Self-Calibrating Dynamic Pressure Transducers for High-Temperature Instrumentation

Measurement of unsteady pressure at critical locations in gas turbine engines is highly desirable for validation of engine design, optimization of the operating envelope, and improvement of safety margins. Unfortunately, availability of sensors andinstrumentation that can be reliably operated in the engine environments is rather limited. Prime Photonics, Inc. proposes to collaborate with the Virginia Tech Photonics Laboratory to develop and demonstrate high-temperature dynamic pressure transducersfor instrumentation in gas turbine engines. The proposed sensors are based on the self-calibrated interferometric/intensity-based (SCIIB) sensor, a new sensor technology based on optical fibers, which for the first time successfully combines fiberinterferometry and intensity-based devices into a single sensor system. The resulting sensor possesses all the major advantages of both interferometry and intensity sensors, including small size, high resolution, high frequency response, high temperaturecapability, ultra-low cross-sensitivity to temperature, and self-calibrating absolute measurement. For this program, sensors will be designed and demonstrated using both glass fibers for temperatures up to 800¿C, and using single-crystal sapphirewaveguides for temperatures up to 1500¿C. An optoelectronic system to process the optical signals will be designed to achieve a bandwidth of 125 kHz. The small size will facilitate flush-mounting of the transducer.The proposed Phase I STTR program willdemonstrate the feasibility of high-temperature high-bandwidth pressure transducers using optical methods in a self-calibrating configuration. Such high-temperature pressure sensors are highly desirable in the gas turbine engine industry for designvalidation and real-time diagnosis. These applications require measurement of pressure at many key locations, such as compressors, combustors, and turbines, there the temperatures are too high to permit the use of commercially available semiconductorpresure sensors, which have a maximum operating temperature of 400 degrees C. Therefore, instumentation of gas turbine engines will form the initial target market for commercialization of the proposed technology. Additional markets in electrical powerproduction, automotive engines, and glass and metal manufacturing will be evaluated and pursued if the market size will support commercialization. During the Phase II program, which will bring the technology demonstrated in Phase I to a level wherecommercial products are viable, Prime Photonics will seek outside investment in order to put in place the corporate infrastructure necessary for product manufacture and marketing.