The unshrouded impeller is widely used in industrial centrifugal compressors and normally operates at high tip speed and large volume flow. However, this type of impeller can be very sensitive to flow excitations such as IGV wake, and hence encounters the challenge of high dynamic stress. Due to the lack of experimental vibration data, this paper aims to enhance the understanding of the IGV preswirl effect. The real operating representative data from strain gauges is acquired during the experiment. The blade transient and quasi-steady response due to upstream IGV wake under different configurations are investigated and quantified. Results show that the blade response increases with larger positive regulation. And under specific operating conditions, the vibration of the blade is quite large, which is comparable with synchronize resonance. This increment is attributed to the aerodynamic loading change due to enhanced distortion of the inlet flow. Based on the current findings, accurate numerical prediction of the blade forced vibration for a large shift of inlet flow condition is also needed for more reliable operating of the impeller.

无护罩叶轮广泛用于工业离心压缩机，通常在高叶尖速度和大体积流量下运行。然而，这种类型的叶轮可能对 IGV 尾流等流动激励非常敏感，因此会遇到高动态应力的挑战。由于缺乏实验振动数据，本文旨在增强对IGV预旋效应的理解。来自应变计的真实操作代表性数据是在实验过程中获得的。研究和量化了由于上游 IGV 尾流在不同配置下引起的叶片瞬态和准稳态响应。结果表明，叶片响应随着更大的正调节而增加。并且在特定工况下，叶片的振动相当大，堪比同步共振。该增量归因于进气流畸变增强引起的气动载荷变化。根据目前的研究结果，为了使叶轮更可靠地运行，还需要对入口流动条件大变化时叶片受迫振动进行准确的数值预测。