CFD-DEM simulation of tube erosion in a fluidized bed

The erosion of the immersed tubes in a bubbling-fluidized bed is studied numerically using an Eulerian-Lagrangian approach coupling with a particle-scale erosion model. In this approach, the motion of gas and particles is simulated by the CFD-DEM method, and an erosion model SIEM (shear impact energy model) is proposed to predict the erosion of the tubes. The model is validated by the good agreement of the simulation results and previous experimental data. By analyzing the simulation results, some characteristics of the tube erosion in the fluidized bed are obtained, such as the distribution of the erosion rate around the tube, the variation of the erosion rate with the position of the tube, the effect of the friction coefficient of particles on the erosion, the relationship between the maximum and the average erosion rate, etc. The microscale behavior of particles around the tubes is also revealed and the linear relationship between the erosion and the shear impact energy is confirmed by the simulation results and experiment. The agreement between simulation and experiment proves that the microscale approach proposed in this article has high accuracy for predicting erosion of the tubes in the fluidized bed, and has potential to be applied to modeling the process in other chemical equipment facing solid particle erosion. (c) 2016 American Institute of Chemical Engineers AIChE J, 63: 418-437, 2017