Effect of Both Radial Position and Number of Porous Plugs on Chemical and Thermal Mixing in an Industrial Ladle Involving Two Phase Flow

Abstract

Gas injection in metallurgical vessels is an important tool to improve chemical and thermal mixing. Chemical mixing has been extensively studied in the past 40 years, however, thermal mixing is still poorly understood. This work reports a mathematical model developed to describe the effect of the number and position of porous plugs on thermal and chemical mixing under industrial conditions.A relevant contribution of this work is the evidence indicating a suppressing effect of bottom gas injection on thermal homogenization with off-center gas injection; furthermore, it also suggests that mixing time is optimized with only one nozzle instead of two or three.

Modeling the Effect of Plug Positions and Ladle Aspect Ratio on Hydrogen Removal in the Vacuum Arc Degasser

“…Selection of the optimal design and process parameters for ladle stirring has been the subject of several studies over the years . These have focused on the argon plug position, number of plugs, argon flowrate, and aspect ratio of the ladle.…”

“…These have focused on the argon plug position, number of plugs, argon flowrate, and aspect ratio of the ladle. Physical and theoretical models of single and multi‐plug ladles have concluded that the lowest mixing times are obtained for plug radial positions in the range of 0.5–0.75 R (where R = vessel radius) …”

“…The two‐phase Eulerian model of Maldonado‐Parra et al identified 0.67 R as the optimal position for the single plug case . Moreover, upon consideration of heat transfer effects, they found that thermal mixing was enhanced with a central plug.…”

“…Selection of the optimal design and process parameters for ladle stirring has been the subject of several studies over the years. [4][5][6][7][8][9][10][11] These have focused on the argon plug position, number of plugs, argon flowrate, and aspect ratio of the ladle. Physical and theoretical models of single and multi-plug ladles have concluded that the lowest mixing times are obtained for plug radial positions in the range of 0.5-0.75R (where R ¼ vessel radius).…”

Effect of Melt Superheat and Alloy Size on the Mixing Phenomena in Argon‐Stirred Steel Ladles

“…Jauhiainen et al studied the effect of porous plug location on alloy mixing theoretically using computational fluid dynamics modeling and reported that a centrically stirred ladle was very sensitive to alloy addition location. Maldonado‐Parra et al suggested that mixing time was optimized with only one porous plug located at a radial position of 0.67 instead of two or three, while Lou and Zhu recommended to use dual plugs with the radial position of 0.6R and the angle of 135°. Cloete et al implemented a mathematical model of a full scale gas stirred ladle in designed experiments to assess the effect of various design variables on mixing efficiency.…”