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

ABSTRACT: Based on the success of the Phase-I effort, the objective of the proposed Phase-II research effort will be to develop and deliver a system of fiber-coupled, high-speed UV-LIF- and PLIF-based sensor. During this effort we will 1) quantitatively measure spatially resolved 2D temperature in laboratory flames, 2) develop technology for simultaneously measuring concentrations of multiple species (such as OH, CH2O, C2H2, and C6H6) using fiber-based UV-LIF and PLIF, 3) further optimize the sensor components to make the system test-cell ready, and 4) demonstrate the capability of the fiber LIF and PLIF technology by making spatially resolved measurements at a rate 10 kHz or more in real combustors. Phase-II development will primarily involve integrating the huge knowledge-base acquired during Phase I on optimal UV fibers and laser parameters and also on OH- and NO-PLIF measurements in laboratory flames into a single unit of a sensor system. The ultimate goal of this effort will be to make a transition to the development of a test-cell-ready sensor with quantitative temperature- and concentration-measurement capability. Finally, we will demonstrate fiber-coupled, high-speed OH-PLIF measurements at 10 kHz in an atmospheric-pressure augmentor test rig and a high-pressure gas-turbine combustor test facility at WPAFB. BENEFIT: Phase-II development of a fiber-based high-speed UV LIF/PLIF is expected to result in a commercially viable system that permits LIF diagnostics of multiple species that was never before possible in harsh reacting flow applications. The whole system would probably limit sales to major combustion and fuels research facilities. However, the UV laser is the most expensive component, and it is not unusual to find such lasers in combustion research facilities that use LIF diagnostics. Therefore, a lower-cost option with significantly higher sales potential exists. Specifically, the UV-fiber-based pitch and catch module for high-speed LIF/PLIF, which consists of the delivery, collection, and detection hardware and the software needed for the measurements and analysis. This significantly expands the market to include university laboratories in the aircraft and automotive combustion and fuels domains.