STUDY AND TESTS TO REDUCE COMPRESSOR SOUNDS OF JET AIRCRAFT.
GENERAL ELECTRIC CO CINCINNATI OHIO AIRCRAFT ENGINE GROUP
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Two methods of reducing compressor noise were studied local sonic velocity regions in inlet guide vanes or partial choking, and the application of acoustic material to vanes, struts, or duct walls. In the process of the study, some unique facilities for evaluating acoustic material performance for jet engine application were constructed and used, and a large body of data on basic acoustic properties of materials was collected. The performance of acoustic treatment in a duct with air flow was studied, with some major effects identified. An analytical technique has been used to identify the effects on the duct and far field sound pressures produced by lining a duct wall with acoustic material. Noise reduction due to partial choking of inlet guide vanes was demonstrated on both a laboratory test fixture and a full scale engine compressor. Finally, correlation of the duct modes with the bladevane number was demonstrated in a model compressor. Author
- Jet and Gas Turbine Engines