Droplet combustion in a turbulent, elevated-pressure environment
Bibliographic record
Abstract
Despite the enduring popularity of single-droplet vaporization studies, few researchers have systematically examined the influence of turbulence on droplet burning dynamics. Existing investigations have looked exclusively at large droplets or porous spheres while utilizing thermally conductive suspension schemes. To further understand how turbulence affects normal-gravity droplet burning, single droplets of heptane were suspended at the center of a fan-stirred chamber on a horizontal microfiber, rapidly ignited, and burned to completion. The experimental conditions were parametrically varied across 112 unique combinations of initial diameter, ambient pressure, turbulence intensity, and background oxygen content. The primary quantity of interest is the burning rate, and how individual and average burning rates are affected by the various parameters. To help interpret the results, the radiant soot emission was recorded alongside the temporal evolution of the droplet diameter. The burning rates of droplets in the super-millimeter range are up to 32% lower than those collected in otherwise identical conditions but with large fiber suspenders. Turbulence has little effect on the droplet burning rate until the ambient pressure is elevated. In these cases, turbulence initially augments the burning rate until a critical turbulence level is reached, after which the burning rate quickly falls. The reduction in the burning rate corresponds to the reoccurring appearance of temporary luminous extinction (TLE), where the hot incandescent region that normally surrounds the droplet disappears for a short period, thus tempering the overall burning rate. The cause of, and behavior during, TLE is contrasted with similar phenomena from the literature. Smaller, sub-millimeter droplets behave in largely the same manner, but with lower peak burning rates and greater run-to-run variation. Modest increases to the background oxygen content, from the baseline 21% up to 25% and 30%, delay the onset of TLE to higher turbulence levels. At the highest pressures, turbulent droplet burning rates of the oxygen-enriched cases can double their counterparts in ambient oxygen levels—a synergistic effect with turbulence playing a critical role.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 teacher head, 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".