| The development of external refinement and the current situation of our country were summarized at the first of this treatise. It introduces the operating principle of the Ruhrstahl Heraeus (RH) Degassing treatment and presents its characteristic, development, the trend of future developing, and so on. In the process of RH Refining treatment, the molten steel flowing has directly impacted components in molten steel and homogeneity of temperature. So conducting an investigation in flow field of molten steel is playing an important role to shorten processing time and improve effect of refinement. To investigate the molten steel flow structure along with the inserted Argon gas bubble mechanistic behaviors in RH Degassing treatment, this paper research molten steel flow in RH degassing device, which is from the basic phenomenon of blowing driving gas in the up-snorkel and based on a few hypothesis. Through numerical analogy calculation, it presents effect of argon injected flow rate and pressure in nozzle inlet on circulation flow rate in RH Degasser, which provide basis and guide to handicraft optimization.The homogeneous water model which was made by Baokuan Li and Fumitaka TSUKIHASHI is thought as the subject investigated. From the viewpoint of circular flow of molten steel, a mathematical model on flowing and mixing of liquid is established using the commercial CFD software FLUENT, and the influence of process and equipment on flowing and mixing of liquid is discussed. On the basis of flow field in the vacuum vessel and ladle, the mechanistic behavior of liquid-gas flow is summed up.Based on the two-fluid (Eulerian-Eulerian) model for a gas-liquid two-phase flow and the normal k-εmodel for turbulent flow, a three-dimensional mathematical model for the flow of liquid in the device during the RH refining process has been proposed. In the adiabatic qualifications, the driving gas properties and entry conditions at the inlet section in the up-snorkel has been calculated, then, the related parameters of the model have been determined. This mathematical model is applied to simulated calculation, and is compare the calculated results with the measured results by the water model. The results showed that the flow pattern of liquid in the device could be well modeled by this mathematical model. When argon injected flow rate and pressure in nozzle inlet is raised, the circulation flow rate in RH water model have been correspondingly enhanced, and the calculated circulation flow rate for the model unit at different driving gas flow rate are in good agreement with the measured value. The driving gas blown is rising mostly near the up-snorkel wall, and it has difficulties to reach the middle of the up-snorkel.The results of flow field in the ladle indicate that, there are two prominent circulation zones in ladle, one is formed between down-snorkel and up-snorkel, the other is formed between down-snorkel and ladle wall. |
PDF Full Text Request