Conserved scalar measurements in turbulent diffusion flames by a Raman and Rayleigh ribbon imaging method

✍ Scribed by S.H. Stårner; R.W. Bilger; K.M. Lyons; J.H. Frank; M.B. Long

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 561 KB
• Volume: 99
• Category: Article
• ISSN: 0010-2180
• DOI: 10.1016/0010-2180(94)90140-6

✦ Synopsis

A new method to obtain images of conserved scalars in turbulent flames is presented and implemented with simultaneous Rayleigh and fuel Raman measurements in a methane/air jet diffusion flame by the use of a single dye laser and two intensified CCD cameras. The laser beam is focused to a line and retroreflected with a slight offset to form a thin ribbon, sufficient to measure gradients in two dimensions. A robust, iterative data reduction technique is used to derive statistics of temperature, fuel mass fraction, mixture fraction (f), and scalar dissipation (X). Results for a flame of Reynolds number 20,600 show that the lower moments, pdfs, and scatter plots of the computed quantities do not differ markedly from published results of point measurements in similar flames, strengthening confidence in this new approach. The computed components of X show behavior similar to that in nonreacting flows; there is some anisotropy, with the ratio of the radial to the axial component in the shear region around 2.0. The azimuthal component, measured by off-axis laser beam alignment, is roughly equal to the radial component. The correlation between f and X is small on the flame axis, but the correlation coefficient Rfx rises to around 0.4 near the edge, which is largely consistent with other recent results for cold jets and jet flames.