Investigation on the Fluid Flow and Decarburization Process in the RH Process

In the current study, mathematical models were developed to predict the fluid flow and motion of gas bubbles in the RH degasser. The multiphase model volume of fluid was employed to simulate the free surface in the vacuum chamber, while injected argon bubbles were treated as discrete-phase particles and tracked using the discrete-phase model. The expansion of argon bubbles was considered. The variation of the liquid level in the vacuum chamber and the effect of the number of nozzles on the recirculation rate were discussed in detail. The optimal number of nozzles was 6. Furthermore, the decarburization process was simulated by considering three reaction sites: the free surface, inner sites of the liquid steel in the vacuum chamber, and the bubble surface. The carbon contents predicted by the decarburization model were well validated by the measured results in the literature. The effect of the gas flow rate on the decarburization process was also investigated. With the increasing gas flow rate, the carbon content gradually decreased, and then reached the steady state. The optimal gas flow rate was 2400 L/min, which was explained by the comparison of the decarburization rate constants. Meanwhile, the decarburization reaction was in a quick decarburization stage for the first 7 minutes, and for the next 13 minutes, the decarburization rate constant rapidly decreased.