A Scaling Study of NO Formation in Turbulent Diffusion Flames of Hydrogen Burning in Air

Abstract
Experimental composition maps have been obtained of four H2-air turbulent diffusion flames of varying diameter but constant Reynolds number. Nitric oxide levels were found to scale with a characteristic “jet time,” modified to include the effects of buoyancy on flame shape. A comparison is made between present measurements, those of Kent and Bilger (1972), and a simple model of NO formation. The results suggest that the rate of NO formation is not predictable on the basis of fluctuating adiabatic equilibrium kinetics but requires consideration of turbulent combustion in detail and possibly the effects of excess radical concentrations.