高速高载荷变转速汽轮机扭叶片优化设计及可靠性分析

为了完成高速高载荷系列工业汽轮机的低压级扭叶片的设计和应用，以常规驱动汽轮机叶片为原型，对其末三级扭叶片组进行了全三维气动性能分析；利用自适应差分进化算法对末三级叶片的型线和积叠规律进行了优化设计；然后根据常规强度计算结果，选择合适的材料并选择松拉筋配枞树型叶根的结构；最后采用有限元仿真软件对其进行了强度振动和动应力及疲劳分析。结果表明：优化后末三级叶片的气动效率提升约1.61%且强度满足要求；设计末两级动叶片时，优先考虑可靠性，其余级因其强度振动问题相对容易解决，优先考虑气动效率；末级叶片材料可能需要选择钛合金，而枞树型叶根是更可靠的叶根形式；选择抗弯模量大、厚度小的叶型搭配松拉筋有利于增加叶片刚度、减小叶片重量，从而为不调频叶片的设计提供参考。

Optimization and Reliability Analysis of Twisted Blades for High Speed and High Load Variable Speed Steam Turbine

In order to complete the design and application of low pressure stage twisted blade of high speed and high load industrial steam turbine, based on a ordinary twisted blade group used in steam turbine, the full three dimensional aerodynamic performance of the last three stage twisted blade groups were analyzed; adaptive differential evolution algorithm was used to optimize the profile and stacking law of the last three stage blades; then, appropriate material and the structure of fir tree blade root with loose reinforcement were selected according to preliminary strength calculation results; finally, the finite element simulation software was used to analyze the strength vibration, dynamic stress and fatigue. The results show that the aerodynamic efficiency of the modified last three stages is improved by about 1.61% and the strength meets the requirements; in the design of the last two stages, reliability is priority, while the aerodynamic efficiency is priority for the other stages because their strength and vibration are relatively easy to solve; the final blade material may need to choose titanium alloy, and the fir tree blade root is more reliable; the selection of the blade and loose reinforcement with large bending modulus and small thickness is beneficial to increase blade stiffness and reduce blade weight, so as to provide a reference for the design of untuned blades.