Speaker
Description
Several precooled JT cryocoolers (JTC) working at 4 K have been developed for space missions. Although these cryocoolers are qualified with high reliability and long life time, their efficiencies are relatively low which is worth further research.
A JT cryocooler has an intrinsic limitation on its cooling power. The intrinsic limitation is that the JTC will be warmed up continuously when the heat load exceeds a certain maximum, which is defined as the maximum specific cooling power (MSCP). The MSCP is equal to the isothermal enthalpy difference at the warm end of the recuperator determined by the high pressure and precooling temperature. The mechanism and the JTC behavior related to the intrinsic limitation will be illustrated with systematic theoretical analysis.
When the MSCP is achieved by a helium-4 JTC, the cooling temperature may be already higher than the critical point. So the maximum specific cooling power at 4 K (MSCP4) should be defined for cooling-performance optimization. The discussion on the MSCP4 explains why the JTC would have optimal high pressures not the same as those give the MSCPs.
Furthermore, the theoretical analysis will be applied to explain a real case based on the acquired experimental data.
