Structure Optimization Of Gas-solid Mixer For Sepiolite Powder And Study Of Its Internal Two-phase Flow Characteristics

The gas-solid mixer is an important part of the sepiolite mineral powder jet classification device,and its gas-solid mixing effect is one of the main factors affecting the subsequent classification effect.In this dissertation,the structure of the sepiolite ore powder gas-solid mixer is improved based on the Venturi effect in view of the problem that the traditional gas-solid mixer has a large material concentration near the wall and is prone to agglomeration and causes the mixer to block.Using COMSOL Multiphysics software,the improved gas-solid mixer combined with sepiolite powder characteristics was numerically simulated,and the influence of its internal flow characteristics and different structural parameters on the internal flow field of the gas-solid mixer was analyzed.The practical design and operation of the gas-solid mixer of the bubble stone ore provides theoretical guidance.This dissertation focuses on the following aspects:(1)Theoretic analysis and structural design of sepiolite powder-solid mixer.Based on the theoretical analysis of the gas-solid mixer,the structure of the traditional gas-solid mixer was improved in view of its shortcomings;the gas dynamic function method was selected as the theoretical basis for the design of the sepiolite powder-solid mixer,combined with the actual working conditions of the gas-solid mixer and according to the relevant experience coefficient,the structure size is preliminarily calculated,and the three-dimensional geometric model is established through creo3.0.(2)Numerical simulation method of sepiolite ore powder gas-solid mixer.The gas phase,sepiolite particle phase and gas-solid two-way coupling simulation method are studied in the gas-solid mixer numerical simulation;the turbulence model and discrete format in the gas phase are selected;the force analysis of the sepiolite particles is carried out to establish the particle motion equation.(3)Numerical simulation of two-phase flow field in sepiolite ore powder gas-solid mixer.Grid division of the calculation domain of the gas-solid mixer,and the irrelevance test and quality judgment of the grid;numerical simulation of the internal flow field of the gas-solid mixer,and the internal velocity and pressure in the axial direction And the simulation of the trajectory of sepiolite particles is compared with the theoretical analysis to verify the reliability of the numerical simulation.(4)The influence of structural parameters on the flow characteristics of sepiolite ore powder gas-solid mixer.Under the condition of certain process parameters,the COMSOL Multiphysics software is used to obtain the internal flow field data of the mixer(such as the sepiolite particle velocity and particle motion trajectory)by changing the contraction angle,expansion angle and throat diameter ratio,and then analyze and compare From these data,the influence of the above parameters on the internal flow characteristics of the sepiolite ore gas-solid mixer is obtained.(5)LDA experiment of sepiolite ore powder in gas-solid mixer.By constructing an LDA experimental platform,the velocity along the flow direction on the axis of the gas-solid mixer and the radial velocity along the vertical center line of the throat section were measured respectively,and the simulation results were compared to verify the authenticity of the numerical simulation.Theoretical analysis,numerical simulation and experimental results show that the improved sepiolite ore powder-solid mixer designed in this dissertation can alleviate the problem of material accumulation near the wall to a certain extent,and realize the rapid and effective mixing of sepiolite ore powder and air.Studying the influence of key structural parameters of sepiolite ore powder gas-solid mixer on its internal flow characteristics is of guiding significance for the structural optimization of later gas-solid mixer.