Study on the Dynamic Performance of the Helium Turboexpander for EAST Subsystems  

作　　者：陈双涛 杨山举 付豹 张启勇 侯予 

机构地区：[1]University of Science and Technology of China [2]Institute of Plasma Physics,Chinese Academy of Sciences

出　　处：《Plasma Science and Technology》2015年第6期517-523,共7页等离子体科学和技术（英文版）

基　　金：supported by Joint Funds of the National Natural Science Foundation of China(No.11176023);National Natural Science Foundation of China(No.51306135);partially supported by the China Postdoctoral Science Foundation(No.2013M532040);Special Financial Grant of China Postdoctoral Science Foundation(No.2014T70917)

摘　　要：An increase of the cooling capacities in the liquid helium temperature area is re- quired by Experimental Advanced Superconducting Tokamak （EAST） due to the extension of its subsystems in the near future. Limited by the heat exchangers, cryogenic pipes, and cryogenic valves, it is difficult to enlarge the present EAST helium system. 102 W@4.5 K level helium cryogenic systems are needed in view of feasibility and economy. A turboexpander is the key com- ponent of a helium cryogenic system. In this article, a hydrostatic gas lubricated cryogenic helium turboexpander for a 900 W@4.5 K cryogenic helium system was developed for the EAST updated subsystem by the Institute of Plasma Physics, Chinese Academy of Sciences and the Institute of Cryogenic and Refrigeration of Xi＇an Jiaotong University. The main components, such as gas bearings, expansion wheel, shaft, and brake wheel, were briefly presented. The dynamic perfor- mance of the journal and thrust gas bearings was investigated numerically. The rotordynamic performance of the developed turboexpander was studied experimentally. The results show that the axial and radial load capacities supplied by the journal gas bearing and thrust gas bearing are enough to balance the axial force and radial force of the rotor. A 43% overspeed operation was achieved, which validated the reasonable design of the turboexpander.An increase of the cooling capacities in the liquid helium temperature area is re- quired by Experimental Advanced Superconducting Tokamak （EAST） due to the extension of its subsystems in the near future. Limited by the heat exchangers, cryogenic pipes, and cryogenic valves, it is difficult to enlarge the present EAST helium system. 102 W@4.5 K level helium cryogenic systems are needed in view of feasibility and economy. A turboexpander is the key com- ponent of a helium cryogenic system. In this article, a hydrostatic gas lubricated cryogenic helium turboexpander for a 900 W@4.5 K cryogenic helium system was developed for the EAST updated subsystem by the Institute of Plasma Physics, Chinese Academy of Sciences and the Institute of Cryogenic and Refrigeration of Xi＇an Jiaotong University. The main components, such as gas bearings, expansion wheel, shaft, and brake wheel, were briefly presented. The dynamic perfor- mance of the journal and thrust gas bearings was investigated numerically. The rotordynamic performance of the developed turboexpander was studied experimentally. The results show that the axial and radial load capacities supplied by the journal gas bearing and thrust gas bearing are enough to balance the axial force and radial force of the rotor. A 43% overspeed operation was achieved, which validated the reasonable design of the turboexpander.

关 键 词：EAST cryogenics helium system turboexpander gas bearing 

分 类 号：TB653[一般工业技术—制冷工程]