A MEMS-Based High Temperature Screech Sensor

The intense sound produced by screech can threaten mission objectives as these acoustic waveforms can be used by enemy detection systems to locate and track US military aircraft. Screech waveforms can also destroy sections of augmentor, which increasesdowntime, costs and maintenance. Active Combustion Control is applied in the augmentor to detect and attenuate these acoustic waves, as well as eliminate the components currently used to mitigate screech. Successful screech mitigation rests on thedevelopment of a high temperature sensor capable of withstanding the harsh engine environment for an extended period of time. Therefore, a robust, dependable and inexpensive sensor is required. Significant barriers to widespread screech sensorimplementation are cost and high temperature durability. Orbital Research is currently developing an uncooled, 450¿C pressure sensor for in-flight turbine engine control applications. This work is being conducted in close cooperation with Pratt &Whitney/UTC to ensure a relevant and integratable technology. This Phase I program will leverage from our extensive experience developing high temperature sensors to demonstrate the feasibility of a screech sensor. This Phase I program focuses on sensorfabrication, extended high temperature life testing and packaging design concepts to be implemented in Phase II. The technologies developed in this program have an established pathway to commercialization. The proposed sensor is an enabling technologyfor many diverse control applications because of its ability to measure pressure with high sensitivity in high temperature environments. This technology also has relevance in a wide variety of civilian and military applications such as diesel engines fortrucks and buses, geothermal and oil drilling applications, and industrial applications.