TY - JOUR
T1 - Simulation of collisional effects on divertor pumping in JT-60SA
AU - Gleason-González, C.
AU - Varoutis, S.
AU - Luo, X.
AU - Shimizu, K.
AU - Nakano, T.
AU - Hoshino, K.
AU - Kawashima, H.
AU - Asakura, N.
AU - Day, Chr
AU - Sakurai, S.
N1 - Funding Information:
This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the EURATOM research and training programme 2014-2018 under grant agreement No. 633053 . The views and opinions expressed herein do not necessarily reflect those of the European Commission. Part of the simulations presented herein were carried out at the computational resource bwUniCluster funded by the Ministry of Science, Research and Arts and the Universities of the State of Baden-Württemberg, Germany , within the framework program bwHPC; and part were carried out using the HELIOS supercomputer system at Computational Simulation Centre of International Fusion Energy Research Centre (IFERC-CSC), Aomori, Japan, under the Broader Approach collaboration between Euratom and Japan, implemented by Fusion for Energy and JAEA.
Publisher Copyright:
© 2016 Karlsruhe Institute of Technology
PY - 2016/11/1
Y1 - 2016/11/1
N2 - In this work, the exhausted neutral gas flow is modeled for two cases of a simplified JT-60SA sub-divertor geometry and compared via three different approaches, namely (i) a collisionless approach based on the ProVac3D code, (ii) the DSMC approach based on the DIVGAS code that can be run with and without consideration of particle collisions, and (iii) the NEUT2D approach which has been extensively used in the past for the JT-60 design. In a first case study, the transmission probability was calculated by the 3 approaches and very good agreement is found between NEUT2D-ProVac3D whereas discrepancies between DIVGAS and NEUT2D are found and further analyzed. In the second case, the assessment of collisions is done by means of DIVGAS. Simulations showed that the flow is found in the transitional regime with Kn numbers between 0.1 and 0.4. The DIVGAS collisionless case yielded lower values of temperature than the collisional one by factors of 0.5–0.8 in regions near the inlets of the sub-divertor whereas in regions near the pump and the chevron, the temperature difference is marginal. Moreover, a relative percentage difference of 16–40% in pressure values was found between collisionless and collisional approaches.
AB - In this work, the exhausted neutral gas flow is modeled for two cases of a simplified JT-60SA sub-divertor geometry and compared via three different approaches, namely (i) a collisionless approach based on the ProVac3D code, (ii) the DSMC approach based on the DIVGAS code that can be run with and without consideration of particle collisions, and (iii) the NEUT2D approach which has been extensively used in the past for the JT-60 design. In a first case study, the transmission probability was calculated by the 3 approaches and very good agreement is found between NEUT2D-ProVac3D whereas discrepancies between DIVGAS and NEUT2D are found and further analyzed. In the second case, the assessment of collisions is done by means of DIVGAS. Simulations showed that the flow is found in the transitional regime with Kn numbers between 0.1 and 0.4. The DIVGAS collisionless case yielded lower values of temperature than the collisional one by factors of 0.5–0.8 in regions near the inlets of the sub-divertor whereas in regions near the pump and the chevron, the temperature difference is marginal. Moreover, a relative percentage difference of 16–40% in pressure values was found between collisionless and collisional approaches.
KW - DSMC
KW - Divertor pumping
KW - Sub-divertor gas dynamics
KW - Tokamak particle exhaust
KW - Vacuum
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U2 - 10.1016/j.fusengdes.2016.02.016
DO - 10.1016/j.fusengdes.2016.02.016
M3 - Article
AN - SCOPUS:84958568555
SN - 0920-3796
VL - 109-111
SP - 693
EP - 699
JO - Fusion Engineering and Design
JF - Fusion Engineering and Design
ER -