Numerical Simulation and Experimental Study of a Deep-Sea Polymetallic Nodule Collector Based on the Coanda Effect

Ore collection devices are important for the collection of deep-sea polymetallic nodules. Based on the CFD-DEM solid-liquid two-phase flow coupling calculation method, this paper simulated the rise and transport phases of polymetallic nodules using the Coanda effect ore collection device. The validity of the numerical simulation method was confirmed through experimental testing. On this basis, the effects of different working and structural parameters on the collection rate were studied. The results indicate that the flow rate of the collection jet and the bottom clearance were the primary factors affecting the collection rate of the polymetallic nodules. An increase in the collection jet flow rate leads to a substantial rise in the collection rate of polymetallic nodules. Conversely, an increase in bottom clearance results in a decrease in the collection rate. A collection rate exceeding 90% can be achieved in both scenarios: a 10 mm bottom clearance with an 8 m/s collection jet flow rate, and a 30 mm bottom clearance with a 10 m/s collection jet flow rate. The collection nozzle slant angle has no substantial impact on the collection rate, and the recommended collection nozzle slant angle is 35 degrees to reduce energy loss.