Study On Transport Behavior Of Bubbles On Liquid Steel/slag Interface In Mold Of Continuous Slab Casting With Argon Blowing

Mold powder has great influence on the quality of billet,the behavior of argon bubbles on steel/slag interface effects the flow performance and heat transfer performance of mold powder directly in continuous slab casting mold with argon blowing,the behavior of argon on steel /slag interface that has been confirmed can provide theoretical basis to study on the transport and distribution of argon bubbles after entering the liquid mold powder.But the behavior of argon bubbles is effected by the factors which include process parameters of continuous casting and structure parameter of submerged entry nozzle(SEN)in mold.Therefore,in order to understand the relationship between the performance of liquid mold powder and molten steel flow in mold with argon flowing well,it is very important to study on the behavior of argon bubbles on steel/slag interface in different conditions in slab mold with argon flowing.This paper establishes water mold model,which is based on continuous casting mold of an iron and steel company and the similar ratio of the prototype and the model is 1:0.6,to study that the behavior of argon bubbles on steel/slag interface is affect by some factors,including the flow rate of argon,casting speed,the depth of submerged entry nozzle(SEN)and angle of nozzle port,in slab mold with argon flowing.The methods of mathematical simulation is used to study on the influence rule of molten steel flow field,the fluctuation of steel/slag interface,the distribution of argon bubbles,the speed of argon bubbles entering the liquid mold powder under different process parameters in mold.The main conclusion of the paper are concluded as follows:(1)With the flow rate of argon increasing,the amount of argon bubbles near the SEN increases,the floating speed of bubbles on the steel/slag interface near the SEN,the fluctuation of steel/slag interface near the SEN all rise.The amount of argon bubbles near the mold narrow surface decreases,the floating speed of bubbles on the steel/slag interface and the fluctuation of steel/slag interface,which are close to the mold narrow surface,all decrease,the impact points of liquid steel on mold narrow surface rise.(2)With the casting speed increasing,as for small argon bubbles diameter,the residence time of bubbles in liquid steel increases,and then the volume fraction of gas phase enlarge,the floating speed of bubbles on the steel/slag interface near the SEN and the fluctuation of steel/slag interface near the SEN all decrease.The floating speed of bubbles on the steel/slag interface near the mold narrow surface firstly increases and then decreases.When the casting speed is too high,the vortex flow near mold narrow surface are easily appeared.(3)With the increase of the depth of SEN,the vortex of bubble stream moves toward SEN,the floating speed of bubbles on the steel/slag interface near the SEN firstly decreases and then increases,the floating speed of bubbles on the steel/slag interface near mold narrow surface firstly increases and then decreases,the fluctuation of steel/slag interface in mold overall decreases,but the change about the fluctuation is not significant.(4)With the increase of the angle of nozzle port,the vortex of bubble stream moves toward SEN,the floating speed of bubbles on the steel/slag interface near the SEN firstly decreases and then increases,the floating speed of bubbles on the steel/slag interface near mold narrow surface increases,the fluctuation of steel/slag interface overall decreases.