Mathematical And Physical Simulation For Single Snorkel RH Vacuum Refining Process

Single snorkel RH is a new vacuum refining equipment. It has a lot of advantages, such as simple structure, high efficiency refining, smelting less vacuum sputtering, and low cost of production. To increase circulation flow rate and to shorten mixing time are two of effective measures to improve the efficiency of the vacuum refining.In this paper, on the basis of 150 ton single snorkel RH and traditional RH, the physical and mathematical simulation are applied to investigate the metallurgical process and to discover the effect of different process parameter, these research results can give technical support for the design and optimization of single snorkel RH vacuum refining equipment.The experimental results show that:the molten steel circulation flow rate increases with the increase of the gas flowing rate, the mixing time decreases with the increase of gas flowing rate. The circulation flow rate increases with the increase of immersion snorkel depth. Under the same conditions, the circulation flow rate of oval RH is 15% greater than that of traditional RH. The mixing time of the single snorkel RH is less than oval RH and traditional RH. If the bottom blowing position is at 0.4R(R is the radius of the snorkel), the mixing time of the single snorkel RH is the least.Numerical results show that:if the argon flowing is 1000NL/min, when the ladle bottom blowing position is at 0.4R, the molten steel circulation flow rate is the greatest, the rate is 150t/min. The argon flowing rate of 1000NL/min is suggested to be more reasonable and economical. The circulation rate of molten steel changes not significantly with the changeable immersion depth. The number of porous brick has a great influence on molten steel flow pattern of single snorkel RH, the molten steel circulation flow rate is the greatest. The mixing time for two and three permeable bricks is less than permeable bricks. Within a certain range of angle 0, when the 0 is greater than the best angle, the molten steel circulation flow rate decreases, the best angle is 60 degree.The flow behavior of the molten steel flow in the single snorkel RH is compared with that in the traditional RH.The velocity of the molten steel in the traditional RH is greater than that of single snorkel RH, so the greater velocity in the traditional snorkel RH cause the stronger corrosion at the inner snorkel in the traditional RH. For the ladle bottom shocking, the impact of single snorkel RH ladle bottom is weaker than the traditional RH. In the case of the argon flowing of 1000NL/min, the molten steel circulation flow rate of single snorkel RH is 1.6 times that of the traditional RH. The mixing time of the single snorkel RH is 55s, and that of the traditional RH is 95s. According to the molten steel circulation flow rate and the mixing time, single snorkel RH is more powerful than the traditional RH. The argon bubble under the condition of the bottom-blowing has a longer travel length than that under the condition of side-blowing. Thus, the argon bubble under the condition of the bottom-blowing can do more work, and have more residence time in the molten steel. It has stronger stirring for molten steel. But the turbulent kinetic energy at the surface of vacuum in the single snorkel RH is almost equal to that in the single snorkel RH.