A Combined Experimental and Numerical Study of Laminar and Turbulent Non-piloted Oxy-fuel Jet Flames Using a Direct Comparison of the Rayleigh Signal

Comparative flame structure investigation of normal and inverse turbulent non-premixed oxy-fuel flames using experimentally recorded and numerically predicted Rayleigh and OH-PLIF signals

“…The burner used in this study was identical to [14], consisting of two co-flows of 95.5 mm (oxidizer/fuel co-flow) and 211.56 mm (shield co-flow) diameter, surrounding a 5 mm inner diameter nozzle of 0.5 mm wall thickness and over 100 diameters long to achieve a fully developed flow. The co-flow gases were homogenized and flow-straightened.…”

“…Finally, a composition of fuel: 17.5% CH 4 , 40% CO 2 , 42.5% H 2 and oxidizer: 68% O 2 , 32% CO 2 (by volume) was used after considering flame stability as well. For more details see [14]. In the NDF, fuel flowed through the nozzle, while oxidizer was supplied to the co-flow.…”

“…The numerical approach is only briefly outlined in the following, details can be found in [14,21]. The flamelet/progress variable (FPV) approach [22] is combined with the LES.…”

“…These errors can be avoided by computing the signals directly from the simulations, c.f. [13,14] for more details. Further, the Rayleigh ratio evaluated across the field of view and the OH-LIF signal for the flame front serve as good flame structure indicators.…”

“…Further, the Rayleigh ratio evaluated across the field of view and the OH-LIF signal for the flame front serve as good flame structure indicators. The Rayleigh ratio was shown to be sensitive to minor (species) changes in addition to the temperature [14]. The OH-LIF ratio also depends on the temperature and concentration of the main species.…”