Research On Two-Phase Flow Characteristics Of Ore Particle Hydraulic Concentration And Lifting In Deep Seabed

Due to the advantages of high economic benefits and less disturbance to the environment,hydraulic ore collecting and lifting technology has gradually become an important supporting technology for commercial mining in deep-sea mining systems.Based on the method of CFD-DEM coupled numerical simulation and experimental verification,this paper studies the dynamic characteristics of solid-liquid two-phase flow in the process of hydraulic concentration and lifting,and analyzes the key factors affecting the safety and operation efficiency of the system.(1)The theoretical analysis model of solid-liquid two-phase flow is introduced,and the Euler-Lagrange method is used to establish the governing equations of fluid and particles,and the fluid force and contact force on particles are analyzed.The data coupling calculation of solid-liquid two-phase flow is realized by using Fluent and EDEM software,and the material parameters and general settings in the numerical simulation are expounded.(2)The simulation model of the double-row nozzle hydraulic ore collector is constructed,and the hydraulic ore collecting process under different parameters is numerically simulated,and the velocity distribution of the flow field and the particle movement trajectory are obtained,and the formation principle of the collecting effect of the collector is expounded.Based on the characteristics of the two-phase flow,the influence law of the velocity of the collecting nozzle and the height above the ground on the collecting performance of the collector is summarized.The proposed parameter setting range is: the flow velocity of the collection nozzle is 12-13m/s;the height above the ground is60-70 mm.The accuracy and reliability of the coupling calculation method are verified by the hydraulic collection test.(3)The coupled simulation of the hydraulic lifting process of the vertical transportation pipeline of the deep-sea mining system is carried out,and the dynamic characteristics of the two-phase flow inside the pipeline under different inlet flow rates,feed concentrations and the degree of nodule breakage are obtained.The influence law of the particle distribution,the particle movement characteristics and the wall shear stress distribution are analyzed.Based on the simulation results,an optimization scheme for improving the transportation parameters is proposed for the deep-sea pipeline transportation system.It is suggested that the parameters should be set as follows: the inlet velocity of the pipeline is 3-4m/s;the feed concentration is about 9%;the particle size of the crushed nodules is within 16 mm.