Numerical studies on the effects of hot end temperature on a single-stage multi-bypass type pulse tube cryocooler

The performance of pulse tube cryocooler is affected by the temperature of hot end, which is mainly influenced by the temperature of environment. Effects on a single-stage multi-bypass type pulse tube cryocooler are investigated by means of numerical simulation. For different opening of multi-bypass orifices, the refrigeration performances are studied when hot end temperature changed in a certain range, and some numerical results are provided and analysed. Together with the temperature at cold head and multi-bypass position, the mass flow rate through the multi-bypass orifice is affected significantly by the temperature of hot end, and the optimum opening of multi-bypass orifice decreases with hot end temperature increasing from 240 K to 320 K. Therefore, to select an optimal opening of bypass orifice according to the temperature of operating environment is necessary.