高特征参数下绝缘圆管内液态金属MHD效应研究

Investigations on the MHD effect of liquid metals through an insulating circular pipe under large characteristic parameters

液态金属磁流体动力学(MHD)效应是聚变堆液态包层需要解决的关键问题之一。通过实验与数值模拟相结合的方法,研究了高特征参数下绝缘圆管内液态金属MHD效应,获得了强磁场下绝缘圆管内压降变化和流速分布的规律。研究结果表明,绝缘圆管内液态金属MHD压降随外加磁场强度的增加而线性增大,随管道内平均流速的增加也呈线性增长的关系,且压降实验结果与数值模拟及理论结果吻合较好;流速分布的特点为哈特曼层内流速变化剧烈,速度梯度大。基于压降的实验数据分析可得,强磁场环境下绝缘圆管中层流湍流的转换分界点约为Re/Ha=45。

The magnetohydrodynamics(MHD)effect of liquid metals is a key issue to be solved for liquid blankets of fusion reactors.In this study,the liquid metal MHD flow through an insulated circular pipe under large character parameters is investigated through experiments and numerical simulations,and then the results such as pressure drops and flow velocity distributions are provided.The experimental results indicate that MHD pressure drops increase linearly with the increase of external magnetic fields and average velocities,which are in good agreement with numerical and theoretical results.The characteristic of velocity distributions is that the velocity in Hartman layer changes sharply due to big velocity gradient.Based on the analysis of the experimental data about the pressure drop,a conclusion can be drawn that the laminar turbulent transition point of MHD flows through insulating pipes under strong magnetic fields is about Re/Ha=45.