弯管处两相流含汽率对流动加速腐蚀的影响

Influence of Vapor Rate of Two-phase Flow on Flow Acceleratedcorrosion at Elbow

电厂管道腐蚀的主要因素为流动加速腐蚀(FAC),其严重时会造成严重的人员伤亡和财产损失,故研究FAC以解决电厂管道腐蚀问题意义重大。采用flunet数值模拟方法建立二维弯管模型,重点研究弯管内弯处的流动加速腐蚀情况。以含汽率和流速两种参数为变量,重点研究含汽率对FAC速率的影响。在不同工况下进行多次模拟,得弯管内弯处,各个点位的剪切力。通过公式可由剪切力得到传质系数,最终可得到FAC的变化规律,在管内弯处,两相流的含汽率在0.5%时,内弯处FAC的速率最大。且在此含汽率下,随着流速的增加,FAC的加剧程度最剧烈。

Flow accelerated corrosion(FAC),the main factors of pipeline corrosion for power plant,power plant of pipeline corrosion can cause serious casualties and property losses,so the study of FAC to solving the problems of power plant pipeline corrosion is of great significance.Focusing on the Flow Accelerated Corrosion at the inner bend of the elbow,a two dimensional elbow model is established with FLUENT for numerial simulation.There are two variables that need to be considered in the model:steam rate and flow velocity.The focus is on the effect of steam rate on FAC rate.The model is used for simulations many times.and the shear force at each point of the elbow under different working conditions is obtained.The mass transfer coefficient is obtained through the shear force,and the change law of FAC is obtained.At the inner bend of the bend,when the steam content of the two-phase flow is 0.5%,the FAC rate at the inner bend is the largest.And under this steam content rate,with the increase of flow velocity,the degree of FAC aggravation is the most severe.