Investigation Of The "L" Type Pluse Tube And Copper Foaming Metal In The Four Valves Pulse Tube Cryocooler

Owning to no moving part at its cold end, pulse tube refrigerator (cryocooler) has considerable system advantages over most other types of refrigerators in terms of reliability, lifetime, vibration, and cost. The advantages and developments of the pulse tube refrigerator achieved in recent years have attracted more and more interests of many laboratories around the world.The internal working process of the pulse tube refrigerator is very complex due to the unsteady, oscillating compressible gas flow, the porous media in the regenerator etc. Therefore, it is difficult for researchers to take into account all the irreversible practical processes of the pulse tube refrigerator in the theoretical studies. Up to now, the usual theoretical analysis method is numerical simulation, which contains complex program and iteration etc. In this dissertation, based on the theory of enthalpy flow and some ideal assumptions, the author derived the theoretical cooling power and compressor work according to the three-gas-group model, in which three groups of gas have undergone the thermodynamic cycle analysis separately using the first law of thermodynamics, state equation of ideal gas, mass conversation equation etc. The developments and results obtained in the theoretical and experimental studies are given as follows:(1) A four valves pulse tube refrigerator (FVPTR) was chosen as the experimental sample machine. Two improvements have been proposed on the FVPTR:â—‹1 the ordinary"I"type pulse tube was replaced by a new"L"type pulse tube, resulting in the original connecting tube between the cold head heat exchangers of the pulse tube and...