The Influence of Changes to Mixing on the Sooting and NOX Emission Characteristics of Unconfined Turbulent Jet Diffusion Flames

Abstract

<jats:title>Abstract</jats:title><jats:p>Results are presented from new measurements of vertically fired unconfined diffusion flames issuing from precessing jet nozzles and new calculations of existing data from simple jet flames. These results provide quantitative information about large‐scale mixing, NO<jats:sub>x</jats:sub> emissions and sooting tendencies of precessing jet flames. It is shown that a characteristic large eddy strain rate at the tip of a precessing jet flame is reduced by an order of magnitude when compared to that in simple jet flames. The reduction in large eddy strain rate correlates with an increased sooting tendency that is consistent with findings for simple jet flames presented elsewhere. The reduction in strain rate correlates with decreased NO<jats:sub>x</jats:sub> emissions and is found to be contrary to flamelet model predictions for simple jet flames.</jats:p>