High-frequency Two-Stage Gas-Bearing Pulse Tube Cryocoolers at 20 K for Space Applications

Gas-bearing pulse tube cryocoolers (PTCs) are efficient and durable for the elimination of supporting and reciprocating parts of the compressor components. Compared with the leaf-spring-suspension compressors, the PTCs with the characteristics of high efficiency, lightweight, compactness, and considerable temperature regulation of PTCs have aroused wide concern but were rarely investigated. Here, we report the regenerative packing sections of two-stage PTCs under harsh working conditions (i.e., the hot-end temperatures of the compressor and cold finger were 333 K and 313 K, respectively), and the dimensions of pulse tubes (1st and 2nd) were systematically explored. The heat functional (sub)structures and obtained compressor curves coupling with the cold fingers showed an excellent cooling capacity of 0.05 W@20 K at the heat rejection temperature of 293 K. The operating frequency is 52 Hz, which is far beyond the typical high-frequency 40 Hz; and the input electric power is 450 W. Gas-bearing PTCs can meet the requirements of space telescopes for 20 K temperature regions. This study makes a difference in promoting the application of gas-bearing PTCs in cryogenic cooling and remote sensing for aerospace applications, which also provides a feasible way to realize the lightweight of space cryocoolers with considerable efficiency, high reliability, and durable lifespan.