Fig 6 - uploaded by Rodolfo D Morales
Content may be subject to copyright.
Swirling motion of the entry jet determined trough PIV measurements; (a) conventional ladle shroud and (b) SLS design.
Source publication
A conventional ladle shroud (LS) is compared with a swirling ladle shroud (SLS) from the points of view of fluid flow dynamics and removal ratio of inclusions from liquid steel flowing through a tundish using water modeling and fluid dynamics approaches. In this tundish the LS generates vortexing flows at the tundish outlets that disappear with the...
Contexts in source publication
Context 1
... swirling from the SLS shroud is actually detected ex- perimentally by PIV measurements as is shown by compar- ing Figs. 6(a) and 6(b) for the conventional and the SLS shroud, respectively. As seen in Fig. 6(a) the conventional LS yields a straight jet that impacts the tundish bottom while, as shown in Fig. 6(b), the SLS yields a twisted- swirling jet. Since neither the k-e model nor the k-w model predict swirling flows under the present experimen- tal conditions we can anticipate that the RSM model of tur- bulence is actually more ...
Context 2
... swirling from the SLS shroud is actually detected ex- perimentally by PIV measurements as is shown by compar- ing Figs. 6(a) and 6(b) for the conventional and the SLS shroud, respectively. As seen in Fig. 6(a) the conventional LS yields a straight jet that impacts the tundish bottom while, as shown in Fig. 6(b), the SLS yields a twisted- swirling jet. Since neither the k-e model nor the k-w model predict swirling flows under the present experimen- tal conditions we can anticipate that the RSM model of tur- bulence is actually more suitable for flow simulation of water in models and, eventually of liquid steel in tundishes, using the SLS as is ...
Context 3
... yields a twisted- swirling jet. Since neither the k-e model nor the k-w model predict swirling flows under the present experimen- tal conditions we can anticipate that the RSM model of tur- bulence is actually more suitable for flow simulation of water in models and, eventually of liquid steel in tundishes, using the SLS as is seen by comparing Fig. 6(b) with Fig. ...
Similar publications
Tornado is a small-scale system which as the maximal horizontal and vertical velocities in the atmosphere. From the governing equations satisfying the balance between pressure gradient force, inertial centrifugal force and viscous force, the three-dimensional velocities of tornado are obtained, and then its funnel structure is depictured theoretica...
Citations
... Many scholars have conducted research and reports on the elimination of nonmetallic inclusions in tundishes. For example, Solorio et al. [6] used computational and physical simulations to investigate the differences in the molten steel flow and inclusion loss rate in a tundish using a traditional ladle shroud and a swirling ladle shroud. Furthermore, the swirling ladle shroud, an improved flow control shroud, could reduce the formation of vortices and the backflow of molten steel under a uniform and uneven temperature distribution, as well as enhance the rotation speed of inclusions, which is helpful for inclusion removal. ...
Impurity elimination in tundishes is an essential metallurgical function in continuous casting. If inclusions in a tundish cannot be effectively removed, their presence will have a serious impact on the quality of the bloom. As a result, this research investigates the locations of inclusion particles in a six-strand induction-heating tundish in depth, combining the flow, temperature, and inclusion trajectories of molten steel under electromagnetic fields. The results show that a pinch effect occurred in the induction-heating tundish, and a rotating magnetic field formed in the channel, with a maximum value of 0.158 T. The electromagnetic force was directed toward the center of the axis, and its numerical distribution corresponds to the magnetic flux density distribution, with a maximum value of 2.11 × 105 N/m3. The inclusion particles’ movement speed accelerated as the molten steel’s temperature rose, and their distribution in the channel was identical to the rotating flow field distribution. When the steel’s temperature rose from 1750 K to 1850 K, the removal percentage of inclusion particles in the discharge chamber rose by 9.20%, the removal rate at the outlet decreased from 8.00% to 3.00%, and the adhesion percentage of inclusion particles in the channel decreased from 48.40% to 44.40%.
