scholarly journals Influence of Subflux Turbulence Controller and Ladle Shroud Asymmetric Using on Hydrodynamic Conditions in One Strand Slab Tundish

Metals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 68 ◽  
Author(s):  
Adam Cwudziński
Keyword(s):  
Liquid Steel ◽  
Plug Flow ◽  
Mixed Volume ◽  
Volume Flow ◽  
Hydrodynamic Conditions ◽  
Velocity Magnitude ◽  
Wedge Shape ◽  
Nominal Capacity ◽  
Transient Zone ◽  
Stable Flow

The tundish plays a key role in the process of continuous steel casting (CSC), as it ensures a stable flow of steel to the mould. Therefore, particular attention is paid to the behavior of liquid steel in the tundish. A wedge-shape tundish with a nominal capacity of 30 tons was tested. The present study has examined different variants of subflux turbulence controller (STC) and ladle shroud (LS) positions relative to one another. For the designed continuous casting variants with the modified tundish pouring zones, numerical simulations of liquid steel behavior were performed. From the computer simulations results, motion, velocity magnitude, and temperature of liquid steel were obtained. Moreover the shares of stagnant volume flow, dispersed plug flow, well-mixed volume flow and transient zone were calculated. It is possible to effectively modify the hydrodynamic conditions by appropriate selection the position of the STC and LS.

Modeling Study of the Influence of Subflux Controller of Turbulence on the Molten Steel Flow in Tundish

2010 ◽  
Vol 654-656 ◽  
pp. 1557-1560 ◽  
Author(s):  
Tomasz Merder
Keyword(s):  
Molten Steel ◽  
Liquid Steel ◽  
Mixed Volume ◽  
Control Device ◽  
Dead Volume ◽  
Model Liquid ◽  
Flow Control Device ◽  
Commercial Code ◽  
Nominal Capacity ◽  
Steel Flow

The objective of the study is to diagnose the current condition of the two-strand tundish. The investigated object is a “T”-type tundish. The nominal capacity of the tundish is 7.5 tonne of liquid steel. By the mathematical simulation, fluid flow and heat transfer of molten-steel in a tundish of a billet caster under different conditions (bare tundish and tundish with flow control device) are analyzed. Three variants of subflux controller of turbulence configurations in the tundish are tested. Numerical simulations of are carried out with the finite-volume commercial code FLUENT using the realizable k- turbulence model. Liquid steel velocity, temperature, turbulent kinetic energy and Residence Time Distribution (RTD) characteristic have been obtained as a result of mathematical calculations. The RTD curve is used to estimate the different volumes such as plug volume, dead volume and mixed volume inside the tundish. The ratio of mixed to dead volume, which indicates the mixing capability of a tundish, is estimated.

scholarly journals Numerical Investigation of the Hydrodynamic Conditions in A Multi-Strand Cc Tundish with Closed Outlets

2014 ◽  
Vol 59 (3) ◽  
pp. 887-892 ◽  
Author(s):  
T. Merder
Keyword(s):  
Liquid Steel ◽  
Stokes Equations ◽  
Thermal Conditions ◽  
Casting Process ◽  
Navier Stokes ◽  
Hydrodynamic Conditions ◽  
Continuous Casting Process ◽  
Navier Stokes Equations ◽  
Steel Flow ◽  
Kinetics Of

Abstract In industrial conditions there are situations when the CC machine works under emergency. It can be result of mechanical or electrical causes, breakout of billet or problem with supplying new parts of liquid steel to the CC machine. As a consequence one or two outlets of the tundish should be closed. However, closing one of the outlets influences the hydrodynamic and thermal conditions occurring in the tundish. Thus, the important information is which of the outlets should be closed to conduct further continuous casting process correctly.The following research was conducted to analyze the influence of liquid steel flow behaviour in the multi-strand tundish when all outlets do not work. Such problem was solved by means of numerical methods based on Navier-Stokes equations (k–ɛ standard turbulence model). Numerical simulations were done using the educational version of CFD program (Computational Fluid Dynamics) – ANSYSFluent. As a result forecasted velocity fields and RTD curves (Residence Time Distribution) were obtained. RTD characteristics were used to determine kinetics of liquid steel mixing and also to calculate parts of particular flow areas for studied cases.

