Turbomachine discrete-frequency tones, a significant environmental concern, are generated by rotor-stator interactions. Specific spatial modes are generated, but not all generated modes propagate to the far field. It is the propagating spatial modes generated by rotor-stator interaction that represent the community-disturbing far field discrete-frequency noise. Fundamental active airfoil source discrete-frequency noise control experiments are performed, with the active airfoil source control optimized to generate propagating spatial modes to cancel the propagating spatial modes generated by the rotor-stator interaction. These experiments demonstrate the viability and effectiveness of rotary-valve discrete-frequency noise control. Specifically, the active noise control system combines the active airfoil source control with in-duct spatial mode measurement. In this unique design, the active airfoils of the stator vane row are driven by a remote centerbody-mounted rotary-valve system. Propagating spatial mode reductions of 5 dB and 9 dB upstream and downstream with negligible modal spillover are demonstrated. [S0742-4795(00)02702-2]
Active Control of Discrete-Frequency Turbomachinery Noise Using a Rotary-Valve Actuator
Contributed by the International Gas Turbine Institute (IGTI) of THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS for publication in the ASME JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER. Paper presented at the International Gas Turbine and Aeroengine Congress and Exhibition, Indianapolis, IN, June 7–10, 1999; ASME Paper 99-GT-403. Manuscript received by IGTI March 9, 1999; final revision received by the ASME Headquarters January 3, 2000. Associate Technical Editor: D. Wisler.
Sawyer, S. D., and Fleeter, S. (January 3, 2000). "Active Control of Discrete-Frequency Turbomachinery Noise Using a Rotary-Valve Actuator ." ASME. J. Eng. Gas Turbines Power. April 2000; 122(2): 226–232. https://doi.org/10.1115/1.483199
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