直流电压下植被燃烧颗粒在火焰间隙中的运动分析

Motion Analysis of Vegetation Combustion Particles in Flame Gap under DC Voltage

近年来山火引起输电线路跳闸事故频发.植被燃烧产生的荷电颗粒畸变电场、产生触发放电是引起间隙放电的关键因素.在正负极性直流电压下,荷电颗粒运动和分布的差异对击穿电压有较大影响.为此,建立简化模型进行温度、流体、电场和颗粒运动的多物理场耦合分析.首先根据典型植被火焰燃烧的放热率,仿真计算温度和流体速度.然后结合流体场和电场,仿真分析不同极性颗粒的受力过程.结果表明,在靠近火焰中部的颗粒受曳力和电场力作用更大,更容易被电极吸附或排斥;荷质比越大,颗粒其受电场力和曳力作用越大.最后分析了不同极性颗粒的运动和分布规律.

In recent years,forest fires have caused frequent tripping accidents of transmission lines.The distorted electric field of charged combustion particles are the key factors causing gap discharge.Under positive and negative DC voltage,the difference of movement and distribution of charged particles has a great influence on the breakdown voltage.In this paper,a simplified model is established for the coupled analysis of temperature,fluid,electric field and particle motion.Firstly,according to the heat release rate of typical vegetation flame combustion,the temperature and fluid velocity are simulated and calculated.Then,combined with the fluid field and electric field,the force process of different polar particles is simulated and analyzed.The results show that the particles near the middle of the flame are more likely to be adsorbed or repulsed by the electrodes because of the drag force and electric field force,and the larger the charge-mass ratio,the greater the electric field force and drag force acting on the particles.Finally,the movement and distribution of different polar particles are analyzed.The results can provide a basis for the study of gap breakdown mechanism under positive and negative polar flame conditions.