CFD-DEM Simulation of the Transport of Manganese Nodules in a Vertical Pipe

Abstract

The present study aims to describe the characteristics of the hydraulic transport of manganese nodules in a vertical pipe. The solid–liquid two-phase flows were simulated using a numerical technique that combines the computational fluid dynamics (CFD) method and the discrete element method (DEM). Manganese nodules with diameters of 5.0 mm, 15.0 mm, and 30.0 mm were selected. The effects of the initial solid volume fraction and the initial mixture velocity were investigated. The results show that with increasing initial solid volume fraction, the liquid and solid velocities decrease but the total pressure drop over the pipe increases. Small particles are responsible for high particle collision frequency, which causes decreases in both the liquid velocity and the total pressure drop. Energy loss is aggravated by increasing the initial mixture velocity, manifesting in the increase of the total pressure drop. The retention ratio of manganese nodules varies inversely with the initial mixture velocity. A formula is proposed to describe the pressure drop due to the presence of solid particles and collisions.

Keywords

• manganese nodules
• hydraulic lift
• vertical pipe
• CFD-DEM coupling
• pressure drop
• slip velocity