Vibrations of a laboratory-scale gas-stirred ladle with two eccentric nozzles and multiple sensors

Alia, Najib; Pylvänäinen, Mika; Visuri, Ville‐Valtteri; John, Volker; Ollila, Seppo

doi:10.1007/s42243-019-00241-x

Cited by 7 publications

(7 citation statements)

References 12 publications

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“…The model was used later for validating CFD simulations [25,37] as well as for studying the vibrations induced by gas-stirring. [38] The dimensions of the water model are presented in Table 2. In the physical model, a porous plug was not employed, but a simple circular plug with same area as the porous plug was used instead.…”

Section: Physical Modeling Studiesmentioning

confidence: 99%

Physical and CFD Modeling of the Effect of Top Layer Properties on the Formation of Open‐Eye in Gas‐Stirred Ladles With Single and Dual‐Plugs

Ramasetti

Visuri

Sulasalmi

et al. 2019

steel research int.

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In secondary steelmaking, the optimal size and position of open-eye is important for effective alloying practice. In the current work, the effect of the top layer thickness and density on the formation of open-eye in a gas stirred ladle was investigated. A one-fifth scale water model of 150-ton ladle was established with single and dual plug configurations for the physical modeling measurements. Air, water and three different oils were used to simulate the argon, liquid steel and slag in the water model, respectively. A transient Computational Fluid Dynamics (CFD) model based on Eulerian Volume of Fluid (VOF) approach was developed for numerical modeling of the fluid flow behavior. The physical modeling results show that the relative open-eye area decreases from 46.7 to 5.6% when top layer thickness was increased from 0.75 to 7.5 cm using a gas flow rate of 7.5 NL min À1 . The effect of the number of plugs on the open-eye area for the same range of top layer thickness mentioned above was also studied. The relative open-eye area generated due to the gas injection through the dual plugs decreased from 49.9 to 5.8%. To study the effect of top layer properties, rapeseed oil, castor oil and paraffin oil were employed for studying the effect of density and dynamic viscosity on the open-eye formation. The results revealed that a larger open-eye is formed when the density is increased. Furthermore, it was found out that the density of the upper phase dominates the open-eye formation while dynamic viscosity has only minor effect. The results obtained from numerical simulations and physical modeling were found to be in good agreement.

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Section: Physical Modeling Studiesmentioning

confidence: 99%

Physical and CFD Modeling of the Effect of Top Layer Properties on the Formation of Open‐Eye in Gas‐Stirred Ladles With Single and Dual‐Plugs

Ramasetti

Visuri

Sulasalmi

et al. 2019

steel research int.

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“…In particular, it focuses on optimizing the gas flow rates as a function of time for fixed nozzle positions and of the two nozzle positions for fixed gas flow rates. Because of the unavailability of data for real steel ladles, the setup used in this paper is based on a laboratory-scale model of a real ladle, for which experimental studies were performed in [14,15]. To perform the numerical simulations, an in-house research code for computational fluid dynamics (CFD) simulations [16,17] is coupled with a freely available library for optimization [18].…”

Section: Introductionmentioning

confidence: 99%

Optimal control of buoyancy-driven liquid steel stirring modeled with single-phase Navier–Stokes equations

Wilbrandt

Alia²,

John

2021

J.Math.Industry

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Gas stirring is an important process used in secondary metallurgy. It allows to homogenize the temperature and the chemical composition of the liquid steel and to remove inclusions which can be detrimental for the end-product quality. In this process, argon gas is injected from two nozzles at the bottom of the vessel and rises by buoyancy through the liquid steel thereby causing stirring, i.e., a mixing of the bath. The gas flow rates and the positions of the nozzles are two important control parameters in practice. A continuous optimization approach is pursued to find optimal values for these control variables. The effect of the gas appears as a volume force in the single-phase incompressible Navier–Stokes equations. Turbulence is modeled with the Smagorinsky Large Eddy Simulation (LES) model. An objective functional based on the vorticity is used to describe the mixing in the liquid bath. Optimized configurations are compared with a default one whose design is based on a setup from industrial practice.

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“…The main tasks of ladle treatments in steelmaking meltshop are alloying, deoxidation, degassing, and heating of steel. As steelmakers strive to reduce variance in composition and temperature as well as improve energy use and yields, various methods, including vibration, optical, and acoustic measurements, have been proposed for indirect measurements.…”

Section: Introductionmentioning

confidence: 99%

“…The ladle vibration spreads from the metal bath onward to the surrounding mechanical structure, from which the vibration can be measured without disturbing the process. The vibration intensity can be used, e.g., for monitoring scrap melting, vessel oscillation, slopping, and rate of gas stirring …”

Section: Introductionmentioning

confidence: 99%

“…A fairly good agreement with experimental data was obtained regardless of the bottom plug status. The relationship between the gas flow rate and the vessel vibration has also been studied with a water model by Alia et al Their results show that the positioning of the accelerometers has a significant effect on the relation between the gas flow rate and measured vibration.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Vibration‐Based Monitoring of Gas‐Stirring Intensity in Vacuum Tank Degassing

Pylvänäinen

Visuri

Nissilä

et al. 2020

steel research int.

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Liquid steel is typically stirred in a vacuum tank using argon gas injection to achieve a homogeneous composition and high‐purity steel. The aim of this work is to study the effect of vessel vibration on the operational state monitoring of the gas stirring in a vacuum tank degasser. Following an extensive analysis of vibration features, the root mean square (RMS) of vertical velocity is found to be the best feature for the measurement of the stirring intensity caused by the volumetric gas injection rate into the ladle. Smoothing is conducted using a centered median filter with a window length of 21 s. In this work, the operational state monitoring of gas stirring is described using a ladle responsiveness value (LRV). This describes the ability of a ladle to generate the maximum amount of vibration with the minimum amount of argon gas. The LRV summarized for each ladle reveals significant differences between them. Correspondingly, a rolling ladle responsiveness value (rLRV) is used for online monitoring of possible gas leakages. The rLRV can also be used for the online monitoring of the stirring efficiency and as its comparison with the overall efficiency of a specific ladle or all ladles.

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Vibrations of a laboratory-scale gas-stirred ladle with two eccentric nozzles and multiple sensors

Cited by 7 publications

References 12 publications

Physical and CFD Modeling of the Effect of Top Layer Properties on the Formation of Open‐Eye in Gas‐Stirred Ladles With Single and Dual‐Plugs

Physical and CFD Modeling of the Effect of Top Layer Properties on the Formation of Open‐Eye in Gas‐Stirred Ladles With Single and Dual‐Plugs

Optimal control of buoyancy-driven liquid steel stirring modeled with single-phase Navier–Stokes equations

Vibration‐Based Monitoring of Gas‐Stirring Intensity in Vacuum Tank Degassing

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