Turbulence–chemistry interactions in non-premixed swirling flames
Bibliographic record
Abstract
Swirling flames with varying departures from blow-off have recently been studied using a simple, yet representative swirl burner. Extensive measurements of flow, stability and composition fields have already been made in turbulent non-premixed swirling flames covering a range of fuel mixtures and swirl numbers. The data, which are now made available on the World Wide Web, have revealed complex flame structures involving vortex breakdown leading to swirl-induced recirculation zones, flow instability, and the occurrence of localized extinction. These effects, which are also typical of what actually occurs in many practical combustors, are most likely inter-related rather than isolated phenomena. The nature of these interactions remains poorly understood. This paper brings together flow-field, stability and composition measurements with the aim of shedding more light on the interaction between complex fluid dynamics and finite-rate chemistry. A threshold for the occurrence of localized extinction is defined and examined with regard to rates of localized flow rotation, the occurrence of flow reversals and the velocity shear stresses. It is found that local extinction occurs in regions of high shear stress that do not necessarily overlap with the mean stoichiometric contours. The formation of an elongated recirculation (bluff-body stabilized) zone or a second, downstream region of flow recirculation is largely controlled by the swirl number and the ratio of momentum in the swirling annulus and central fuel jet.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".