Establishment And Verification Of A Numerical Optimization Model Of High Frequency Pulse Tube Cryocooler Working At 20K

The high frequency pulse tube cryocooler working at 20 K has great potential in deep space detection,cryogenic pump,low temperature superconductivity(LTS).Owing to many adjustable parameters and the complicated stage-coupling,the study of high frequency pulse tube cryocooler working at 20 K is insufficient with respect to systematic theoretical analysis and experimental research in domestic currently.Meanwhile,the integral numerical model of the pulse tube cryocooler is mostly established at 80 K and above and there is less research on the 20 K.Based on these,the modeling of high frequency pulse tube cryocooler working at 20 K and related experimental verification work have been carried out.The research includes the following parts:1.The key components of the pulse tube cryocooler were simulated and selected,and a basic numerical model of the high frequency pulse tube cryocooler working at 20 K was successfully established by Sage.2.The overall Sage model of single-stage multi-bypass type pulse tube cryocooler was established with the basic numerical model of high frequency pulse tube cryocooler.The influence of regenerator,multi-bypass,double-inlet,inertance tube and other configurations on temperature of cold head and overall performance were simulated and analyzed in detail,and reasonable interpretation of simulation results and phenomena were obtained based on internal parameters changes in the cryocooler.Meanwhile,an experimental rig of a single-stage multi-bypass pulse tube cryocooler has been set up,by which problems about regenerator,multi-bypass,double-inlet,inertance tube and other components of the cryocooler have been tested and verified.By comparing the experiment and simulation results of the changes of related parameters on cryocooler,it is proved that the Sage model of single-stage multi-bypass pulse tube cryocooler is certainly viable.3.Using the basic numerical model of high frequency pulse tube cryocooler,the overall Sage model of a coaxial two-stage gas-coupled type pulse tube cryocooler was established,with which the effect of the gas distribution for the coaxial two-stage gascoupled pulse tube cryocooler and the effect of the cryogenic inertance tube on the cold head temperature and overall performance of the cryocooler were simulated and analyzed,and the simulation results were also reasonably explained.An experimental rig of a coaxial two-stage gas-coupled pulse tube cryocooler has been set up and relevant experiment was also carried out.The accuracy of the Sage model has been proved once again by comparison of simulation and experiment.Besides,the relevant optimization of a U-type two-stage gas-coupled pulse tube cryocooler on the regenerator,double-inlet,and inertance tube was carried out with this Sage model,and parameters of all components were obtained,with which the cryocooler has been designed.Based on Sage,an integral numerical model of high frequency pulse tube cryocooler working at 20 K was established,the accuracy of the model also has been verified,which is of great significance to the design and optimization of the high frequency pulse tube cryocooler working at 20 K and even lower temperatures.