Numerical And Experimental Study On The Hydraulics And Particle Transport Characteristics Of Deep Sea Lifting Pump

The deep-sea lifting pump is the main power component for transporting deep-sea polymetallic nodules to mining vessels.In order to obtain the hydrodynamic performance,particle distribution in complex flow fields and transport characteristics of the deep sea lifting pump under multiple operating conditions,this paper carried out experimental and numerical study on slurry conveying of the deep sea lifting pump,modified and used a large test site to carry out a full-scale slurry conveying experiment on deep sea lifting pump.The main research contents are summarize as follow:(1)Based on the Euler-Lagrange two-phase flow simulation method,a CFD-DEM solid-liquid coupling model was established,and coupled simulation study was conducted on the hydraulical performance of the deep-sea lifting pump and the transport characteristics of polymetallic nodules through the FLUENT-EDEM coupling platform,and the flow rate,head and shaft power of the deep-sea lifting pump under different transport flow rate,slurry concentrations and electric pump speed were obtained.The particle dynamics and motion behaviour were analysed,and the risk of the deep-sea lifting pump under extreme operating conditions were clarified,which provided reference data for the operation of deep sea lifting pump under complex sea trial conditions.(2)Designed a test program for slurry conveying experiment of the deep-sea lifting pump and a test site modification program,and carried out four tests of high flow rate,high concentration of coarse particle slurry conveying.The slurry conveying capacity,conveying stability and maximum overflow particle diameter of the deep sea lifting pump were assessed,and accurate test data were obtained by combining the electronic data acquisition and slurry manual calibration system,verifying the accuracy of the CFD-DEM solid-liquid coupling model.(3)The second generation six-stage pump prototype developed by Central South University was redesigned for weight reduction and annular flow channel outlet improvement without changing the parameters of the over-flow components,and the effects of the three flow channel improvement solutions were analysed using CFD-DEM simulations.The optimum solution was determined based the combination of particle transport characteristics and hydraulics,solving the problem of local accumulation of particles at the exit of the annular flow channel.