Using Unsteady Analysis to Improve the Steady State CFD Assessment of Minimum Flow in a Radial Compressor Stage

2013 ◽  
Author(s):  
Clementine Vezier ◽  
Michael Dollinger ◽  
James M. Sorokes ◽  
Jorge E. Pacheco
Keyword(s):  
Steady State ◽  
High Volume ◽  
Volume Flow ◽  
Stage Model ◽  
Compressor Stage ◽  
Steady State Condition ◽  
Flow Features ◽  
High Mach ◽  
Flow Compressor ◽  
Stable Flow

This paper presents a Computational Fluid Dynamics (CFD) study performed to assess the prediction of the minimum stable volume flow for a high Mach number, high head, and high volume flow compressor stage. CFD was run on a “pie slice” or sector stage model in steady-state condition and on a full 360° stage model under both steady and unsteady state conditions. The predictions of the minimum stable flow were compared to experimental data. Results showed the CFD performed on the “pie slice” stage model over-predicted the minimum stable flow by 9% compared to the test results, while the transient CFD predicted the minimum stable flow within 5.8%. Flow field comparisons of the impeller between unsteady and steady state CFD revealed that the steady state CFD accurately predicted the flow phenomena until the onset of surge. However, the unsteady flow features could not propagate through the diffuser because of the limitations of the impeller-diffuser interface modeling in the steady state analysis.

scholarly journals Effect of Temperature Fields Heterogeneity in the Tundish on Primary Structure of Continuously Cast Ingots

2015 ◽  
Vol 60 (1) ◽  
pp. 227-233
Author(s):  
J. Pieprzyca ◽  
Z. Kudliński ◽  
T. Merder
Keyword(s):  
Liquid Steel ◽  
Primary Structure ◽  
Plug Flow ◽  
Temperature Fields ◽  
Effect Of Temperature ◽  
Laboratory Research ◽  
Solidification Velocity ◽  
Cooling Zone ◽  
Working Space ◽  
Steel Flow

AbstractThe formation of the cast strands’ primary structure is a very complex process in terms of the thermodynamics and physicochemical. It occurs during solidification and crystallization of the liquid steel in the crystallizer and in the secondary cooling zone of the CC device. On the basis of the experience gained in the industry and knowledge arising from theory of metals and alloys solidification it can be concluded, that substantial influence on the shape of cast strands primary structure have the temperature of overheating of the liquid steel above liquidus temperature and solidification velocity. A proper control of those casting parameters allows to obtain the cast strands with desired primary structure. In the one and two-way symmetric devices regulation like this is not problematic, in the multi-way devices - specially in the asymmetric - causes a series of problems. In those devices can occur a major temperature difference in each outlet zone of the tundish working space caused by i.e. the distance length diversity of liquid steel stream from the inlet to each outlet and by disadvantageous layout of liquid steel flow zones (turbulent flow zone, plug flow and dead zones) in working area of tundish. Particularly high values of those diversity can be expected in the asymmetric tundishes.The article presents results of laboratory research - model and industrial regarding impact of the liquid steel overheating temperature, but also heterogeneity of the temperature fields in the tundish on primary structure of the cast strands.

scholarly journals A Simulation Study on the Flow Behavior of Liquid Steel in Tundish with Annular Argon Blowing in the Upper Nozzle

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 225 ◽  
Author(s):  
Xufeng Qin ◽  
Changgui Cheng ◽  
Yang Li ◽  
Chunming Zhang ◽  
Jinlei Zhang ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Flow Velocity ◽  
Flow Rate ◽  
Casting Speed ◽  
Liquid Steel ◽  
Flow Behavior ◽  
Volume Flow ◽  
Vertical Flow ◽  
Argon Flow Rate ◽  
Argon Flow

A three-dimensional mathematical model of gasliquid two-phase flow has been established to study the flow behavior of liquid steel in the tundish. The effect of the argon flow rate and casting speed on the flow behavior of liquid steel, as well as the migration behavior of argon bubbles, was investigated. The results from the mathematical model were found to be consistent with those from the tundish water model. There were some swirl flows around the stopper when the annular argon blowing process was adopted; the flow of liquid steel near the liquid surface was active around the stopper. With increased argon flow rate, the vortex range and intensity around the stopper gradually increased, and the vertical flow velocity of the liquid steel in the vicinity of the stopper increased; the argon volume flow in the tundish and mold all increased. With increased casting speed, the vortex range and intensity around the stopper gradually decreased, the peak value of vertical flow velocity of liquid steel at the vicinity of the stopper decreased, and the distribution and ratio of argon volume flow between the tundish and the mold decreased. To avoid slag entrapment and purify the liquid steel, the argon flow rate should not be more than 3 L·min−1. These results provide a theoretical basis to optimize the parameters of the annular argon blowing at the upper nozzle and improve the slab quality.

The Influence of the Shape of Turbulence Inhibitors on the Hydrodynamic Conditions Occuring in a Tundish

2013 ◽  
Vol 58 (4) ◽  
pp. 1111-1117 ◽  
Author(s):  
T. Merder
Keyword(s):  
Time Distribution ◽  
Residence Time Distribution ◽  
Concentration Distribution ◽  
Water Model ◽  
Hydrodynamic Conditions ◽  
Working Space ◽  
Transient Zone ◽  
Turbulence Inhibitor ◽  
The Impact ◽  
Kinetics Of

