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空冷50MW机组低压缸变工况三维流场数值分析 总被引:1,自引:0,他引:1
介绍了采用Numeca的Fine/Turbo软件对某空冷50MW机组低压缸末三级进行了变工况三维粘性数值模拟,重点分析了不同背压条件对机组低压缸性能的影响。详细分析各工况下的三维流场信息,结果显示背压变化对末级的影响比较大,在高背压、小容积流量工况下,在末级动叶中部出现较大的分离区。通过分析研究低压缸全工况三维流场,可深入了解透平内部流动机理,有助于进一步优化空冷机组设计。 相似文献
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针对大型空冷汽轮机背压和排汽温度随环境温度变化的运行特点,指出了末级叶片变工况问题、低压内缸严重变形以及低压轴承箱变形导致轴承标高不断变化等关键难点。根据多年来空冷汽轮机的设计实践,提出了高阻尼结构末级长叶片、落地式低压缸和落地式轴承等设计技术,设计制造了空冷汽轮机,圆满解决了以上难题,在实际运行中安全高效。 相似文献
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一、前言现代汽轮机单机功率越大,末级叶片就越长。末级的功率占整台机组功率7~9%左右。因此,保证汽轮机低压末级长叶片在设计工况特别是在变工况下的安全经济运行,是发展大功率供热、调峰、空冷机组的关键技术问题在深度变工况下,末级喷嘴与动叶之间的轴向间隙顶部产生旋涡,动叶出口根部产生脱流和倒流,排汽部分过热,使末级效率显著降低,动应力水平增高,发生失速颤振和动叶根部出汽边水蚀,造成叶片断裂事故。为了保障末级叶片的工作可靠性,应从 相似文献
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简要介绍空冷汽轮机运行的工况特点和末级叶片的设计特点,通过对空冷末级叶片的结构力学设计特性和气动设计特性的定性分析,总结了叶片的大刚度大阻尼结构设计、成圈结构调频设计、优化排汽环形面积设计(最佳叶高)、优良的叶形通道设计、优良的变工况性能设计,以及小容积流量下叶片的动应力和颤振特性等设计原则。 相似文献
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For a better design of tidal stream turbines operated in off-design conditions, analyses considering the effects of blade deformation and yawed inflow conditions are necessary. The flow load causes deformation of the blade, and the deformation affects the turbine performance in return. Also, a yawed inflow influences the performance of the turbine. As a validation study, a computational fluid dynamics (CFD) simulation was carried out to predict the performance of a horizontal axis tidal stream turbine (HATST) with rigid blades. The numerical uncertainty for the turbine performance with blade deformation and a yawed inflow was evaluated using the concept of the grid convergence index (GCI). A fluid–structure interaction (FSI) analysis was carried out to estimate the performance of a turbine with flexible composite blades, with the results then compared to those of an analysis with rigid blades. The influence of yawed inflow conditions on the turbine performance was investigated and found to be important in relation to power predictions in the design stages. 相似文献
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A general-purpose performance prediction program, which can simulate various types of gas turbine such as simple, recuperative, and reheat cycle engines, has been developed. A stage-stacking method has been adopted for the compressor, and a stage-by-stage model including blade cooling has been used for the turbine. The combustor model has the capability of dealing with various types of gaseous fuels. The program has been validated through simulation of various commercial gas turbines. The simulated design performance has been in good agreement with reference data for all of the gas turbines. The average deviations of the predicted performance parameters (power output, thermal efficiency, and turbine exhaust temperature) were less than 0.5% in the design simulations. The accuracy of the simulation of off-design operation was also good. The maximum root mean square deviations of the predicted off-design performance parameters from the reference data were 0.22% and 0.44% for the two simple cycle engines, 0.22% for the recuperative cycle engine, and 0.21% for the reheat cycle engine. Both the design and off-design simulations confirmed that the component models and the program structure are quite reliable for the performance prediction of various types of gas turbine cycle over a wide range of operations. 相似文献
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针对45°叶型转折角扩压叶栅及增加小叶片后组成的大小叶片叶栅,分别测量了其在设计工况及不同气流攻角下的叶栅气动性能,通过PIV实验获得了对应工况下的叶栅内部流动状态.结果表明:增加小叶片后,叶片压力面至吸力面的压力梯度明显降低,大叶片载荷降低;在设计工况下,叶栅气流落后角仍可参考霍威尔半经验公式进行计算,但偏离设计工况后,该公式存在较大误差;大小叶片叶栅的气流落后角仅在小气流攻角下明显减小,在其余工况下变化不大;不同气流攻角下小叶片对大叶片表面气流流动分离起到约束作用;在设计工况至大气流攻角工况变化过程中,叶栅扩压损失有所降低. 相似文献
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An understanding of the physics of the mutual interaction between gas flow and oscillating blades, and the development of predictive capabilities is essential for improving overall efficiency, durability and reliability. In this study presented the algorithm proposed involving the coupled solution of 3D unsteady flow through a turbine stage and dynamic problem for rotor blades motion by action of aerodynamic forces without separating outer and inner flow fluctuations. There has been performed the calculations for the last stage of the steam turbine under design and off-design regimes. It has investigated the mutual influence of both outer flow non-uniformity and blades oscillations. It has shown that amplitude-frequency spectrum of blade oscillations contains the high frequency harmonics, corresponding to rotor moving one stator blade pitch, and low frequency harmonics caused by blade oscillations and flow non-uniformity downstream from the blade row. 相似文献
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