Engine Acoustic/Screech Sensor

High performance military gas turbine engines are often equipped with augmenters also known as afterburners, to provide increased levels of thrust for relatively short periods of time. The level of thrust desired is determined by the requirement 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 the onset of the debilitating combustion instabilities of screech and rumble. The instrumentation development proposed herein is addressed to avoid these instabilities. The objective of this proposal is to combine the latest research and the successful results of Phase I into a single small, rugged, highly accurate high temperature pressure transducer suitable for the severe environment in the augmenter. The use of piezoresistive technology and the MEM fabrication procedures make possible the obtaining of highly accurate static and dynamic pressure data. It is anticipated that this transducer will have a natural frequency in excess of 100KHz and excellent static characteristics. Moreover, the transducer will be designed to resist shock and vibration in excess of 100g, and will provide output in a digital format.