| With the lack of land mineral resources,the exploitation of deep sea mineral resources has been paid more attention by all countries in the world.The deep sea mining is a complex and huge system engineering,among which the ore mixed transport lifting system is an important system to transport the mined deep sea minerals from the seabed to the sea,is the key to the mining of mineral resources to the deep sea,and is also the most immature system in the deep sea mining.At present,the development of special lifting pump,which is the core of high efficiency mixed transport lifting system,has been delayed,which has become the bottleneck of the development of deep sea mining technology.At present,the centrifugal lifting pump has some defects such as short service life,easy wear,inconvenient replacement and maintenance.In view of such problems,this thesis takes the diaphragm lifting pump as the basic research object,and develops a special diaphragm pump suitable for deep-sea mixed transport lifting.The purpose is to improve the efficiency of the deep-sea mining system and prolong the service life of the pump.For this purpose,the performance and structure of the diaphragm lift pump can be used in 1000m depth of the sea,and the transport parameters and working performance of the lift pump are determined by the onshore mixed transport lift test system.It lays the foundation for the national deep sea mining strategy to advance and realize.The main work contents are as follows:(1)According to the basic theory of hydraulic pipeline lifting,the working principle of diaphragm lifting pump is improved,and through the calculation and analysis of the performance parameters of diaphragm lifting pump,the performance parameters of the onshore test prototype of diaphragm lifting pump are preliminarily determined as follows:The output flow rate is 24m~3/h,the concentration of transported ore is 5%～10%,the maximum particle size can be transported is 15mm,and the head of the land test prototype is 50m.At the same time,according to the basic theory of diaphragm design of diaphragm lifting pump,analyze the factors that affect the service life of diaphragm,in order to facilitate the subsequent calculation and analysis of structural parameters of diaphragm lifting pump.Finally,the numerical model and coupling method are explained to provide a theoretical basis for the subsequent simulation.(2)Complete the calculation and analysis of the basic structural parameters of the diaphragm lifting pump,build the three-dimensional model of the diaphragm lifting pump and draw the engineering drawings,so as to facilitate the subsequent prototype processing and working performance test research.On the premise of improving the service life of diaphragm,an important component of diaphragm lift pump,the tensile and fatigue tests of five diaphragm materials were carried out by Zwick tensile testing machine and Instron E10000 fatigue testing machine.PTFE with tensile strength of 47.0125Mpa was selected as the final diaphragm material.The fatigue analysis of the diaphragm was carried out through the finite element analysis method.The minimum safety factor of the diaphragm was 2.049,and the lowest safety factor was fixed at the boundary of the diaphragm circumference.The fatigue life of the diaphragm as a whole could reach 10~6times,which could reach the standard life of the diaphragm in the high-pressure diaphragm pump.In order to ensure that diaphragm lifting pump in the normal process of work will not appear diaphragm damage.(3)The simulation of two-phase flow in hydraulic transportation of deep-sea mining vertical lifting system was carried out by CFD-DEM method,and the influences of different inlet velocity,feed concentration,particle size and particle shape on local concentration,local flow and particle concentration distribution in vertical lifting pipeline were analyzed.According to the analysis of the influence of various parameters on the vertical lifting effect,the inlet flow rate of the diaphragm lifting pump working performance test is preliminatively determined to be 2.72～4m/s,the feed concentration is 5%-10%,the particle size used in the test is 10～20mm,and the polished particles are used as test materials,so as to ensure the efficiency and safety of the whole test system.(4)In order to study the working performance of the diaphragm lifting pump prototype,the land mixed transport lifting test system was designed and built,and the test scheme was designed.The performance of diaphragm lift pump under clear water condition and two-phase flow condition is analyzed by lifting test system,and the optimal transmission parameters of diaphragm lift pump are determined by combining with the simulation analysis.The final results show that under clear water condition,when the working flow of the diaphragm lifting pump is controlled at 24m~3/h,the lift of the diaphragm lifting pump can be guaranteed to reach 50m.Under the two-phase flow condition,when the working flow of the diaphragm lifting pump is controlled at 15m~3/h,the concentration of the transported ore can be guaranteed to be 5%～10%,the conveying particle size is 15mm,and the head of the diaphragm lifting pump can reach 50m. |
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