Analysis Of Mixing Performance For Light Particles Based On KR Stirring Process

KR stirring process is one of the effective and important desulfurization process in the pretreatment of hot metal.Improving the desulfurization effect of KR mechanical stirring has been the focus of many researchers in iron industry.From the aspect of dynamics of multiphase flow transmission,this paper studied the mixing performance of light particles with CFD and water model method.As for the simulations in this paper,the liquid surface is captured by VOF model and the particles mixing process is simulated with DPM model.The water model experiments are used to measure the drawdown rotation speed and verify the accuracy of numerical simulation.At first,the light-particle drawdown mechanisms in transformed cross KR impeller are studied.The drawdown rotation speeds are measured by water model experiments.And referring to the way of flow field analysis in open water simulations in ship industry,the flow fields at drawdown rotation speed in the stirred tank are studied with numerical simulations.With the quantitative analysis of mean circulation,turbulent fluctuation and large scale eddies near the liquid surface,the effective drawdown mechanisms for different stirred tank,pumping mode and submergence are explicit.Then,the measurement for mixing results of light particles is studied for the PBT impeller with numerical simulation.Based on the standard deviation,the particle dispersion curve which is suitable for the particles simulation with Euler-Language method is proposed.Referring to the open water characteristic curve in ship industry,the mixing characteristic curve for the light-particle stirring process is proposed.And the applicability of the mixing characteristic curve is studied for different time,rotation speeds and submergences.At last,by the cross impeller in the KR stirring process as the research object,the applicability of the mixing characteristic curve in KR stirring process is studied from two aspects: the geometrical and physical factor.The geometrical factors,which are submergence,impeller-to-tank ratio,number of impeller blades and baffling mode,are studied with water model experiments.The physical factor,which is the dynamic viscosity,is studied with numerical simulations.The mixing characteristic curve in KR stirring process is analyzed in two parts: the particles dispersion and the power consumption.The mixing characteristic curve in KR stirring process has good applicability and can help to study the mixing performance.The particle dispersion curve helps to assess the particle distribution simulated with Euler-Language method.The mixing characteristic curve in KR stirring process and the analysis of light-particle drawdown mechanism helps to improve the mixing efficiency of light particles and provide theoretical basis for the optimization design of KR stirring process.