基于Dean涡效应的弯管冲蚀机理分析

Analysis of Erosive Corrosion Mechanism of Elbow Pipe Based on Dean Vortex Effect

冲刷腐蚀是船舶管路损伤失效的重要原因,而管道内介质的流动速度是影响冲刷腐蚀速率的关键因素。基于数值模拟方法,对90°弯管不同位置的液相介质速度分量进行了计算与分析,发现管道冲刷腐蚀速率并非由介质流动合速度决定,而是由与管道轴向垂直的横截面内的速度分量(Dean涡强度)决定。横截面内的Dean涡强度越大,介质与壁面金属基材之间的传质过程越快,越容易导致管道冲刷腐蚀加速。

Erosive corrosion is an important cause of damage and failure of ship pipelines,and the flow velocity of the medium in the pipeline is a key factor affecting the rate of erosive corrosion.Based on numerical simulation method,the velocity components of the liquid medium at different positions of the 90°elbow pipe are calculated and analyzed,and it is found that the erosive corrosion rate of the pipeline is not determined by the combined velocity of the medium flow,but determined by velocity component(i.e.the Dean vortex strength)in the cross section perpendicular to the axial direction of the pipeline.The greater the Dean vortex strength in the cross section,the faster the mass transfer process between the medium and the metal substrate on the wall,and the easier to accelerate the erosive corrosion of the pipeline.