REDUCTION OF UNSTEADY STATOR–ROTOR INTERACTION USING TRAILING EDGE BLOWING
✍ Scribed by THOMAS A. LEITCH; C.A. SAUNDERS; W.F. NG
- Publisher
- Elsevier Science
- Year
- 2000
- Tongue
- English
- Weight
- 178 KB
- Volume
- 235
- Category
- Article
- ISSN
- 0022-460X
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✦ Synopsis
An aeroacoustic investigation was performed to assess the e!ects of adding mass #ow at the trailing edges of stators upstream of an aircraft engine simulator. By using trailing edge blowing to minimize the shed wakes of the stators, the #ow into the rotor was made more uniform, hence reducing the unsteady stator}rotor interaction. In these experiments, a reduced number of stators (four) was used in a 1/14 scale model inlet which was coupled to a 4)1 in (10)4 cm) turbofan engine simulator. Steady state measurements of the aerodynamic #ow "eld and acoustic far "eld were made in order to evaluate the aeroacoustic performance at three simulator speeds: 30k, 50k, and 70k r.p.m. The lowest test speed (30k r.p.m.) showed a noise reduction as large as 8)9 dB in the blade passing tone. At 50k and 70k r.p.m., the reduction in blade passing tone was 5)5 and 2)6 dB respectively. In addition, trailing edge blowing reduced the overall sound pressure level in every case. Aerodynamic measurements showed that fan face distortion was signi"cantly reduced due to trailing edge blowing. The addition of trailing edge blowing from the four upstream stators did not change the operating point of the fan, and the mass #ow added by the blowing was less than 1% of the fan mass #ow rate. The results of these experiments clearly demonstrate that blowing from the trailing edges of the stators is e!ective in reducing unsteady stator}rotor interaction and the subsequent forward radiated noise.