Simulation Study On Flow Field Of Hot Metal And Drainage Behavior During The Tapping Process Of Blast Furnace

Blast Furnace is the main current ironmaking technology.Efficient and stable drainage of hearth has important technical and economical significance for prolonging the life of the blast furnace.Because of monitoring the flow field of hot metal of hearth is very difficult.In the present study,the VOF multiphase flow model of FLUENT software is used to simulate the transient flow and drainage process of hot metal in hearth,that can estimate the effects of hearth various characteristic factors on flow field,wall shear stress,in the taphole the slag-iron-gas three phase flow characteristics and flow pattern,as well as the residual rate of slag.The conclusions are as follows.(1)The deadman shapes has a great influence on the flow field in the hearth,fully packed deadman in the hearth the flow field of hot metal is stable.The spherical and cylindrical deadman filling in the hearth,the circulation flow of hot metal is obvious,at the corner of the bottom of the hearth would form mixed zone.There are swirl flows,above and far from the taphole in the area near the slag iron interface..(2)Fully packed deadman in the hearth,the hearth erosion has minimal impact.Furthermore,the wall shear stress increases with increasing the diameter of the taphole and the blast pressure.However,the wall shear stress decreases with increasing the taphole depth,salamander depth and the porosity of the deadman.When the angle of the taphole is 20?,the wall shear stress of the underside of the taphole and the clay pack is obviously increased.(3)Fully packed deadman floating in the hearth,the hot metal drainage flow increased.The spherical and cylindrical deadman floating or sinking have less influence on the hot metal drainage flow.The hot metal drainage flow increases with increasing the diameter of the taphole and the blast pressure.the taphole depth,the salamander depth,the porosity of the deadman and the angle of the taphole have less influence on the hot metal drainage flow.(4)In the taphole the slag-iron-gas three phase flow characteristics and flow pattern can be divided into different types at different positions and in different periods.: Slag-iron mixed interfacial stratified flow;Slag-iron stratified flow;Slag droplets stratified and Slag-iron stratified mixed flow;Slag-iron-gas stratified flow;Dispersed flow,respectively.When the hot metal liquid holdup in the taphole is higher,the slag-iron phase interface change from bow shape to subrounded.(5)During the tapping process the residual slag almost concentrates in deadman,but in the free zone of hot metal around the hearth is very low.The residual rate of slag decreases with increasing the porosity of the deadman.The residual rate of slag increases with increasing the viscosity of slag.