Mathematical Simulation On Ladle Stirring By Ultrasonic

The stirring of ladle refining in the liquid steel is mainly by blowing gas from the bottom to improve the effect of deoxidation, desulfurization, dephosphorization and removal of inclusions in recent years. But due to the presence of a dead area by blowing gas from the bottom, the kinetic condition of desulfurization, dephosphorization, Deoxidization can not be satisfied efficiently. Taking on 180t ladle of some steel factory as prototype, simulation calculation of fluid flow in ultrasonic cavitation and blowing gas from the bottom is performed by FLUENT in the paper. Through comparing the pressure and velocity magnitude in flow field between ultrasonic and blowing gas from bottom, the feasibility of improving the dynamical condition in ladle refining by high-power ultrasonic is analyzed. The main results are as follows:(1) One big and one small circular flow forms in the flow field simulation stirring by blowing gas from the bottom; with the gas flow changing, the size of circular flow is different, which affects the absolute velocity of fluid, so that the mixing effect changes. The best gas flow is 0.1 m3/h through analyzing the simulation calculation results.(2) The first movement of the radiator makes the flow field pressure change dramaticly according to the simulation results. There is a large negative pressure area in the end of the radiator, so the fluid flows regularly from the high pressure zone into the low pressure. Through the comparative analysis, when the ultrasonic radiator is 250mm below the liquid surface , power is 2000 W, the stirring effect is best.(3) Comparing with the blowing gas stirring, the negative pressure area forms in the flow field due to the vibration of the radiator, in which a large number of cavitation bubbles generate , when the bubbles collapse or close instantly, there is a great local pressure in the flow field, so the ultrasonic stirring has a good mixing effect. With the gas flow increasing by blowing gas from the bottom, Slag-Entrapment occurs. The liquid surface fluctuates less as stirring by ultrasonic so as to avoid the Slag-Entrapment polluting the liquid steel. The dead area at the bottom of the container can be reduced by ultrasonic.