Double-Diffusive Mixed Convection and Radionuclides Removals from the Tail Gas Treatment Unit in Nuclear Medicine Building: Multiple Sifting Structures and Porous Medium
This paper investigates the effect of porous-media arrangement, hot-plate arrangement, heat flux, and inlet flow on the mixed convection heat transfer, and uniformity of temperature and concentration in an open enclosure. This model is considered for use as an adsorption treatment unit for radioacti...
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MDPI AG
2022-11-01
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| Online Access: | https://www.mdpi.com/2075-5309/12/11/1842 |
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| author | Jian Li Yi-Chao Chen Jian Hong Hang Xu Fu-Yun Zhao Jiang-Hua Guo |
| author_facet | Jian Li Yi-Chao Chen Jian Hong Hang Xu Fu-Yun Zhao Jiang-Hua Guo |
| author_sort | Jian Li |
| collection | DOAJ |
| description | This paper investigates the effect of porous-media arrangement, hot-plate arrangement, heat flux, and inlet flow on the mixed convection heat transfer, and uniformity of temperature and concentration in an open enclosure. This model is considered for use as an adsorption treatment unit for radioactive waste gas in a nuclear medicine building. The radioactive waste gas flows through the cavity from bottom to top. The two-dimensional governing equations have been solved using the finite volume method. The Prandtl number and aspect ratio of the cavity are fixed at 0.71 and 1, respectively. The problem has been governed by five parameters: −10 ≤ <i>Br</i> ≤ 10, 10<sup>−6</sup> ≤ <i>Da</i> ≤ 10<sup>2</sup>, 0.1 ≤ <i>Kc</i> ≤ 10, 10<sup>−2</sup> ≤ <i>Ri</i> ≤ 10, and 0.1 ≤ <i>Kr</i> ≤ 10, and the layouts of the porous layer and hot plates. The simulation results indicate that the Type C (polymeric porous media) has excellent heat transfer characteristics with a 10% increase in the Nusselt number (<i>Nu</i>). The contours of streamlines, isotherms and heatlines indicate that, with the increase of Richardson number (<i>Ri</i>), the trend of <i>Nu</i> varies for different arrangements of hot plates. It is interesting to note that the convective heat transfer of Type F (surrounded arrangement) was found to have the lowest <i>Nu</i> number for the same <i>Ri</i> number. The convective heat transfer is more pronounced for Type E (symmetrical arrangement). The <i>Nu</i> number of Type E (symmetrical arrangement) is about 110% higher than that of Type F (surrounded arrangement) and it is about 35% higher than that of Type D (centralized arrangement). This type also has a more uniform temperature distribution, as indicated by the temperature variance. The findings of this study can guide preheating system optimization. |
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| language | English |
| last_indexed | 2024-03-09T19:13:05Z |
| publishDate | 2022-11-01 |
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| spelling | doaj.art-3c96993656a34aee8fb4313a80a120762023-11-24T03:58:30ZengMDPI AGBuildings2075-53092022-11-011211184210.3390/buildings12111842Double-Diffusive Mixed Convection and Radionuclides Removals from the Tail Gas Treatment Unit in Nuclear Medicine Building: Multiple Sifting Structures and Porous MediumJian Li0Yi-Chao Chen1Jian Hong2Hang Xu3Fu-Yun Zhao4Jiang-Hua Guo5The First Construction Engineering Limited Company of China Construction Third Engineering Bureau, Wuhan 430070, ChinaThe First Construction Engineering Limited Company of China Construction Third Engineering Bureau, Wuhan 430070, ChinaThe First Construction Engineering Limited Company of China Construction Third Engineering Bureau, Wuhan 430070, ChinaSchool of Power and Mechanical Engineering, Wuhan University, Wuhan 430072, ChinaSchool of Power and Mechanical Engineering, Wuhan University, Wuhan 430072, ChinaSchool of Power and Mechanical Engineering, Wuhan University, Wuhan 430072, ChinaThis paper investigates the effect of porous-media arrangement, hot-plate arrangement, heat flux, and inlet flow on the mixed convection heat transfer, and uniformity of temperature and concentration in an open enclosure. This model is considered for use as an adsorption treatment unit for radioactive waste gas in a nuclear medicine building. The radioactive waste gas flows through the cavity from bottom to top. The two-dimensional governing equations have been solved using the finite volume method. The Prandtl number and aspect ratio of the cavity are fixed at 0.71 and 1, respectively. The problem has been governed by five parameters: −10 ≤ <i>Br</i> ≤ 10, 10<sup>−6</sup> ≤ <i>Da</i> ≤ 10<sup>2</sup>, 0.1 ≤ <i>Kc</i> ≤ 10, 10<sup>−2</sup> ≤ <i>Ri</i> ≤ 10, and 0.1 ≤ <i>Kr</i> ≤ 10, and the layouts of the porous layer and hot plates. The simulation results indicate that the Type C (polymeric porous media) has excellent heat transfer characteristics with a 10% increase in the Nusselt number (<i>Nu</i>). The contours of streamlines, isotherms and heatlines indicate that, with the increase of Richardson number (<i>Ri</i>), the trend of <i>Nu</i> varies for different arrangements of hot plates. It is interesting to note that the convective heat transfer of Type F (surrounded arrangement) was found to have the lowest <i>Nu</i> number for the same <i>Ri</i> number. The convective heat transfer is more pronounced for Type E (symmetrical arrangement). The <i>Nu</i> number of Type E (symmetrical arrangement) is about 110% higher than that of Type F (surrounded arrangement) and it is about 35% higher than that of Type D (centralized arrangement). This type also has a more uniform temperature distribution, as indicated by the temperature variance. The findings of this study can guide preheating system optimization.https://www.mdpi.com/2075-5309/12/11/1842radioactive waste gasheat and mass diffusionporous mediacomputational fluid dynamicsboundary condition |
| spellingShingle | Jian Li Yi-Chao Chen Jian Hong Hang Xu Fu-Yun Zhao Jiang-Hua Guo Double-Diffusive Mixed Convection and Radionuclides Removals from the Tail Gas Treatment Unit in Nuclear Medicine Building: Multiple Sifting Structures and Porous Medium Buildings radioactive waste gas heat and mass diffusion porous media computational fluid dynamics boundary condition |
| title | Double-Diffusive Mixed Convection and Radionuclides Removals from the Tail Gas Treatment Unit in Nuclear Medicine Building: Multiple Sifting Structures and Porous Medium |
| title_full | Double-Diffusive Mixed Convection and Radionuclides Removals from the Tail Gas Treatment Unit in Nuclear Medicine Building: Multiple Sifting Structures and Porous Medium |
| title_fullStr | Double-Diffusive Mixed Convection and Radionuclides Removals from the Tail Gas Treatment Unit in Nuclear Medicine Building: Multiple Sifting Structures and Porous Medium |
| title_full_unstemmed | Double-Diffusive Mixed Convection and Radionuclides Removals from the Tail Gas Treatment Unit in Nuclear Medicine Building: Multiple Sifting Structures and Porous Medium |
| title_short | Double-Diffusive Mixed Convection and Radionuclides Removals from the Tail Gas Treatment Unit in Nuclear Medicine Building: Multiple Sifting Structures and Porous Medium |
| title_sort | double diffusive mixed convection and radionuclides removals from the tail gas treatment unit in nuclear medicine building multiple sifting structures and porous medium |
| topic | radioactive waste gas heat and mass diffusion porous media computational fluid dynamics boundary condition |
| url | https://www.mdpi.com/2075-5309/12/11/1842 |
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