Inlet Unstart Detector

ABSTRACT: Southwest Sciences proposes the development of an inlet unstart detector based on the measurement of flow velocity at very high bandwidth using lower power electronics and simpler analyses within a compact footprint. Early detection of thermal choking and engine unstart in the isolator section is necessary for trimming fuel flow rates into the combustor to prevent loss of thrust. The proposed detector is based on wavelength modulation spectroscopy (WMS) of chemical species absorption lines and will overcome many of the limitations of these other methods such as particle velocimetry, shadowgraphy, Schlieren imaging, pressure and temperature probes to provide high-sensitivity, fast measurements that are essential in noisy high-speed flows as encountered by hypersonic air-breathing vehicles. This sensor will be compact, non-intrusive, flight capable, high-precision, high-speed and self-calibrating. It will be suitable for monitoring high-speed flows along the propulsion flow-path of an air-breathing engine. This sensor will monitor the propulsion system performance characteristics for in-flight, real-time modifications. This information will safely expand the flight envelope of aerospace vehicles. The sensor may be utilized for flight regimes ranging from subsonic to hypersonic. Our goal is to design an in-flight sensor that is applicable to both piloted and unmanned hypersonic air-breathing flight vehicles. BENEFIT: This project will be of great benefit to the Federal Government, especially the Air Force and NASA; providing an important diagnostic and control instrument for advanced aircraft engines. In collaboration with military aircraft engine and instrumentation manufacturers, this high-speed inlet unstart detector would be developed into a commercial product combining modest cost with high performance and reliability for in-flight diagnostic use and as feedback for engine performance control. For the primary function of this work, we envision three major customers. NASA and DOD play a major role in the study and development of advanced and new engines for aircraft and space vehicles. Our sensor will be an important tool for improving the design of these engines and in understanding the complex properties in combustion flow. Within the commercial sector, jet engine manufacturers would find this sensor useful for product development and quality assurance. Beyond the aerospace community, high-speed sensors may also have use in a wide variety of fields. Biomedical breath analysis requires high sensitivity and new research indicates that the ability to distinguish the time evolution of a species within a single breath can be critical in identifying specific conditions or diseases. Other applications may exist in airborne environments measurements, and for feedback and control in industrial processes and power generation.