On the Use of Blades Stagger and Stacking in Turbine Stage Optimization
Bibliographic record
Abstract
The flow in modern turbines is highly three dimensional and fairly complex. This paper presents a practical and effective optimization approach to minimize 3D-related flow losses by re-staggering and re-stacking the blades. This approach is applied to the redesign of a low speed high subsonic single stage turbine, that was designed and tested in Hannover, Germany. The optimization is performed at the design point and the objective function is given by a weighted sum of individual objectives, namely stage efficiency and streamwise vorticity downstream of the rotor and stator, and is penalized with one constraint, namely the design mass flow rate. A Genetic Algorithm (GA) is coupled with a Response Surface Approximation (RSA) of the Artificial Neural Network (ANN) type. A relatively small data set of high fidelity 3D flow simulations that is obtained using Fluent, is used to train and test the ANN model. The variation of stagger angle and stacking are parametrically represented using a quadratic rational Bezier curve (QRBC). The QRBC parameters are directly related to the design variables, namely the rotor and stator lean & sweep angles, and their stagger distribution. Moreover, it results in eliminating infeasible shapes and in reducing the number of design variables to a minimum while providing a wide design space for the blade shape. This optimization approach results in an improvement of 1.74% to 1.91% in stage efficiency. This optimization approach is found to be helpful in understanding the physical implications of the design variables and in interpreting their effect on the stage performance.
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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 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| 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".