CFD Analysis of Erosion on Elbows in Series for Gas-Solid Flows: Effect of Connecting Pipe Length between Two Elbows

Solid particle erosion (SPE) is one of the main causes of equipment failure in pipelines that convey solid particles. The characteristics of erosion in secondary elbows mounted in series, which are common in industrial pipelines, differ from the erosion observed in primary and single elbows. This difference is due to the secondary flows developed in the primary elbow, which influence the motion of particles impacting the secondary elbow. In the present work, computational fluid dynamics (CFD) based modeling, using the Eulerian-Lagrangian approach, is performed to simulate particle motion in a gas stream through a pipeline containing two elbows mounted in series. The particle-wall collision data is then used to predict the erosive wear behavior of the elbows using an available erosion model. The modeling is validated using available experimental data. Furthermore, the effect of the connecting pipe length between the two elbows on the erosion characteristics of the secondary elbow (H-V arrangement) is investigated. Simulations are conducted with connecting pipe lengths equal to three times the pipe diameter (3D), 8D, 16D, 30D, and 50D, for three different velocities and four different particle sizes. It has been found that the erosion of the primary elbow is more compared to the secondary elbow and increases with increase in particle size and velocity. The increase in connecting pipe length increases the erosion of the secondary elbow.