... control of the liquid steel flowing through the tundish is usually accomplished by the use of flow control devices (FcD), including weirs, dams [1][2][3][4][5][6][7][8] and turbulence inhibitors [9][10][11][12][13]. Intensive scientific research popularised the use of trumpet (TLS) [14][15], dissipative (DLS) [16][17][18] and swirling ladle shrouds (SLS) [19][20][21] as devices controlling the flow, but the basic feature of these ladle shrouds is that they begin and end with one hole. Several studies have presented an analysis of the impact of modifying the ladle shroud by including a larger number of holes in the shroud, but the obtained results were not sufficiently satisfactory [22][23][24]. ...
... as mentioned earlier treating ladle shroud as a flow control device which has an effect on liquid steel behaviour is one of the subjects on which scientists' attention is focused. Finding the right ladle shroud is a complex task, which consists of, among others, determination of share of individual flows, liquid steel impact on slag layer, impact of pouring stream on tundish refractory lining, nonmetallic inclusions removal, temperature distribution in tundish or calculating of the transition zone and the mass of the slab with mixed chemical composition [14][15][16][17][18][19][20][22][23][24]35]. ...
... analysed factors which were the diameters of the holes located in the dome, as well as the method of setting the ladle shroud in relation to the longitudinal axis of the tundish. some researchers [14,17,19] studied new ladle shroud impact on turbulence intensity and velocity in pouring zone and in volume of the tundish. It is favorable to reduce its value to avoid destruction of refractory lining protecting tundish walls. ...
... Selected studies related to the modification of the internal space of the ladle shroud, the depth of its immersion [20] or the introduction of inert gas into it [21,22] are a reference point for the search for new solutions. Trumpet [23], dissipative [24][25][26] or swirling [27][28][29] LS are recognized modifications of the internal space of the ladle shroud. This paper presents the results of numerical simulations concerning the modification of aladle shroud for a one-strand tundish. ...
A tundish is a device from which liquid steel is pour into a mold. Therefore tundish hydrodynamic conditions have a significant impact on solidification during continuous steel casting (CSC) process. Modification of ladle shroud workspace, allows for the modification of liquid steel movement in the tundish. In the following work, numerical simulations were performed which allowed the impact of the modification of the ladle shroud workspace on the liquid steel flow structure in a one-strand tundish to be determined. In order to assess the impact of the modification of the ladle shroud on the behavior of the liquid steel in the tundish, simulations were performed, on the basis of which the percentage share of stagnant, ideal mixing and plug flow zones were determined. In addition, the mixing parameters were determined, allowing the estimation of casting duration during sequential casting. The flow fields of liquid steel for each modification of the ladle shroud were performed. The average velocity of liquid steel flowing through the tundish, the Reynolds number and turbulent intensity were also described. The obtained results showed, among others, that the application of three cylinders with a diameter of 0.041 m into the ladle shroud with a diameter of 0.11 m increases the share of active flow in the tundish in relation to the tundish with Conventional Ladle Shroud. At the same time, applying a ladle shroud with a diameter of 0.11 m during casting is the most favorable in relation to the hydrodynamics of the tundish.
... As a result, the jet flow of ladle shroud largely determines the flow pattern in the pouring zone and consequently influences the whole flow field of the tundish. Several novel ladle shroud designs have been developed for this purpose, such as trumpet-shaped ladle shroud (TLS), [16][17][18] swirling ladle shroud (SLS) 12,13,19,20) and dissipative ladle shroud (DLS), 14,15,21) which outperformed the conventional ladle shroud (CLS) in terms of flow control. In particular, the TLS has been practiced owing to its ease of manufacturing and various metallurgical benefits. ...
... Their main features were briefly summarized in our previous work. 15) Morales et al. 12,13,19,20) proposed the concept to use ladle shrouds to control the fluid flow inside a tundish and devel- 13) The tip of the shroud has bell shape to reinforce the braking effect on the fluid which flows into the tundish. 46) Permitting safe submerged opening with bell-shaped. ...
