磁约束聚变堆液态包层磁流体动力学稳定性研究

Blanket system of magnetic confinement fusion reactors is critical for the future commercial application of fusion energy, and is also the key energy conversion component to achieve high environmental adaptability and low cost of power generation for the fusion energy. Liquid fusion blanket system with its adaptability for complex geometry, high tritium breeding rate and excellent performance for thermal capacity and heat transfer has received considerable attention in the community of the magnetic confinement fusion research, is the most potential design scheme of the fusion blanket. However, in the liquid fusion blanket system there exist corrosion issues for structural materials, tritium transport/permeation and heat transfer problems, which are closely related to magnetohydrodynamic behavior of liquid metal flows with the actions of strong magnetic field and neutron volume heating. The project will take liquid metal conducting fluids in the liquid fusion blanket environment as the research object, and investigate three dimensional global linear stability of magnetohydrodynamic (MHD) mixed-convection duct flow under the strong magnetic field and neutron volume heating. Theoretical study of absolute and convective instabilities, weak nonlinear analysis as well as optimal linear transient growth analysis will be performed for the MHD duct flow based on the global linear modes. High-resolution spectral element method is used to simulate the spatiotemporal evolution of the MHD duct flow under initial disturbances. The mechanisms on the flow instability and the laminar-turbulent transition will be studied detailedly to provide a beneficial theoretical guidance for the engineering design of liquid fusion blankets.

磁约束聚变堆的包层系统是聚变能最终走向商业应用的关键，是实现高环境适应性和低成本发电的聚变能源利用的关键能量转换部件。液态聚变包层系统以其复杂几何适应性、较高的氚增殖率和优良的导热载热能力得到了磁约束聚变领域学者的广泛关注，是最具发展潜力的聚变包层设计方案。液态聚变包层系统面临着结构材料腐蚀、氚输运/渗透以及热传输问题，这些问题均与其在强磁场和中子体加热环境下的磁流体动力学行为息息相关。本项目将以液态聚变包层环境下液态金属导电流体流动为研究对象，考察强磁场和中子体加热作用下的磁流体方腔槽道混合对流流动的三维整体线性稳定性，以整体线性特征模态为基础开展线性绝对与对流不稳定性分析、弱非线性分析以及最优线性瞬态增长研究，采用高精度谱元法模拟扰动的时空演化过程，揭示磁流体方腔槽道混合对流的失稳机制以及层流至湍流的转捩机制，为液态包层工程设计提供强有力的理论指导。

磁约束聚变堆的包层系统是聚变能最终走向商业应用的关键，是实现高环境适应性和低成本发电的聚变能源利用的关键能量转换部件。液态聚变包层系统以其复杂几何适应性、较高的氚增殖率和优良的导热载热能力得到了磁约束聚变领域学者的广泛关注，是最具发展潜力的聚变包层设计方案。液态聚变包层系统面临着结构材料腐蚀、氚输运/渗透以及热传输问题，这些问题均与其在强磁场和中子体加热环境下的磁流体动力学行为息息相关。本项目对强磁场和壁面加热作用下的液态金属方腔槽道混合对流流动的三维整体线性稳定性进行了深入研究，给出各个不稳定模态的稳定性边界曲线，分析无量纲物理参数对整体线性稳定性的影响规律，揭示各个模态的内在失稳机制。依据本项目的研究结果，证实了在强磁场条件下磁流体动力学不稳定性是物理实验中温度场大幅值脉动的内在物理机制，为液态包层工程设计提供强有力的理论指导。