Effects of fuel sulfur content and nvPM emissions on contrail formation: A CFD-microphysics study including the role of organic compounds
Bibliographic record
Abstract
Aviation-induced contrails impact the climate significantly by altering atmospheric properties at cruise altitudes. Understanding the formation and evolution of ice crystals in aircraft engine plumes is essential for improving contrails prediction and mitigating their climate effects. This study introduces an innovative CFD-microphysics coupling methodology to simulate ice crystal formation in the near field of a turbofan engine plume. A 2.5D axisymmetric Eulerian-Lagrangian framework was employed, integrating gas-phase chemistry (60 reactions with 22 reactive species) and a detailed microphysical model. The model accounts for soot surface activation, condensation of organic vapors and sulfur species (H 2 SO 4 and SO 3 ), as well as freezing and deposition processes. Results demonstrate that colder ambient temperatures (e.g., 212 K) enhance water supersaturation, accelerating ice crystal formation and growth, with soot-derived ice crystals reaching mean radii of up to 680 nm. Lower FSC increase the number of ice crystals due to the accompanying higher water supersaturation, while higher FSC promote larger ice crystals through enhanced condensation on soot particles. Organic compounds were shown to play a critical role in soot particle activation and growth, particularly under high FSC and lower temperature conditions, where they dominate the surface composition as compared to sulfur species. The soot emission index significantly influences the ice crystal number and size, with a soot emission index of 1.38 × 10 13 #/kg-fuel producing the largest soot-derived ice particles due to reduced competition for available moisture. Hydrates and volatile particles exhibit peak concentrations of 10 13 #/cm 3 under high FSC, reflecting the role of sulfuric acid in their growth. • A CFD-microphysics model predicts ice crystal formation in aircraft engine plumes. • Lower FSC increases ice crystal number, while higher FSC enhances ice crystal growth. • Organic compounds play a key role in soot activation and ice nucleation at cruise level. • Colder temperatures enhance water supersaturation, favoring faster ice crystal growth. • Soot emission index strongly influences the size and concentration of ice crystals.
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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".