超临界机组流动加速腐蚀边界层流动模拟与分析

Simulation and Analysis on Boundary Layer Flow in Supercritical Units with Accelerated Corrosion

流动加速腐蚀(FAC)是电厂高压漏水、管道断裂等主要事故的原因,采用Fluent软件模拟管道的流动加速腐蚀规律,将微观与宏观研究联系起来,分析了温度、流速、管型与边界层流动及流动加速腐蚀之间的规律。结果表明:与其他温度相比,150℃时管道边界层处的Fe2+质量浓度增大,边界层的厚度更薄,边界层的腐蚀较严重,对流动加速腐蚀的影响也较大,为最易腐蚀温度;腐蚀速率随流速的增大而增大;T型三通管相比直管易发生腐蚀,且在流向改变处腐蚀最严重。

To solve the problems of water leakage and tube burst failures occurring in supercritical units at high pressures caused mainly by flow accelerated corrosion(FAC),an analysis was conducted from both micro and macro views to simulate the flow accelerated corrosion using Fluent software,and to study the effects of following factors on the flow accelerated corrosion,such as the temperature,flow rate,tube shape and boundary layer flow characteristics,etc.Results show that at 150℃,the Fe^2+concentration is relatively high in boundary layer,with smaller thickness of boundary layer,and severer corrosion in that place,indicating that flow accelerated corrosion is easy to occur at 150 ℃.The corrosion rate increases with rising flow rate.Flow accelerated corrosion appears more easily in tee tube compared with straight tube,and the severest corrosion generally occurs in the place where flow direction changes.