Abstract The article presents results of the research that was carried out taking into account the influence of the (impact pads) turbulence inhibitor geometry and its equipment of the working space on the hydrodynamic conditions occurring in T-type tundish. Four different turbulence inhibitors were discussed. They differ in shape and configuration of external walls. The research was conducted basing on the numerical simulations as well as on tests performed on physical water model. As a result of calculations the velocity field distribution, turbulence field and marker concentration distribution in the liquid steel for the tested geometrical variants of turbulence inhibitors were obtained. Worked out RTD curves (Residence Time Distribution) allowed to determine the kinetics of steel mixing (the range of transient zone was estimated), and the percentage participation of the particular flow zones. The test carried out on the water model concerned one of the tested turbulence inhibitors. Research was done to verify the parameter settings of the numerical model applied in calculations. Obtained results gave valuable information about the work of the object after applying different turbulence inhibitors.

scholarly journals Influence of Hydrodynamic Structure on Mixing Time of Alloy Additions with Liquid Steel in One Strand Tundish

2016 ◽  
Vol 61 (1) ◽  
pp. 295-300 ◽  
Author(s):  
A. Cwudziński
Keyword(s):  
Liquid Steel ◽  
Mixing Time ◽  
Hydrodynamic Conditions ◽  
Step Method ◽  
Ansys Fluent ◽  
Working Space ◽  
Alloy Addition ◽  
Steel Flow ◽  
Mixing Curves ◽  
Active Flow

The knowledge of the hydrodynamic pattern aids in designing new and modernizing existing tundishes. The device under examination is an one-strand tundish of a capacity of 30 Mg. Computer simulation of the liquid steel flow, tracer and alloy addition behaviour in turbulent motion conditions was done using the Ansys-Fluent®computer program. The hydrodynamic conditions of steel flow were determined based on the distribution of the characteristics of tundish liquid steel residence time distribution (RTD). The alloy addition was introduced to the liquid steel by the pulse-step method. Based on computer simulations carried out, steel flow fields and RTD and mixing curves were obtained, and the shares of stagnant volume flow and active flow and the mixing time were computed. Dispersion of the alloy addition in liquid steel during its flow through the tundish is a dynamic process which is determined by the hydrodynamic conditions occurring in the tundish working space.

scholarly journals Optimization of Steel Flow in the Tundish by Modifying its Working Area

2016 ◽  
Vol 61 (4) ◽  
pp. 2071-2078 ◽  
Author(s):  
P. Warzecha ◽  
A. M. Hutny ◽  
M. Warzecha ◽  
T. Merder
Keyword(s):  
Time Distribution ◽  
Hydrodynamic Conditions ◽  
Ansys Fluent ◽  
Flow Control Devices ◽  
Commercial Code ◽  
Nominal Capacity ◽  
Continuous Casting Tundish ◽  
Control Devices ◽  
Steel Flow

Abstract Presented paper describes model investigations carried out on six-strand continuous casting tundish. Numerical analysis is based on simulations performed with the use of commercial code ANSYS Fluent. The analysis concerns determination of hydrodynamic conditions of the flow in the analysed tundish, with nominal capacity of 22 Mg, and its optimisation by modification of the flow structure in the tundish working area. Four different flow control devices (FCD) were proposed. Results of investigations presented in the paper include the distribution of velocity vectors and distribution of temperature and turbulence kinetic energy. Additionally, for more detailed comparative analysis, the macroscopic characteristics of residence time distribution (RTD) in the reactor, and the transition zone ranges were determined for each of the variants.

scholarly journals Numerical Prediction of Hydrodynamic Conditions in one Strand Tundish. Influence of Thermal Conditions and Casting Speed/ Numeryczna Prognoza Warunków Hydrodynamicznych W Jednozyłowej Kadzi Posredniej. Wpływ Warunków Cieplnych I Predkosci Odlewania

2014 ◽  
Vol 59 (4) ◽  
pp. 1249-1256
Author(s):  
A. Cwudzinski
Keyword(s):  
Computer Simulations ◽  
Casting Speed ◽  
Liquid Steel ◽  
Thermal Conditions ◽  
Hydrodynamic Conditions ◽  
Ansys Fluent ◽  
Working Space ◽  
Flow Control Devices ◽  
Pattern Forming ◽  
Steel Flow

Abstract This paper reports the results of computer simulations of the flow of liquid steel in a single-nozzle tundish, which describe the flow hydrodynamics, depending on the thermal conditions and casting speed. In this paper, five casting speeds, namely 0.3, 0.6, 0.9, 1.2 and 1.5 m/min., have been examined. In view of the fact that tundishes are being equipped with various flow control devices and the process of creating specific hydrodynamic conditions is influenced also by the temperature gradient, computer simulations of liquid steel flow under isothermal and non-isothermal conditions were performed. Computer simulations of liquid steel flow were performed using the commercial program Ansys-Fluent ®. In order to explain the phenomena occurring in the tundish working space, the buoyancy number (Bu) has been calculated. The next research step in the analysis of the flow pattern forming in different casting conditions was to record the E and F-type RTD characteristics and to describe the pattern of flow.

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