Experimental Study Of The Two Stage Pulse Tube Crycooler Which Maintenance Below Liquid Helium Temperature

As a new type of refrigerator,pulse tube cryocooler has no moving parts in the low-temperature region compared with traditional refrigerators such as G-M and Stirling, which gives pulse tube cryocooler the advantages of simple structure, low cost, high reliability, low vibration and low electromagnetic noise, etc. Pulse tube cryocooler is widely used in application fields such as superconducting, military, communication. In this paper, based on reviewing the development of pulse tube cryocooler and latest research work, we carry out experimental research on two-stage pulse tube cryocooler which works below 4K. Detailed work is as follows:Firstly, we estimate of the second stage refrigeration of the two stage pulse tube cryocooler. Currently there is few research work related with the computation of refrigeration based on experience formula. In this paper, we first estimate the theoretical refrigeration of the second stage of two-stage pulse tube cryocooler based on Radebaugh enthalpy flow theory, then compute various types of loses of the second stage of cryocooler. Finally real refrigeration is obtained by subtracting theoretical refrigeration by all loses. On the base of the calculation, the refrigeration of second stage of the pulse tube cryocooler is determined.Secondly, the experimental setup of two stage pulse tube cryocooler is implemented. The experimental table of pulse tube cryocooler includes refrigerator system, measuring system, data collecting system and vacuum system. The table has advanced equipments, high measuring precision, convenient manufacturing, etc. Especially, the rotate valve is made of Rulon, and the second regenerator uses magnetic materials HoCu₂ and Er₃Ni. The temperature of the second stage cold head is tested using precisely labeled diode sensor DT470 with the precision of 0.01K. The tested temperature is transmitted to computer via data collection system. The setup of experimental table lays the foundation of experimental research and performance test.Thirdly, we conduct experimental research and performance test of the two-stage pulse tube cryocooler. We use coiled tube instead of orifice valve to...