Structure of Laminar Methane-Oxygen Diffusion Flames at High Pressures
Bibliographic record
Abstract
Characteristics of laminar methane-oxygen diffusion flames were studied at sub-critical and supercritical pressures up to 100 atmospheres. The influence of pressure on soot formation and on the structure of the temperature field was investigated over the pressure range of 10 to 90 atmospheres in a high pressure combustion chamber using a non-intrusive, line-of-sight spectral soot emission diagnostic technique. Two distinct zones characterized the appearance of a methane and oxygen diffusion flame: an inner luminous zone similar to the methane-air diffusion flames and an outer blue flame zone. The flame height, marked by the visible soot radiation emission, was reduced by over 50% over the pressure range of 10 to 100 atmospheres at the higher methane flow rate. At the lower methane flow rate, above 10 atmospheres, the luminous flame zone started collapsing and solid carbonaceous structures appeared on the fuel nozzle rim. Further increase in pressure resulted in shrinking of the luminous zone into mostly solid material and only the blue flame zone was visible. For the higher methane flow rate, between 10 and 40 atmospheres, the soot levels increased with increasing pressure; however, above 40 atmospheres the soot concentrations reached a plateau and then began decreasing with increasing pressure.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| 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".