CFD elucidation of high-pressure subcooled boiling flow towards effects of variable refrigerant properties using OpenFOAM empirical closures
•The investigation of high-pressure subcooled boiling flow, employing OpenFOAM, the RPI boiling algorithm, and variable refrigerant properties, has yielded significant and insightful outcomes.•Higher inlet temperatures intensify evaporation, leading to increased void fraction, while R12′s declining...
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Veröffentlicht in: | Applications in engineering science 2024-09, Vol.19, p.100187, Article 100187 |
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Sprache: | eng |
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Zusammenfassung: | •The investigation of high-pressure subcooled boiling flow, employing OpenFOAM, the RPI boiling algorithm, and variable refrigerant properties, has yielded significant and insightful outcomes.•Higher inlet temperatures intensify evaporation, leading to increased void fraction, while R12′s declining boiling point facilitates more efficient bubble growth with elevation.•Exploring the intriguing relationship between elevation and saturation temperature near the heated surface reveals a gradual decrease, suggesting improved condensation efficiency.•The results emphasize the urgent requirement for further code developments, especially concerning RPI closures, to improve prediction accuracy and broaden the scope of subcooling boiling.
Boiling flow presents a significant concern, especially when a liquid surpasses its boiling point, potentially leading to catastrophic consequences. This research utilizes a two-phase code in the OpenFOAM software to investigate bubble formation during flow boiling. The well-established empirical models for calculating wall heat components were selected based on the operating conditions. The study incorporates experimental data from high-pressure boiling flow (10–30 bars) with variable properties of refrigerant R-12. The predictions reveal underpredictions in void fraction and liquid temperature compared to experimental observations. Significantly, the impact of the subcooling degree on void fraction behaviour is emphasized, and a potential underprediction of the evaporation portion is highlighted, particularly near the wall. Challenges in modelling bubble size distribution are evident through discrepancies in bubble diameter and velocity data, indicating the necessity for further advancements in the code. In summary, this numerical study provides valuable insights into the intricate dynamics of high-pressure subcooled boiling flow, especially when considering variable working fluid properties. Future efforts will focus on refining models for nucleation site density, bubble departure size, and lift-off frequency to enhance prediction accuracy. |
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ISSN: | 2666-4968 2666-4968 |
DOI: | 10.1016/j.apples.2024.100187 |