Estimation of the Fluidelastic Instability Boundary for Steam-Generator Tubes Subjected to Two-Phase Flows
Bibliographic record
Abstract
The estimation of tube wear due to vibration-induced tube-support impacting remains an important problem for operating steam generators. For fluidelastic excitation this requires a realistic model for the excitation fluid forces. Recently the authors (Mureithi et al., 2008) have presented detailed force measurements in a rotated triangular tube bundle subjected to air-water two-phase flow. The data provides new potential to designers to estimate expected fluid dynamic loads for two-phase flow conditions. In particular, the data may be used for quantitative estimation of critical velocities for fluidelastic instability — the most important excitation mechanism for steam generator tube bundles. In the work reported here the fluid force field is employed along with the quasi-steady vibration stability model, adapted to two-phase flows, to model the two-phase flow problem and predict the critical instability velocity for a steam-generator U-tube subjected to non-uniform two-phase flow. The implication of the present model, with respect to improved estimation of tube wear is discussed in the paper.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 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".