托克马克装置中面向等离子体部件在不同的位置存在很大的温差，导致面向等离子体部件表面液态金属产生自由对流。以此为背景，实验研究液态金属受横向磁场影响下竖直壁面上的自由对流换热规律。实验采用K型热电偶测量环境与壁面两侧的温度，利用多普勒超声波测速仪测量壁面上的液态金属速度，分析不同磁场强度和加热热流密度条件对竖直平板外表面的流动与换热影响规律。研究表明：竖直平板的局部换热系数与特征长度成反比，即距加热平板起始段越远换热越弱，同时增强加热功率使表面换热系数增加。在强磁场条件下，壁面边界层的流动与换热均普遍被抑制；但是在弱磁场下，增加磁场会强化平板表面的自由对流与换热，根据实验结果发现该转折点出现在磁相互作用数为1~4的范围。
There are big temperature differences at different positions on the first walls facing the plasma in Tokamak device. Free convection experiments of liquid metal on the vertical wall are carried out under the influence of transverse magnetic field. In the experiments, K thermocouple is used to measure the temperatures of the environment and the both sides of the wall, and the flow boundary layer velocity of the wall is measured using a Doppler ultrasonic velocimeter.The experimental results show that the local heat transfer coefficient of the vertical plate is inversely proportional to the characteristic length, while the enhanced heating power increases the surface heat transfer coefficient. Under the condition of the strong magnetic field, the flow and heat transfer effect of the wall boundary layer are generally inhibited. However, in the weak magnetic field, increasing the magnetic field will enhance the effect of free convection and heat transfer on the surface of the plate. Based on the experimental results and existing simulation results, this turning point appears in the N range 1-4.
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