Experiment on Heat Transfer Enhancement for a Double Pipe Heat Exchanger with Air Injection of Perforated Turbulator
Bibliographic record
Abstract
In this study, an attempt is made to evaluate the performance of a double pipe heat exchanger (DPHE) through an experiment. The outside surface of the inner pipe of the DPHE is surrounded with perforated helical tube, where the perforations allow air to enter the annulus. The air injection and the turbulator itself are expected to increase the number of vortices in the boundary layer of the inner pipe (annulus side) and expand the heat transfer regions. Due to the bouncy effect, the small air bubbles within the cold water promote flow eddies and hence increase the thermal performance. The Reynolds number based on the hydraulic diameter of the annulus is ranged from 5,000 to 17,000. The findings demonstrate that for a flow affected by an air injector, performance varies with Reynolds number. Both the Nusselt number and efficiency increase percentages are approximately 27 for each. However, the friction factor raises to 43% compared to the plain case, which only increases the performance evaluation criteria (PEC) by 8%.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 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".