The Interdisciplinary Consulting Corporation (IC2) proposes to develop an instrumentation-grade, robust, high-temperature, low-profile, fiber-optic pressure sensor for model-scale ground test and full-scale static engine and in-flight test applications. This work is aimed at addressing the aerospace industry’s need for technically feasible and economically viable high-temperature, aft-engine measurement capabilities that enable required noise diagnostic capabilities including characterization of fundamental jet noise sources and structures, and robust measurement capability for making combustion noise measurements. The proposed fiber-optic pressure sensor consists of a microfabricated silicon optical pressure sensor with an optical fiber exiting the side of the device. Placed within a low-profile housing, this design represents a robust, surface-mounted, miniature pressure sensor that possesses superior sensor survivability for aft-engine (high-temperature) measurements and immunity to electromagnetic interference (EMI). The flow disturbance for this sensor is minimal because of the surface-mount design and small footprint. Use of fiber optics facilitate the remote placement of all sensor optoelectronics and this extends the upper temperature limit of the measurement capability. A custom-built, ruggedized optoelectronics system that leverages a novel dual-wavelength common-mode signal rejection method for amplitude modulated optical sensors, will be paired with the sensor to provide an output that is suitable for voltage input to dynamic data acquisition systems that are typically used in the test and measurement world for acoustic and dynamic pressure sensor measurements.
The proposed high-temperature, low-profile fiber-optic pressure sensor system has the potential to be transportable across multiple NASA facilities where model-scale and full-scale engine tests occur. The Nozzle Acoustic Test Rig (NATR) and the new DGEN Aeropropulsion Research Turbofan (DART) at NASA Glenn are excellent candidates for the sensor technology. In addition, NASA’s Commercial Supersonic Technology Project will need research testing of exotic engine designs.
Commercial turbofan engine manufacturers have long desired modal array measurements within the primary nozzle to reduce cost and increase information return compared with far-field static engine testing. External customers for the technology include government agencies such as the Air Force and Navy as well as commercial engine manufacturers such as GE, Pratt & Whitney and Rolls Royce.