A numerical study of the slurry erosion in 90° horizontal elbows

The slurry erosion processes of horizontal elbows are investigated numerically using an Eulerian-Lagrangian method coupled with particle rebound and erosion model. First, a mechanical model for the internal multiphase flow involving slurry erosion in the 90° horizontal elbow is established and the corresponding governing equations are presented. Then, a two-way coupled numerical solution procedure is developed and its accuracy and stability are examined carefully using benchmark pipe flow models with experimental results. Using the validated numerical methods, the effects of flow velocity, fluid density and fluid viscosity on the flow and slurry erosion in the horizontal elbow are analyzed in detail. Finally, a prediction method of erosion rate distribution based on the pipe Froude number, particle Stokes number and the Dean number is proposed. In this method the pipe Froude number is employed to qualify the effect of ununiform distribution of particles, particle Stokes number and Dean number are combined to qualify the effects of inertia force, drag force and secondary flow. Using this approach, the location of the maximum erosion rate in horizontal elbows under different operating conditions can be predicted more conveniently.