Numerical Investigation of Recommended Operating Parameters Considering Movement of Polymetallic Nodule Particles during Hydraulic Lifting of Deep-Sea Mining Pipeline

Abstract

Previously conducted studies have established that pipeline hydraulic transport systems are currently the most promising deep-sea mining systems, and the pipeline transport performance of polymetallic nodules is one of the technical priorities. In this paper, a coupled CFD–DEM approach is adopted to numerically calculate the solid–liquid two-phase flow of seawater with polymetallic nodules. Small-scale experiments were conducted to validate the coupled model. Particle dynamics analysis was carried out under different inlet flow rates, feed concentrations and nodule fragmentation levels. The simulation results show that different operating parameters have significant effects on the pipeline transportation process. With low inlet flow rate, high feed concentration, and high percentage of large particles, the particle distribution and motion characteristics show a trend that is not conducive to safe transport. A set of recommended operating parameters for hydraulic transport of polymetallic nodule pipelines was summarized.