水平磁场作用下金属液滴撞击电解质液池表面的实验研究

Liquid metal drop impingement on an electrolyte solution pool surface under the influence of a horizontal magnetic field

通过实验研究磁场环境中金属液滴撞击电解质液池所产生的物理现象。实验装置包括恒定磁场系统、金属液滴发生系统、具有氩气保护的液滴撞击实验容器、高速摄影系统4个部分。本实验可以实现高速精细地观察无氧环境中不同水平磁场强度、液滴直径、初速度条件下金属液滴撞击液池的物理过程。实验中液面上方现象可以归纳为3种:伴随二次液滴的细射流、伴随即时飞溅的粗射流,以及伴随二次液滴的粗射流。其中,伴随即时飞溅的粗射流为施加水平磁场后特有的现象。并且,外部水平磁场会抑制中心射流的高度和二次液滴的产生,且磁场强度越大,抑制效果越明显。同时,在液面下方观测到5种现象(椭球震荡、扁平震荡、碗状形变、解体破碎、第2次碗状形变)。外部水平磁场可以改变这些现象发生的临界We以及液滴在运动过程中的演化形态。此外,通过对比液面上方和液池内部金属液滴所产生的现象,获得2种不同区域液滴运动特性的关联性。实验结果表明在外部磁场环境下,金属液滴撞击电解质液池会产生复杂的物理现象,需要后期开展更为详细的实验和数值模拟工作。

In the present paper,we experimentally investigate the impingements of a liquid metal drop on the electrolyte solution pool.The experimental setup consists of an electromagnet,liquid metal droplet generating system,argon-protecting vessel for drop impact,and high-speed imaging system.The setup can capture the dynamic phenomena of droplet impact upon and below the free surface of the electrolyte pool under different conditions(with or without a magnetic field,different droplet diameters,and impact velocities).Upon the surface of pool,we observed three typical outcomes after drop impact on the pool,namely,thin jet with second droplet,prompt splash with a thick jet,and thick jet with second droplet,among which the prompt splash with the thick jet is only observed in the presence of horizontal magnetic field.The horizontal magnetic field can inhibit the height of central jet and the occurrence of second droplet,and such effect becomes stronger when the strength of magnetic field increases.On the other hand,several phenomena were observed below the surface of pool,i.e.ellipsoid vibration,flat vibration,bowl deformation,the collapse and second bowl deformation with or without magnetic field.The horizontal magnetic field,which promotes a“bulge”of the flat vibration and bowl deformation,affects the critical We of the occurrence of bowl deformation,the collapse and second bowl deformation.In addition,we found the relationships between the motion of liquid metal drop upon and below the surface of pool.Experimental results reveal that the complex phenomena can be observed when the liquid metal drop impacts on the electrolyte solution pool under the influence of an external magnetic field,it is worthy of further investigations both by detailed experiments and numerical simulations.