Model for Choking of Subcooled Flashing Flow Through a Steam Generator Tube Crack
Bibliographic record
Abstract
Recently there is some database available on choking flow through cracks relevant to steam generator (SG) tubes to model the critical flow. A one dimensional mechanistic model was developed to model two-phase choking flow through slits from conservation principles. The model takes into account channel entrance loss as well as frictional pressure drop for single-phase subcooled liquid. Flashing criteria are defined and temperature and pressure of the fluid are assumed to follow the saturation curve. The two-phase mixture was treated as a quasi-fluid with mixture properties and both homogenous equilibrium (HE) and homogeneous non-equilibrium models were considered. The models were compared with the choking flow rates for various experimental conditions for subcooled flashing flow through narrow slits with L/D varying from small values ( 5) to large values (100). Results are presented on the effects of thermal non-equilibrium on the choking flow for small L/D channels. A comparison of model results to experimental data shows that the HE based models grossly under predict choking flow rates in such geometries. As subcooling increases, and channel length decreases the non-equilibrium effects play a greater role in the choking phenomenon, therefore the difference in model predictions and experimental results increases for HE case.
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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) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".