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Abstract
Abstract– Measurements of stabilization heights in lifted turbulent methane-air jet diffusion flames are performed in order to test a theory on local quenching of dilfusion flamelets. The global residence time (d/u0 the nozzle diameter, u0, the nozzle exit velocity) is scaled with Zq the instantaneous scalar dissipation rate at quenching. This quantity had been identified before to be charncteristic for the extinction of diffusion flamelets. Values for Zg, are deduced from measurements of laminar diffusion flames in a counter flow geometry. The scaling is performed for constant values of Zq the conserved scalar variable at sioichiometric conditions. Both the fuel and the air stream are diluted to obtain constant values of Zq. Scaling with Zq makes the curves for different residence times collapse into one curve with however, considerable experimental scatter. From this is concluded that Zq, is the essential kinetic parameter describing quenching effects in turbulent diffusion flames.