由于超导托卡马克装置等聚变实验设备运行过程会产生较强的脉冲热负荷,这将对其配备的氦低温制冷系统的稳定运行提出更加苛刻的要求.本文介绍了大型氦低温制冷系统的一般流程,对比了三种超导托卡马克装置中产生的脉冲热负荷特征,并系统分析了超导托卡马克装置中低温制冷系统应对不同脉冲热负荷时的调控方法,为此类低温制冷系统的调控提供工程经验.

大型低温制冷系统是国家战略高技术领域不可替代的核心基础平台,关系到新一代航空航天(液氢燃料等)、能源和环境安全(核废料处理、热核聚变等)、资源和国防安全(战略氦资源等)、国家大科学工程(强流重离子加速装置、可控核聚变(人造小太阳)等)等的发展.这就使得我国对稳定、高效的大型低温制冷系统需求急剧增加,全面缺乏大型低温制冷系统、关键子设备及集成技术的问题日益突出.为打破国外相关技术领域的封锁,中国科学院理化技术研究所李青研究员作为国家重大科研装备专项"大型低温制冷设备研制"项目首席科学家带领科研团队攻坚克难,致力于自主研制大型低温制冷系统.

Large-scale superfluid helium refrigeration system plays an important role in large-scale scientific projects.The bearing technology of helium cold compressor is still the key technical issue. High-temperature superconducting (HTS) magnetic bearings with the way of non-contact bearing and advantages of self-control and stability, but there is no report about superconducting magnetic bearings used in special helium cold compressor. Based on the structure and operating parameters of active maglev bearings which have been successfully applied in centrifugal cold compressor, the maximum levitation force per unit area of the superconducting magnetic bearings was calculated and the current research situation of typical radial superconducting magnetic bearings was analyzed. From two aspects of theoretical calculation and engineering application, it is demonstrated that the superconducting magnetic bearing has the feasibility of being applied to the cold compressor system. The key technologies that the superconducting magnetic bearing is applied to cold compressor are briefly analyzed.

High temperature superconducting magnetic levitation bearing, compared with other bearings, has significant advantages, when applied to a high-speed turbine machinery of large-scale low-temperature system with complex conditions. For a permanent magnet rotor with concentrated arrangement of magnetic fluxes, the influence of the rotor structure parameters on the suspension performance of the bearing was calculated and analyzed by the electromagnetic field analysis software. The maximum levitation force of unit area was used as the design target, and the rotor dynamics analysis was used to obtain the structural parameters of permanent magnet rotor. It can provide a reference for the rotor structure design and bearing production of the superconducting magnetic bearing in high speed turbine machinery.

Centrifugal turbo cold compressor is the key component of large superfluid cryogenic system.Due to the low temperature,negative pressure and high speed,the operating life of bearing is limited.The high temperature superconductive (HTS) maglev bearing has high loading capacity,well antijamming capacity,and without the requirement of active control,which makes it very suitable for the engineering application.Aiming at considering both of loading capacity and rotor dynamics,the optimization method and index were proposed.The ANSYS magnetic analysis software was applied to design and optimize a high temperature superconductive maglev bearing.Then the magnetic stiffness of this structure was up to 5.21 × 105N/m.The results of this article demonstrate that the HTS bearing can acquire enough maglev force and stiffness by optimal design.

从973-RFQ束流传输线上束流位置(BPM)测试需求出发,开发了一套完整的束流位置读出系统,其将移植到CSNS工程的京流位置测量系统中.该系统由信号采集、处理和显示模块组成.BPM读出系统采用EPICS作为软件开发平台,并选用Motorola公司的MVME5100作为IOC；硬件采用Hytec公司的ADC8411U卡实现对束流位置信号100 kHz的同步触发采样.信号处理模块对采集到的信号进行数值平均滤波,并实现到束流位置的转换.信号显示模块选用EPICS客户端软件EDM实现对束流位置信息2种不同方式的显示.经测试,整个系统最终读出的束流位置分辨率远好于0.2 mm,符合设计要求.

皮博地煤炭公司在依利诺斯州西南的美利莎生产矿采用了三种不同的运输系统.其中的一套系统--灵活的输送机FCT美利莎矿处于领先地位.这套系统是皮博地公司与久益采煤设备公司合作生产的连续式运输系统.这个矿是首家使用久益12CM27s型高压连续采煤机的煤矿,这种设备可增加产量而不致超过切割电机的能力.