Investigation of film flow of a conducting fluid in a transverse magnetic field, (2)

In the case of liquid film flow, when the flow rate decreases, the liquid film becomes thin and breaks down, thus dry patches and stria form rivulets arise locally. Only the bottom of rivulets is in contact with a solid wall, and the side is supported by surface tension. Accordingly, they are apt to be affected by a lateral external force, and under magnetic field gradient, the width as well as the thickness of rivulets seem to change. Concerning the form control of molten metals in metallurgical and casting industries and the problem of cooling in nuclear fusion reactors, it is technologically important to clarify such flow. In this study, the effect of magnetic field gradient exerted on rivulets was clarified by analysis and experiment. The simple analysis was carried out to determine the distribution of the width and height of rivulets under magnetic field gradient. The experimental setup was the same as that in the previous report. Magnetic field gradient acted as a kind of non-contact nozzle or diffuser to rivulets. In the region of positive gradient, the height increased and the width decreased with the increase of a magnetic field. (Kako, I.)