Numerical simulation of subcooled boiling in a vertical pipe with twisted tape inserts
Subcooled flow boiling occurs in many industrial applications and it is characterized by a large heat transfer coefficient. In this paper, numerical simulation of subcooled flow boiling in a vertical pipe is investigated by ANSYS CFX 14. Variation of void fraction as a function of increasing enthalp...
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| Format: | Article |
| Language: | fas |
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Nuclear Science and Technology Research Institute
2015-11-01
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| Series: | مجله علوم و فنون هسته‌ای |
| Subjects: | |
| Online Access: | https://jonsat.nstri.ir/article_10_26c503a39b1d79fe51e715f77f34b37a.pdf |
| _version_ | 1797835085699874816 |
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| author | Hossein Kazeminejad Mehdi Tafreshi |
| author_facet | Hossein Kazeminejad Mehdi Tafreshi |
| author_sort | Hossein Kazeminejad |
| collection | DOAJ |
| description | Subcooled flow boiling occurs in many industrial applications and it is characterized by a large heat transfer coefficient. In this paper, numerical simulation of subcooled flow boiling in a vertical pipe is investigated by ANSYS CFX 14. Variation of void fraction as a function of increasing enthalpy along the pipe is validated against the RELAP5 and experimental results available in the literature. The RELAP5 has a broad acceptance as a tool for analyzing the thermal-hydraulic behavior of the nuclear reactors. The code is based on a non-homogeneous and non-equilibrium two-phase model of six equations solved by a fast and partially implicit numerical scheme. The model does not have the ability to simulate two phase flow with a twisted tape insert. The effect of the twisted tape inserts on improving the subcooled boiling heat transfer is investigated in a vertical pipe of 2m in length and 154mm in diameter using CFX14. The pressure and wall heat flux is 45 bar and 0.57 MW m-2, respectively. The range of the twisted tape pitch investigated to be between 0.04 m and 0.16 m. A comparison of the predicted void fractions for a plain vertical tube without tube inserts revealed a good agreement with the experimental data. It was found that, heat transfer and pressure drop both increase with a reduction of the twisted tape pitch. Also, within the pitch range investigated, the 0.08 m pitch had the highest performance with respect to the pressure drop and heat transfer. |
| first_indexed | 2024-04-09T14:47:36Z |
| format | Article |
| id | doaj.art-3c229799156e4f16a6ca2ac36c96356c |
| institution | Directory Open Access Journal |
| issn | 1735-1871 2676-5861 |
| language | fas |
| last_indexed | 2024-04-09T14:47:36Z |
| publishDate | 2015-11-01 |
| publisher | Nuclear Science and Technology Research Institute |
| record_format | Article |
| series | مجله علوم و فنون هسته‌ای |
| spelling | doaj.art-3c229799156e4f16a6ca2ac36c96356c2023-05-02T10:27:37ZfasNuclear Science and Technology Research Instituteمجله علوم و فنون هسته‌ای1735-18712676-58612015-11-01363334110Numerical simulation of subcooled boiling in a vertical pipe with twisted tape insertsHossein Kazeminejad0Mehdi Tafreshi1پژوهشکده‌ی کاربرد پرتوها، پژوهشگاه علوم و فنون هسته‌ای، سازمان انرژی اتمی، صندوق پستی: 3486-11365، تهران ـ ایرانپژوهشکده‌ی کاربرد پرتوها، پژوهشگاه علوم و فنون هسته‌ای، سازمان انرژی اتمی، صندوق پستی: 3486-11365، تهران ـ ایرانSubcooled flow boiling occurs in many industrial applications and it is characterized by a large heat transfer coefficient. In this paper, numerical simulation of subcooled flow boiling in a vertical pipe is investigated by ANSYS CFX 14. Variation of void fraction as a function of increasing enthalpy along the pipe is validated against the RELAP5 and experimental results available in the literature. The RELAP5 has a broad acceptance as a tool for analyzing the thermal-hydraulic behavior of the nuclear reactors. The code is based on a non-homogeneous and non-equilibrium two-phase model of six equations solved by a fast and partially implicit numerical scheme. The model does not have the ability to simulate two phase flow with a twisted tape insert. The effect of the twisted tape inserts on improving the subcooled boiling heat transfer is investigated in a vertical pipe of 2m in length and 154mm in diameter using CFX14. The pressure and wall heat flux is 45 bar and 0.57 MW m-2, respectively. The range of the twisted tape pitch investigated to be between 0.04 m and 0.16 m. A comparison of the predicted void fractions for a plain vertical tube without tube inserts revealed a good agreement with the experimental data. It was found that, heat transfer and pressure drop both increase with a reduction of the twisted tape pitch. Also, within the pitch range investigated, the 0.08 m pitch had the highest performance with respect to the pressure drop and heat transfer.https://jonsat.nstri.ir/article_10_26c503a39b1d79fe51e715f77f34b37a.pdfsubcooled flow boilingtwisted tape inserts |
| spellingShingle | Hossein Kazeminejad Mehdi Tafreshi Numerical simulation of subcooled boiling in a vertical pipe with twisted tape inserts مجله علوم و فنون هسته‌ای subcooled flow boiling twisted tape inserts |
| title | Numerical simulation of subcooled boiling in a vertical pipe with twisted tape inserts |
| title_full | Numerical simulation of subcooled boiling in a vertical pipe with twisted tape inserts |
| title_fullStr | Numerical simulation of subcooled boiling in a vertical pipe with twisted tape inserts |
| title_full_unstemmed | Numerical simulation of subcooled boiling in a vertical pipe with twisted tape inserts |
| title_short | Numerical simulation of subcooled boiling in a vertical pipe with twisted tape inserts |
| title_sort | numerical simulation of subcooled boiling in a vertical pipe with twisted tape inserts |
| topic | subcooled flow boiling twisted tape inserts |
| url | https://jonsat.nstri.ir/article_10_26c503a39b1d79fe51e715f77f34b37a.pdf |
| work_keys_str_mv | AT hosseinkazeminejad numericalsimulationofsubcooledboilinginaverticalpipewithtwistedtapeinserts AT mehditafreshi numericalsimulationofsubcooledboilinginaverticalpipewithtwistedtapeinserts |