Transition Criterion of Bubbly-slug Flow Pattern in Rectangular Narrow Channel
In the two-phase flow system, the flow pattern affects the frictional resistance and heat transfer characteristics of the system. Accurate identification of different flow patterns is of great significance to the calculation of twophase flow. For the gasliquid flow in narrow channels, especially...
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| Format: | Article |
| Language: | English |
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Editorial Board of Atomic Energy Science and Technology
2022-12-01
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| Series: | Yuanzineng kexue jishu |
| Subjects: | |
| Online Access: | https://www.aest.org.cn/CN/abstract/abstract21619.shtml |
| _version_ | 1797955461151981568 |
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| author | HAN Jinyu;HE Wen;ZHAO Chenru;BO Hanliang |
| author_facet | HAN Jinyu;HE Wen;ZHAO Chenru;BO Hanliang |
| author_sort | HAN Jinyu;HE Wen;ZHAO Chenru;BO Hanliang |
| collection | DOAJ |
| description | In the two-phase flow system, the flow pattern affects the frictional resistance and heat transfer characteristics of the system. Accurate identification of different flow patterns is of great significance to the calculation of twophase flow. For the gasliquid flow in narrow channels, especially the flow pattern and flow pattern transition criterion in rectangular narrow channels, some researchers have done some experimental studies. For the study of flow pattern in narrow rectangular channels, the classification of flow patterns is basically consistent with that in conventional rectangular channels, including bubbly flow, slug flow, churn flow and annular flow. However, the performance of existing flow pattern transition criteria for twophase flow in narrow rectangular channels still needs further and comprehensive assessments. In this paper, a parameter representing the success rate of boundary separation of bubblyslug flow transition was introduced to quantitatively evaluate the performances of five typical bubbly-slug flow transition criteria and experimental data reported by 10 previous researchers, covering channel sizes ranging from 0.6 mm to 30 mm. Results show that the success rate of boundary separation of the Jones & Zuber criterion, Taitel criterion, MishimaIshii criterion and Xu criterion in predicting the experimental data varies from 61.86% to 98.10%. The variation mainly attributes to the assumption of constant critical void fraction in these criterions, since analyzing shows that the critical void fraction of flow pattern transition is related to the channel geometry. Although the HibikiMishima criterion considers the effect of channel size on the critical void fraction, the bubbly diameter (Db) is also needed in this model, which is difficult to obtain. The influence of channel size on the flow transition was quantitatively analyzed based on a dimensionless parameter of confinement number (Co). Finally, the flow pattern transition function (f(k)) was correlated with Co, and a new flow pattern transition criterion of bubbly-slug flows in narrow channel considering the physical properties of working fluid and the size of flow channel with higher accuracy and wider application range was established, which predicts the experimental data with success rates of boundary separation of 83.78% to 98.10% within the range of 0.486 57≤Co≤1.471 04, 0.016 m/s≤jg≤6.758 m/s, and 0.058 m/s≤jf≤5.059 m/s. The conclusions of this paper can provide references for the design and optimization of reactor heat exchanger components and compact heat exchangers. |
| first_indexed | 2024-04-10T23:33:30Z |
| format | Article |
| id | doaj.art-01f703c84ed54152bb2260477c8a853c |
| institution | Directory Open Access Journal |
| issn | 1000-6931 |
| language | English |
| last_indexed | 2024-04-10T23:33:30Z |
| publishDate | 2022-12-01 |
| publisher | Editorial Board of Atomic Energy Science and Technology |
| record_format | Article |
| series | Yuanzineng kexue jishu |
| spelling | doaj.art-01f703c84ed54152bb2260477c8a853c2023-01-12T01:56:44ZengEditorial Board of Atomic Energy Science and TechnologyYuanzineng kexue jishu1000-69312022-12-01561225242532Transition Criterion of Bubbly-slug Flow Pattern in Rectangular Narrow ChannelHAN Jinyu;HE Wen;ZHAO Chenru;BO Hanliang 0nstitute of Nuclear and New Energy Technology, Collaborative Innovation Center for Advanced Nuclear Energy Technology, Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Tsinghua University, Beijing 100084, China In the two-phase flow system, the flow pattern affects the frictional resistance and heat transfer characteristics of the system. Accurate identification of different flow patterns is of great significance to the calculation of twophase flow. For the gasliquid flow in narrow channels, especially the flow pattern and flow pattern transition criterion in rectangular narrow channels, some researchers have done some experimental studies. For the study of flow pattern in narrow rectangular channels, the classification of flow patterns is basically consistent with that in conventional rectangular channels, including bubbly flow, slug flow, churn flow and annular flow. However, the performance of existing flow pattern transition criteria for twophase flow in narrow rectangular channels still needs further and comprehensive assessments. In this paper, a parameter representing the success rate of boundary separation of bubblyslug flow transition was introduced to quantitatively evaluate the performances of five typical bubbly-slug flow transition criteria and experimental data reported by 10 previous researchers, covering channel sizes ranging from 0.6 mm to 30 mm. Results show that the success rate of boundary separation of the Jones & Zuber criterion, Taitel criterion, MishimaIshii criterion and Xu criterion in predicting the experimental data varies from 61.86% to 98.10%. The variation mainly attributes to the assumption of constant critical void fraction in these criterions, since analyzing shows that the critical void fraction of flow pattern transition is related to the channel geometry. Although the HibikiMishima criterion considers the effect of channel size on the critical void fraction, the bubbly diameter (Db) is also needed in this model, which is difficult to obtain. The influence of channel size on the flow transition was quantitatively analyzed based on a dimensionless parameter of confinement number (Co). Finally, the flow pattern transition function (f(k)) was correlated with Co, and a new flow pattern transition criterion of bubbly-slug flows in narrow channel considering the physical properties of working fluid and the size of flow channel with higher accuracy and wider application range was established, which predicts the experimental data with success rates of boundary separation of 83.78% to 98.10% within the range of 0.486 57≤Co≤1.471 04, 0.016 m/s≤jg≤6.758 m/s, and 0.058 m/s≤jf≤5.059 m/s. The conclusions of this paper can provide references for the design and optimization of reactor heat exchanger components and compact heat exchangers.https://www.aest.org.cn/CN/abstract/abstract21619.shtmlrectangular channelnarrow slottwo-phase flowpattern transition |
| spellingShingle | HAN Jinyu;HE Wen;ZHAO Chenru;BO Hanliang Transition Criterion of Bubbly-slug Flow Pattern in Rectangular Narrow Channel Yuanzineng kexue jishu rectangular channel narrow slot two-phase flow pattern transition |
| title | Transition Criterion of Bubbly-slug Flow Pattern in Rectangular Narrow Channel |
| title_full | Transition Criterion of Bubbly-slug Flow Pattern in Rectangular Narrow Channel |
| title_fullStr | Transition Criterion of Bubbly-slug Flow Pattern in Rectangular Narrow Channel |
| title_full_unstemmed | Transition Criterion of Bubbly-slug Flow Pattern in Rectangular Narrow Channel |
| title_short | Transition Criterion of Bubbly-slug Flow Pattern in Rectangular Narrow Channel |
| title_sort | transition criterion of bubbly slug flow pattern in rectangular narrow channel |
| topic | rectangular channel narrow slot two-phase flow pattern transition |
| url | https://www.aest.org.cn/CN/abstract/abstract21619.shtml |
| work_keys_str_mv | AT hanjinyuhewenzhaochenrubohanliang transitioncriterionofbubblyslugflowpatterninrectangularnarrowchannel |