Interaction between surface behavior and inner flow pattern of liquid Li jet for fusion neutron sources

• Published in: Fusion engineering and design Vol. 160; p. 111842
• Main Authors: Hoashi, Eiji, Fujii, Yasuhiro, Yamada, Shunya, Okita, Takafumi, Kondo, Hiroo, Park, Chang Ho, Nakamura, Makoto M., Ochiai, Kentaro, Kasugai, Atsushi
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.11.2020; Elsevier Science Ltd
• Subjects: CFD; Computational fluid dynamics; Fluid flow; Free surface flow; Free surfaces; Fusion neutron source; Liquid Li target; Liquid lithium; Neutron sources; Neutrons; Nozzles; Roughness; Scale models; Secondary flow; Simulation; Turbulent flow on rough wall; Japan; CFD; Fusion neutron source; Free surface flow; Liquid Li target; Turbulent flow on rough wall
• ISSN: 0920-3796; 1873-7196
• DOI: 10.1016/j.fusengdes.2020.111842

•MSGD model was introduced to LES as wall roughness model and this was applied to parallel plate flow of Li.•Vortices on rough wall keep finer structure than that on smooth wall.•Surface deformation of the Li jet and the vortex structure inner the Li jet were evaluated by using SAS turbulent model.•Secondary flow inner the Li jet and the contact angle affected to the surface deformation of the Li jet. Liquid lithium (Li) jet is planned as a beam target in fusion neutron sources (FNSs), such as IFMIF in Japan and EU, A-FNS in Japan and IFMIF-DONES in EU. For the safety and the efficiency of such FNSs, it is desirable to keep the high-speed Li jet stable. In addition to many experimental researches, numerical approaches using CFD simulation have been also required to evaluate the detailed flow pattern inner the Li jet because of the opacity. In our previous simulation, it was found that the vortex structure under the free surface of the Li jet had the strong influence on the surface fluctuation using LES simulation. In this study, for evaluating the interaction between the Li surface behavior and the flow pattern inner the Li jet, two simulations are conducted: one is the LES simulation considering wall roughness, and another one is the RANS simulation using full-scale model with the nozzle and the Li jet. The influence of wall roughness on the vortex structure becomes an issue in long-term operation of actual FNSs, and the influence of the secondary flow generated due to the side wall on the surface shape is evaluated in the latter simulation.