Air Pocket Removal during Siphon Priming
Bibliographic record
Abstract
Siphon frequently is employed in pump stations as a pump outlet with a convenient flow cutoff mode for pump shutdown, and it usually works with axial-flow pumps with a large discharge and low head. After the pump starts, the initial air pocket in the siphon should be removed quickly from the siphon to generate a primed siphon flow, a process called priming. In this study, experiments were conducted to investigate the characteristics of air pocket removal during priming, in which two stages can be defined: air-compression and air-entrainment stages. During the air-compression stage, the air is compressed by the pumped water, and the increased air pressure can break the downstream water seal and expel some air out of the siphon. During the air-entrainment stage, the air is removed mainly in the form of bubbly flow. The air-entrainment stage can be divided further into two states: at a small water discharge, the priming process stays in State 1, in which the air pocket always remained in the siphon hump; and at a large discharge, the residual air pocket can be entirely swept out of the siphon in State 2, finally generating the primed siphon flow. The air-compression stage accounts for less than 5% of the priming time but discharges 20%–60% of the initial air. For the bubbly flow during the air-entrainment stage, the bubble diameters follow a log-normal distribution with the median of about 2.3 mm. The critical flow rate for generating primed siphon flow was predicted based on the bubble clearing velocity and force and on the motion analysis of the bubble, which can be a rough value for the calculation of the critical flow rate. The prediction indicates that the critical flow rate should increase with the descending angle and cross-section area of siphon.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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 teacher head, 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".