U型弯头内气固两相流动磨损特性数值模拟

Numerical investigation on erosion characteristics of U-type elbow suffering gas-solid two-phase flow

在燃煤电站中,受外部空间所限,在管道布置中存在大量的U型弯头,这些U型管道中固体颗粒的流动是高雷诺数气固两相流,管壁的冲蚀磨损严重影响了火电厂安全可靠运行。本文采用计算流体力学的方法对U型管内气固两相流动磨损特性进行了研究,得到了管壁磨损分布特征以及颗粒在U型管内流动特点,研究了气流速度、颗粒浓度和颗粒尺寸对管壁磨损率的影响。结果表明:在研究参数范围内,管壁最大磨损率随气流速度呈指数增大,随颗粒浓度增大呈线性增大;颗粒直径增大也会加重管壁磨损。

In coal-fired power plants,the U-type bend is commonly used in the pipe system due to the constraints of outer space.In these pipelines,the flow of solid particles is gas-solid two-phase flow with high Reynolds number.The erosion on the tube wall seriously affects the safety operation of the power plant.In this paper,the erosion characteristics of the U-type bend were investigated through the computational fluid dynamics(CFD)method.The wear distribution on the tube wall was obtained,and the particle flow characteristics in the U-type bend were analyzed.Moreover,the influence of inlet velocity,mass loading rate and particle size on the erosion rate was studied.The result shows that,within the study scope,the maximum erosion rate increases exponentially with the inlet velocity and linearly with the mass loading rate.Additionally,increasing the particle size can also aggravate the wear on the tube wall.