60 K直线型百赫兹脉管制冷机优化及实验研究

Experimental Research and Optimization of a 100 Hz In-line Type Pulse Tube Refrigerator in the 60 K Temperature Region

  • 摘要: 目前空间用红外探测器对工作温区和冷量的需求日益增长,在低温制冷机的轻量化方面提出了更高的要求。高频脉管制冷机因具备结构紧凑、轻便、低噪声以及高运行可靠性等特性,而被视为冷却红外探测器件的理想冷源。国内外对于60 K温区下100 Hz频率的脉管制冷机方面研究较少,工作频率均在50 Hz左右。为了满足空间红外焦平面阵列所需温区及冷量,本文设计并研制了一台小型直线型100 Hz高频60 K脉管制冷机,利用Regen3.3对关键部件-回热器进行了优化分析,得出回热器长度、填料丝网目数以及分层填充时的比例对回热器损失以及制冷系数的影响规律。基于Sage软件对脉管制冷机内脉冲管、调相机构等重要部件结构参数进行仿真模拟与优化设计,其中制冷机的冷指部分质量仅为1.5 kg。此外,通过搭建脉管制冷机测试系统,深入分析运行频率、水冷温度以及输入电功对脉管制冷机性能的影响。研究结果表明:当回热器内混合填充1∶1的400目和635目的不锈钢丝网时,脉管制冷机的性能达到最优。与单段惯性管调相相比,采用变径的多段惯性管可显著提高制冷机的制冷性能。实验结果显示:在输入300 W电功时,可以获得42.69 K无负荷最低温度;在60 K可以得到7.4 W的制冷量,整机相对卡诺效率为9.6%。 研究结果为相同温区下小型高频脉管制冷机设计提供有益参考。

     

    Abstract: Currently, the demands on the operating temperature range and cooling capacity for the infrared detectors in space are growing rapidly, and the higher requirements are being placed on the light weight design of cryogenic refrigerators. With their compact structure, light weight, low noise and high operational reliability, high frequency pulse tube refrigerators are considered as ideal cold sources for the cooling infrared detectors. At home and abroad, there are few research on the pulse tube refrigerator with 100 Hz frequency in the 60 K temperature zones, while the current operating frequency is about 50 Hz. A miniature linear 100 Hz high-frequency 60 K pulse tube refrigerator is designed and developed to meet the temperature range and cooling capacity requirements of infrared focal plane arrays in the space applications. Using the Regen3.3 software, the key component—the regenerator—is optimized and analyzed. The effects of the regenerator's length, the mesh count of packing wire mesh, and the ratio of the layered filling on the loss of the regenerator and the coefficient of performance are obtained. Based on Sage software, simulations and optimizations are performed on the structural parameters of the pulse tube, the phase shifter, and other critical components within the refrigerator. The weight of the cold finger part is only 1.5 kg. In addition, the effects of operating frequency, water cooling temperature, and input power on the pulse tube refrigerator's performance are analyzed. The results show that the performance of the pulse tube refrigerator is optimal when the regenerator is filled with a 1∶1 mixture of 400-mesh and 635-mesh stainless steel screens. Compared to a single-stage inertial tube, the variable-diameter multi-stage inertial tube can significantly enhance the performance of the refrigerator. The experimental results show that, with an input electrical power of 300 W, the minimum no-load temperature achieved is 42.69 K. A cooling capacity of 7.4 W can be obtained at 60 K, and the relative Carnot efficiency of the system is 9.6%. These findings provide valuable reference for the design of small high-frequency pulse tube refrigerator operating in the same temperature ranges.

     

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