Numerical analysis of gas exhaust in Wendelstein 7-X using the direct simulation Monte Carlo method
The present work is focused on a 3D numerical assessment of the Wendelstein 7-X (W7-X) particle exhaust. For all the numerical simulations the direct simulation Monte Carlo solver of the DIVGAS workflow, has been employed. The complex 3D geometry of the sub-divertor region includes the pumping gap p...
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IOP Publishing
2025-01-01
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| Series: | Nuclear Fusion |
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| Online Access: | https://doi.org/10.1088/1741-4326/addbf1 |
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| author | S. Varoutis C. Tantos H. Strobel D. Boeyaert Y. Igitkhanov F. Litovoli C.P. Dhard V. Haak D. Naujoks the W7-X Team |
| author_facet | S. Varoutis C. Tantos H. Strobel D. Boeyaert Y. Igitkhanov F. Litovoli C.P. Dhard V. Haak D. Naujoks the W7-X Team |
| author_sort | S. Varoutis |
| collection | DOAJ |
| description | The present work is focused on a 3D numerical assessment of the Wendelstein 7-X (W7-X) particle exhaust. For all the numerical simulations the direct simulation Monte Carlo solver of the DIVGAS workflow, has been employed. The complex 3D geometry of the sub-divertor region includes the pumping gap panel, supporting structures, cooling pipes as well as the cryo-vacuum pump. All the considered flow simulations correspond to the Standard magnetic configuration of W7-X. The main conclusions, which can be extracted from the present numerical analysis could be summarized as follows; The coupling between EMC3-EIRENE and DIVGAS, which considers the fact that the incoming neutral particle flux at the sub-divertor is based on realistic plasma background, has been demonstrated. Three plasma scenarios have been considered, for which is clearly seen that by increasing the heating power, the neutral pressure as well as the resulting pumping efficiency is increased. The obtained numerical results of the neutral pressure in the sub-divertor lie within a more general scan matrix, which assumes a wider range of incoming particle flux, namely 10 ^19 –10 ^24 (s ^−1 ). It has been observed that, the sub-divertor neutral pressure is proportional to the incoming neutral particle flux, with the effective pumping speed to be a constant of proportionality. The influence of switching off the cryo-vacuum pump on the sub-divertor pressure is rather modest and a weak increase of the neutral pressure in the sub-divertor is expected. Correlations of the sub-divertor pressure with the total incoming particle flux as well as the individual pumped flux at each of the AEH and AEP sections have been deduced. Moreover, it has been demonstrated that the influence of the incoming neutral particle flux on the albedo coefficient at the AEH and AEP pumping gaps is rather weak. All the above numerical findings will actively support the optimization of the W7-X particle exhaust, in view of future experimental campaigns. |
| format | Article |
| id | doaj-art-e308cfb0740f49aabe540b7f91d6fa2f |
| institution | OA Journals |
| issn | 0029-5515 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
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| series | Nuclear Fusion |
| spelling | doaj-art-e308cfb0740f49aabe540b7f91d6fa2f2025-08-20T02:17:04ZengIOP PublishingNuclear Fusion0029-55152025-01-0165707600110.1088/1741-4326/addbf1Numerical analysis of gas exhaust in Wendelstein 7-X using the direct simulation Monte Carlo methodS. Varoutis0https://orcid.org/0000-0002-7346-9569C. Tantos1https://orcid.org/0000-0003-1382-2364H. Strobel2D. Boeyaert3https://orcid.org/0000-0003-0920-8660Y. Igitkhanov4F. Litovoli5C.P. Dhard6V. Haak7https://orcid.org/0000-0001-9158-5566D. Naujoks8the W7-X TeamKarlsruhe Institute of Technology , Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, GermanyKarlsruhe Institute of Technology , Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, GermanyKarlsruhe Institute of Technology , Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, GermanyDepartment of Nuclear Engineering and Engineering Physics, University of Wisconsin-Madison , 1500 Engineering Drive, Madison, WI 53706, United States of AmericaKarlsruhe Institute of Technology , Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, GermanyKarlsruhe Institute of Technology , Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, GermanyMax-Planck-Institut fuer Plasmaphysik , Wendelsteinstraße 1, 17491 Greifswald, GermanyMax-Planck-Institut fuer Plasmaphysik , Wendelsteinstraße 1, 17491 Greifswald, GermanyMax-Planck-Institut fuer Plasmaphysik , Wendelsteinstraße 1, 17491 Greifswald, GermanyThe present work is focused on a 3D numerical assessment of the Wendelstein 7-X (W7-X) particle exhaust. For all the numerical simulations the direct simulation Monte Carlo solver of the DIVGAS workflow, has been employed. The complex 3D geometry of the sub-divertor region includes the pumping gap panel, supporting structures, cooling pipes as well as the cryo-vacuum pump. All the considered flow simulations correspond to the Standard magnetic configuration of W7-X. The main conclusions, which can be extracted from the present numerical analysis could be summarized as follows; The coupling between EMC3-EIRENE and DIVGAS, which considers the fact that the incoming neutral particle flux at the sub-divertor is based on realistic plasma background, has been demonstrated. Three plasma scenarios have been considered, for which is clearly seen that by increasing the heating power, the neutral pressure as well as the resulting pumping efficiency is increased. The obtained numerical results of the neutral pressure in the sub-divertor lie within a more general scan matrix, which assumes a wider range of incoming particle flux, namely 10 ^19 –10 ^24 (s ^−1 ). It has been observed that, the sub-divertor neutral pressure is proportional to the incoming neutral particle flux, with the effective pumping speed to be a constant of proportionality. The influence of switching off the cryo-vacuum pump on the sub-divertor pressure is rather modest and a weak increase of the neutral pressure in the sub-divertor is expected. Correlations of the sub-divertor pressure with the total incoming particle flux as well as the individual pumped flux at each of the AEH and AEP sections have been deduced. Moreover, it has been demonstrated that the influence of the incoming neutral particle flux on the albedo coefficient at the AEH and AEP pumping gaps is rather weak. All the above numerical findings will actively support the optimization of the W7-X particle exhaust, in view of future experimental campaigns.https://doi.org/10.1088/1741-4326/addbf1Wendelstein 7-Xstellaratorparticle exhaustvacuum pumpingDSMC methodneutral gas dynamics |
| spellingShingle | S. Varoutis C. Tantos H. Strobel D. Boeyaert Y. Igitkhanov F. Litovoli C.P. Dhard V. Haak D. Naujoks the W7-X Team Numerical analysis of gas exhaust in Wendelstein 7-X using the direct simulation Monte Carlo method Nuclear Fusion Wendelstein 7-X stellarator particle exhaust vacuum pumping DSMC method neutral gas dynamics |
| title | Numerical analysis of gas exhaust in Wendelstein 7-X using the direct simulation Monte Carlo method |
| title_full | Numerical analysis of gas exhaust in Wendelstein 7-X using the direct simulation Monte Carlo method |
| title_fullStr | Numerical analysis of gas exhaust in Wendelstein 7-X using the direct simulation Monte Carlo method |
| title_full_unstemmed | Numerical analysis of gas exhaust in Wendelstein 7-X using the direct simulation Monte Carlo method |
| title_short | Numerical analysis of gas exhaust in Wendelstein 7-X using the direct simulation Monte Carlo method |
| title_sort | numerical analysis of gas exhaust in wendelstein 7 x using the direct simulation monte carlo method |
| topic | Wendelstein 7-X stellarator particle exhaust vacuum pumping DSMC method neutral gas dynamics |
| url | https://doi.org/10.1088/1741-4326/addbf1 |
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