Flow patterns and pressure gradients of viscous oil–water core–annular flow in a vertical upward pipe
Bibliographic record
Abstract
Abstract Using a vertical upward pipe and annular flow generator, the flow pattern, pressure gradient, and drag reduction efficiency of viscous oil–water flow were investigated (superficial oil velocity u o = 0.09 ~ 0.88 m/s, superficial water velocity u w = 0.12 ~ 0.95 m/s) with #500 white oil (20°C, μ o = 1184.7 mPa · s, ρ o = 899.5 kg/m 3 ) and water. Five flow patterns were observed: oil‐in‐water dispersion flow (Do/w), bubble flow (Bo), slug flow (SLo), semi‐annular flow (Semi‐Anw), and annular flow (Anw). Considering the oil contamination on the pipe wall, the friction factor of the Rodriguez model was corrected by introducing the Lockhart–Martinelli parameter X . The pressure reduction factor RF ranged from 10 ~ 120. Water annular flow can increase the viscous oil flow rate by 7 times, and the pressure gradient is reduced to 1/7 that of pure oil.
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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".