Performance enhancement and optimization for rod‐baffle heat exchangers with twisted oval tubes
Bibliographic record
Abstract
Abstract Twisted oval tubes were proposed to be installed in rod‐baffle heat exchangers (RBHXs) to enhance heat transfer performance. A comparison between RBHXs with twisted oval tubes and those with circular tubes is performed. The results show that the heat transfer coefficient ( h ) per unit pressure drop (Δ p ) of RBHXs with twisted oval tubes is larger than 36.01%~100.24% compared with that of circular tubes when Reynolds numbers are 4577~22 889, and heat transfer enhancement is more obvious under lower inlet velocity. Then the structural parameters of RBHXs with twisted oval tubes are optimized using the response surface model and genetic algorithms. The results show that the h decreases first and then remains constant with the increase of the twisted pitch length, and decreases first and then rises again with the increase of the ratio of long axis to short axis. The Δ p almost keeps constant with increasing twisted pitch length and decreases by 36.67% with the increase in the ratio of long axis to short axis. The comprehensive performance index h /Δ p of the RBHXs with twisted oval tubes is enhanced by an average of 26.42% compared with that of original structure. The research results have a good guideline for heat transfer enhancement and the structural design of RBHXs.
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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".