Discrete Particle Simulation of Plug Conveying in a Vertical Pipe

摘要

This paper describes a numerical simulation of the plug conveying in a vertical pipe. Trajectories of individual particles are solved by modeling the contact forces with the discrete element method(DEM). The motion of the fluid is calculated by solving the locally averaged equations taking account of the interaction between the fluid and the particles. The axisymmetry is assumed in the calculation of the fluid phase. The typical behavior of vertical plugs is obtained, that is, particles rain down from the back of a plug and are collected by the front of the plug below. The calculated pressure drop between two vertical positions is twice larger than that due to the weight of the particles as observed in the experiment by Konrad and Totah. It is confirmed that the shear stress acting on the pipe wall increases significantly when the falling particles hit the front of the plug.