脉冲放电破岩等离子体通道长度预测方法

Method for predicting plasma channel length for rockbreaking by pulsed discharge

针对高压脉冲放电破岩电弧等离子体通道长度难以预测的问题,构建了高压脉冲放电破岩综合试验平台,测量了花岗岩-自来水组合介质下电弧等离子体通道发展特性及典型电流、电压参数,提取了不同电极间距和脉冲放电次数下岩石表面形成的破碎区域。基于能量平衡方程建立了岩石中电弧等离子体通道的阻抗模型,采用迭代优化算法获取阻抗模型参数的近似最优解,模型计算结果与试验结果的相对误差小于7%。基于优化参数,利用实测电流电压数据预测了等离子体通道的长度。模型预测的等离子体通道长度与实测值的绝对误差均处于毫米量级,且两者的相对误差小于10%,为高压脉冲放电破岩系统电源-电极负载的匹配设计提供了理论支撑。

Aiming at the difficulty of predicting the length of rock-breaking arc plasma channel by high voltage pulse discharge,a comprehensive test platform for rock-breaking arc plasma channel by high voltage pulse discharge was constructed.The development characteristics and typical current and voltage parameters of arc plasma channel under granite-tap water combined medium were measured,and the broken region formed on the rock surface under different electrode spacing and pulse discharge times was extracted.Based on the energy balance equation,the impedance model of the arc plasma channel in rock is established.The approximate optimal solution of the impedance model parameters is obtained by iterative optimization algorithm.The relative error between the calculated results and the experimental results is less than 7%.Based on the optimized parameters,the length of plasma channel is predicted by the measured current and voltage data.The absolute error between the plasma channel length predicted by the model and the measured value is in the order of mm,and the relative error is less than 10%,which provides theoretical support for the matching design of power-electrode load in the high-voltage pulse discharge rock breaking system.