Naphthenic Acid Erosion-Corrosion Analysis of Eccentric Reducing Elbow Pipe Based on Fluent

In the environment of high temperature naphthenic corrosion, the flow distribution in the straight parts and elbow parts of eccentric reducing elbow pipes in different structures and sizes was analyzed using software of Fluent. The change of flow velocity and wall shear stress in eccentric reducing elbow was analyzed in conjunction with the high temperature erosion mechanism of naphthenic acid, to show how the erosion-corrosion in eccentric reducing elbow was influenced by flow distribution, and to predict and verify the places easily corroded. The results show that elevated levels of shear stress were found along the elbow lateral, elbow extrados and the 180°~360° of the straight pipe after the reducer, where naphthenic acid erosion-corrosion easily occured. With the increase of the straight pipe length, the shear stress in elbow intrados increased, the shear stress in elbow lateral decreased, the shear stress in elbow extrados did not change. Therefore in the actual testing, not only the elbow lateral and extrados but also the elbow intrados are necessary to be checked for eccentric reducing elbow with long straight pipe.