Theoretical Study of a Novel CO2 Supersonic Two-phase Expansion Refrigeration Cycle
Bibliographic record
Abstract
Natural refrigerants such as CO2 have become a research hotspot. Under high-pressure conditions, a large throttling loss becomes the primary reason for the low circulation efficiency of the CO2 refrigeration cycle. Therefore, reducing the throttling loss is an effective method to improve efficiency. This study proposes a supersonic two-phase expander with a Laval nozzle as the core component. A CO2 supersonic two-phase expansion refrigeration cycle model is established, and an ideal cycle thermodynamic analysis and simulation investigation are conducted. The results show that the inlet pressure and temperature of the supersonic two-phase expander and the outlet pressure of the cyclone separation section affect the cooling performance of the system. The coefficient of performance (COP) of the CO2 supersonic two-phase expansion refrigeration cycle is 6.69, which is 1.63 times that of the existing CO2 transcritical refrigeration cycle, with relatively optimal refrigeration performance. Additionally, the operating pressure of the system is considerably reduced. The loss of liquid-phase velocity during gas-liquid separation affects the refrigeration performance of the system. The COP of the system decreases from 9.56 to 6.01, and the relative Carnot efficiency decreases from 0.95 to 0.60; however, it still remains at a high level. The preliminary thermodynamic analysis and simulation show that the proposed CO2 supersonic two-phase expansion refrigeration cycle is feasible and exhibits good development prospects.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.016 | 0.020 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.003 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.004 | 0.002 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.026 | 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 teacher head, 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".