Holographic vibration measurement of a rotating fluttering fan
Abstract
The use of holographic interferometry to determine the deflection shape of a rotating aero engine fan undergoing unstalled supersonic flutter is described. A mirror-Abbe image rotator was employed in a double pulse holographic system to compensate for fan rotational motion and maintain correlation between the two resultant holographic images. The mirror-Abbe unit rotated the illuminating beam and derotated the light returned from the rotating fan. Holographic interferograms were recorded of a 0.86 m diameter fan rotating at speeds just under 10,000 rpm. The amplitude and spatial distribution of blade torsion and axial bending on the fluttering fan were obtained from the holograms. Errors due to misalignment of the system and unsteady aerodynamics are discussed.
- Publication:
-
NASA STI/Recon Technical Report N
- Pub Date:
- January 1982
- Bibcode:
- 1982STIN...8313437S
- Keywords:
-
- Holographic Interferometry;
- Supersonic Flutter;
- Turbofans;
- Vibration Measurement;
- Aeroelasticity;
- Alignment;
- Axial Stress;
- Deflection;
- Image Rotation;
- Spatial Distribution;
- Torsional Stress;
- Unsteady Aerodynamics;
- Instrumentation and Photography