Fiber-coupled high-speed OH-PLIF imaging in turbulent flames
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A fiber-coupled, ultraviolet, planar laser-induced-fluorescence (UV-PLIF) system operating at 10-kHz repetition rate is developed and demonstrated for probing hydroxyl radicals (OH) in turbulent flames. A 283-nm, nanosecond-duration laser is used to excite the (1,0) band of the OH A-X system, and the subsequent fluorescence from the (0,0) and (1,1) bands are detected. The system is designed to transmit the required excitation pulse energy through a 6-m-long optical fiber to enable OH-PLIF measurements. Single-laser-shot PLIF images at 10 kHz are obtained for visualizing OH distribution in pulsating turbulent flames. It is experimentally demonstrated that by utilizing a long multimode fiber, a non-uniform input-beam profile can be transformed to a desired, nearly Gaussian beam profile for PLIF imaging. The current results show significant promise for extending fiber-coupled highspeed UV-PLIF diagnostics to harsh environments such as those associated with combustors and gas-turbine-engine test facilities. © 2012 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
author list (cited authors)
Hsu, P. S., Kulatilaka, W. D., Jiang, N., Kostka, S., Roy, S., Patnaik, A. K., & Gord, J. R.