A Critical Review of the Modified Froude Number in Ladle Metallurgy

The modeling of gas–liquid plumes in steelmaking ladles has been the subject of many investigations. In most studies, the “modified” Froude number, based on the momentum of the injected gas, has been employed to characterize two-phase plumes. This approach has several shortcomings and is critically reviewed in the present work. Based on an extensive review of previous work and theoretical considerations, it is demonstrated that the injected momentum and consequently, the modified Froude number has no significance to gas blowing operations in Ladle Metallurgy. Instead, an approach based on the “plume” Froude number, derived from the buoyancy of the plume, is shown to be more useful in modeling the plume as well as ladle hydrodynamics. The dissipation behavior of the gas momentum in the vicinity of the injector is further clarified.