PRELIMINARY EXPERIMENTAL STUDY ON THE LIQUID METAL FILM FLOW RELATED WITH FUSION NUCLEAR

Liquid lithium film flow is a superior choice for the plasma facing components in magnetic confinement fusion due to its advantages of removing impurities, protecting the solid surface directly against the plasma. However, it is a great challenge to overcome the magnetohydrodynamic effect on film flow and to realize the uniform spreading of film flow on a solid plate under the influence of an intense magnetic field in the nuclear fusion plant. In the present paper, based on the liquid GaInSn loop and the liquid lithium loop, we carry out experiments of liquid metal film flowing on the inclined electric conductive plate with the applied transverse magnetic field. The visualization method is adopted to observe the surface structures of film flow under different experimental conditions. By comparing the experimental results of liquid GaInSn and liquid lithium, we find that the characteristics of surface waves of liquid metal are the same as that of normal liquid without a magnetic field, namely the surface waves become chaotic with the increase of Reynolds number, while the characteristics change greatly under the influence of transverse magnetic field. The surface waves of liquid GaInSn film flow become quasi two-dimensional and parallel to the magnetic lines, while the liquid lithium film flow is nearly stagnated at a fixed position, indicating the existence of a strong magnetohydrodynamic resistance. Moreover, the stagnation point moves far away from the film generator at a larger Reynolds number. Finally, by analyzing the force loaded on the film, we make a detailed explanation of the phenomenon that the magnetohydrodynamic effect is much stronger on the liquid lithium flow than on the liquid GaInSn flow.