3D numerical study of neutral gas dynamics in the DTT particle exhaust using the DSMC method

Bibliographic Details
Title: 3D numerical study of neutral gas dynamics in the DTT particle exhaust using the DSMC method
Authors: C. Tantos, S. Varoutis, V. Hauer, C. Day, P. Innocente
Source: Nuclear Fusion, Vol 64, Iss 1, p 016019 (2023)
Publisher Information: IOP Publishing, 2023.
Publication Year: 2023
Collection: LCC:Nuclear and particle physics. Atomic energy. Radioactivity
Subject Terms: divertor tokamak test facility (DTT), vacuum pumping, DSMC method, particle exhaust, SolEdge2D-Eirene, pumped fluxes, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
More Details: Recently the design of the divertor tokamak test (DTT) Facility divertor has been modified and consolidated. The new divertor design presents significant geometrical differences compared to the previous ITER-like one, including the presence of a more flattened dome shape. This paper presents a complete 3D numerical analysis of the neutral gas dynamics inside the DTT subdivertor area for the latest divertor design. The analysis has been performed based on the direct simulation Monte Carlo method by applying the DIVGAS simulator code. SOLEDGE2D-EIRENE plasma simulations have been performed for a deuterium plasma scenario at the maximum additional power in partially detached condition achieved by neon impurity seeding and the extracted information about the neutral particles has been imposed as incoming boundary conditions. The pumping efficiency of the DTT divertor is examined by considering various cases with respect to the pumping probability and the effect of the toroidal and poloidal leakages is quantified. The results show that a significant percentage of the incoming flux of neutrals returns back to the plasma site through the entry gaps (60% for deuterium and 40% for neon), and, consequentially, only a small percentage (∼2%–15%) of the incoming flux can be pumped out from the system. The toroidal leakages affect significantly the pumping performance of the divertor causing a significant decrease in the pumped flux (and also in the pressure at the pumping opening) about 37%–47% and 43%–56% for deuterium and neon respectively. It is discussed how many pumping ports are needed depending on the achievable pumping performance per port. The number can be reduced by closing the toroidal gaps. The analysis shows that enlarging the poloidal gaps by a factor of two causes a significant increase in the poloidal flux losses by a factor 1.7. It is also illustrated how the presence of the cooling pipes leads to conductance losses.
Document Type: article
File Description: electronic resource
Language: English
ISSN: 1741-4326
0029-5515
Relation: https://doaj.org/toc/0029-5515
DOI: 10.1088/1741-4326/ad0c80
Access URL: https://doaj.org/article/9e2db946befc4ac0b55196c1e7e0bf28
Accession Number: edsdoj.9e2db946befc4ac0b55196c1e7e0bf28
Database: Directory of Open Access Journals
More Details
ISSN:17414326
00295515
DOI:10.1088/1741-4326/ad0c80
Published in:Nuclear Fusion
Language:English