Flow Structure of Lifted Swirling Jet Flames

摘要: Swirling combustion is widely applied in various applications such as gas turbines, utility boilers or waste incinerators. This article contributes to the ongoing research by providing experimental data that are gathered mixing zone of a lifted swirling premixed natural flame. The objective this paper fivefold: (1) introduce flame featuring low NOx emissions (2) provide major species distributions, temperature and streamlines flow pattern, (3) report on velocity bias probability density function (PDF) distributions present PDF sequences velocities medium scale flows, (4) make an assessment local small-scale turbulence layer (5) new for model verification development. PDFs corrected order compensate phenomenon, which typical randomly sampled LDA data. Sequences axial presented measure- ment locations interest selected look at characteristics internal external recirculation zones, onset reacting into detail. covered wide range revealed bimodality; even concept multi-modality suggested explored. Analysis showed sum two Gaussian can accurately envelop PDFs. reason broadband behavior be found combination precessing flapping motion structures, also generated instabilities As result, brush (large motion) (small-scale turbulence) flattens any high temperatures process. multi-scale subsequently used layer. idea capture both contributions flow-inherent fine grain (u � ) superposed slow large fluctuating structures. It uthat will continued classification regime diagram (e.g. Borghi diagram). Finally, bimodality character flows prediction large-scale structures may challenge LES researchers.