Fluidic Injection Flow Control for High Pressure Turbine Area Modulation - A Computational Fluid Dynamics Investigation
Bibliographic record
Abstract
High-pressure turbine flow path area control has lo ng been sought after to provide highly desirable cycle benefits for gas tur bine engines. This is no less true today, if not potentially more desirable, when cons idering the multi-mission operational expectations from future generations of gas turbine engines. The use of active flow control presents a potentially new appr oach to an old problem and this paper presents the findings resulting from the VARIANT (VARIable Area Nozzle Turbine) study. Lockheed Martin Aeronautics Company utilized Computational Fluid Dynamics (CFD) to simulate a high pressure turbine stator with applied fluidic injection as a means to modulate the effect ive flow path area by a target of 50%, as evaluated via a typical discharge coefficie nt. During the course of the computational investigation, a preferred injection location for maximum area reduction (throttling) potential was identified on the suction side (SS) of the airfoil at the gauge point, independent of the simulated in jector properties. Stator exit swirl angle was minimally impacted and was consistently varied on the order of one to two degrees. Fluidic injection oriented upstream toward the incoming flow direction on the SS airfoil surface exhibited super ior throttling characteristics over pressure side or inner/outer diameter endwall injec tion with a similar orientation when evaluated purely on a area reduction performance-to-input “cost” basis. However, upstream-oriented SS airfoil injection als o exhibits severe and potentially prohibitive stagnation pressure loss characteristic s of approximately 20% for large gas path area reductions. Pressure side injection w as not as effective/efficient as SS injection but offered greatly reduced loss characte ristics by approximately a factor of two at moderate area reductions of approximately 20% of the nominal flow path area. The first phase of the effort concluded a hyb rid fluidic-mechanical approach may be best suited for gas path area reductions tar geting 50%. The second phase of the effort is investigating radical, novel approach es to HPT stator area control.
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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 | 0.000 | 0.001 |
| 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 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".