Effects of local velocity components on flow-accelerated corrosion at 90° elbow

Abstract

Experimental and numerical studies are conducted to investigate the effects of turbulent parameters on flow-accelerated corrosion (FAC) behavior of low carbon steel at 90° elbow. The experimental testing of flow-accelerated corrosion behavior was carried out by the array electrode technique in a circulating loop system. The measurement of electrochemical corrosion test shows that the maximum corrosion current density is located in the extrados side of test section while the minimum value appears at the intrados side, consistent with the typical flow-accelerated corrosion induced failures of turbine plant pipelines and equipment. In addition, the flow behavior inside piping components of the loop system were sufficiently simulated by computational fluid dynamics (CFD) simulation and turbulent parameters were compared with flow-accelerated corrosion rate. With respect to the comparison of the results, the radius direction local velocity component (vr) is in good accordance with the configuration of corrosion current density. Therefore, the present results reveal the radius direction local velocity component is a major parameter for predicting the pipe-wall thinning of the 90° elbow due to flow-accelerated corrosion.