Mathematical Simulation Of Arc In Vacuum Arc Remelting Furnace

Vacuum arc remelting furnace is a kind of furnace that uses arc to heat and smelting metal. The pinch effect of arc makes plasma’s density and temperature of central arc column increase greatly, So the amount of plasma bombarding the central part of consutrode is larger than anywhere else, this causes an effect that the molten speed along the radial direction of consutrode is not even. This phenomenon tends to extinguish the arc and goes against the normal operation of electric arc furnace. This thesis focus on building the model of vacuum arc and simulating it to provide theoretical foundation for the design of technological parameter of electric arc furnace.This thesis regards arc as a kind of fluid and builds a cone shape passage for the arc, which is the physical model of the vacuum arc. The vacuum arc follows the universal laws of both hydrodynamics and electromagnetism. According to the above characteristic of arc, the thesis has amended the momentum equation under 3D coordinate by adding separately the x direction momentum source term, y direction momentum source term, z direction momentum source term to it and added the joule heat produced by electric field to the source term of energy conservation equation. By introducing potential (p and magnetic vector potential A, the thesis has successfully deduced continuity equation of electric current and three-dimensional magnetic vector potential equation. The thesis also provides the boundary conditions of flow field and electromagnetic field.This thesis uses CFD software FLUENT as the platform for calculation and has accomplished the secondary development of FLUENT by using C language and its user defined functions. Then it has built a calculating model for vacuum arc and simulated the vacuum arc by using this model.The directional movement of charged particles will generate current and this current will generate toroidal magnetic field. The simulated result shows that the distribution of toroidal magnetic field along the radial direction of arc column is not even, Its intensity at the central part is relatively weak, but its gradient here is even. And its intensity at the edge of arc column is the strongest and its gradient is larger than anywhere else. The toroidal magnetic field distribute mainly near the cathode. It tend to distribute equably along the axis of arc column.The directional movement of charged particles in the lateral section of arc will generate current and this current will generate transverse magnetic field. The simulated result shows that its intensity will first increase and then decrease along the axis of arc column, and it will gradually increase reduction.The simulated result also shows that the pressure on the surface of weld pool distribute unequally. The applied force on it is the largest and will decrease from the center to its edge. But it mainly focus on the central part of weld pool.The simulation results show that the pinch effect of self-generated magnetic field compresses the volume of arc; the additional longitudinal magnetic field can increase the dynamic pressure to go against the pinch effect; the main reason causing the deformation of weld pool surface is melting current. It also gets the actual regularties of distribution of self-generated magnetic field and the additional longitudinal magnetic field. According to this distribution regularties, the thesis find the reason for rotary arc.