针对35K温区应用这一制冷要求,围绕多路旁通方案高频同轴脉冲管制冷机这一拥有我国自主知识产权的技术开展了系统的实验研究。实验表明多路旁通流通面积和惯性管长度都有最佳值,是关键影响因素;引入双向进气后,制冷剂温度降低10K左右,是35K应用不可缺少的因素。实验表明多路旁通优于传统单级和二级的形式。在原理样机阶段,实现了200W输入功率下最低温度2叠1K,0.6W/35K的性能。在此基础上,完成了另一套全焊接结构的实用样机的研制,测试得到了200W输入功率下O5W/34K的性能。这一工作的顺利开展代表了高频多路旁通方案实用化的突破,为我国35K高频微型低温制冷机的研制奠定了基础。
For the cooling requirement operating at 35 K, multi-bypass version high frequency coaxial pulse tube refrigerator was investigated through experiments. The experiments show that the multi-bypass flow area and inertance tube are two key parameter and they have the optimized value to reach the lowest temperature. Double-inlet could further gain about 10 K temperature drop, this is fundamental for 35 K temperature scope. The experiments show that the multi-bypass version is better than that of traditional single stage version or two stage version. For the prototype pulse tube refrigerator, with 200 W input power, the lowest temperature acquired is 23.1 K and the cooling power is 0.6 W/35 K. Based on this, the practical version refrigerator is redesigned and fabricated with the typical feature of all-welding, the experiment shows the cooling power is 0.5 W/34 K with 200 W input power, quite the same to the prototype. This work means that multi-bypass version is suitable for operating at high frequency.