D05 4K-GM冷凍機蓄冷器特性の検討 : 2段蓄冷材の鉛粒径の影響(再生熱交換器の基本特性)

抄録

Recently, the development of the magnetic regenerator materials greatly contributes to improve the cryocooler in the 4K temperature territory. The specific heat of 2^<nd> regenerator materials so far used for the regenerator material decreases greatly comparing to that of He in the temperature area below 10K. So, most of regenerator of 4K cooler is composed of mixture of lead and magnetic materials because some magnetic materials have same order of specific heat as that of He temperature territory below 10K. We have estimated the 4K-GM cryocooler performance with several kinds of regenerators because of the cost reduction of the 4K-GM cryocooler and the efficiency improvement. An examination by the numerical analysis was done to grasp the characteristics of regenerator material of the 4K-GM cryocooler and to attempt future performance improvement. Numerical result of Pb diameter dependnce of cooling capacity has been compared with the experimental result. Cooling capacity has nearly same maximum value at about diameter 0.45mm both in the experiment and calculation.