Characterization of the ellipsoidal particle motion in a two-stage lifting pump using CFD-DEM method

The lifting pump is the core power equipment of the solid–liquid mixing system in deep-sea mining, but maintaining its stable operation while transporting particles is a major challenge for deep-sea mining hydro-transportation technology. This paper employs a CFD-DEM model suitable for the motion of ellipsoidal particles within a lifting pump and calculates the particle upstream surface at different inclination angles. Hydraulic transport of three types of ellipsoidal particles with aspect ratios of 1.0, 1.5 and 2.0 was simulated. An analysis of the motion characteristics of particles with different aspect ratios in a two-stage lifting pump found that an increase in aspect ratio decreased the overall velocity of the particles. When the aspect ratio increased, the aggregation effect of particles at the impeller inlet became more significant, and the conveying stability of the lifting pump decreased. Particles with high aspect ratios tend to clog the impeller vane inlets and create gyrations in the diffusion section of the pump. The peak velocity slip of particles in the diffusion section (pump outlet) decreases with an increasing aspect ratio. The results of the study will provide engineering theoretical support for the stable operation of lifting pumps.