Engine Acoustic/Screech Sensor

High performance military gas turbine engines are often equipped with augmentors also know as afterburners, to provide increased levels of thrust for relatively short periods of time. The level of thrust augmentation desired is determined by the aircraftrequirement for specific excess power for maneuver. However, the augmentation level, which can be supplied by engines, is limited by the oxygen in the air after the turbine, by cooling requirements for augmenter walls and downstream nozzle, and by theonset of the debilitating combustion instabilities of screech and rumble. It is for the avoidance of these instabilities that the instrumentation development proposed herein is addressed. The objective of this proposal is to combine the latest researchinto a single small, rugged highly accurate temperature transducer suitable for the severe environment in the augmenter. The use of piezoresistive technology and the MEMS fabrication procedures make possible the obtaining of highly accurate static anddynamic pressure data. It is anticipated that the transducer so designed and fabricated will have a natural frequency in excess of 100KHz while still of excellent static characteristics. Moreover, the transducer will be designed to resist shock andvibration in excess of 100g, and will provide output in a digital format. The developed transducer will be suitable for use on all aircraft engines using afterburners to address the debilitating combustion instabilities. The first use will be for enginedevelopment. The second use will be for when in-service problems arise. The third use will be for real-time diagnostic, detection and control.