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The helium cryogenic system supplies supercritical helium cooling capacity at 4.5 K for the superconducting magnets in the EAST superconducting tokamak.Four low-temperature helium turbines are used in the 2 kW helium refrigeration system,and their performance and reliability are critical for the continuous operation of the tokamak.The turbines were made by the Helium Mechanics Company in Russia.The start-up process is very unstable,easily broken,and thus testing and improvements are needed.In this paper,we analyze the structure of the helium turbine,make improvements,and describe the testing process and results of the improved helium turbines.Some of the operational experiences during the start-up process and tests are also presented. 相似文献
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由于氦透平膨胀机在设计工况下进行低温性能测试的实验平台和配套设施很难满足要求,且低温工况较难达到,因此通常用膨胀机在空气中的实验来检验其性能,并通过相似模化方法得到膨胀机低温下的性能。通过分析工质在透平膨胀机中的流动及能量转化过程,发现特性比U1/CS、膨胀比P1/P2、马赫数Ma、雷诺数Re是影响膨胀机性能的关键参数。结合相似理论,以透平膨胀机变工况性能预测程序计算结果为依据,筛选出了以U1/CS为第一相似准则,以Ma、k-1·Ma-2、Ma·k-1、k·Ma2作为第二相似准则的四组相似准则数。以流体动力学计算结果为依据,从四组相似准则中选择出了模化误差最小的相似准则,即U1/CS与Ma·k-1组合。结果表明:相似模化前后氦气与空气透平膨胀机间等熵效率的最大误差在±1.4%以内,且在内部流场预测(马赫数... 相似文献
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An experimental method is presented to analyze the dynamic stability of the gas bearing for small cryogenic turbo-expanders. The rotation imbalance response and... 相似文献
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To make the large-scale helium cryogenic system of fusion device EAST (experimen- tal advanced super-conducting tokamak) run stably, as the core part, the helium turbine expander must meet the requirement of refrigeration capacity. However, previous designs were based on one dimension flow to determine the average fluid parameters and geometric parameters of impeller cross-sections, so that it could not describe real physical processes in the internal flow of the tur- bine expander. Therefore, based on the inverse proposition of streamline curvature method in the context of quasi-three-dimensional flows, the all-over-controlled vortex concept was adopted to design the impeller under specified condition. The wrap angle of the impeller blade and the whole flow distribution on the meridian plane were obtained; meanwhile the performance of the designed impeller was analyzed. Thus a new design method is proposed here for the inverse proposition of the helium turbine expander impeller. 相似文献
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超导核聚变低温系统用末级氦透平膨胀机在运行过程中受到磁体放电"交流损耗"的影响,使得其运行工况变得十分恶劣,这是导致氦透平膨胀机性能下降与损坏的主要原因。本文从理论分析出发,详尽的分析了末级氦透平膨胀机受"交流损耗"影响的原因,并提出了降低或延缓此影响的措施。通过商业软件模拟结果发现,增加旁通阀门并进行自动控制可以有效降低交流损耗对末级氦透平膨胀机的影响,压力波动由之前的48.57%减小到改进后的7.1%;转速波动由之前的9.4%减小到改进后的1.16%。因此,采用增加旁通低温阀门的方案可以作为现有超导核聚变低温系统末级氦透平膨胀机改进方式的一个参考。 相似文献