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Study on Unsteady Flow Induced by Annular Cascade

环形叶栅引起的非定常流研究

基本信息

批准号：
07455081
负责人：
YOSHIKI Haruo
金额：
$ 5.06万
依托单位：
The University Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07455081/
关键词：
Unsteady Flow Inlet Guide Vane Annular Cascade Swirling Flow Velocity Distribution Flow Visualization Numerical Analysis Separation Flow

项目摘要

To investigate phenomena of an unsteady flow induced by annular cascade of inlet guide vanes for a centrifugal compressor, experiments and numerical analysis were conducted. In experiments, fluctuating wall pressure distributions were measured by small semi-condustor pressure transducers and instantaneous velocity distributions at 10% chord length after the cascade were gotten by a hot-wire anemometer and flow streak lines around the vanes were visualized by sheet light of an argon ion razor and smoke. As a result, the followings are found : (1)In case that blade setting angle from radial direction is smaller than 30 degrees, the unsteady flow with noise is not induced, but in case that the angle is larger than 50 degrees, the unsteady flow is produced. (2)A core installed in center of a pipe passage to reduce unsteadiness of a swirling flow does not affect occurrence of the unsteady flow with noise. (3)Both blade width and chord length also have no influence for the occurrence of the unsteady flow. (4)Fundamental frequency of the unsteady flow almost has a linear relation to flow velocity. (5)Strouhal number is constant and independent of Reynolds number in some flow conditions. (6)The occurrence of the unsteady flow is considered to have a relation to flow separation from blade surface. (7)Flow direction of blade wake strongly fluctuates under the occurrence of the unsteady flow. (8)The unsteadiness travels counter direction of swirling stall cell. (9)A tab protecting the unsteady flow with noise is quit effective. Furthemore, numerical analysis was success in simulation of pressure fluctuations corresponding to be experimental results in 60 degrees of angle. Accuracy of calculation is not yet sufficient but it is say that the numerical opens the way to establish a flow model for the unsteady flow induced by annular cascade.

为了研究离心压气机进口导叶环形叶栅诱导的非定常流动现象，进行了实验和数值分析。实验中采用小型半稳态压力传感器测量了叶栅壁面脉动压力分布，采用热线风速仪测量了叶栅后10%弦长处的瞬时速度分布，采用氩离子刀片光和烟雾显示了叶栅周围的流纹线。结果表明：（1）叶片安装角与径向夹角小于30 °时，不产生带噪声的非定常流，而叶片安装角大于50 °时，产生非定常流。(2)A安装在管道通道中心以减少旋流的不稳定性的芯不会影响带有噪声的不稳定流的发生。（3）叶片宽度和弦长对非定常流动的发生也没有影响。（4）非定常流的基频与流速几乎呈线性关系。（5）Strouhal数是常数，在某些流动条件下与雷诺数无关。（6）非定常流动的发生与叶片表面的流动分离有关。（7）在非定常流的作用下，叶片尾迹的流向发生了强烈的波动。（8）非定常流与旋转失速区方向相反。(9)A带噪声的非定常流保护片是非常有效的。数值分析成功地模拟了60 °角范围内的压力脉动，与实验结果吻合较好。计算精度尚不够，但可以说，数值方法为建立环形叶栅非定常流动模型开辟了道路。