Large Eddy Simulation on Flow Structure in a Dissipative Ladle Shroud and a Tundish

Abstract

Flow structures were investigated in a dissipative ladle shroud (DLS) and a tundish using Large Eddy Simulation. The numerical results were validated inside the DLS and the tundish with PIV experiments. Velocity distribution, vorticity islands and strain rate were analyzed in the DLS respectively, compared with that of a bell-shaped ladle shroud (BLS). The results showed that the three chambers of the DLS gave rise to velocity differences, fluctuating strain rates and vortices, and promoted an increase on turbulence dissipation rate; and the average velocity of outflow ranged from 0.25 to 0.5 m/s when the inlet velocity was 0.708 m/s. In the BLS, the stream flowed straightforward with relatively consistent velocity; apparent vortices were only formed in the bell end; and the outflow went down with high speed and turbulent kinetic energy. The dissipative effect of the DLS was also validated by the flow structure in the tundish. When the stream left the outlet of the DLS, it swung, got twisted and was mixed with more surrounding fluid in the tundish which decreased the mean skin friction coefficient of tundish wall and the velocity of free surface, and finally contributed to a better tundish performance.KEY WORDS: large eddy simulation; dissipative ladle shroud; bell-shaped ladle shroud; flow structure.

“Vacuum Shroud (VS)”-A Green Flow Control Device (FCD) towards Replacement of “Turbo Stop” In Tundish Metallurgy

“…So in the current study it is not numerically simulated. Figure 2(e) is bending nozzle basically apply in centrifugal flow tundish which has limited application and high erosion rate of nozzle [7,27]. So it is not discussed in current study.…”

“…Not only conventional shroud and turbostop as seen from the Figure 2 (a), some researchers have tried to compare the effect of other flow control device like baffles and dams incorporation with impact pad to control the flow pattern in tundish in comparison to bare tundish as well [23]. Dissipative ladle shroud shown in the diagram Figure 2 (b) is a relatively new technology recently developed by few metallurgists to avoid turbulent related problems in the so called metallurgical vessel tundish and physical modeling, mathematical modeling as well as particle image velocimetry have been employed to see the insight and performance of this new device which have been compared to the performance of commonly used conventional shroud, as a results shows sufficient open eye formation, slag emulsification generation, air entrapment for both cases during ladle change over period [4,7,24]. Long nozzle with bell type shroud and trumpet shaped shroud as embodied in Figure 2 (c) have been used by few steelmaking industry to decrease re-oxidation and nucleation of detrimental macro inclusions [3,9].…”

“…So certainly it is required for the metallurgist to get an ultimate solution of these problems. Several researchers have developed different shroud configurations like trumpet shaped shroud [3], dissipative shroud [4], advanced pouring box [5], swirling ladle shroud [6], bending nozzle [7], velocity interrupted shroud [8] etc to inhibit to happen these phenomena. But still these detrimental effects are occurring in tundish during daily operation time to some extent.…”

Modeling of Gas-Steel-Slag Three-Phase Flow in Ladle Metallurgy: Part II. Multi-scale Mathematical Model

“…The LES approach, which resolves large eddies directly and models small eddies using the subgrid scale (SGS) model, is successfully taken into industrial applications for transient phenomena. [20][21][22][23] The diagrammatic sketch of gas bubble stirring process in ladle is displayed in Fig. 1, where the illustration of the multi-scale phenomenon is shown in Fig.…”

A Comparative Study of Fluid Flow and Mass Transfer in a Trumpet-Shaped Ladle Shroud Using Large Eddy Simulation

“…While, the CLS was reported to be suffering several defects [7][8][9] , namely air pick-up, nozzle clogging, slag-eye around the ladle shroud etc., which need to be minimized or avoided. Apart from the newly-emerged swirling ladle shroud (SLS) [10] , dissipative ladle shroud (DLS) [6,11] and inert gas injection [12] , trumpet-shaped ladle shroud (TLS also known as bell-shaped ladle shroud) [8,13,14] is one of the designs that are widely applied in steelmaking plants. The TLS is characterized with a trumpet tip with gradually enlarged diameter which changes the flow patterns both inside the ladle shroud and the tundish.…”