Deep-sea Mining Slurry Transportation Concentration Variation Study

Pump-vessel combined ore transporting equipment is a kind of conveying device, this apparatus pressurized sea-water with pure water pump and mixed ores into high-pressure hose with storage tank, then or pulp delivered under the action of sea-water pressure-energy. In view of the problem that the ore conveying volume concentration will be difficult to control according to our deep-sea mining pilot requirements, this paper simulated and analyzed the internal flow field of pump-vessel combined ore transporting equipment with fluid analysis software, revealed the basic characteristics of the internal flow field in the transporting equipment, and got elementary alteration rules of ore conveying volume concentration. In this paper the main research contents and research results are as follows:Firstly, on condition that the pump-vessel combined ore transporting equipment's structure had been analyzed, designed and calculated the transporting pipe according to production capacity requirements; then analyzed storage vessel's working environment and working demand and designed a kind of storage vessel which is suitable for deep-sea working; after that, aiming at the problem during the feeding process designed a kind of Venturi feeding device; lastly, analyzed the characteristic parameters of nozzle jet, such as impact force, suction force, roll absorb quantity, and all those analyses can be used to predict ore flow condition.Secondly, established mathematical model of solid-liquid two-phase flow in pump-vessel combined ore transporting equipment, then chose the Euler-Euler double fluid model, RNG turbulent model and Gidaspow solid-liquid drag model to simulate the liquid-solid two-phase flow in the transporting equipment.Thirdly, analysed and obtained the basic features of internal flow field in the transporting equipment by computational fluid dynamics analysis software Fluent, and got the general rules that equipment parameters, conveying parameters, particle size and ore accumulation height influence on the ore conveying concentration. Basic conclusions are as follows:(1) all else being equal, nozzle diameter size decided the conveying efficiency, the larger the nozzle diameter was, the taller the ore transmission efficiency was; (2) when the distance from nozzle exit to the bottom of tank is 800mm, or the height ranges from 800 to 900mm, ores were transported smoothly and ore volume concentration changed small; (3) when vinlet1 remained unchanged, ore conveying volume concentration increased with vintel2 decreasing, so it can control the ore volume concentration by adjusting the inlet velocity of inlet2; (4) in the same condition, ore maximum transmission volume concentration reduced with the increasing of the particle size; (5) the filling degree of storage tank had little influence on ore conveying volume concentration.Fourthly, established experimental model of ore transporting equipment according to similarity theory, and verified the feasibility of conveying equipment through the experimental analysis. At the same time, the curve obtained from ore conveying volume concentration parameters under different conveying conditions fitting with corresponding numerical simulation results, verified the numerical simulation results was accurate and effective.