Ladle shroud is a small but significant device in tundish metallurgy to facilitate both production process and steel quality. Past decades have witnessed its evolution from a simply shrouding tube to a multi-functional device in continuous casting processes. Advances in the functions of ladle shroud in tundish metallurgy have been reviewed in this work, including shrouding the teeming stream, fluid flow control, slag carry-over detection, and the potentials of heating and additive feeding. The features of various commercialized and novel ladle shrouds are discussed. The effect of practical operations, such as argon injection and misalignment, on the performance of ladle shrouds is also analyzed in this review.
... Following this tendency, Canale [11] advices that to reduce the emulsification phenomenon, a better control of the energy contained into the tundish fluid must be achieved. To achieve this, in a first try to reduce the energy contained in the steel before it enters into the tundish, Solorio [12] changes the internal ladle shroud design using cylindrical chambers, nevertheless this changes indices inclusion entrapment at the ladle entry. In a second work, Solorio [13] change the cylindrical chambers for rhombus chambers obtaining a reduction of the kinetic energy into the steel delivered by the ladle shroud without the problem of inclusion entrapment at the ladle entry. ...
The research work objective is to study a new ladle shroud internal design to reduce the slag emulsification in the tundish during ladle transient periods. A 3D mathematical model of the tundish was created to solve the fundamental equations, a turbulence model, and a multiphase model. The results show that using a conventional ladle shroud, the fluid is delivered with an excessive amount of kinetic energy being dissipated inside the tundish bath, generating strong mixing flow patterns and entrapping a massive amount of slag. In the other hand, the proposed ladle shroud dissipates the kinetic energy before the fluid enters the tundish promoting less intense mixing patterns; thus, the amount of slag emulsification is reduced significantly. Consequently, if the internal design of the ladle shroud is able to dissipate the kinetic energy before the fluid enters the tundish, it shall be possible to reduce considerable the slag emulsification and the slag opening area.
... [6] A conventional ladle shroud (CLS) is typically a straight bore nozzle made of refractory materials, serving as a flow channel between a ladle and a tundish to protect the liquid steel, while the CLS was reported to be suffering with several defects, [7][8][9] namely air pick-up, nozzle clogging, and slag-eye around the ladle shroud, 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 is 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. ...
The advantages of trumpet-shaped ladle shrouds (TLS) have been frequently demonstrated over conventional straight-bore ladle shrouds (CLS) with respect to production efficiency and molten steel quality in continuous casting practices. The present study is to shed some lights on why the TLS are better than the CLS design by examining the fluid dynamics and mass transfer using large eddy simulation. The obtained numerical results were validated with particle imaging velocimetry experiments. Flow velocity, deformation, turbulent energy dissipation, and mixing kinetics of tracer were discussed. The results showed that the entering jet of the CLS flowed straight down into the tundish with a relatively high speed (average at 0.710 to 0.815 m/s) and turbulent kinetic energy. However, the trumpet section of a TLS intensified velocity differences, strain rates, and vortices, and promoted an increase on turbulence dissipation rate in the interior of the ladle shroud. The average speed of the entering jet to the tundish was decreased to 0.270 to 0.410 m/s from the 0.708 m/s of the inlet speed. The entering jet from the TLS swung, twisted and well mixed with surrounding fluid in the tundish, and dissipated its kinetic energy. Consequently, the turbulence of the whole flow field as well as the mean skin friction coefficient of tundish wall and the velocity of free liquid surface were reduced. A tracer experiment was carried out to study mass transfer and flow mixing behavior, and the results demonstrated that the use of the TLS increased the plug volume and decreased the dead zone, thereby enhancing inclusion flotation. © 2015 The Minerals, Metals & Materials Society and ASM International
... It is generally assumed that fully developed funnel vortex initiates through a dimple formation on surface, then the dimple starts extending downwards the exit nozzle as liquid height in tundish decreases. Only few researchers have done mathematical modeling on vortex formation in tundish or during draining of metallurgical vessels [7,8]. Garcia-Hernandez et al [8] developed a mathematical model to study the significance of the fluid dynamics of vortex formation in tundish operations. ...
