MHD Flow And Heat Transfer In Liquid Metal Blankets Under Buoyancy Force

Blanket technology is the key technology of fusion energy, and liquid metal fusion blanket is a key candidate of blanket concepts design and ITER TBM program because of its good heat transfer ability and high tritium breeding ratio. However, the motion of liquid metal under fusion reactor magnetic field can cause serious magnetohydrodynamics (MHD) effect, and the non-uniform volumetric heat deposited by the fusion neutrons can produce buoyancy effect, which affect the flow, heat transfer and mass transfer and are constraint issues in the design of liquid metal blankets.In this paper, based on the background of MHD flow in the liquid metal blanket under the influence of buoyancy force, numerical models and methods for MHD buoyant flow were studied, and the code MTC for the MHD buoyant flow in liquid metal blanket was developed and validated. The research includes:(1) choosing proper physical mode, flow solver, potential solver and buoyancy model according to the MHD flow characteristics of liquid metal blanket, a MHD code MTC for the simulation of MHD buoyant flow and heat transfer was developed; (2) based on the existing MHD turbulence model and characteristics, a MHD RANS model fit for MHD turbulence under high Hartmann number was developed; (3) the code was validated by a series of benchmarks including fully developed flow,3D flow, buoyant flow and turbulence flow, covering MHD laminar flow and turbulent flow under Ha close to liquid metal blankets.With large scale computing, the flow and heat transfer characteristics under the fusion magnetic field and non-uniform volumetric heating were studied:(1) the characteristics of MHD buoyant flow in typical structure of ITER and DEMO liquid blanket were analyzed, and the mechanism of MHD buoyant flow was concluded, and the necessity of FCI material with heat conductivity below 1 W/mK was assured to achieve high temperature outlet of PbLi; (2) the characteristics of MHD buoyant flow in typical liquid blanket DFLL TBM were analyzed and optimization of liquid blankets were suggested. The main results are:(1) the high temperature of structure in SLL TBM was 704K, which was below the temperature limit of structure and had no need to optimize. (2) the high structure temperature of DLL TBM was 1126K, which was close to the temperature limit 1273K, and the optimized design lowered the highest temperature of PbLi by 96K, which greatly increased the structure safety allowance...