P11钢在湿蒸汽中流动加速腐蚀性能的模拟与实验研究

Research of Flow Accelerated Corrosion of P11 in Wet Steam

在核电厂中,二回路碳钢管道的流动加速腐蚀(FAC)对安全生产造成很大影响。根据工程经验和实验室数据,采用Cr含量超过0.1%的碳钢管道可大幅减轻或避免FAC。Cr含量大于1%的SA335-P11钢以其较好的性价比而多被推荐用于核电站蒸汽管道。为了确认P11钢表面氧化膜在高流速湿蒸汽作用下的稳定性,本文采用小型管状试样进行了FAC实验,得到了试样的减重规律和内表面的腐蚀形貌。实验结果表明,试样入口部分形成了明显的FAC形貌,表面氧化膜破坏严重,而在试样的中部,FAC不明显。CFD模拟结果表明,试样入口处局部流速较平均流速高约24%,表面剪切力大,与实验结果一致。

In nuclear power plants, the flow accelerated corrosion （FAC） of carbon steel occurs mainly in the secondary circuit, causing a significant impact on production safety. According to engineering experience and experiment data, carbon steel pipes with Cr more than 0.1% can greatly reduce or avoid the FAC, and based on the high cost performance, SA335-Pll steel with Cr greater than 1% is recommended for steam pipes of nuclear power plants. In order to confirm the Pll steel surface oxide film under wet steam at high velocity, the small tubular specimens to finish FAC experiments were adopted, achieving the sample weight loss and morphology of inner surface corrosion. Experimental results show that a clear FAC morphology is formed at the inlet part of sample and the surface oxide film is damaged severely, and in the center of the sample, flow accelerated corrosion is not obvious. CFD simulation results show that the entrance velocily is about 24% higher than the average flow velocity, resulting into larger surfaceshear force, which is consistent with the experimental results.