大电流真空电弧磁流体动力学模型与仿真

为了对大电流真空电弧进行深入研究,以真空电弧双温度磁流体动力学模型为基础,通过计算流体动力学软件FLUENT,采用控制容积法,对大电流真空电弧特性进行了仿真研究。对于大电流真空电弧而言,等离子体的流动处于亚音速状态,因此,在阴极和阳极边界条件的选择上将区别于超音速流动的真空电弧。同时对等离子体密度、轴向电流密度、等离子体速度、马赫数、离子温度、电子温度、离子压力、等离子体压力以及注入阳极的能流密度分布的形成机理进行了分析。从仿真结果可以发现,大电流真空电弧等离子体压力的最大值出现在阴极附近,等离子体将在压力梯度的作用下从阴极到阳极做加速运动,这一点明显区别于超音速流动的真空电弧。另外,仿真结果与高速CCD照片也是吻合的。

Magnet Hydro Dynamic Model and Simulation of High-current Vacuum Arc

In order to research high-current vacuum arc more deeply, based on two-temperature magnet hydro dynamic MHD model of vacuum arc, characteristics of high-current vacuum arc are simulated and analyzed through computing fluid dynamic (CFD) software FLUENT and controlling- volume method. For high-current vacuum arcs, the plasma flow is in the subsonic status, so the boundary conditions of cathode side and anode side will be different from that of supersonic vacuum arcs. Simultaneously, the formation mechanism of the following plasma parameters distribution including plasma density, axial current density, plasma velocity, Mach number, ion temperature, electron temperature, ion pressure, plasma pressure and heat flux density to anode was analyzed. The simulation results show that the maximal plasma pressure of vacuum arc appears near the cathode side, and the plasma velocity increases from the cathode side to the anode side, which is significantly different from that of supersonic vacuum arc. The simulation results are in agreement with the high speed CCD photographs.