Abstract:

Aiming at the flow-accelerated corrosion (FAC) problem in feed water system and drain system of supercritical boilers, a combination of experimental data and numerical simulation was used to analyze the corrosion of the 90° elbow. In the experiment, the FAC rate of elbows at different inlet velocities was measured by electrochemical method, and the experimental data were analyzed; the flow field of elbows at different inlet velocities was calculated by using numerical simulation methods; finally, based on the M.I.T model, the FAC model of the 90° elbow is simplified at room temperature, and the field synergy principle was used to analyze the characteristics and influencing factors of the FAC distribution at different positions of the elbow from the perspective of fluid dynamics. The analysis shows that along the flow direction, the higher the mass coefficient is, the higher the cross-section is; the greater the radial velocity of the center, the greater the rate of the bend FAC.

Key words: numerical simulation, model reduction, hydrodynamics, flow-accelerated corrosion, elbow

摘要：

针对超\超超临界机组给水、疏水系统的流动加速腐蚀（FAC）问题，采用了实验和数值模拟相结合的方法来分析90°弯管的腐蚀情况。实验中，利用电化学方法测得不同入口速度下弯管的FAC速率，并对实验数据分析；利用数值模拟的方法，计算出不同入口速度下弯管的流场；最后，基于M.I.T模型，在常温条件下简化90°弯管的FAC模型，结合场协同理论从流体动力学角度分析了弯管不同位置的FAC分布的特点及影响因素，得出在沿流动方向上传质系数越高，指向截面中心的径向速度越大，弯管FAC速率越大。

关键词: 数值模拟, 模型简化, 流体动力学, 流动加速腐蚀, 弯管