考虑kick效应的汽轮机调节级叶片安全性分析

Security Analysis for Governing Stage Blade of Steam Turbine with Consideration of Kick Effect

采用喷嘴配汽的汽轮机调节级,部分进汽不仅对机组的气动性能和效率产生影响,而且还会产生很强的汽流激振力,影响到其自身和整个机组的安全性能。文章首先基于ANSYS CFX,计算了某调节级叶片的全三维气动特性,对调节级非定常气动特性和汽流激振力的变化进行了研究,分析得到了动叶进出不进汽弧段所受到的汽流载荷急剧变化的现象,该现象被称之为调节级的kick效应;然后基于ANSYS的结构动力学模块,考虑kick效应对调节级动叶在考虑气流载荷下的动响应进行了分析;最后,根据动响应计算结果,对调节级的安全性进行了评价。整个研究过程和结论,对于调节级的安全性设计具有重要的工程参考价值和指导意义。

In nozzle governing stage of steam turbine, partial admission affects aerodynamic performance and efficiency, and produces strong fluid excitation, which affects the security of the governing stage together with the whole turbine. Basing on ANSYS CFX, 3D aerodynamic performance is calculated on some governing stage blade in this paper, and the change of unsteady aerodynamic performance and fluid excitation in governing stage is researched at first. The study showes that fluid excitation force changes rapidly when the moving blade enters or leaves the un-admission arc, and the phenomenon is called kick effect of the governing stage. Then, basing on the structural dynamic module in ANSYS software, dynamic response of governing stage under the kick effect is analyzed with consideration of fluid load. In the end, security of governing stage is evaluated according to the dynamic response calculating result. This study and results have important reference value and guidance for security design of governing stage.