The Interdisciplinary Consulting Corporation (IC2), in partnership with OptiNav, Inc., proposes to develop advanced phased array instrumentation and processing capabilities for aircraft engine-inlet measurements. High channel-count, high-density, reduced cost-per-channel microphone arrays, using microelectromechanical systems (MEMS) piezoelectric microphones with backside contacts and advanced packaging technology, will be integrated into model-scale inlet design/build efforts to revolutionize engine-inlet array-measurement capabilities through increases in array density and channel count while significantly reducing the cost per channel. These measurement advances will be coupled with development of advanced processing techniques to take full advantage of the enhanced measurement capabilities, including handling of the three-dimensional (3D) problem related to non-uniform inlet geometries.
One focus of this project is to combine proven design principles and established device structures to develop, package, and install high channel-count, high-density arrays of MEMS piezoelectric microphones into model-scale engine inlets. Back-side contact piezoelectric MEMS microphones combined with advanced packaging methods will enable ultra-smooth sensor installation to avoid flow disturbances that would perturb the conditions inside the inlet and/or reduce the effectiveness of the measurement due to extraneous flow noise generated by the sensor.
A second focus of this project is to develop innovative processing algorithms to take advantage of the newly-enabled, high-fidelity data-acquisition capabilities. The increased sensor density and lower-cost sensors will enable measurements with higher modal density and dynamic range than previous measurement campaigns have been able to achieve. An even more significant advancement is the enabling of source-diagnostic capabilities in non-uniform inlets that require new algorithm development to account for the more complex geometry.
The proposed advanced phased array instrumentation and processing technology has the potential to be transportable across multiple NASA facilities such as the newly renovated 9' x 15' Low Speed Wind Tunnel. The new DGEN Aeropropulsion Research Turbofan (DART) is an excellent candidate for inlet phased array tests. NASA’s Commercial Supersonic Technology Project will need research testing of exotic inlets, and NASA has Space Act Agreements with numerous companies developing Advanced Air Mobility (AAM)/Urban Air Mobility (UAM) vehicles.
Commercial turbofan engine manufacturers have long wanted in-duct testing of real engines to reduce cost and increase information return compared with far-field static engine testing. External customers for the technology include government agencies as well as commercial engine manufacturers such as GE, Pratt & Whitney and Rolls Royce, and commercial AAM/UAM developers.