NASA SBIR 00-1 SOLICITATION

FORM 9B - PROJECT SUMMARY


PROPOSAL NUMBER 00-1 02.02-9579 (Chron: 000422 )
PROJECT TITLE
Active Control of Fan Noise Using Distributed Phased Pulsed Flows



TECHNICAL ABSTRACT (LIMIT 200 WORDS)
A program for the development of an active pulsed flow noise control solution for turbomachinery noise caused by rotor wake interactions with stators is proposed. The system utilizes an array of pulsed jet flows near the leading edges of several stator blades to generate volume velocity sources to counter the fluctuating lift dipole sources caused by the wake-stator interaction. By placing the acoustic canceling sources adjacent to the location of the dipole sources rather than on the inner surface of the nacelles, better more efficient control of particularly the higher order radial modes can be achieved. Other advantages of the proposed noise canceling method are its extremely small size and light weight for producing a given sound power level. Lastly, the proposed system uses very small amounts of air available from the compressor and requires practically no electrical power, thus the heat generated and the weight required by conventional sound sources are largely eliminated. Initial laboratory tests indicate that this concept has the potential to meet and exceed the 115 to 120 dB re 1 pW sound power level that appears to be required from the work of previous investigators.



POTENTIAL COMMERCIAL APPLICATIONS
This proposed noise reduction concept will have application to both commercial and military aircraft to reduce their noise impact on community residents, aircraft passengers and crew and render military aircraft less detectable and classifiable. The development and application of this technology will support NASA's intention "to provide enabling technologies to reduce the perceived noise levels of future aircraft by a factor of two (10 EPNDB) from 1997 technology by 2007and a factor of 4 (20 EPNDB) by 2022." The ability of this technique to provide the higher than currently available acoustic source levels with a robust system will allow the development of more capable noise reduction systems based in part on theoretical work that has been demonstrated to have great benefit for silencing quieter simulated sources in the laboratory.



NAME AND ADDRESS OF PRINCIPAL INVESTIGATOR (Name, Organization Name, Mail Address, City/State/Zip)
Fred R. Kern
Physical Sciences Inc.
20 New England Business Center
Andover , MA   01810 - 1077



NAME AND ADDRESS OF OFFEROR (Firm Name, Mail Address, City/State/Zip)
Physical Sciences Inc.
20 New England Business Center
Andover , MA   01810 - 1077