Investigation of Wall Effect on Packing Structures and Purge Gas Flow Characteristics in Pebble Beds for Fusion Blanket by Combining Discrete Element Method and Computational Fluid Dynamics Simulation
In a tritium-breeding blanket of a fusion reaction, helium, used as a tritium-purging gas, will purge the tritium breeder pebble beds to extract the tritium in blanket. The purge gas flow characteristics will affect the tritium extraction efficiency. The effect of the fixed wall on the pebble packin...
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MDPI AG
2024-03-01
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| Series: | Applied Sciences |
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| Online Access: | https://www.mdpi.com/2076-3417/14/6/2289 |
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| author | Baoping Gong Hao Cheng Bing Zhou Juemin Yan Long Wang Long Zhang Yongjin Feng Xiaoyu Wang |
| author_facet | Baoping Gong Hao Cheng Bing Zhou Juemin Yan Long Wang Long Zhang Yongjin Feng Xiaoyu Wang |
| author_sort | Baoping Gong |
| collection | DOAJ |
| description | In a tritium-breeding blanket of a fusion reaction, helium, used as a tritium-purging gas, will purge the tritium breeder pebble beds to extract the tritium in blanket. The purge gas flow characteristics will affect the tritium extraction efficiency. The effect of the fixed wall on the pebble packing structures and purge gas flow characteristics was investigated by combining the discrete element method (DEM) and computational fluid dynamics (CFD) method. The results indicate that the fixed wall leads to a regular packing of the pebbles adjacent to the fixed wall in association with drastic fluctuations in the porosity of the pebble bed, which can affect the purge gas flow behaviors. Further analyses of helium flow behaviors show that the helium pressure in the pebble bed decreases in a linear manner along the flow direction, whereas the pressure drop gradient of helium increases gradually with an increase in the packing factor. The reduction in porosity in the pebble bed leads to a notable escalation in helium flow velocity. Concerning the direction perpendicular to the helium gas flow, the evolution of the cut-plane averaged velocity of helium is similar to that of the porosity, except in the region immediately adjacent to the wall. The pressure drop and flow characteristics obtained in this study can serve as input for the thermohydraulic analysis of the tritium blowing systems in the tritium-breeding blanket of a fusion reactor. |
| first_indexed | 2024-04-24T18:35:47Z |
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| id | doaj.art-8a1b9cdf7d6443ffae4d2da964bf0108 |
| institution | Directory Open Access Journal |
| issn | 2076-3417 |
| language | English |
| last_indexed | 2024-04-24T18:35:47Z |
| publishDate | 2024-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Applied Sciences |
| spelling | doaj.art-8a1b9cdf7d6443ffae4d2da964bf01082024-03-27T13:19:13ZengMDPI AGApplied Sciences2076-34172024-03-01146228910.3390/app14062289Investigation of Wall Effect on Packing Structures and Purge Gas Flow Characteristics in Pebble Beds for Fusion Blanket by Combining Discrete Element Method and Computational Fluid Dynamics SimulationBaoping Gong0Hao Cheng1Bing Zhou2Juemin Yan3Long Wang4Long Zhang5Yongjin Feng6Xiaoyu Wang7Southwestern Institute of Physics, Chengdu 610041, ChinaSouthwestern Institute of Physics, Chengdu 610041, ChinaSouthwestern Institute of Physics, Chengdu 610041, ChinaSouthwestern Institute of Physics, Chengdu 610041, ChinaSouthwestern Institute of Physics, Chengdu 610041, ChinaSouthwestern Institute of Physics, Chengdu 610041, ChinaNuclear Power Institute of China, Chengdu 610041, ChinaSouthwestern Institute of Physics, Chengdu 610041, ChinaIn a tritium-breeding blanket of a fusion reaction, helium, used as a tritium-purging gas, will purge the tritium breeder pebble beds to extract the tritium in blanket. The purge gas flow characteristics will affect the tritium extraction efficiency. The effect of the fixed wall on the pebble packing structures and purge gas flow characteristics was investigated by combining the discrete element method (DEM) and computational fluid dynamics (CFD) method. The results indicate that the fixed wall leads to a regular packing of the pebbles adjacent to the fixed wall in association with drastic fluctuations in the porosity of the pebble bed, which can affect the purge gas flow behaviors. Further analyses of helium flow behaviors show that the helium pressure in the pebble bed decreases in a linear manner along the flow direction, whereas the pressure drop gradient of helium increases gradually with an increase in the packing factor. The reduction in porosity in the pebble bed leads to a notable escalation in helium flow velocity. Concerning the direction perpendicular to the helium gas flow, the evolution of the cut-plane averaged velocity of helium is similar to that of the porosity, except in the region immediately adjacent to the wall. The pressure drop and flow characteristics obtained in this study can serve as input for the thermohydraulic analysis of the tritium blowing systems in the tritium-breeding blanket of a fusion reactor.https://www.mdpi.com/2076-3417/14/6/2289pebble bedflow characteristichelium gaspressure dropsDEM-CFD |
| spellingShingle | Baoping Gong Hao Cheng Bing Zhou Juemin Yan Long Wang Long Zhang Yongjin Feng Xiaoyu Wang Investigation of Wall Effect on Packing Structures and Purge Gas Flow Characteristics in Pebble Beds for Fusion Blanket by Combining Discrete Element Method and Computational Fluid Dynamics Simulation Applied Sciences pebble bed flow characteristic helium gas pressure drops DEM-CFD |
| title | Investigation of Wall Effect on Packing Structures and Purge Gas Flow Characteristics in Pebble Beds for Fusion Blanket by Combining Discrete Element Method and Computational Fluid Dynamics Simulation |
| title_full | Investigation of Wall Effect on Packing Structures and Purge Gas Flow Characteristics in Pebble Beds for Fusion Blanket by Combining Discrete Element Method and Computational Fluid Dynamics Simulation |
| title_fullStr | Investigation of Wall Effect on Packing Structures and Purge Gas Flow Characteristics in Pebble Beds for Fusion Blanket by Combining Discrete Element Method and Computational Fluid Dynamics Simulation |
| title_full_unstemmed | Investigation of Wall Effect on Packing Structures and Purge Gas Flow Characteristics in Pebble Beds for Fusion Blanket by Combining Discrete Element Method and Computational Fluid Dynamics Simulation |
| title_short | Investigation of Wall Effect on Packing Structures and Purge Gas Flow Characteristics in Pebble Beds for Fusion Blanket by Combining Discrete Element Method and Computational Fluid Dynamics Simulation |
| title_sort | investigation of wall effect on packing structures and purge gas flow characteristics in pebble beds for fusion blanket by combining discrete element method and computational fluid dynamics simulation |
| topic | pebble bed flow characteristic helium gas pressure drops DEM-CFD |
| url | https://www.mdpi.com/2076-3417/14/6/2289 |
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