Unsteady Natural Convection in a Cylindrical Containment Vessel (CIGMA) With External Wall Cooling: Numerical CFD Simulation
In the case of a severe accident, natural convection plays an important role in the atmosphere mixing of nuclear reactor containments. In this case, the natural convection might not in the steady-state condition. Hence, instead of steady-state simulation, the transient simulation should be performed...
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MDPI AG
2020-07-01
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| Series: | Energies |
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| Online Access: | https://www.mdpi.com/1996-1073/13/14/3652 |
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| author | Ari Hamdani Satoshi Abe Masahiro Ishigaki Yasuteru Sibamoto Taisuke Yonomoto |
| author_facet | Ari Hamdani Satoshi Abe Masahiro Ishigaki Yasuteru Sibamoto Taisuke Yonomoto |
| author_sort | Ari Hamdani |
| collection | DOAJ |
| description | In the case of a severe accident, natural convection plays an important role in the atmosphere mixing of nuclear reactor containments. In this case, the natural convection might not in the steady-state condition. Hence, instead of steady-state simulation, the transient simulation should be performed to understand natural convection in the accident scenario within a nuclear reactor containment. The present study, therefore, was aimed at the transient 3-D numerical simulations of natural convection of air around a cylindrical containment with unsteady thermal boundary conditions (BCs) at the vessel wall. For this purpose, the experiment series was done in the CIGMA facility at Japan Atomic Energy Agency (JAEA). The upper vessel or both the upper vessel and the middle jacket was cooled by subcooled water, while the lower vessel was thermally insulated. A 3-D model was simulated with OpenFOAM<sup>®</sup>, applying the unsteady Reynolds-averaged Navier–Stokes equations (URANS) model. Different turbulence models were studied, such as the standard k-ε, standard k-ω, k-ω shear stress transport (SST), and low-Reynolds-k-ε Launder–Sharma. The results of the four turbulence models were compared versus the results of experimental data. The k-ω SST showed a better prediction compared to other turbulence models. Additionally, the accuracy of the predicted temperature and pressure were improved when the heat conduction on the internal structure, i.e., flat bar, was considered in the simulation. Otherwise, the predictions on both temperature and pressure were underestimated compared with the experimental results. Hence, the conjugate heat transfer in the internal structure inside the containment vessel must be modeled accurately. |
| first_indexed | 2024-03-10T18:27:57Z |
| format | Article |
| id | doaj.art-be07337b8e6d42409e389feca8456b74 |
| institution | Directory Open Access Journal |
| issn | 1996-1073 |
| language | English |
| last_indexed | 2024-03-10T18:27:57Z |
| publishDate | 2020-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Energies |
| spelling | doaj.art-be07337b8e6d42409e389feca8456b742023-11-20T06:51:42ZengMDPI AGEnergies1996-10732020-07-011314365210.3390/en13143652Unsteady Natural Convection in a Cylindrical Containment Vessel (CIGMA) With External Wall Cooling: Numerical CFD SimulationAri Hamdani0Satoshi Abe1Masahiro Ishigaki2Yasuteru Sibamoto3Taisuke Yonomoto4Japan Atomic Energy Agency, Nuclear Safety Research Center, 2–4, Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195, JapanJapan Atomic Energy Agency, Nuclear Safety Research Center, 2–4, Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195, JapanJapan Atomic Energy Agency, Nuclear Safety Research Center, 2–4, Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195, JapanJapan Atomic Energy Agency, Nuclear Safety Research Center, 2–4, Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195, JapanJapan Atomic Energy Agency, Nuclear Safety Research Center, 2–4, Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195, JapanIn the case of a severe accident, natural convection plays an important role in the atmosphere mixing of nuclear reactor containments. In this case, the natural convection might not in the steady-state condition. Hence, instead of steady-state simulation, the transient simulation should be performed to understand natural convection in the accident scenario within a nuclear reactor containment. The present study, therefore, was aimed at the transient 3-D numerical simulations of natural convection of air around a cylindrical containment with unsteady thermal boundary conditions (BCs) at the vessel wall. For this purpose, the experiment series was done in the CIGMA facility at Japan Atomic Energy Agency (JAEA). The upper vessel or both the upper vessel and the middle jacket was cooled by subcooled water, while the lower vessel was thermally insulated. A 3-D model was simulated with OpenFOAM<sup>®</sup>, applying the unsteady Reynolds-averaged Navier–Stokes equations (URANS) model. Different turbulence models were studied, such as the standard k-ε, standard k-ω, k-ω shear stress transport (SST), and low-Reynolds-k-ε Launder–Sharma. The results of the four turbulence models were compared versus the results of experimental data. The k-ω SST showed a better prediction compared to other turbulence models. Additionally, the accuracy of the predicted temperature and pressure were improved when the heat conduction on the internal structure, i.e., flat bar, was considered in the simulation. Otherwise, the predictions on both temperature and pressure were underestimated compared with the experimental results. Hence, the conjugate heat transfer in the internal structure inside the containment vessel must be modeled accurately.https://www.mdpi.com/1996-1073/13/14/3652natural convectionCFDconjugate heat transfercontainment vesselthermal hydraulicsCIGMA |
| spellingShingle | Ari Hamdani Satoshi Abe Masahiro Ishigaki Yasuteru Sibamoto Taisuke Yonomoto Unsteady Natural Convection in a Cylindrical Containment Vessel (CIGMA) With External Wall Cooling: Numerical CFD Simulation Energies natural convection CFD conjugate heat transfer containment vessel thermal hydraulics CIGMA |
| title | Unsteady Natural Convection in a Cylindrical Containment Vessel (CIGMA) With External Wall Cooling: Numerical CFD Simulation |
| title_full | Unsteady Natural Convection in a Cylindrical Containment Vessel (CIGMA) With External Wall Cooling: Numerical CFD Simulation |
| title_fullStr | Unsteady Natural Convection in a Cylindrical Containment Vessel (CIGMA) With External Wall Cooling: Numerical CFD Simulation |
| title_full_unstemmed | Unsteady Natural Convection in a Cylindrical Containment Vessel (CIGMA) With External Wall Cooling: Numerical CFD Simulation |
| title_short | Unsteady Natural Convection in a Cylindrical Containment Vessel (CIGMA) With External Wall Cooling: Numerical CFD Simulation |
| title_sort | unsteady natural convection in a cylindrical containment vessel cigma with external wall cooling numerical cfd simulation |
| topic | natural convection CFD conjugate heat transfer containment vessel thermal hydraulics CIGMA |
| url | https://www.mdpi.com/1996-1073/13/14/3652 |
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