Numerical Study on Thermal–Flow Characteristics of Liquid Metal Blankets in a Magnetic Field

The tokamak is a toroidal device that utilizes magnetic confinement to achieve controlled nuclear fusion. One of the major technical challenges hindering the development of this technology lies in effectively dissipating the generated heat. In this study, the inner blanket structure of a tokamak is selected as the research object, and a multi–physics numerical model coupling magnetic field, temperature field, and flow field is established. The effects of background magnetic field strength, blanket channel width, and inlet velocity of the liquid metal coolant on the thermal–flow characteristics of the blanket were systematically investigated. The results indicate that compared with the L-shaped channel, the U-shaped channel reduces flow resistance in the turning region by 6%, exhibits a more uniform temperature distribution, and decreases the outlet–inlet temperature difference by 4%, thereby significantly enhancing the heat transfer efficiency. An increase in background magnetic field strength suppresses coolant flow but has only a limited impact on the temperature field. When the background magnetic field reaches a certain strength, the magnetic field has a certain hindering effect on the flow of the working fluid. Increasing the thickness of the blankets appropriately can alleviate the hindering effect of the magnetic field on the flow and improve the velocity distribution in the outlet area.