Experimental study of cylinder wakes in electrolytes under axial magnetic field

导电性流体在磁场影响下的流动在很多情况下都会发生，从地核中液态铁的流动到材料加工过程中熔融钢、铝或钛的运动。由于液态金属是不透明的，它们的内部不能被可视化，这严重阻碍了我们对磁流体动力学（MHD）流动的理解。本项目的目的是证明，由于伊尔梅瑙工业大学的超导5特斯拉磁体，可以克服实验MHD的这一基本限制。该设备允许我们用透明电解质代替不透明液态金属进行MHD实验。实验计划将包括设计、建造和开发一个紧凑的电解质通道，在该通道中，将研究围绕圆柱形障碍物的mhd流动。实验过程将包括使用示踪粒子和染料进行速度可视化，以及使用激光多普勒测速仪和电势测速仪对30 < Re < 900范围内的可变雷诺数和0 < Ha < 30范围内的可变哈特曼数进行速度测量。这是第一次，实验将提供一个直接的光学途径，以达到以前从未被直接观察到的柱体上方的mhd柱。这一信息对于包括夹杂物分离和磁制动在内的各种磁场工业应用具有潜在的用途。

Flows of electrically conducting fluids under the influence of a magnetic field occur under a wide range of circumstances ranging from the flow of liquid iron in the Earth s core to the movement of molten steel, aluminium or titanium in materials processing. Since liquid metals are opaque, their interior cannot be visualized, which severely hampers our understanding of magneto hydrodynamic (MHD) flows. The purpose of the present project is to demonstrate that this fundamental limitation of experimental MHD can be overcome thanks to a superconducting 5-Tesla magnet at Ilmenau University of Technology. This facility permits us to perform MHD experiments with transparent electrolytes instead of opaque liquid metals. The experimental program will involve design, construction and exploitation of a compact electrolyte channel in which the MHD-flow around a cylindrical obstacle will be studied. The experimental procedure will involve velocity visualizations using tracer particles and dye as well as velocity measurements using laser Doppler velocimetry and electric potential velocimetry for variable Reynolds number in the range 30 < Re < 900 and with variable Hartmann numbers in the range 0 < Ha < 30. For the first time the experiments will provide a direct optical access to MHD-columns above the cylinders which have never before been directly observed. This information is potentially useful for a variety of industrial applications of magnetic fields including separation of inclusions and magnetic braking.