities of the refrigerator due to external heat transfer with the reservoirs, heat leak, flow and heat transfer in regenerator are included in the model. Expansion and compression efficiencies are introduced in the model to account for the losses in these processes. The effect of a control phase shift between the mass flow rate and pressure across regenerator on the performance of the refrigerator is presented. Analytical solutions representing important quantities in the design of Stirling refrigerators such as the load curve, cooling power and efficiency in terms of basic system input parameters are developed. Thermodynamic bounds for the performance of Stirling refrigerators are obtained. Results indicating a compromise between cooling power and efficiency that are dependent on the constraint of the system are presented and discussed.     

5W@80K自由活塞斯特林制冷机工况及重力特性实验研究

利用现有的脉冲管制冷机性能测试实验台,针对某型号自由活塞斯特林制冷机,设计了热端水冷器并进行了性能测试.实验研究了工作频率、充气压力、输入功率等参数对制冷机性能的影响规律,结果表明斯特林制冷机的最佳运行工况为充气压力2.0 MPa,频率42 Hz.改变冷头在竖直方向和水平面不同的朝向,实验结果表明冷头竖直向下时最低制冷...     

Measurement of cryogenic regenerator characteristics under oscillating flow and pulsating pressure

This paper describes an experimental apparatus developed to investigate detailed thermal and hydrodynamic characteristics of a regenerator at cryogenic temperature under oscillating flow and pulsating pressure conditions. Cold-end of the regenerator is maintained at approximately 85 K for G-M cryocooler type and 100 K for Stirling cryocooler type operations by means of two cryogenic heat exchangers. At both ends of the regenerator, fine hot wire probes are installed to measure the fast oscillating gas temperature and mass flow rate. The gas temperature sensors installed very close to the ends of the regenerator matrix assure precise gas temperature measurement in the regenerator. In this study, thermal and hydrodynamic behaviors of the well-defined wire-screen regenerator are fully characterized. First, pressure drop characteristics are discussed for different frequencies under room temperature. Second, ineffectiveness of the regenerator is obtained for different cold-end temperatures.