Effect of Swirl on the Performance of a Gas Turbine Reversing Exhaust Duct
Bibliographic record
Abstract
Poor pressure recovery and flow control in gas turbine exhaust ducts can significantly reduce overall engine performance. For aircraft installations, a configuration that presents a challenging design is the single port tractor exhaust that is used where the turbine is facing the direction of travel. This duct consists of an annular to rectangular transition and a turn of approximately 160°. The combination of a diffusing duct with strong curvature produces a flow that has a non-uniform velocity profile throughout the duct, large areas of separation and strong vortices. These flow conditions lead to insufficient diffusion and large pressure losses, making the design of a low loss duct difficult. The problem of design is further complicated by the need for the duct to operate over a range of flow Mach number and swirl angles. An experimental study has been undertaken to identify the main flow structures that lead to poor performance in tractor exhausts and how the key geometric and flow parameters affect the flow. A half scale model of the exhaust duct has been tested using cold flow over a range of swirl conditions. Flow measurements include static wall pressures, and inlet and outlet velocity profiles. This paper presents experimental results showing the effects of swirl on a gas turbine single port tractor exhaust duct.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".