Numerical Study of a Liquid Metal Oscillating inside a Pore in the Presence of Lorentz and Capillary Forces
Numerical Study of a Liquid Metal Oscillating inside a Pore in the Presence of Lorentz and Capillary Forces
复制标题
洛伦兹和毛细管力存在下液态金属在孔内振荡的数值研究
作者：
M. Vlachomitrou;N. Pelekasis
为了确保稳定的功率排放并保护聚变反应堆的壁，通过毛细管多孔系统（CPS）输送到壁表面的液态金属被认为是替代的面向等离子体的组件（PFC）。然而，可能会出现液滴喷射和等离子体污染等操作问题。在这项研究中，研究了在洛伦兹力存在下液态金属在 CPS 单个孔内的不稳定流动。通过有限元方法结合椭圆网格生成来执行数值求解。发现了一个临界磁数 (Bondm = 4.5)，低于该磁数，在几次振荡后，流量会达到具有温和旋转模式的稳定状态。高于该阈值，界面表现出饱和振荡。随着洛伦兹力进一步增加，Bondm > 5.8，随着界面在增加的磁压力的影响下加速，瑞利-泰勒不稳定性会发展，并捕获有限时间奇点。据推测，最终会发生液滴喷射，这将破坏界面的内聚力并污染周围的介质。最后，研究了不同工作流体（例如镓）的动态响应，并证明了增加的电导率和表面张力的稳定作用。
In order to ensure stable power exhaust and to protect the walls of fusion reactors, liquid metals that are fed to the wall surface through a capillary porous system (CPS) are considered as alternative plasma-facing components (PFCs). However, operational issues like drop ejection and plasma contamination may arise. In this study, the unsteady flow of a liquid metal inside a single pore of the CPS in the presence of Lorentz forces is investigated. A numerical solution is performed via the finite element methodology coupled with elliptic mesh generation. A critical magnetic number is found (Bondm = 4.5) below which the flow after a few oscillations reaches a steady state with mild rotational patterns. Above this threshold, the interface exhibits saturated oscillations. As the Lorentz force is further increased, Bondm > 5.8, a Rayleigh–Taylor instability develops as the interface is accelerated under the influence of the increased magnetic pressure and a finite time singularity is captured. It is conjectured that eventually, drop ejection will take place that will disrupt cohesion of the interface and contaminate the surrounding medium. Finally, the dynamic response of different operating fluids is investigated, e.g., gallium, and the stabilizing effect of increased electrical conductivity and surface tension is demonstrated.