Dynamic Mixing Pipe Under Deep Sea Current Disturbance

Abstract Deep-sea mining offers a promising avenue to address the escalating global demand for mineral resources; however, substantial challenges persist in achieving efficient and stable transport of minerals from the seabed to the surface. This research explores the impact of pipeline vibrations induced by ocean currents on the dynamic behavior of solid-liquid two-phase flow within hydraulic lifting systems, employing a coupled CFD-DEM methodology. A systematic analysis was conducted to evaluate the influence of feed concentration, transport velocity, and oscillation frequency on particle dynamics, flow characteristics, slip velocity, and solid volume fraction. The findings reveal that an increase in feed concentration enhances both axial velocity and turbulent kinetic energy, resulting in intensified particle interactions, albeit accompanied by a rise in system instability. Low-frequency oscillations (0.25 Hz) were found to promote particle clustering and augment flow resistance, whereas moderate-frequency oscillations (0.5 Hz) facilitated mixing while maintaining system stability. In contrast, high-frequency oscillations (1 Hz) exacerbated turbulence and particle collisions, thereby elevating the risk of blockages. Sensitivity analysis identified feed concentration as the most critical factor affecting particle clustering, surpassing the effects of transport velocity and oscillation frequency. These insights contribute significantly to the optimization of deep-sea mining hydraulic lifting systems, enhancing both stability and efficiency in complex oceanic environments.