Investigation of motion characteristics of coarse particles in hydraulic collection

The solid-fluid two-phase flow with coarse particles is an important research object in the two-phase transportation field, such as deep-sea mining. This paper adopts the resolved computational fluid dynamics-discrete element method to investigate the motion and mechanical characteristics of the coarse particles during the hydraulic collection. First, the rising process of coarse particles by combining the particle trajectory with the qualitative force analysis is analyzed during the hydraulic collection. The spiral phenomenon of the particle is found through the particle trajectory in numerical results, and the centripetal force is the reason for the spiral phenomenon of the particle. Second, the variations of the normalized fluid drag force and the rise time of particles are investigated at different fluid velocities and particle sizes. The results show that the rise of particles during hydraulic collection results from the rising and settling effects characterized by the fluid drag force and the relative gravity, respectively. Finally, appropriate particle size is recommended to save energy and improve the efficiency of hydraulic collection. In addition, the influence of the horizontal distance between coarse particles and the inlet of the suction pipe on particle rise is discussed.