In order to investigate forced vibration problems of centrifugal impellers subjected to gas excitation in flow fields,an algorithm to calculate harmonic responses of a centrifugal impeller under non-cyclic symmetric exciting forces was realized with a cyclie and symmetric model considering the cyclic symmetry of impeller structures.For the spatially periodic inflow conditions,firstly the load vector was constructed according to the phase differences of periodic excitations of sectors,and then utilizing the modal shape data of different nodal diameters of the impeller its harmonic response dynamic equations were established under the modal coordinate system to calculate its displacement responses. Finally,the harmonic response analysis for a radial impeller under non-cyclic symmetric aerodynamic exciting forces was performed.It was shown that the displacement response results of the radial impeller obtained with the cyclic and symmetric model agree well with those with the whole body model;the responses under the exciting frequencies near two resonance points have relatively higher amplitudes;the correctness and effectiveness of the proposed algorithm to predict the resonance of a centrifugal impeller caused by gas excitation are verified.%为研究流场中离心叶轮受气流激振的受迫振动问题，利用叶盘结构的循环对称性编制计算程序，实现了使用循环对称模型进行非循环对称力作用下离心叶轮的谐响应分析。针对空间周期性的来流条件，由各扇区所受周期激励的相位差建立载荷向量，然后根据按扇区展开的叶轮各节径模态的振型数据，建立模态坐标系下的谐响应运动方程，计算得到叶轮的谐响应位移；以一半开式径向叶轮为例，进行了叶盘结构在气动力非循环对称分布情况下的谐响应分析。循环对称模型与整体模型计算的位移响应结果符合较好，两个共振点附近激振频率下的振动响应均呈现出较高的幅值，表明了算法的正确性和预测气流激励导致共振的有效性。
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