| タイトル | Characterization of Aeromechanics Response and Instability in Fans, Compressors, and Turbine Blades |
| 本文（外部サイト） | http://hdl.handle.net/2060/20030064154 |
| 著者（英） | Tan, Choon S. |
| 著者所属（英） | Massachusetts Inst. of Tech. |
| 発行日 | 2003-08-06 |
| 言語 | eng |
| 内容記述 | This study investigated the effect of interaction between tip clearance flow, steady and unsteady upstream wakes in rotor and stator blade rows in terms of blade forced response. In a stator blade row, the interaction of steady wakes in the upstream rotor frame with the stator imply a blade forced response whose spectrum contains the Blade passing frequency (BPF) and its harmonics, with a decaying amplitude as the frequency increases. When the incoming wakes are unsteady, however, the spectrum of blade excitation exhibits unexpectedly amplified high frequencies due to the modulation of BPF with the fluctuation frequency. In a rotor blade row, a tip flow instability has been demonstrated with a frequency (TVF) equal to 0.45 times the Blade Passing frequency corresponding to a reduced frequency (F(sub c) (sup +)) of 0.7. Under uniform inlet flow conditions, the frequency and spatial content of the tip flow region have been characterized. The disturbance TVF was the dominant disturbance in the flow field and was found to imply variations of the pressure coefficient of more than 30% on the blade tip (between 35% to 90% chord) and in the rotor-generated wake (from 75% to 100% hub-to-tip position). In an attempt to better understand the origin of the instability, the structure of the tip flow has also been analyzed. The interface between the tip flow region and the core flow has been found to have periodical wave-like flow patterns which proceed downstream at a speed of approximately 0.42 times the core flow speed at a frequency corresponding to TVF. A list of conclusions derived from these interactions is presented. |
| NASA分類 | Aircraft Stability and Control |
| 権利 | No Copyright |
| URI | https://repository.exst.jaxa.jp/dspace/handle/a-is/90065 |
|
