磁场环境下Rayleigh-Bénard湍流流动机制与机理研究

磁约束核聚变是实现聚变能和平利用的一个重要途径。液态金属包层作为实现聚变能转换和燃料氚增殖的关键部件，其内部金属流体在强磁场和大温差极端条件下的磁流体力学和湍流热对流耦合效应是包层研发的关键科学问题。本项目旨在通过直接数值模拟的方法，开展磁场作用下Rayleigh-Bénard(RB)湍流热对流动力学特性与传热特性的研究。首先探索竖直强磁场作用下，RB湍流主要的流动机制，如胞状机制与壁模型机制，揭示机制产生的内在机理及对流动特性和传热特性的影响。其次研究水平磁场作用下，对流涡结构从三维向二维转换的内在机理，揭示对流涡反转与分裂的原因，分析磁场强度对系统流动特性和传热特性的影响。该项目的研究不仅能丰富RB湍流热对流相关理论，更重要的是能为磁约束液态包层内热对流湍流的分析提供理论指导，具有重要的学术价值和实际应用价值。

Magnetic confinement provides a promising prospect for the peaceful use of the nuclear fusion. The blanket is a key component in the fusion device to promote the energy conversion and tritium breeding, and the liquid metal flowing inside it experiences great influences from high magnetic field and large temperature difference, which cause the problem to be rather complex by coupling the magnetohydrodynamics and the turbulent thermal convection flow. Through performing the direct numerical simulations, the present project aims to investigate the mechanical characteristics and the heat transfer behaviors of the turbulent Rayleigh-Bénard convection (RBC) under the influence of magnetic fields. First, the main characteristics of the turbulent RBC in different regimes will be explored in presence of a streamwise magnetic field, e.g. the cellular regime and the wall mode regime, in order to uncover the in-depth mechanisms governing the flow patterns and the heat transfer performance. Second, we will further investigate the influences of transverse magnetic fields, which are known to have anisotropic effects on the flow field. In particular, why and how does the flow pattern transit from three-dimensionality to three-dimensionality will be focuses, and the mechanisms about the reversal and splitting of the convection vortex will be detected. This project not only enriches the theories about the turbulent RBC, and moreover, it will provide the guidance for the design of the liquid metal blanket in the magnetic confinement fusion device, consequently it is both of academician and application interest.