Heat transfer and fluid dynamics of offset unsubmerged axial and tangential jets impinging on a confined heated rotating disk
Bibliographic record
Abstract
This study numerically investigates offset unsubmerged axial and tangential jets impingement on a confined heated rotating disk for electric motor cooling applications. The motor's rotor and stator are modeled as rotating and stationary solid regions, respectively. The multi-phase flow and heat transfer characteristics are analyzed over a range of rotational Reynolds numbers from 1 × 10 5 to 3.7 × 10 6 and jet Reynolds numbers ranging from 4.5 × 10 2 to 7.3 × 10 3 in a confined space. The jet nozzle diameter is 1.5 mm with the jet location fixed at an offset of 70 % of the disk radius. For axial and tangential jets, the ratio of jet impingement distance to nozzle diameter is held constant at 12 and 14.7, respectively. The Volume of Fluid method and a moving mesh rotation model are used to simulate the two-phase flow dynamics. The results show that axial jets achieve effective rotor cooling at a mid-range rotational Reynolds number of 2 × 10 6 and a jet Reynolds number of 7.3 × 10 3 but struggle to cool the stator due to limited oil distribution. Axial jet efficiency improves with higher jet Reynolds numbers; however, performance reduces at extreme rotational speeds, as oil contact with critical areas is reduced. Axial jets are thus most suitable for high rotor heat loads and oil flow rates, as their direct impingement enhances cooling effectiveness. In contrast, tangential jets rely heavily on an optimal velocity ratio between jet exit velocity and rotor speed to achieve efficient cooling. At rotational Reynolds number of 6.1 × 10 5 , tangential jets deliver superior heat transfer and temperature uniformity with a lower jet Reynolds number of 3.7 × 10 3 and an ideal velocity ratio of 1, which promotes oil-air mixing and helical impingement. Tangential jets also exhibit up to 23 % lower drag losses at rotational Reynolds number of 6.1 × 10 5 , and maintain lower pressure losses than axial jets, with an 15 % reduction at rotational Reynolds number of 3.7 × 10 6 due to better alignment with the rotating air. Overall, tangential jets are more efficient for lower flow rates and stator-focused cooling, while a mid-range rotational Reynolds number of 2 × 10 6 optimally balances oil distribution and cooling efficiency for both jet types.
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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".