| Pollutants are one of the main factors affecting the performance of hydraulic components and hydraulic systems.In general,the material of the particles is metal,which is denser than hydraulic oil.The principle of the cyclone is centrifugal separation.In a high speed rotating flow field,the cyclone screens media of different densities.The study of the flow law of the cyclone flow field and the separation law of pollutants can provide a theoretical basis for the separation and removal of pollutants in the hydraulic system.The flow field in the cyclone is complicated,and it is very difficult to predict the flow field and particle trajectory.Therefore,the theoretical analysis and structural design of the solidliquid cyclone are carried out by using numerical analysis and experimental method.Firstly,the research status of hydrocyclones at home and abroad is investigated.And the research progress of theoretical analysis,structural parameter analysis,numerical simulation and experimental application is summarized.By comparing different cyclone models with different structures,the advantages and disadvantages of each model are pointed out.The structure which is beneficial to the separation of pollutant particles in hydraulic oil is analyzed.The research content of this paper is clarified.Secondly,the structural parameters of the cyclone are designed.The tangential velocity,axial velocity and radial velocity of the flow field are analyzed respectively.At the same time,the influence of boundary layer effect on particle motion is analyzed.The mechanical equation of state of particles was established.The mechanical properties of particles in swirling flow field are analyzed.The relationship between particle velocity and fluid velocity is determined.The radial settling velocity distribution of particles is obtained by analyzing the force of particles in the radius direction.For the whole cyclone,the performance evaluation method is put forward.Thirdly,the finite-volume model of the hydrocyclone flow field was established.And the suitable turbulence model was selected to analyze.And the separation process of the solid-liquid cyclone by Euler-Lagrange method.A simple comparison method was used to optimize the structural parameters of the solid-liquid cyclone.The effects of structural parameters on flow field characteristics and particle trajectories were analyzed.And the structure combination with the highest separation efficiency was obtained by comparisonFinally,the flow field of the solid-liquid cyclone was tested by PIV test.The flow field motion law and particle motion process were obtained.And the process verifies the correctness of theoretical analysis and finite element simulation results.By orthogonal experiment,the structure of the cyclone was optimized again,and the structure combination with the highest separation efficiency was obtained.A structure of solid-liquid cyclone for hydraulic system is designed.The separation theory of solid-liquid hydrocyclone is obtained.The method for removing pollutant particles in hydraulic oil by solid-liquid hydrocyclone that provides a theoretical basis for the miniaturization design of hydraulic tank,which is of great significance to further reduce the weight of hydraulic system and improve the performance of hydraulic system. |
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