Dynamic pressure measurements using silicon carbide transducers

Pressure sensors capable of operating at higher temperatures have long been sought for testing of aircraft engines, since each improvement in sensor durability opens new areas of the engine to the straightforward measurement of rapidly varying pressures. A silicon carbide pressure sensor has been developed which can operate at 500/spl deg/C, a temperature at which the mechanical properties of silicon, the most commonly used pressure sensor material, are severely degraded. The prototype SiC pressure transducer was successfully tested on a gas turbine engine, thereby demonstrating its ability to survive the hostile engine environment. Testing in a shock tube showed the packaged sensor to have a natural frequency of 30 kHz, which is adequate for many dynamic pressure measurement applications. It is expected that the frequency response could be increased by a simple modification of the package to reduce the setback of the SiC die.

Introduction

Pressure sensors capable of operating at temperatures of and higher are urgently needed for applications such as compressor stall studies and the determination of blade passing forcing functions. A complete set of requirements has been developed by the Dynamic Pressure Measurements Subteam of the Propulsion Instrumentation Working Group (PIWG), a consortium of US engine manufacturers. ^[1] Pressure sensors capable of operating at are sought immediately, while, longer term, operation is desired. A natural frequency greater than 50 kHz is needed to satisfy all engine testing needs.