Research on the Non-uniform Flow Characteristics in a Screw Mixed-flow Deep-sea Mining Pump

Deep-sea slurry pump is a crucial component for achieving vertical transportation of ore particles in pump-pipe lifting deep-sea mining systems. However, traditional mining pump structures face challenges, such as insufficient particle flow capacity and blockage susceptibility, which affect the slurry pump's operational stability. This study introduces a novel deep-sea slurry pump design that incorporates the non-clogging structural characteristics of a screw mixed flow impeller combined with a diffuser. The pump flow capacity was evaluated using the CFD-DEM (Computational Fluid Dynamics - Discrete Element Method) coupling method for transporting 10 mm spherical particles at various flow rates. The motion patterns and non-uniform distribution characteristics of particles were analyzed qualitatively and quantitatively within the pump under different inflow conditions. The proposed pump demonstrated a robust coarse particle overflow capacity for varying particle transport states and unequal particle distribution among flow components. The particle quantity changed consistently throughout the transportation process and was divided into a growth phase and a stable phase. The main flow components exhibited a dynamic non-uniform particle flow with a more pronounced periodic nature in the impeller channel. The degree of non-uniform particle flow in the diffuser channel was inversely related to the flow rate， and was higher compared to the impeller channel.