Numerical investigation of the hydraulic transport of coarse particles in a vertical pipe based on a fully-coupled numerical model

The hydraulic transport of coarse particles in a vertical pipe is simulated in this work and the influences of different mechanisms of the fluid-particle interactions on the liquid-solid flow are estimated. The two phase flow is simulated based on the Eulerian-Lagrangian framework. An in-house interface code is created to couple the commercial solvers of the Computational Fluid Dynamics (CFD) and the Discrete Element Method (DEM). The code also provides a platform to implement the advanced fluid-particle interactions, such as the modification of lift force, the turbulent fluctuation of particle and the turbulence modulation. The numerical model is validated with the experiments in a vertical pipe. The results indicate the role of lift force is not trivial even in the simple vertical pipe for liquid-solid flow. The widely used Saffman and Magnus lift force is not appropriate for such flow from the perspective of modeling particle distribution. The Loth lift force provides the best match with the experiment. The pressure gradient force significantly affects the particle distribution in the pipe while the virtual mass force is marginally acted. Finally, the particles and turbulence are mutually affected in a complex manner and this interaction should be considered in the simulation.