红外系统应用的高频同轴脉冲管制冷机惯性管调相实验分析

Experimental Analysis for a High Frequency Coaxial Pulse Tube Cooler with Different Inertance Tubes for IR Applications

直线压缩机SL400用于高频同轴脉冲管制冷机PT08的研制,优化的工作频率为40Hz,在气库与脉冲管间连接不同长度不同管径的惯性管作为调节脉冲管冷端处压力波与流速波合适相位的调节机构。不同排气量及额定输入功率的直线压缩机SL150驱动该制冷机,不同内径及长度的惯性管用于PT08脉冲管制冷机SL150压缩机的匹配调试,给出了不同的工作频率下制冷机的最低制冷温度及压缩机的效率数值,调节压缩机的工作频率,无双向进气,制冷机的最低制冷温度在59.1-65.1 K的范围。随着惯性管的管径变粗,长度变短,压缩机驱动制冷机的最佳制冷性能(最低制冷温度)的工况条件往高的驱动频率方向变化。在实用化简易化商业化应用考虑的条件下,为SL150压缩机驱动PT08 制冷机优化了较小直径较短长度的惯性管,该惯性管利于直接封装于气库的内部,使得气库可与同轴式脉冲管制冷机的冷指集成为一整体。

A high frequency coaxial Pulse Tube cooler PT08 was developed and optimized at a working frequency of 40Hz by using a linear compressor SL400 from AIM (AEG Infrarot-Module GmbH, Germany). Another compressor with small outline dimensions and small swept volume, SL150, has been used to drive this coaxial Pulse Tube cooler. Inertance tubes with different inner diameters and lengths are connected between the buffer volume and the pulse tube. Detailed experimental data of the minimum refrigeration temperature and the efficiency of the compressor at different working frequencies are given. When different inertance tubes with different diameters are used, without Double-Inlet effect, the minimum refrigeration temperatures are in the range between 59.1 K and 65.1 K by adjusting the lengths of the inertance tube and the working frequency of the compressor. When inertance tube length is made shorter or inertance tube cross section is increased, the optimum cooling performance (minimum refrigeration temperature) could be moved to a higher frequency. In this case a compromise has to be found between the length and the diameter to fulfill the inertance and resistance values required by the phase shift control of the oscillating pressure and the flow velocity at the cold end of the cooler. An optimum diameter and length for the inertance tube are given for this cooler PT08 driven by SL150. For the simplicity consideration in the practical and commercial applications, a good cooling performance could be achieved by using an inertance tube with short length and small diameter. The buffer volume could be integrated with the cold finger of the PTC.