Design And Numerical Simulation Of Deep-sea Mining Sediment Disturbance Simulation Experimental Device

At present,the exploitation and utilization of deep-sea minerals have gradually become a general trend.When humans conduct large-scale deep-sea mining,it will inevitably have a huge impact on the deep-sea environment.However,China is relatively lacking in the methods and technical means of monitoring and assessment of the environmental impact of deep-sea mining.In the future,the research on key technologies in the direction of monitoring and assessment of the deep-sea environment will become more and more important.In this context,a sediment disturbance simulation device is proposed in this paper,which simulates the disturbance of the seabed sediments caused by mining vehicles in the process of mining,and provides a means for the environmental impact assessment of deep-sea miningThis paper introduces the research status of deep-sea mining on sediment disturbance simulation at home and abroad,focuses on the domestic and foreign deep sea mining environmental impact of the test,the design of the test scheme,test equipment,etc.,and according to the working environment of the device,work requirements,put forward the main research content of this paper.In this paper,the whole and key parts of the sediment disturbance simulator are described respectively.In the introduction of the overall structure,feasible technical indicators are proposed according to the working environment and requirements of the device,and the observation instruments carried by the device are determined.In the introduction of the key components of the device,the structure design and Workbench analysis and simulation are carried out for the three components of the sediment jet device,namely,the mud jet propeller,the nozzle and the pressure-resistant and heat-insulation battery cabin.By comparing the analysis results,the 3-blade mud jet propeller,the transition nozzle and the 5mm pressure insulation battery cabin are finally selected.In this paper,the numerical simulation of sediment perturbation suspension redeposition is carried out based on FLUENT software.The position of the simulated nozzle was defined in the flow field,and the inlet and outlet boundary conditions of the continuous phase as well as the particle size range,jet velocity,mass flow rate and other parameters were set to realize the transient monitoring of sediment particles in the flow field.Three groups of comparison simulations were set up: changing the depth,changing the height of the nozzle and changing the initial velocity of particles.The results show that the change of depth has little effect on particle settling.When the height of the nozzle is changed,the settling time and trajectory of particles are directly affected.Changing the initial jet velocity of particles has little effect on the settling time.In order to ensure the safe and stable operation of the device under actual working conditions,this paper designs three stages of pool test,namely indoor small pool test,large pool test and harbor pool test,and designs feasible experimental schemes respectively.Through the research in this paper,the design of the overall and key components of the proposed sediment disturbance simulation experimental device has been successfully completed,the feasibility and stability of the key components have been proved by using the analysis software,and a feasible test scheme of the device has been put forward.These works provide experience for the environmental impact assessment and monitoring of deep-sea mining in China.