Fiber-optic Pressure Sensor For Time-of-flight Measurements In A Shock Wave

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2010-11-01

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Aerospace Engineering

Abstract

Fiber-optic sensors are widely employed to detect pressures and temperatures precisely. In particular, MEMS-based ber-optic sensors are immune to electromagnetic interference but may have limitations at high temperatures as encountered in combustors. To ensure high-temperature survivability, such sensors may be bondedanodically. This project explains the development of a ber-optic pressure sensor utilizing intensity based principle whereby a fused silica optical window was glued to the tungsten carbide enclosure. The development was estimated to determine high pressures of up to at least 3.5 MPa (507 psi). The sensor is designed to capture the pressure pulse and the time-of-flight (TOF) of a propagating detonation wave for implementation shock tubes. Time-of- flight is critically important in detonation studies as it relates directly to the detonation wave velocity. Generally, the TOF is obtained by discrete sensors separated by a distance of at least a few cm. Thus, the propagation velocity, is strictly the average over that distance, thereby introducing a certain uncertainty. In order to obtain a point measurement, the separation distance between the sensors should be kept as short as possible. Advances in MEMS and electro-optics have made it possibleto devise such an integrated TOF sensor together with high-speed data acquisition.

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