Investigation on High-Power Stirling-Type Pulse Tube Coolers for Cooling HTS Motors

High-power Stirling-type pulse tube coolers (HSPTCs) driven by oil-free linear compressors are promising candidates for cooling HTS devices for the advantages of simple configuration, low noise and stable operation. Three U-shaped two-stage pulse tube coolers driven by a 10 kW linear compressor were built and studied. The effects of flow inhomogeneity on the temperature profiles along the regenerator and on the cooling capacity were investigated experimentally. By optimizing the impedance matching and operating conditions, the first cooler can reach a base temperature of 44.2 K; the second cooler reaches a base temperature of 27.1 K and provides a cooling power of 50 W at 45.6 K with 4.8 kW of power; the last cold head reaches a base temperature of 13.27 K and provides a cooling power of 18.3 W at 30 K. The present results form a foundation for building a HSPTC system capable of providing a cooling power of 80 W at 30 K.