Numerical Simulation And Model Study Of Underflow Discharge State Of Hydrocyclone

Hydrocyclones is a general efficient separator in industrial fields.It has been found in long-term operation practice that the classification performance of the hydrocyclone can be estimated through the underflows spray discharge angle.On the other hand,as a kind of fluid machinery,the characteristics of the internal flow field of hydrocyclone are the fundamental reason of its macroscopic performance.However,the relationship between the discharge angle and the characteristics of the flow field inside the hydrocyclone has not been thoroughly elucidated,which results in the lack of theoretical basis to distinguish the classification performance of hydrocyclone by using the discharge Angle.In addition,the mathematical relationship between the drainage angle and the key working parameters of the hydrocyclone has not been described in detail,so it is impossible to use the discharge angle to quantitatively control the working parameters of the hydrocyclone and then optimize its classification performanceIn this dissertation,the solid-liquid hydrocyclone is used as the research object The computational fluid dynamics tools are used to compare the results of the cyclone with the experimental data.The high agreement of the results indicates that the computational fluid dynamics method is used in the research of cyclones.Have higher reliability.The internal flow field characteristics of the hydrocyclone under different ore discharge angles are compared and analyzed.The movement behavior of particles and liquid phase under the umbrella and rope ore discharge conditions are discussed The different operations and structural parameters of the cyclone are discussed through experiments.The main research results on the impact of classification results are as follows:Using Fluent 15.0 as the calculation tool,a comparative study of different discharge angles of the cyclone was carried out by selecting a suitable calculation model under four different feeding conditions.The results show that the discharge angle of the cyclone is based on the internal flow field parameters.Under the condition of spray discharge,there is an air column inside the cyclone,and the pressure is similar to the rope dischange.When it changes to rope discharge,the negative pressure area also rises to a high pressure area,and at the same time,a high concentration area appears in the grit opening area,and the internal air column will disappear.Compared with spray discharge,rope discharge has smaller tangential velocity,turbulence intensity and smaller zero-speed envelope surfaceThe experimental results of the cyclone operation and structural parameters are shown.The lower the concentration of the ore,the finer the particle size,and the higher the ore pressure,when the structural parameters of the cyclone are constant,the more easily the spray discharge of the cyclone is made.when the cyclone operating parameters are constant,the smaller the cone ratio,the larger the cone angle,the easier it is to transition to rope drainage.Finally,based on the experimental data and existing models,the new dischange angle model established by regression analysis as ?=2.437 ×?Du/Dc?^-0.061?D_o/D_c?^0.126Re_i^0.276?^-1.559?tan ??^0.005.