Measurements of Oxides of Nitrogen Emissions from Turbulent Propane Jet Diffusion Flames

Abstract

Measurements of global emission indices for NO and NO,were made in unconfined,vertical,propane jet diffusion flames. Initial fuel jet velocities were varied to provide a range of jet Reynolds numbers from 10000 to 60000. The measurements showed that scaling of NO, emission indices with velocity changes as the flame character changes from transitional-turbulent (Re ≈ 10000) to fully turbulent (Re > 20000). At the lower Re condition. the observed scaling approaches that reported in the literature for similar conditions. Arguments are presented to show that radiation losses from the flames may account for the observed scaling. Significant amounts ofN02 were found in the flame plumes. The variation of NO2/NOx, ratios with jet velocity and with radial position was consistent with the hypothesis that NO2is formed in the cooler post-flame regions. in agreement with the findings of others for CO and CO/H2 fueled diffusion flames.