Numerical analysis of diameter influence on droplet fluorescence.
Laser-induced fluorescence (LIF) is used in planar droplet sizing, assuming that the signal integrated over the droplet is proportional to its volume. Nevertheless, this assumption is rigorously valid in nonabsorbing mixtures. We performed an examination of the LIF signal with a fluorescence model, based on the Lorenz-Mie theory and on ray-tracing methods, for n-heptane droplets seeded by 3-pentanone. A parametrical study quantifies the bias caused not only by the absorption of the laser, but also by shadow zones in the droplets, which do not contribute to the fluorescence signal. Moreover, the effect of the first- and higher-order internal reflections is examined. The results of this study have immediately implications for the design of measurement techniques.
Frackowiak
Bruno
B
Technische Universität Darmstadt-Fachbereich Strömungslehre und Aerodynamik (SLA),Petersenstrasse 30, D-64287 Darmstadt, Germany. Bruno.Frackowiak@sla.tu-darmstadt.de
Tropea
Cameron
C