Parameter Design And Simulation Study On Submarine Pump In Deep Sea Mining

The mineral resources are rich in deep sea, and are of great practical significance for solving resource crisis. Lifting pump is the key part in deep-sea mineral mining system, which provides the power for carrying fluid and transports the mineral particles with diameter of 20-50 mm as well. Semi-axial pump, according to the current research, is feasible for deep-sea mining with high water head and large flow. Two stage lifting pump has been designed in the eleventh Five-Year Plan, but there is still particles clogging in pump. It is important in theory and practice to reveal solid-fluid motion mechanism and the relationship between lifting pump parameters and particles motion for pump design.According to lifting pump theory, the impeller and vane of lifting pump was designed; the performance curve and internal flow field was studied with CFD and experiment; the influence of impeller setting angle to lifting pump performance was analyzed; by discrete numerical model and physical model, the motion characteristics of different size particles in lifting pump and the influence of impeller setting angle was revealed. The performance of blocked particle in lifting pump is studied as well. The results are as follows:(1) The optimum duty point flow of lifting pump is at the point of water flux of 28 m3/h and water head of 4.8 m, where the hydraulic efficiency is 66%. The results match well with design requirements. The error between simulation result and experiment data is less than 10%, which shows the mathematical model is reliable and efficient.(2) Adding 10°inlet attack angle to impeller, the flow at the optimum duty point of lifting pump is 25 m3/h and water head is 4.8 m, with hydraulic efficiency of 61%. With inlet attack angle increasing, the head and efficiency of lifting pump descend, while the flow at optimum operating point tend to smaller.(3) Particles spiral in lifting pump, and are prone to get collision with impeller with the increase of size. Particles collide with vane blade 2-4 times at three locations:the inlet of back vane, middle of work face, and outlet of back vane. With increase of impeller inlet setting angle, the particles trajectory get smoother and tends to impeller working face. The frequency of collision between particles and vane is higher, and particles are more scattered in vane.(4) With increase of particles size, velocity of particles at inlet of vane decreases while time through lifting pump increase. Large motion angle at vane leads to more collision. Long time through lifting pump leads to clog easily in lifting pump.(5) For particles with a certain concentration, the particles are blocked at inlet of vane while velocity of water decreases. The critical water velocity when lifting pump is blocked increase with bigger size particles.