Advanced Phased Array Instrumentation and Processing for Engine Inlet Measurements

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.