电弧的温度场、速度场及辐射对螺旋不稳定性影响的数值模拟

【作者】 徐翔；

【导师】 宫野；

【作者基本信息】 大连理工大学 ， 等离子体物理， 2004， 硕士

【摘要】 电弧等离子体放电电压较低(10～100V)，而放电电流则可以很大(0.1～1000A以上)，在电极间整个弧区发出很强的光和热，具有温度高、能量集中和反应环境可控等特点，在很多领域里都获得了广泛的应用。因此，有必要了解电弧的温度场和速度场分布及其不稳定性。 本文的研究分为两个部分。 第一部分：采用标准SIMPLE算法，并作了一些修正，给出了具体的计算步骤和流程图，将其应用于磁流体动力学(MHD)方程进行数值求解。得到了轴对称情况下，自由燃烧弧的温度场和速度场的分布，和实验结果比较接近。分析了不同辐射模型对温度场的影响，发现辐射导致电弧温度降低，但在弧温较低的情况下对温度影响很小。 第二部分：采用沿径向双通量辐射模型和与时间有关的线性微扰理论，讨论了在轴向磁场中影响电弧螺旋不稳定性的一些因素。在考虑这些因素的情况下，给出了电弧的稳定性条件，不稳定性增长率，临界Maecker’s数等定量结果。计算结果表明，对于小电流电弧，辐射使得电弧的螺旋不稳定性降低。更多还原

【Abstract】 The discharge voltage of arc plasma is very low, about 10-100V, but the current is very high, about 0.1-1000A or more. There are strong light and heat between the electrodes. The characteristics of arc such as high temperature, concentrated energy, easily control and so on make arc applied in wide fields.My paper includes two parts.In the first part, the SIMPLE algorithm is used to solve the MHD equations and the solutions of MHD equations are presented for the whole free-burning arc, excluding the electrodes. The SIMPLE algorithm has been revised in order to solve MHD equations, and the flow chart is showed. A self-consistent numerical solution of the MHD equations yields the temperature and velocity distributions. And different types of radiation term are examined on the numerical results and it is found that the radiation term redults in a small decrease on the temperature of the arc.In the second part, the yan jingxiang shuangtongliang model for radiation and the linear time perturbation theory are used in this paper, and the helical magnetic instability is analysed in an axial magnetic field. The marginal Maecker’s number and the growth rate of the helical instability are given. The numerical results show that the radiation term redults in a small decrease on the temperature of the arc for the low current arc.更多还原