基于电位矩阵法的金属管道腐蚀剩余厚度监测研究

Research on Monitoring the Remaining Thickness of the Corrosion of Metal Pipe Based on the Field Signature Method

针对目前电位矩阵法在坑蚀的情况下求解剩余厚度的精度仅为壁厚的±(10%～15%),并且要用经验系数修正的问题,在分析了监测区域在腐蚀前后的电流场的改变是产生坑蚀精度误差的主要原因的基础之上,提出了一种利用电阻网络的数学模型来计算坑蚀剩余厚度的方法。管道腐蚀可以等效为探针之间电阻值的变化,因此根据监测的金属管道上所布置的探针间距和数量来确定1个单层电阻网络,然后利用基尔霍夫定律计算出各个电阻在腐蚀前后的电流值,最后建立腐蚀前后电阻函数关系,将坑蚀时电流变化的因素消除,得到精度较高的剩余厚度值计算公式。有限元分析软件仿真和实际实验结果表明,新的坑蚀剩余厚度算法的精度可以达到壁厚的3%,且不需要经验系数修正,验证了新算法的可行性。

Aiming at the problem that the accuracy of remaining thickness of the field signature method（FSM） is ±（10%~15%） of the wall thickness in pit corrosion and should be modified by empirical coefficient,a new method was proposed to calculate the remaining thickness in FSM using the mathematical model of resistor network,which was based on the analysis of change of current field in monitoring area.The corrosion of pipe can be equivalent to the change of resistor between probes,and a single resistor network can be determined by the distance and amount of probes in monitoring area of pipe.The current of resistor can be calculated before and after corrosion with Kirchhoff’s law.The function relation of resistor before and after corrosion is established,and the formula of remaining thickness in high accuracy is obtained after the factor of change of current field is eliminated.The simulation in finite element analysis software and experiment results showed that the new algorithm of remaining thickness of pit corrosion is much higher than the algorithm commonly used at present in accuracy,and don’t need to modify by empirical coefficient,which showed that the efficiency calculation method is practical.