Spout eyes formed by an emerging gas plume at the surface of a slag-covered metal melt

Abstract

This article deals with the spout eyes developing, at the surface of a metal melt, in the ladle during argon stirring. Cold model experiments involving a mercury bath with an oil layer as slag and industrial experiments on a 350 t steel ladle have been carried out. The eye geometry as measured with a video technique is highly dynamic. The time average of the free surface area and the time fraction of complete coverage have been determined and are represented with dimensionless correlations.

Some Considerations Concerning Empirical Correlations for Plume (Spout) Eye Area in Slag Covered Metalic Melts

“…Despite many uncertainties in the plant scale measurements it was also noted by the authors 1) that both plant scale as well as cold model data can be correlated reasonably well via similar functional relationship, such as the one presented above.…”

“…It was also suggest 2) that the dimensionless correlations, proposed by Yonezawa and Schwerdtfeger, 1) do not unify the plant as well as cold model measurements sufficiently accurately. A need for an unique, physically meaningful and relatively more accurate correlation was therefore advocated by these authors.…”

“…1) A video photographic technique was applied by these investigators to measure the area of the exposed eye of the spout as a function of gas flow rates (Q), gas injection nozzle dimensions (d o ), slag layer thickness (H) and liquid depth (h) in two different gas agitated systems namely, a mercury-silicon oil cold model and a 350 t industrial size argon stirred ladle. To quantify their measurements, empirical correlations between two dimensionless groups, namely, A es /hH and Q 2 /gH 5 (for symbols refer to nomenclature) were developed through regression.…”

“…... (1) It was suggested by Yonezawa and Schwerdtfeger 1) that exact relationships between, A es /hH and Q 2 /gH 5 are specific to gas injection nozzle dimensions. Despite many uncertainties in the plant scale measurements it was also noted by the authors 1) that both plant scale as well as cold model data can be correlated reasonably well via similar functional relationship, such as the one presented above.…”

“…As such, the geometry and dimension of the gas injection nozzle do not influence a wide range of phenomena in Froude dominated ladle flows to any significant extent. In view of such, it is difficult to rationalise empirical correlations 1) for spout eye area specific to nozzle dimensions.…”