Analysis of Arc Phenomena in Boundary Layer Of MHD Generator Channel

Abstract

By means of a time-dependent two-dimensional numerical simulation utilizing the Finite Element Method, we study arc phenomena analytically in the boundary layer of the Faraday MHD power generator using petroleum-fired gas plasma as the working fluid, and get the following several results. On the anode side, the calculated values of the electrode voltage drop agree very well with the experimental ones, which demonstrates that the calculation simulates the experiment considerably well. On low temperature electrode, the current flow becomes the big arc with high temperature and large current density. The generation, movement, keeping and disappearance of the arc depend on a balance among the effect of convection, the Hall effect and the braking force based on the Lorentz force. The positions of the generated arc and the behavior of the arc-cycle are decided mainly by the effect of convection and by the electrode temperature. The period of the arc-cycle and the width of the arc are closely connected with the temperature of the electrode wall and the load resistance.