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Published February 2004 | public
Journal Article

Scalar concentration measurements in liquid-phase flows with pulsed lasers

Abstract

he suitability of pulsed lasers for laser-induced-fluorescence (LIF) measurements of the local concentration of scalars in liquid-phase flows is investigated. Experiments were performed to measure the fluorescence intensity of aqueous solutions of rhodamine-6G chloride excited by a Q-switched, frequency-doubled, Nd:YAG laser. The fluorescence intensity is found to be linear with dye concentration, but not with illumination power density. The fluorescence intensity saturates at laser power densities easily exceeded by short-pulse-duration lasers. A procedure for calibrating and normalizing the raw image data is discussed which relies only on weak absorption and the linearity of fluorescence intensity with concentration. This procedure enables quantitative concentration measurement with pulsed-laser-induced fluorescence.

Additional Information

© 2003 Springer-Verlag. Received: 23 December 2002 / Accepted: 27 August 2003. We thank Daniel Gargas and Jimmy Fung who helped develop the instrumentation and data acquisition software used for this experiment. Additionally, we thank Manooch Koochesfahani for useful discussions. This work was supported by the Air Force Office of Scientific Research (F49620-98-1-0052 and F49620-01-0006) and the California Institute of Technology John K. Northrop Chair.

Additional details

Created:
August 19, 2023
Modified:
October 18, 2023