An Evaluation of a Two-Phase Damping Model on Tube Bundles Subjected to Two-Phase Cross Flow
Bibliographic record
Abstract
The analytical model (Sim; 2007), to predict the two-phase damping ratio for upward cross-flow through horizontal tube bundles, has been evaluated. The damping model was formulated, based on Feenstra’s model (2000) for void fraction and various models (homogeneous, Levy, Martinelli-Nelson and Marchaterre) for two-phase friction multiplier. The analytical results of drag coefficient on a cylinder and two-phase Euler number were compared with the experimental results by Sim-Mureithi (2010). The factor, a relation between frictional pressure drop and the hydraulic drag coefficients, could be determined by considering experimental results. The two-phase damping ratios, given by the analytical model, were compared with existing experimental results. It was found that the model, based on Marchaterre’s model, is suitable for air-water mixture while the Martinelli-Nelson’s model for steam-water and Freon mixtures. The two-phase damping ratio is independent on pitch mass flux for air-water mixture, but it is more or less influenced by the mass flux for steam-water/Freon(134) mixtures. The two-phase damping ratios, given by the present model, agree well with experimental results for a sufficiently wide range of pitch mass ratio, quality and p/d ratios.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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".