CFD modelling of the influence of particle loading on erosion using dense discrete particle model

Abstract

The present study aims at modelling erosion using Dense Discrete Particle Model (DDPM). The numerical model is based on Eulerian-Eulerian-Lagrangian approach which has been developed for modelling both dilute and dense particulate flows. In this approach, the continuous phase is modelled on a fixed Eulerian grid and particles are tracked by using Lagrangian model. However, the particulate phase is also represented on the Eulerian grid and the inter-particle interactions are modelled by employing the kinetic theory of granular flows. Numerical simulations are first performed for a low Stokes number flow of slurry jet test and a high Stokes number flow of dry jet test. The numerical results for slurry jet test indicate a reasonable accuracy of the model in predicting the erosion distribution. Furthermore, the obtained numerical results suggest a reduction of erosion ratio at high particle loadings which agree well with the experimental data in this study. However, the predicted erosion reduction for the high Stokes number flow of dry jet test is significantly higher than that in low Stokes number slurry flow. The present results indicate that there exist a critical particle loading beyond which the erosion reduction becomes significant (more than 20%). However, the magnitude of the critical particle loading for the high Stokes number flow is significantly lower than that in low Stokes number flow. Moreover, the influence of particle loading on the erosion ratio and the flow-field in an elbow conveying two-phase gas-sand flow is investigated. The numerical results clearly revealed a reduction of erosion ratio at high particle loading conditions. Furthermore, a comparison of the obtained results by using DDPM and one-way coupled DPM model shows the importance of considering the influence of inter-particle collisions as wells as coupling between the fluid and particles at high particle loading conditions.