Experimental Study on Impeller Blade Vibration During Resonance—Part I: Blade Vibration Due to Inlet Flow Distortion
Experimental Study on Impeller Blade Vibration During Resonance—Part I: Blade Vibration Due to Inlet Flow Distortion
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DOI：
10.1115/1.2968869
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发表时间：
2009-03
影响因子：
1.5
通讯作者：
A. Kammerer;R. Abhari
中科院分区：
文献类型：
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作者：
A. Kammerer;R. Abhari
本文分为两部分，第一部分介绍了获取共振振动数据的实验方法。第二部分讨论阻尼的估计。在涡轮机械部件的设计过程中，叶片受强迫响应或颤振的高周疲劳必须保证其机械完整性。这需要确定叶片内的应力水平，而这又取决于强迫函数和阻尼。该领域的绝大多数实验研究都是在压气机和涡轮的轴向配置上进行的。本实验研究旨在深入了解径向压缩机在共振时的强迫响应振动。为此，用动态应变仪对研究叶轮进行了测量，并在共振条件下进行了实验。用有限元法分析了模态特性，并用电子-散斑-图样相关干涉法进行了验证。在实验过程中，叶轮上游的栅格装置产生了作用在叶片上的非定常力，造成了进口流型的畸变。使用气动探头测量了相关的流动特性。采用非定常计算流体力学方法对叶片表面的压力波动和相应的频率含量进行了计算。通过叶片的激励阶数和固有频率来区分叶片在三个共振交叉点上的响应。测量了许多进口压力设置，从接近真空开始，然后增加。总体结果表明，安装的畸变屏除基频外还产生谐波。第一和第二叶片模态的共振响应表明底层动力学支持单自由度模型。
Forming the first part of a two-part paper, the experimental approach to acquire resonant vibration data is presented here. Part II deals with the estimation of damping. During the design process of turbomachinery components, mechanical integrity has to be guaranteed with respect to high cycle fatigue of blades subject to forced response or flutter. This requires the determination of stress levels within the blade, which in turn depend on the forcing function and damping. The vast majority of experimental research in this field has been performed on axial configurations for both compressors and turbines. This experimental study aims to gain insight into forced response vibration at resonance for a radial compressor. For this purpose, a research impeller was instrumented with dynamic strain gauges and operated under resonant conditions. Modal properties were analyzed using finite element method and verified using an optical method termed electronic-speckle-pattern-correlation-interferometry. During the experiment, unsteady forces acting on the blades were generated by grid installations upstream of the impeller, which created a distorted inlet flow pattern. The associated flow properties were measured using an aerodynamic probe. The resultant pressure fluctuations on the blade surface and the corresponding frequency content were assessed using unsteady computational fluid dynamics. The response of the blades was measured for three resonant crossings, which could be distinguished by the excitation order and the natural frequency of the blades. Measurements were undertaken for a number of inlet pressure settings starting at near vacuum and then increasing. The overall results showed that the installed distortion screens generated harmonics in addition to the fundamental frequency. The resonant response of the first and the second blade mode showed that the underlying dynamics support a single-degree-of-freedom model.