Performance of a transcritical CO <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si59.svg" display="inline" id="d1e973"> <mml:msub> <mml:mrow/> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msub> </mml:math> vortex tube: A first experimental campaign
Bibliographic record
Abstract
An experimental setup is designed, constructed and operated to test for the first time a vortex tube in a closed CO 2 transcritical cycle. The objective is to study the operation of the vortex tube within a range that was not studied before. This will pave the road towards the aim of integrating this device in a transcritical CO 2 heat pump to raise its efficiency. However, to achieve this aim, a proper investigation is started in this article to analyze the feasibility of the vortex tube operation in such regime and find methodologies of improvement. The test bench system includes compressor, heat exchanger, expansion valve, vortex tube, back-pressure regulators and evaporating electric heaters. Different parameters are varied to mainly study their effect on temperature separation and hot and cold exit temperatures of the vortex tube. These parameters include inlet temperature and pressure, mass flowrate, cold mass fraction and cold exit pressure. It is shown that under the conditions studied, the temperature (energy) separation has significantly deteriorated mainly due to the operation under non-ideal gas states and operating near the saturation region of CO 2 . The maximum temperature separation reached is 1.18 ° C . This temperature separation is not enough to provide the needed benefit to integrate the vortex tube in a heat pump operating under such conditions. However, several improvements to the system are suggested that can suit these transcritical operating conditions. These improvements will help in understanding the reasons behind the deterioration and might improve the performance of the vortex tube. • First experimental measurements on transcritical CO 2 vortex tube are performed. • Influences of flowrate, inlet conditions, cold mass fraction and cold exit pressure are quantified. • The maximum temperature separation reached is 1.18 ° C . • Suggestions are proposed to improve the temperature separation.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.004 | 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".