Numerical Simulation of Erosion Wear for Continuous Elbows in Different Directions

The purpose of the present study is to simulate the continuous bend erosion process in different directions, using the dense discrete particle model (DDPM). The influence of the length of the straight pipe in the middle of the continuous bend is investigated. The Rosin–Rammler method is introduced to define the diameter distribution of erosion particles, which is theoretically closer to the actual engineering erosion situation. The numerical model is based on the Euler–Lagrange method, in which the continuous phase and the particle phase are established on a fixed Euler grid. The Lagrange model is used to track the particles, and the interaction between particles is simulated by particle flow mechanics theory. The velocity field distribution, pressure variation, and turbulent kinetic energy of gas–solid two-phase flow, composed of natural gas and gravel in the pipeline, are studied. The simulation results, using the one-way coupled DPM and the four-way coupled DDPM, are compared and analyzed. The results show that the DDPM has good accuracy in predicting the distribution of the continuous bend erosion processes in different directions. The erosion rates of particles with an average distribution size of 50 µm are significantly increased (8.32 times), compared with that of 10 µm, at the same gas transmission rate. It is also indicated that it is important to consider the impact between particles and the coupling between fluid and particles in the erosion simulation of the continuous elbow when using the CFD method.