Abstract For a radial turbine with vaneless volute, the inflow of turbine rotor usually has a circumferential flow distortion due to the influence of the volute tongue. The rotating blades of the rotor are exposed to harmonic aerodynamic loads caused by the distortion, which may induce rotor resonance and lead to high cycle failures (HCF). To understand the forced response mechanism clearly, a numerical analysis was carried out based on a fluid structure interaction (FSI) method. The pressure functions were extracted from the results of a computational fluid dynamics (CFD) analysis by Fourier decomposition. The first three harmonic pressures were identified as the primary engine order (EO) excitations and imposed on the structural model for computational structural dynamics (CSD) simulation. The quantification and assessment of the rotor response were attained by mode superposition method. The simulation results are shown to be consistent with the predictions of Singh’s advanced frequency evaluation (SAFE) diagram.

中文翻译：

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无叶片蜗壳径向涡轮机流动畸变产生强迫响应的研究

摘要 对于无叶蜗壳径流式涡轮机，涡轮转子的流入由于蜗壳舌的影响，通常会产生周向流动畸变。转子的旋转叶片承受由畸变引起的谐波气动载荷，这可能引起转子共振并导致高周故障（HCF）。为了清楚地理解受迫响应机制，基于流固耦合 (FSI) 方法进行了数值分析。压力函数是通过傅立叶分解从计算流体动力学 (CFD) 分析的结果中提取的。前三个谐波压力被确定为主要发动机阶次 (EO) 激励，并强加于计算结构动力学 (CSD) 模拟的结构模型。转子响应的量化和评估是通过模式叠加方法实现的。仿真结果表明与 Singh 的高级频率评估 (SAFE) 图的预测一致。