摘要
线性压缩机驱动的液氦温区闭式JT(Joule-Thomson)节流制冷系统,是实现深空探测目标的核心技术.为进一步探究闭式JT循环的压缩机工况影响和制冷温度变化情况,搭建了预冷型液氦温区闭式JT节流制冷机实验台.实验中,采用单向阀组与传统线性压缩机结合,获取JT循环所需直流流动氦气工质并提供节流所需大压比.考虑单级有阀线性压缩机压力能力,选取10 K左右预冷温度,测试了不同压缩机工况特性及节流孔的压力流量特性.通过调节活塞位移和压缩机运行频率,可以获得3.91 K的最低温度.该闭式循环JT制冷机在4.09 K稳定工况下可以获得10.8 mW的最大制冷量,为后续多级压缩和更低温区的闭式系统提供可靠的研究基础.
The JT cryocooler at liquid helium temperature driven by large pressure ratio linear compressor(s) is one of the core components in the deep space detectors. Also, future quantum detection technology needs to work at or below the liquid helium temperature zones. The JT cryogenics system for obtaining the liquid helium temperature zone is mainly composed of a regenerative precooling unit and a JT cooling unit. The relative technology of the regenerative precooling unit is more mature than that of the JT unit, and related research reports are also numerous. A valved linear compressor(VLC) capable of providing a large pressure ratio is a key technology in the JT cryocooler. At present, the deep space exploration projects such as JWST and SPICA have adopted the VLC. In order to study the working characteristics of VLC, a test system of a closed JT cryocooler operating at liquid helium temperature is built. The cryocooler is precooled by a GM cooler and the precooling temperature of 10 K is selected. A single-stage VLC is used in the study and the output performance is tested independently. The experimental results show that when the charging pressure is 0.15 MPa, a pressure ratio of 3.7 with the mass flow of 4.5 mg/s can be obtained. While raising the charging pressure to a value of 0.21 MPa, the pressure ratio can increase to 4.5. Based on this performance of the single-stage VLC, the theoretical cooling capacity of JT cycle is analyzed.The coupling performance test of the VLC with a JT unit is developed. After about 30 h later, the evaporator temperature can be cooled down to the liquid helium temperature zone. By increasing the piston displacement of the VLC, the dead volume of the compression chamber can be reduced, thereby improving the output performance. With the displacement increased from 6.2 to 7.5 mm by supplementing the input power of 15 W, the cooling temperature can be reduced from about 4.4 to 3.94 K. A minimum temperature of 3.91 K is achieved by further adjusting the piston displacement and the VLC o
作者
刘少帅
丁磊
蒋珍华
董彩倩
汤逸豪
向振之
吴亦农
Shaoshuai Liu;Lei Ding;Zhenhua Jiang;Caiqian Dong;Yihao Tang;Zhenzhi Xiang;Yinong Wu(Shanghai Institute of Technical Physics,Chinese Academy of Sciences,Shanghai 200083,China)
出处
《科学通报》
EI
CAS
CSCD
北大核心
2020年第8期750-756,共7页
Chinese Science Bulletin
基金
国家自然科学基金(51806231)
上海市自然科学基金(18ZR1445600)
中国博士后科学基金(2018M630476)资助。
