液氢温区热耦合斯特林/脉管小型化复合制冷机性能提升及参数优化研究

Research on Performance Improvement and Parameter Optimization of Liquid Hydrogen Temperature Thermal-coupled Stirling/Pulse Tube Miniature Composite Cryocooler

脉管制冷机冷端温度低至液氢温区时,往往需要采用两级结构,其中预冷级是影响整机效率的关键之一。本文针对15 K两级脉管制冷机应用需求,选用单级气动斯特林制冷机为第二级脉管制冷机提供预冷,通过模拟仿真研究了气动斯特林制冷机机械刚度和推移杆直径的影响,提高80 K单级斯特林制冷机的设计比卡诺效率(计算制冷量/PV功)至37.4%。实验验证了单级斯特林制冷机的预冷能力,斯特林/脉管热耦合两级制冷机在15 K可获得制冷量1.12 W,各级总输入电功为357 W,相对于单级脉管制冷机预冷时消耗电功减少30 W,整机比卡诺效率提升至5.96%。对预冷温度开展实验研究,验证了第二级脉管所需最佳预冷温度,冷端在15 K获得0.6 W时的预冷温度实验最优值在90 K附近。

For pulse tube cryocoolers,when the cold end temperature drops to liquid hydrogen temperature,a two-stage structure is often required,with the pre-cooling stage being one of the key factors affecting the overall system efficiency.This article focuses on the application requirements of a 15 K two-stage pulse tube refrigerator and selects a single stage Stirling cryocooler to provide precooling for the second stage pulse tube cryocooler.Through simulation,the influence of mechanical stiffness and push rod diameter of the Stirling cryocooler is studied,improving the design ratio Carnot efficiency of an 80 K single stage Stirling cryocooler to 37.4%.The experiment verified the pre-cooling ability of a single stage Stirling cryocooler.The Stirling/pulse tube thermal-coupled two-stage cryocooler can obtain a cooling capacity of 1.12 W at 15 K.At this time,the total input power of each stage is 357 W,which reduces the power consumption by 30 W compared to the pre-cooling of a single stage pulse tube cryocooler,and the overall Carnot efficiency is increased to 5.96%.Experimental research was conducted on the pre-cooling temperature to verify the optimal pre-cooling temperature required for the second-stage pulse tube cooling finger.The optimal precooling temperature for the cooling head when obtaining 0.6 W at 15 K was around 90 K.