Design and operation of the sub-cooled helium test facility for the LHD helical coils
Design and operation of the sub-cooled helium test facility for the LHD helical coils
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LHD 螺旋线圈过冷氦测试装置的设计和运行
DOI：
10.1109/tasc.2004.830638
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发表时间：
2004
影响因子：
1.8
通讯作者：
O. Motojima
中科院分区：
文献类型：
--
作者：
Y. Hishinuma;S. Imagawa;N. Yanagi;T. Mito;A. Nishimura;S. Yamada;K. Takahata;H. Chikaraishi;H. Tamura;A. Iwamoto;S. Hamaguchi;K. Seo;T. Honda;T. Shinba;S. Yoshinaga;M. Satoh;H. Kakui;O. Motojima
为了提高螺旋线圈的冷却稳定性，计划将冷却方案从4.4 K池沸腾升级为流量约50克/秒的3.0 K过冷氦气。我们设计并建造了一个由与螺旋线圈相同的超导体制成的研发线圈和一个以实际大型螺旋装置（LHD）应用为假设的过冷氦测试设备。该设施由用于过冷氦发生的减压罐、研发线圈、电流铅储存罐等组成，安装在带有液氮屏蔽的低温恒温器中。顶部法兰安装两级低温压缩机，将饱和液氦从0.12 MPa减压至24 kPa，产生过冷氦气。 4.4 K、0.12 MPa的液氦经减压罐内的过冷氦进行热交换，从底部供给研发盘管。已开展过冷研发实验。实验结果发现，饱和液氦可以在8小时内从4.4 K冷却到3.0 K，并维持在3.0 K。第一级和第二级低温压缩机的转速分别约为87,000和88,000 rpm。这些值与两级低温压缩机的设计值非常吻合。最终，该设施在两次过冷研发实验的8天内稳定运行。
In order to increase the cooling stability of the helical coils, an upgrade of the cooling scheme is planned from 4.4 K pool-boiling to 3.0 K sub-cooled helium of flow rate of about 50 g/sec. We have designed and constructed a R&D coil made of the same superconductor as that used for the helical coils and a sub-cooled helium test facility on the assumption of the application for actual large helical device (LHD). This facility is composed of decompression tank for the sub-cooled helium generation, the R&D coil, a current lead storage tank, etc., installed in a cryostat with a liquid nitrogen shield. Two stage cryogenic compressors are installed in the top flange, and sub-cooled helium is generated by decompressing of saturated liquid helium from 0.12 MPa to 24 kPa. Liquid helium of 4.4 K and 0.12 MPa is heat exchanged by the sub-cooled helium in the decompression tank and supplied to the R&D coil from the bottom. The sub-cooling R&D experiment has been carried out. As the results of experiment, we found that the saturated liquid helium could be cooled from 4.4 K to 3.0 K in 8 hours and maintained at 3.0 K. The rotation speed of the first and second stage cryogenic compressors were about 87,000 and 88,000 rpm, respectively. These values agreed well with the designed values of the two-stage cryogenic compressors. Finally, this facility operated stably during 8 days of the two sub-cooling R&D experiment campaigns.