NASA SBIR 2005 Solicitation


SUBTOPIC TITLE:Noise Breakthrough Turbine-Based Propulsion Technologies
PROPOSAL TITLE:Optimizing Noise Attenuation in Aircraft Exhaust Ducts Employing Passive and Active Absorbing Splitters and Struts

SMALL BUSINESS CONCERN (Firm Name, Mail Address, City/State/Zip, Phone)
KJB Consultants
11641 Weston Pointe
Strongsville ,OH 44149 - 9270
(440) 238 - 6861

PRINCIPAL INVESTIGATOR/PROJECT MANAGER (Name, E-mail, Mail Address, City/State/Zip, Phone)
Kenneth   Baumeister
11641 Weston Pointe
Strongsville, OH  44149 -9270
(440) 238 - 6861

NASA requires accurate numerical simulation of high bypass nacelle acoustics and the development of advanced nacelle absorption techniques to reduce engine noise levels. Thus, this Phase I effort will expand current Transient Finite Difference (TFD) nacelle algorithms to include
? Simulation of active and passive nacelle exhaust splitters,
? 3D simulation of passive and active absorbing radial struts,
? Optimization of multiple segment wall, splitter and strut absorbers for maximum noise reduction.
The exceptional performance and accuracy of the TFD method has already been documented for passive and active noise reductions in 2D aircraft nacelles. Recent experimental data have show promise for significant noise reduction for active noise treated struts as well as classic exhaust splitters. Therefore, this Phase I study will extend the current TFD nacelle algorithms to optimize splitter rings usage in exit nacelle ducts and 3D active and passive treatment of exhaust duct struts. The Phase II effort will include the capability of analyzing more complex 3D ducts with circumferential-segmented absorbing liners as well as external cowling and airframe noise sources. The numerical algorithms of this TFD Phase I study will provide NASA Glen and industry an innovative tool for acoustic nacelle design.

The Phase I code will allow NASA to significantly reduce both tone and broadband engine noise in scale and full size engine nacelle exhaust ducts as well as inlets. The code will predict both engine noise reductions for both passive and active treatments over a wide frequency range. The exact analytical predictions will eliminate some expensive experimental design and testing of complex 3D engine hardware with splitters and engine struts. The Phase II study will analyze advanced noise treatment concepts such as circumferential passive phase treatment, which has been shown to significantly reduce engine noise. The code will be very versatile; thus, it could also be used in the acoustic design and testing of NASA's advanced engine concepts such as the pulse detonation engine or other advances in combustion-based propulsion. The code should increase NASA's productivity and reduce operational costs by reducing expensive experimental testing of large-scale engine hardware.

The Phase I code will allow aircraft nacelle manufactures to significantly reduce the time between initial prototype and final design of acoustically treated nacelles. The code will aid in their reduction of tone and broadband noise by the optimal application of both conventional and advanced engine acoustic treatments. The manufacturer will be able to quickly evaluate both passive and active treatments for complex 2D and 3D nacelle structures over a wide frequency range. To meet a variety of other commercial needs, the geometry and grid generation codes will be constructed with enough flexibility to model mufflers, automobile interiors, and other business applications besides an aircraft nacelle. The code could also be useful in quieting large exhaust ducts in power and industrial plant operations. Architectural engineers may find the code useful in quieting their duct ventilation systems.

NASA's technology taxonomy has been developed by the SBIR-STTR program to disseminate awareness of proposed and awarded R/R&D in the agency. It is a listing of over 100 technologies, sorted into broad categories, of interest to NASA.

Aircraft Engines

Form Printed on 09-19-05 13:12