中文摘要：

非定常性是透平机械内部流动的固有特性。非定常流动不仅对透平机械的气动性能具有一定的影响，还会产生导致动叶片振动疲劳的气流激振力，所以对于透平级的非定常流动分析十分必要。文中基于CFX软件，采用RNG k-ε湍流模型、双时间步法、滑移界面法以及结构化网格建立了一级半透平级（静叶／动叶／静叶）三维非定常粘性流场的数值模型及计算方法；在此基础上详细分析了流场特性随时间的变化，发现时均非定常等熵效率小于相应的定常等熵效率；同时获得了作用于动叶上随时间变化的气流力以及气流激振力因子，该因子数值与汽轮机设计人员广泛采用的由实践而来的数据吻合良好。文中研究结果有利于分析非定常流动对透平机械气动性能影响的机理，并且为叶片的振动响应以及疲劳寿命分析提供必要的参数。

英文摘要：

Flow in turbomachinery is inherently unsteady. The unsteady flow has effect on aerodynamic performance of turbomachinery and induces excitation force leading to vibration of blade, so it is necessary to investigate unsteady flow in turbomachinery stage. Based on the CFD software CFX, the numerical model and calculation method was developed by adopting RNG k-ε turbulence model, dual time step method, sliding interface model and structure grid, and then the flow field varied with time was studied. It is seen that the time-averaged unsteady isentropic efficiency is lower than that from steady analysis. Meanwhile, the unsteady aerodynamic load and excitation force factor were obtained too, and the excitation force factor is agreement with the data which comes from engineering practice and is widely used by engineers. The numerical results will do benefit to understand the effect of unsteady flow on aerodynamic performance of turbomachinery and provide essential parameters for response and fatigue analysis of blade.