A ~ 0.5 scale physical model was fabricated to investigate and improve the performance of a 10 tonne, delta shaped, three strand, and bloom caster tundish. Residence time distribution (RTD) and slag vortexing were studied to predict the performance of the tundish system. It is shown that by incorporating proper flow control devices, such as dam, weir, wedge, baffles with holes, pouring pad, etc., it was possible to (1) 40 % reduction in tundish skull and thereby improve productivity / yield and (2) produce cleaner steel by ensuring better inclusion flotation and removal.
... They investigated the behavior of solid alumina particles using a Euler–Lagrangian method. In this method, the particle trajectories were computed in a Lagrangian frame of reference.This method is discussed in more detail in Section 4.6, page 8. To simulate the chaotic effect of the turbulence eddies of the liquid phase on the inclusion trajectories, a discrete random-walk model was applied by Solorio-Diaz et al. [150]. In this model, a fluctuant random-velocity vector (u 0 i ) is added to the calculated time-averaged vector ( u i ), in order to obtain the inclusion velocity (u i ) at each time step, as particles travel through the fluid. ...
Section 4.3 provides an updated literature review and discussion of the many metallurgical processes that have been modelled using Computational Fluid Dynamics (CFD). Following a brief introduction to CFD techniques, their application to flows in Iron Blast Furnaces and to the design of these impressive reactors, and to others, such as COREX, FINEX, and HIsarna, are presented. These latter reactors are succeeding in by-passing the coke production step needed for the blast furnace route. CFD applications in Basic Oxygen Furnaces and in its off-gas management are next reviewed, followed by flows in ladles, in tundishes, and in continuous casting moulds. It is concluded that the advent of CFD and ever increasing computing “power” has created a revolution in the field of liquid metal processing, and that this will lead to better processes, and to better quality products.
... Wang et al. [12] using water modeling and numerical simulation techniques in a one-strand centrifugal flow tundish, reported that the rotational motion induced by the magnetic field in the centrifugal chamber reduces the dead flow related to the dam position. Solorio-Diaz et al. [13] proposed a swirling ladle shroud (SLS), which is able to control turbulence of the entry jet in a slab tundish. This achievement is due to a swirling jet that promotes a recirculating flow in the horizontal planes of the reactor. ...
... Nevertheless, it fails to provide reliable results in swirling flows and highly strained angular velocities of rotating flows. [13][14][15] For these reasons the RSM to track the turbulence [20] was employed, which uses a set of additional equations to calculate the Reynolds Stresses of the flow and being well described in a previous work. [14] 2 ...
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.
... [17,18]), the k-o turbulence model (used by Ref. [19]), the CK, and more recently the Reynolds stress model (RSM) (used by Refs. [10,[19][20][21]) have also been used. A discussion of all these models would require a separate review. ...
Section 4.2 reviews the various models that have been proposed for modelling the effects of turbulent motions on the overall fluid flow pattern. These strongly affect the processes of heat and mass transfer within the turbulent fluid. Apart from the widely-used κ–ɛ model of turbulence, many others have been proposed and tested, including the Low Reynolds Number κ–ɛ model, the RNG κ–ɛ model for swirling and rotational flows, the κ–ω model for impinging flows, and the Large Eddy Scale Simulation (LES). One must select one or more of these models, since direct solution of the Navier-Stokes Equation that would be able to capture the effects of the smallest sizes of eddies, termed DNS (Direct Numerical Solution), require ultra-fine grids and minute time intervals that are beyond the capabilities of present day computing systems.
