Experimental Validation of Numerically Optimized Short Annular Diffusers
Bibliographic record
Abstract
Short annular diffusers with negative wall angles were evaluated numerically and experimentally with up to 40 deg inlet swirl at an inlet Reynolds number of Ret ≈ 1.4 × 105 and Mach number of Mt ≈ 0.16. The 80% experimental effectiveness of the 1.61 and 1.91 area ratio (AR) diffusers with 0–20 deg inlet swirl were on par with unswirled maximums reported in literature and computational fluid dynamics (CFD) predicted reasonable outlet axial velocity profiles and wall pressure distributions. The AR = 2.73 diffuser's effectiveness without swirl was 13% below the maximum for the given AR and larger discrepancies occurred in the CFD results due to the incorrect prediction of the recirculation zone strength. Preference was given to the realizable k–ε model on coarse grids with wall functions that predicted performance of all cases with at least 20 deg inlet swirl to within 20%.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".