PIV investigation of the flow features of double and single 45° up‐pumping pitched blade turbines in a square tank
Bibliographic record
Abstract
The non‐conventionally square stirred tank with up‐pumping impellers has been recently adopted in wastewater treatment processes due to its simplicity and high efficiency. In this paper, the time‐averaged flow fields in the square tank with both double and single 45° up‐pumping pitched blade turbines (PBTs) are investigated using particle image velocimetry (PIV). Flow field generated by double impellers are directly compared with the flow fields by single impeller. The flow number (FI), anisotropy, total kinetic energy, and energy dissipation rate are calculated to further investigate the flow features of the double impellers and single impeller. The results show that the high velocity region generated by a single impeller is about 0.4 T ( T is the length of square cross‐section of tank) in z direction. Flow number of the upper impeller is much larger than that of the lower impeller. In flow fields with a single impeller, the higher the impeller, the larger the flow number. The high flow anisotropy in terms of large scales occurs in the areas both above and beneath the impeller and near wall region. However, the high kinetic energy area corresponds to the high velocity region. Three numerical methods commonly used in the traditional cylindrical tank are employed to calculate . The maximum happens in areas near the impeller. Three methods give similar dissipation rate distributions but different values, which is the same as that in the cylindrical tank. It means that these methods could also be well used in square stirred tanks.
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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 | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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 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".