Measurement of Natural Circulation Two-Phase Flow by Hybrid Doppler Contrapropagating and Pulse Echo Ultrasonic Techniques
Bibliographic record
Abstract
In this work, a hybrid ultrasonic technique for diagnostic natural circulation gas-liquid two-phase flow is experimentally investigated. The method is applied on a two-phase natural circulation loop using a contrapropagating transmission flow rate measurement technique in the single phase section and a Doppler velocity measurement and single transducer pulse echo technique in the two-phase region. The two-phase natural circulation loop used in this work consists of a two-phase vertical section where the liquid has an induced flow rate by an air-lift pumping technique. Gas is injected into the lower region of the two-phase test section, and rises to a separation tank causing the liquid to circulate naturally about the loop. The liquid slug velocities, the air flow rates, and the liquid flow rates are measured, respectively, in the two-phase and single-phase section of the loop as well as two-phase interfaces and time averaged void fraction. A comparison with available results from other investigators is given, in terms of liquid superficial velocity and bubble velocity for two flow patterns generated in the loop; bubbly flow and slug flow. The results show that the present hybrid system can be used to identify not only flow regime but also key two-phase flow parameters for natural circulation conditions.
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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) | 0.000 | 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 | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".