Numerical Investigation of Gas Flow Rate Optimization for Enhanced Mixing in RH Degassing

Optimizing the operational parameters of an RH degasser is essential for increasing the production of high-quality steel while reducing energy and resource consumption. This paper presents a study on the impact of different injection gas flow rates on the mixing characteristics of an industrial-scale RH degasser and evaluates the optimal flow rate for achieving the lowest mixing time. A 3D simulation model was developed using a VOF–DPM framework, with gas flow rates being varied from 18 to 72 SCFM to assess mixing time and associated flow behavior. The results indicate that the mixing time has a non-linear relationship with the gas flow rate, and increasing the flow rate does not always lead to a reduced mixing time. A flow rate of 45 SCFM (a 1.5-fold increase from 18 SCFM) provided the best mixing efficiency, reducing the mixing time by 52%. Additionally, beyond 36 SCFM, a saturation limit was observed in the circulation rate, where further increases in the gas flow rate resulted in a less than 5% improvement in steel flowing through the snorkels. These findings highlight the need for careful evaluation of injection gas flow rates in RH operations to identify the optimal value that maximizes mixing efficiency, minimizes resource consumption, and enhances productivity by enabling greater steel output in less time.