A flexible connector of lifting pipes in a deep sea mining system is designed. The buttress thread （ based on API standard） is used and foreign experience in connector design is referred to. With this kind of connec...A flexible connector of lifting pipes in a deep sea mining system is designed. The buttress thread （ based on API standard） is used and foreign experience in connector design is referred to. With this kind of connector, the lifting pipe wiU only bear the axial force, free of moment. The strength of the connector is analyzed in detail, including the connecting strength of the buttress thread, the dynamic load of the pipe system, pressures inside and outside of the pipe, the lateral stress of the pipe wall and so on. Especially, a geometric model is built for 3-D contact stress analysis. The distribution graph of contact stress is presented. It is indicated that the strength of the spherical connector meets the demand.展开更多
A 3-D geometrical nonlinear model for the entire lift system of 1000-m sea trial system of China Ocean Mineral Resources R&D Association was established with finite element method.The model was utilized to analyze...A 3-D geometrical nonlinear model for the entire lift system of 1000-m sea trial system of China Ocean Mineral Resources R&D Association was established with finite element method.The model was utilized to analyze the dynamic characteristics of the vertical pipe under the influence of moving velocity,current direction and wave.The simulation results show that the axial stress is dominant on the vertical pipe,its maximum is located at the pipe top,all stresses are much less than the allowable value of the vertical pipe and joint;the heave motion leads to violent fluctuation of the force and stress,but a period of 8 s is not likely to resonate the present pipe;against the current,0.50 m/s is the suggested moving velocity of the ship and miner,while along the current,the moving velocity can be slightly higher than 0.75 m/s.展开更多
Hydraulic transport in pipelines is the most promising conveying method for large ore particles in deepsea mining.The dynamic performances of particles during transportation in vertical,inclined and horizontal pipelin...Hydraulic transport in pipelines is the most promising conveying method for large ore particles in deepsea mining.The dynamic performances of particles during transportation in vertical,inclined and horizontal pipelines are significant for the design of hydraulic transport systems.In the present study,we focus on the statistical characteristics and flow regimes of the mixture composed of ore particles and seawater in the pipelines.Numerical simulations are conducted by using Computational Fluid Dynamics(CFD)and Discrete Element Method(DEM).The influences of inclination angle and particle diameter are evaluated through two sets of numerical tests.The regulation of the inclined transport is totally different from that of the vertical transport,whereas the dynamics of the mixtures in inclined and horizontal pipes are similar.A number of particles accumulate on the pipe wall even with a small inclination angle.Large hydraulic gradient and local concentration would occur when the inclination angle of the pipe is in the range of30°-60°.With the decrease of particle diameter,the particle flow becomes uniform,reflected by the almost uniform particle distribution in the vertical pipe and the clear interface between the suspended load and the bed-load in the inclined pipe.However,small particles will introduce larger local concentrations and hydraulic gradients in the inclined pipe,which is not conducive to particle transport.展开更多
基金This research was financially supported by China Ocean Mineral Resources R &D Association (Grant No. DY105-03-02-17) .
文摘A flexible connector of lifting pipes in a deep sea mining system is designed. The buttress thread （ based on API standard） is used and foreign experience in connector design is referred to. With this kind of connector, the lifting pipe wiU only bear the axial force, free of moment. The strength of the connector is analyzed in detail, including the connecting strength of the buttress thread, the dynamic load of the pipe system, pressures inside and outside of the pipe, the lateral stress of the pipe wall and so on. Especially, a geometric model is built for 3-D contact stress analysis. The distribution graph of contact stress is presented. It is indicated that the strength of the spherical connector meets the demand.
基金Project (DY105-03-02-02) supported by the Deep-Ocean Technology Development Item of China
文摘A 3-D geometrical nonlinear model for the entire lift system of 1000-m sea trial system of China Ocean Mineral Resources R&D Association was established with finite element method.The model was utilized to analyze the dynamic characteristics of the vertical pipe under the influence of moving velocity,current direction and wave.The simulation results show that the axial stress is dominant on the vertical pipe,its maximum is located at the pipe top,all stresses are much less than the allowable value of the vertical pipe and joint;the heave motion leads to violent fluctuation of the force and stress,but a period of 8 s is not likely to resonate the present pipe;against the current,0.50 m/s is the suggested moving velocity of the ship and miner,while along the current,the moving velocity can be slightly higher than 0.75 m/s.
基金financially supported by the National Natural Science Foundation of China (Grant No.51909164)the Hainan Provincial Joint Project of Sanya Yazhou Bay Science and Technology City (Grant No.520LH052)。
文摘Hydraulic transport in pipelines is the most promising conveying method for large ore particles in deepsea mining.The dynamic performances of particles during transportation in vertical,inclined and horizontal pipelines are significant for the design of hydraulic transport systems.In the present study,we focus on the statistical characteristics and flow regimes of the mixture composed of ore particles and seawater in the pipelines.Numerical simulations are conducted by using Computational Fluid Dynamics(CFD)and Discrete Element Method(DEM).The influences of inclination angle and particle diameter are evaluated through two sets of numerical tests.The regulation of the inclined transport is totally different from that of the vertical transport,whereas the dynamics of the mixtures in inclined and horizontal pipes are similar.A number of particles accumulate on the pipe wall even with a small inclination angle.Large hydraulic gradient and local concentration would occur when the inclination angle of the pipe is in the range of30°-60°.With the decrease of particle diameter,the particle flow becomes uniform,reflected by the almost uniform particle distribution in the vertical pipe and the clear interface between the suspended load and the bed-load in the inclined pipe.However,small particles will introduce larger local concentrations and hydraulic gradients in the inclined pipe,which is not conducive to particle transport.
