Structural Optimization Design And Performance Study Of A Seabed Sediment Hydrocyclone

The global mineral consumption is increasing,and the proven mineral reserves on land are insufficient.However,with the rapid development of new energy vehicles,the demand for rare metals such as manganese,cobalt,and copper is increasingly strong.The development of deep-sea mineral resources has become a research and development hotspot for marine power.Currently,deep-sea mining is at the stage of exploration and trial production,and the potential environmental impact of deep-sea mining has become a key factor restricting the commercial development of deep-sea mineral resources.The research group has developed a sediment plume suppression device for deep-sea mining vehicles based on the national key research and development plan project"Research on New Mining Mode and Principle Prototype of Deep Sea Polymetallic Nodules",which can timely and efficiently handle sediment plumes caused by mining vehicle operations.Among them,the hydrocyclone,as a key equipment in the plume suppression device,is a high-speed centrifugal solid-liquid separation device with advantages such as simple structure,high separation efficiency,and long seabed continuous operation time.This article provides a basic theory for the development and application of sediment plume suppression devices through the optimization design and performance research of cyclone structures,and assists in the green development and environmental protection of deep-sea mineral resources.The structural parameters and working conditions of a hydrocyclone are key factors affecting the separation efficiency.Firstly,according to the structural characteristics of the hydrocyclone,the numerical simulation method and Reynolds stress Model(RSM)are used to calculate the turbulence;Combining the Discrete Phase Model(DPM)to capture particles inside the cyclone,describe the solid-liquid flow field characteristics and separation performance in the hydrocyclone.The characteristics of the solid-liquid flow field and separation performance in the hydrocyclone are described.Then,a screening test(Plackett Burman,PB)was used to analyze the significance of the structural factors of the hydrocyclone and screen out the key factors.Finally,based on Central Composite Design(CCD),the structural dimensions of the hydrocyclone are optimized,and a second-order regression model between the separation efficiency and key factors of the hydrocyclone is constructed.After structural optimization,the separation efficiency of the cyclone increased by 4.59%,and the average relative error between the predicted values of the regression model and the numerical simulation results was 0.64%.The accuracy of the model is good.After that,the flow field characteristics under different hydrocyclone throughput,particle size,and solid-liquid specific gravity conditions were analyzed.The results show that after structural optimization,the separation efficiency of the hydrocyclone increases by 2.69%on average under the operating conditions of 6～10.5m~3/h treatment capacity;An average increase of 2.31%for particles with a particle diameter of 5～75μm;In the working condition of 1/4000～1/500 solid-liquid specific gravity,the average increase is 2.46%.In this paper,four parallel schemes of hydrocyclones are studied.The numerical experiment results show that the separation efficiency of circular array is 97.19%and 96.96%,both higher than that of linear array.In order to verify the accuracy of the numerical simulation results,the performance of the cyclone separator was tested and verified The results show that the average relative error between the simulated value and the experimental value is 2.29%in the 6～10.5m~3/h treatment capacity test of the hydrocyclone,and the separation efficiency gradually increases with the increase of the treatment capacity;In the experiment of particles with a particle diameter of 5～75μm,the separation efficiency of the hydrocyclone shows a parabolic trend as the particle diameter decreases;In the solid-liquid specific gravity test from 1/4000 to 1/500,the change in separation efficiency was relatively small,and the average relative error between the simulated and experimental values was 2.24%.