Enhancement of cooling performance of a helium-cooled divertor through the addition of rib structures on the jet-impingement area

Highlights: • The thermo-hydraulic behavior in a helium-cooled divertor module with rib structures is investigated. • An enhanced cooling performance with rib structures in a helium-cooled divertor is revealed. - Abstract: The development of nuclear fusion, which is an environmentally friendly and future-oriented power generation method, needs to be developed for the prevention of global warming caused by the excessive use of fossil fuels. However, there are many scientific and technical challenges that should be overcome for the use of nuclear fusion reactors. The development of a divertor is one such challenge, in that it should be able to endure a high heat flux (∼10 MW/m²) and a particle flux (∼10²⁴/s). To solve this challenge, the Karlsruhe Institute Technology (KIT) has been developing a helium-cooled divertor with a multi-array impingement jet. The main objective of developing this divertor module is not only to sufficiently dissipate the high thermal load from plasma for a reliable operation, but also to maintain a moderate pressure drop. To achieve this objective, we should understand the heat transfer characteristics of the divertor module and enhance the thermal performance, namely, the thermal conductance and pressure drop. The present study is aimed at an enhancement of the cooling performance of a helium-cooled divertor through the addition of rib structures in the divertor module. The results show that the convective conductance with rib turbulators is increased through an increase in the interfacial area on a heated surface. In addition, the thermal performance of the divertor module is enhanced by 20% or more compared with a no rib case.