SIMULTANEOUS CH PLANAR LASER-INDUCED FLUORESCENCE AND PARTICLE IMAGING VELOCIMETRY IN TURBULENT NONPREMIXED FLAMES

We report the simultaneous measurement of the flamefront location, usi ng single-shot CH planar laser-induced fluorescence (PLIF), and the ve locity field, using two-color digital particle imaging velocimetry (PI V), in nonpremixed turbulent flames. To minimize the influence of part icle scattering on the CH PLIF images, we pump a CH B-X(0,0) transitio n at 390 nm and detect A-X fluorescence at 420-440 nm, employing Schot t glass filters to reject the strong particle scattering. The PIV imag es are recorded on a high-resolution (2036 x 3060 pixels) color CCD ca mera, and the velocities are derived from 64- or 128-pixel-square inte rrogation regions. We demonstrate this technique in a non-sooting, per manently blue nonpremixed turbulent jet flame (Re-jet = 18600). Here, PLIF images reveal a CH layer of thickness typically < 1 mm from flame base to tip. Furthermore, in these permanently blue flames, we observ e instantaneous flamefront strain rates - derived from the PIV data - in excess of +/-10(4) s(-1) without flame extinction.