Characterization of Flow Structures in a Diesel Injector for Different Needle Lifts and a Fluctuating Injection Pressure
Bibliographic record
Abstract
This paper aims at analyzing the needle lift's influence on the internal flow of single-hole diesel injector to identify flow structures. A numerical Reynolds-Averaged Navier–Stokes (RANS) model of a single-hole diesel injector was developed and validated to study the flow's dynamic for different needle's lifts and subjected to realistic injection pressure. The main findings are: (1) under steady injection pressure, flow coefficients reached a steady-state value and maximum injected fuel mass flow rate is reached at intermediate needle's lifts. (2) The sac volume is the area with several vortex structures due to the throttling between the needle body and the injector body. (3) The frequency of the fluctuating injection pressure can excite the initial jet entering the sac volume similarly to the Coanda effect. Finally, using a proper orthogonal decomposition (POD) allowed extracting coherent structures within the sac volume and putting in evidence a reorganization of the flow.
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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 | 0.000 |
| 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) | 0.001 | 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".