Blowoff Dynamics of Interacting Swirl Premixed Flames
Bibliographic record
Abstract
View Video Presentation: https://doi.org/10.2514/6.2023-2179.vid In this paper, we present experimental results that provide insights into the flow-combustion dynamics leading to flame blowoff inside a model gas turbine combustor housing three interacting swirl premixed flames. In particular, we focus on the mechanism of quasi-periodic extinction reignition phenomena and the final blowoff event i.e. complete flame extinction. The studies were performed inside a multi-swirler combustor which comprises of three swirling premixed flames arranged in an inline configuration. The dynamics of the system close to the blowoff condition was characterized using simultaneous pressure and multi-kHz OH∗ chemiluminescence measurements. Stereoscopic Particle Image Velocimetry (sPIV) and OH-Planar Laser Induced Fluorescence (OH-PLIF) were used to probe the flow-flame interactions. Chemiluminescence and pressure measurements reveal that there exists low frequency, large amplitude oscillations due to the large-scale extinction and reignition events occurring inside the combustor. Further analysis based on the high-speed OH∗ imaging and sPIV-PLIF measurements reveal that there exist two possible routes to the reignition, which we call as Type 1 and Type 2 reignition processes, respectively. Type 1 reignition occurs when the flame can propagate from a reacting swirling jet to its extinguished neighbors across the regions where the swirling jets interact. However, even when all the swirling jets are individually extinguished, a detached and roving flame kernel can still swirl back into the swirler recirculation zone to cause a quasi-explosive reignition event. This is identified as Type 2 reignition. The detailed mechanisms of both types of reignition events are elucidated in the paper.
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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 | 0.001 | 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) | 0.003 | 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".