温度对碳钢管道流动加速腐蚀失效影响的数值模拟

Numerical Simulation of Effect of Temperature on the Flow Accelerated Corrosion Failures of Carbon Steel Pipe

在电厂汽水管道的运行中,流动加速腐蚀(FAC)普遍存在,威胁着管道系统安全。为很好地预测电厂管道流动加速腐蚀,基于电厂管道实际工况,采用流体动力学软件调整水的物性参数,模拟碳钢在T型三通分流管的流场,并结合预测模型精确分析了FAC速率随温度的变化。结果显示:T型三通分流碳钢管道在辅出水口下游迎流面处的速度、湍流动能及壁面剪切力均出现最高值,流动加速腐蚀最严重;温度通过影响速度及粘性系数,进一步影响到壁面剪切力及传质系数,最终影响到FAC速率;在150℃以下,温度对FAC速率的影响主要是通过传质系数实现的。

During the operation process of steam and water pipes in power plant,flow accelerated corrosion(FAC)is widespread,threatening the safety of pipeline system.In order to predict accurately the accelerated corrosion of power plant pipelines,based on the actual working conditions of power plant pipelines,fluid dynamics software was employed to adjust the physical properties of water,simulate the flow field of carbon steel in T-type three-way shunt,and accurately analyze the variation of FAC rate under different temperate through prediction model.Results showed that the velocity,turbulent flow energy and wall shear force of the T-type three-way splitting carbon steel pipe at the upstream surface of the auxiliary water outlet reached the maximum,and the FAC was the most serious.Furthermore,the temperature affected the speed and viscosity coefficient,and further changed the wall shear force and mass transfer coefficient,which ultimately played important role on the FAC rate.When the value was lower than 150℃,the effect of temperature on the FAC rate was mainly achieved by the mass transfer coefficient.