Three-dimensional Compressible Flow Simulation of Top-blown Multiple Jets in Converter

Abstract

A three-dimensional mathematical model has been developed to simulate the compressible jets flow from the top-blown lance with multi-nozzles in converter to a free surrounding domain. The variations of fluid density and viscosity, high temperature, and Mach number were taken into consideration in this model which was validated against the physical modeling results. More specifically, computations were obtained to compare the widely used realizable k-e turbulence model against the standard k-w turbulence model, which shows that the latter one is superior to calculate diverse turbulent conditions within the multiple jets. Moreover, the coalescence pattern of the multiple jets has been illustrated by their Mach number distribution, and each individual jet proceeds in a curve course, bending to the lance center and tending to unite. The effects of the inclination angles on the jets coalescence were also investigated, which indicates that the lower the inclination angle is, the stronger the interfering extent between the multiple jets is. With the help of this model, the dynamic power of the multiple jets to support the cavity formation was demonstrated, and additionally, a mathematical model concerning the effective penetration radius and digressing path of the multiple jets was proposed by taking the inclination angle and the axial distance from the nozzle tips as arguments.KEY WORDS: BOF; top blowing; multiple jets; coalescence; inclination angle; CFD; turbulence model; three dimensional simulation. 491© 2010 ISIJ under the commercial conditions to analyses their essentials in detail, for example the jet coalescence pattern. As imagined, the jet coalescence, if it occurs, reduces the impact of the individual jet as the jets engulf a huge mass of ambient medium. Jet coalescence is thus considered detrimental. Furthermore, wide ranges of Reynolds and Mach numbers in the converter strengthen the complex characteristics of the jets. In order to study the pattern of the jets interference extent and their influence on the metal bath, there are a lot of efforts required to make in the establishment of an accurate numerical method for the multiple jets in the LD vessel.This article proposes a three-dimensional mathematical model aimed to simulate the supersonic free-surrounding jets flow from a lance assumed under the converter conditions, which is verified with physical modeling data.12) A 4-De-Laval-nozzles lance with prescribed nozzle configurations was put into use with inclination angles of 10°, 12°a nd 14°. First, this computational model and its mathematical equations are described. Thereafter, the final 3D simulating results of the jet regimes as well as physical data or semi-analytical method for confirming the model are presented. Finally, the fluid flow field of characteristic parameters, the jet coalescence pattern, and the usefulness of these results on an augmented knowledge for a top-blown process are discussed. Computational Model 2.1. Numerical AssumptionsIn order to formulate the transport equations for ...

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