A new design of a ladle shroud, obtained through water modeling, that controls turbulence of the entry jet in continuous casting tundishes is proposed. Particle Image Velocimetry (PIV) measurements indicate that this design decreases the impact velocity on the tundish bottom to close to 1/3 of that provided by a conventional ladle shroud. This achievement is due to a swirling jet that promotes a recirculatory flow in the horizontal planes of the tundish. The swirling effects help to dissipate the turbulence energy of the jet before it impacts the tundish bottom making possible decreases of fluid velocities that impact the back and front walls of the tundish. Turbulence models like k -e, k -w and RSM were applied to simulate the experimental PIV measurements of velocities in the fluid flow. Only the RSM model yielded results that agree remarkably well with the experimental determinations. These results make possible to avoid the employment of flow control devices such as dams, weirs, turbulence inhibitors and the like in tundishes.KEY WORDS: tundish; ladle shroud; turbulence dissipation; PIV; mathematical models. and a density of 1 030 kg/m 3 was fed through a syringe in the upper part of the ladle shroud. By following the tracks of these particles, using a Particle Image Velocimetry (PIV) equipment, velocity fields of water were recorded. Particle tracks were recorded by a Coupled Charged Device (CCD) equipped with a lens of depth field. All signals are processed in a PC; using the cross correlation technique and Fast Fourier Transforms they are converted into fluid velocities. [23][24][25] Figure 2 shows a scheme of the experimental setup. Two ladle shrouds were investigated the first one is of a conventional (LS) design and its dimensions are shown in Fig. 3(a) the second is a swirling ladle shroud (SLS) which consists of central pipe with three intermediate chambers that work as a brake of fluid velocity and an upper blade whose function is to start a swirling motion of the fluid all through the shroud length up to its tip. The tip of the shroud has bell shape to reinforce the braking effect on the fluid which flows into the tundish. Water flow rate was 5.83ϫ10Ϫ4 m 3 /s corresponding to 3.8 tons of liquid steel/min in the current tundish, according to the Froude criterion. This flow was maintained constant for this work. Theory of Turbulence ModelsThe most commonly used turbulence model is that devised by Jones and Launder 28) and known as k-e, it has many advantages; its concept is simple, is implemented in very commercial codes and it has demonstrated capability to simulate correctly many industrial processes like combustion, 27) fluid flow in tundishes 15,16) and multiphase flows 28) among many other applications. Nevertheless, it fails to provide reliable results of swirling flows and highly strained angular velocities of rotating flows.30) Since we are dealing here with a complex swirling flow two other turbulence models were tried; the k-w model of Wilcox 29) and the Reynolds Stress model (RSM) which ...
en Ingenierfa Mscaruoa, Morelia Mich., Mexico.Non-metallic inclusion removal from liquid steel in a tundish is studied using two-phase flow modelling by Particle Image Velocimetry (PIV) techniques and mathematical simulation. The removal efficiency is studied as a function of Flow Control Devices (FCD) arrangements inside the tundish, gas bubbling and mass flow rate. The mathematical two-phase model includes an Eulerian-Eulerian approach for the gasliquid system and a Lagrange approach for the solid particles trajectories. The validation of this model was acceptably proved through PIV measurements and colour tracer experiments in a two-phase water model. The removal efficiency of the tundish in the cases of gas bubbling becomes independent of particle size and FCD arrangements. An increase of mass flow rate decreases the particle mean residence time in the tundish and therefore the removal efficiency. Under the same conditions coupling-uncoupling phenomena of solid particles from the liquid flow depends strongly on their response time. Where this phenomena occurs, it is determined that the particle response time in the model goes from 10-5 to 10-3 seconds for particle size ranging from 20 to 160 11m, respectively; this transition is dependent on particles size and mass flow rate.
In the current research study, a mathematical model was developed to study the dissipation phenomena inside a new design of ladle shroud and its effects on flow patterns and inclusion removal rate. The New Ladle Shroud performance is evaluated in a conventional slab tundish, and the results are compared to different flow control arrangements. The velocity of the entry jet is decreased and the bulk flow is well controlled, the inclusion removal rate is improved, and compared to those arrangements where turbulence inhibitors are used.
This work shows the analysis of the fluid-structure over the mixing time in a ladle furnace. A 1/7 scale acrylic model is constructed from a 135 t ladle, the injection configuration, and the gas flow injected at the bottom of the model are varied. The techniques applied for this study are Colorimetry, Conductimetry (KCl), and Particle Image Velocimetry (PIV). The results indicate that the number, size, and location of the recirculations in the bulk of the fluid have a noteworthy effect on the mixing time of the ladle. The results show that, for configurations involving one gas injection, the increase in gas flow rate does not diminish the degree of homogenization in the analyzed ladle, which is contrary to the logic regarding the energy state of the system. This is explained by taking into account the fluid dynamics structure obtained for the corresponding cases of study.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.