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A radial turbine is one of the vital components of a helium liquefaction plant. The design of a turbine becomes critical due to its compact size and high-speed configuration. In this study, numerical optimization has been performed for the three-dimensional steady flow of helium gas in the radial inflow turbine of a helium liquefaction plant at a nominal condition. The mean line design is an appropriate method to obtain the approximate results. The computational fluid dynamics simulation algorithm is adopted in this study to reach the final results and Ansys CFX is used for the simulation. From the analysis, it has been reported that the number of rotor blades was overestimated in the mean line design. Performance parameters like total-to-static efficiency and velocity ratio were also found to be optimum numerically under a preliminary design condition. Finally, power of 1.7 kW was achieved at total-to-static efficiency of 71.4%. The deviation in analytical and numerical results is within for performance as well as geometric parameters. 相似文献
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《等离子体科学和技术》2015,17(6):517-523
An increase of the cooling capacities in the liquid helium temperature area is required 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.10~2 W@4.5 K level helium cryogenic systems are needed in view of feasibility and economy.A turboexpander is the key component 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 performance 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. 相似文献
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采用CFD方法对某型号中压低温透平膨胀机膨胀端进行整机全周数值模拟,全面考虑了进气蜗壳、叶顶间隙气封、轮背气封和轴封等细节结构对膨胀端气动性能和流场的影响.研究结果表明:进气蜗壳的几何形状是造成喷嘴进口气流沿叶高方向分布不均匀的主要原因;轮背气封、叶顶气封和轴封内存在明显的旋涡流动,且叶顶气封是典型的后台阶流动,齿封内和台阶后旋涡涡轴方向相反;喷嘴和叶轮之间过小的间隙导致气流在喷嘴压力面一侧形成激波,激波/附面层干扰使叶片和下端壁附面层同时分离,在上、下端壁角区各形成一个弯曲的涡管,最后终止于动静交界面. 相似文献
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为解决空气制冷技术对气源的依赖问题,同时简化系统回收膨胀功,本文以高速电机驱动的无油气浮轴承压缩-膨胀一体机为核心部件,搭建了采用开式逆增压循环的全新风家用空气制冷系统实验台,可实现膨胀机、压缩机进出口的温度、压力、流量测量,并可与焓差室对接,获得制冷系统的制冷量和送风参数。在标准空调工况下进行了多个转速下的性能测试,额定转速为38 000 r/min时,制冷量为1.6 kW。送风温度随转速升高而降低,制冷量随转速升高而增大,基于该特点,空气制冷系统有直接送风和送风温度可调的优势,使空气制冷技术在新风空调领域的应用成为可能。 相似文献
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箔片动压气体轴承(CFB)采用弹性支承和顶层平箔组成的弹性箔片结构,具有极端环境下良好的抗转子不对中和高速下的抗涡动性能,对于实现低温透平膨胀机高效稳定运行具有重要意义。回顾了国内箔片动压气体径向轴承在低温透平膨胀机中的应用,阐述了分段弹性支承、粘弹性支承、波箔箔片、鼓泡箔片等几种典型箔片轴承在高速透平膨胀机上的研究进展及其支承特性。进一步分析对比了上述轴承对高速低温透平膨胀机转子动力学和气动特性的影响规律,结果显示CFB具有优异的静动态特性,能够实现高速低温透平膨胀机的稳定运转,与此同时保证了低温透平高速转子较小的同步涡动和稳定的轴心位置,在高速透平机械的应用领域具有重要价值。 相似文献
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