Fiber-Coupled Pulsed and High-Intensity Ultraviolet Optical Measurements for Propulsion Systems

ABSTRACT: Augmentor designs are rapidly evolving as goals of high performance, static and dynamic stability, and low emissions are pursued. To understand the details of the combustion in these and other devices, one generally requires spatially resolved, continuous high-repetition-rate (Y 20 kHz) monitoring of species concentrations and temperature. Optical access must be made using fibers through high-temperature walls that are subject to fouling. Many diagnostics that perform well in laboratory flames experience challenges in these situations, including traditional laser-induced-fluorescence (LIF) techniques. Current state-of-the-art laser-based measurement technologies are not amenable to fiber-coupled measurements in the ultraviolet regime and are incapable of providing quantitative, continuous engineering information with the temporal resolution required to address the instabilities associated with combustors or afterburners. We propose an innovative fiber-coupled sensor based on hyperspectral UV sources to provide LIF-based temperature and OH concentration in reacting flows at Y 20 kHz. The sensor system will also be able to monitor other species including NO, CH2O, and possibly C6H6 with straightforward modifications. The hyperspectral ultraviolet sensor to be developed will be rack mounted with required accessories accompanied by the state-of-art ultra-low-solarization fibers that can be coupled to the test article. BENEFIT: A hyperspectral UV fiber-based sensor would be of great value to scientists and engineers for monitoring a wide variety of chemical species remotely. The detection of illegal drugs, chemical warfare agents, and chemical pollution for both airborne and water-bound substances could be monitored with such a system. Rapid analysis of chemical signatures could be useful for the Federal Law Enforcement Community (DEA and FBI), the Environmental Protection Agency, the Department of Homeland Security, and the Department of Defense. A hyperspectral UV source would allow combustion engineers to monitor combustion efficiency and minimize the production of pollution in combustion processes with a high temporal resolution. Higher efficiency translates into lower fuel costs, while lower pollution translates into reduced green-house emission, which resulting in a cleaner and safer environment for everyone. The results of the Phase-I Market Need Assessment are detailed below.