Simulation Study Of Fluid Flow During Filling Process Of Big Steel Ingot Casting With Different Bottom Argon Blowing

Physical and mathematical simulation of the fluid flow in the mold casting process was carried out in a casting model with bottom Ar bubbling.For the case of the off-centre inlet and rounded gas porous plug and the centre inlet and annular gas porous plug,the effect of different blowing parameters on mixing time at different casting height was investigated.By observing the flow of the tracer,the flow patterns of the fluid in the mold under different experimental conditions were understood.The fluid velocity fields in the mold were simulated with FLUENT Software.In the physical modeling experiments,experimental results showed that gas blowing can significantly reduce the mixing time of the liquid.The mixing time in the case of the centre inlet and annular gas porous plug was longer than the case of off-centre inlet and round gas porous plug.There was no large difference in mixing time for the round gas porous plug located at a distance of 30 mm or 70 mm from the model bottom center.The velocity field was symmetric when annular gas porous plug was fixed at the bottom centre of model.The velocity field was relatively symmetric when the round gas porous plug was located at a distance of 30 mm from the bottom centre of model.It was proposed that annular gas porous beam should be chosen.By measuring the diameter and the numbers of bubbles,the majority of bubbles was in the diameter range of 0.5-2mm.It was recommended that the suitable gas blowing flow rate was 0.045m3/h.In the case without gas blowing,at the initial stage of filling height of 40 mm,slag entrapment found,but at the filling height of 80 mm,the phenomenon of slag entrapment disappeared.In the case of blowing with annular gas porous plug or round gas porous plug slag entrapment could be limited.Spout height,spout shape and bubble flow shape at the early stage of filling in the physical model were verified by the mathematical simulation,and the results from the mathematical model were consistent with the results from the physical model.For the mathematical simulation in ingot model and industrial ingot,the results showed that blowing is conducive to improve the flow speed of liquid.when the round gas porous plug were located at a distance of 30 mm from the bottom centre of model,the vortex centers of velocity field are approximately at the same height and the flow field is relatively symmetrical.When the annular gas porous plug was arranged around the inlet,the vortex centers of velocity field were completely at the same height and the flow field was symmetrical.