On the Influence of Magnetic and Electrical Fields in Gas Lubrication

Abstract

The paper examines some of the possibilities of MGD lubrication by considering some typical examples of external electromagnetic conditions and some simple types of bearings. Thus, for self-acting films, the case when an external tangential magnetic field combined with a transversal electrical field is studied. Pressures and load capacity are thus improved and, in addition, the friction forces can be diminished and even eliminated. For externally pressurized films, insulated surfaces subjected to an external transversal magnetic field can reduce the flow, provided that the Hartmann number has a sufficiently high value. Finally, it is pointed out that it is possible to produce pressures by electromagnetic means only. The electromagnetic pumping effect is produced, for instance, when a transversal electrical field is applied, combined with a tangential magnetic field, even when both lubricated surfaces are at rest. Some considerations concerning the practical possibilities of obtaining an electrically conductive gas at relatively low temperatures are also given.