Flame-vortex interactions in a jet diffusion flame are studied in a controlled experiment. The vortices are periodically generated in a methane jet diffusion flame at the frequency of 30 Hz. Phase-locked reactive-Mie-scattering technique is used to visualize the interactions between the vortices and the flame. The second harmonic output (532 nm) of a pulsed Nd:YAG laser is expanded to a thin laser sheet vertically across the centerline of the jet. The scattering particles, TiO2, are formed as a result of the reaction of H2O and TiCl4 vapor added to the fuel. The large vertical structure containing fuel pushes the flame surface outward in the radial direction. When the flame is stretched, the local flame extinction occurs as is evident by the disappearance of the blue flame.

References:

1. K.Y. Hsu, L.D. Chen, V.R. Katta, L.P. Goss, and W.M. Roquemore, "Experimental and numerical investigations of the vortex-flame interactions in a driven jet diffusion flame," 31st Aerospace Meeting and Exhibit, AIAA Paper No. 93-0455, 1933.

2. L.D. Chen and W.M. Roquemore, "Visualization of jet flames," Combustion and Flame, 66, 81 (1986).

*University of Iowa

+Air Force Research Laboratory).