15 K热耦合两级脉管制冷机低温段回热器长径比理论及实验研究

Theoretical and Experimental Study on the Length-Diameter of the Regenerator in the Low Temperature Section of a 15 K Thermal-Coupled Two-Stage Pulse Tube Cryocooler

为了提高脉管制冷机的制冷量和效率,解决液氢温区以下多级脉管制冷机效率低下的问题,对关键部件之一的低温段回热器尺寸进行了设计优化。针对15 K两级脉管制冷机,首先采用数值模拟仿真的方法研究了低温段回热器尺寸对制冷机内部各项损失以及性能的影响,获得了等效长径比的最优值3.81;然后研制了等效长径比分别为3.81、6.80的两种低温段回热器进行实验对比。实验结果表明,制冷机低温段回热器等效长径比为3.81时,制冷机性能更好,且在30 Hz下,可以在15 K获得制冷量0.91 W,此时各级总输入电功为386 W,整机的比卡诺效率达到4.45%。该研究可为制冷机低温段回热器的设计优化提供参考,对多级脉管制冷机的效率提升具有一定的指导意义。

To improve the cooling capacity and efficiency of the pulse tube cryocooler and solve the problem of low efficiency of the multi-stage pulse tube cryocooler below the liquid hydrogen temperature area,the regenerator in the low temperature section is optimized in size.First,for the regenerator in the low temperature section of the 15 K two-stage pulse tube cryocooler,the influence of the regenerator size on the internal losses and performance is studied by numerical simulation,and it is obtained that the length-diameter ratio has an optimal value of 3.81.Then two kinds of regenerators with the length-diameter ratio of 3.81 and 6.80 are developed for experimental comparison.Experimental results show that the cryocooler has a better performance at the ratio of 3.81 and can obtain a maximum cooling capacity of 0.91 W at 15 K at 30 Hz.The total input power is 386 W and the rCOP reaches 4.45%.The research provides a reference for the design optimization of a regenerator in the low temperature section of the cryocooler and has guiding significance in improving efficiency of the multi-stage pulse tube cryocooler.