scholarly journals A Novel Multiphase Methodology Simulating Three Phase Flows in a Steel Ladle

Processes ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 175 ◽  
Author(s):  
Marco Ramírez-Argáez ◽  
Abhishek Dutta ◽  
A. Amaro-Villeda ◽  
C. González-Rivera ◽  
A. Conejo
Keyword(s):  
Gas Phase ◽  
Molten Steel ◽  
Physical Nature ◽  
Navier Stokes ◽  
Multiphase System ◽  
Steel Ladle ◽  
System A ◽  
Liquid Phases ◽  
Three Phase ◽  
Turbulent Flow Structure

Mixing phenomena in metallurgical steel ladles by bottom gas injection involves three phases namely, liquid molten steel, liquid slag and gaseous argon. In order to numerically solve this three-phase fluid flow system, a new approach is proposed which considers the physical nature of the gas being a dispersed phase in the liquid, while the two liquids namely, molten steel and slag are continuous phases initially separated by a sharp interface. The model was developed with the combination of two algorithms namely, IPSA (inter phase slip algorithm) where the gas bubbles are given a Eulerian approach since are considered as an interpenetrating phase in the two liquids and VOF (volume of fluid) in which the liquid is divided into two separate liquids but depending on the physical properties of each liquid they are assigned a mass fraction of each liquid. This implies that both the liquid phases (steel and slag) and the gas phase (argon) were solved for the mass balance. The Navier–Stokes conservation equations and the gas-phase turbulence in the liquid phases were solved in combination with the standard k-ε turbulence model. The mathematical model was successfully validated against flow patterns obtained experimentally using particle image velocimetry (PIV) and by the calculation of the area of the slag eye formed in a 1/17th water–oil physical model. The model was applied to an industrial ladle to describe in detail the turbulent flow structure of the multiphase system.

Mathematical and Physical Modeling of Three-Phase Gas-Stirred Ladles

2016 ◽  
Vol 1812 ◽  
pp. 29-34
Author(s):  
Juan A. López ◽  
Marco A. Ramírez-Argáez ◽  
Adrián M. Amaro-Villeda ◽  
Carlos González
Keyword(s):  
Mathematical Model ◽  
Physical Model ◽  
Stokes Equations ◽  
Steel Slag ◽  
Flow Patterns ◽  
Navier Stokes ◽  
Steel Ladle ◽  
Phase System ◽  
Navier Stokes Equations ◽  
Three Phase

ABSTRACTA very realistic 1:17 scale physical model of a 140-ton gas-stirred industrial steel ladle was used to evaluate flow patterns measured by Particle Image Velocimetry (PIV), considering a three-phase system (air-water-oil) to simulate the argon-steel-slag system and to quantify the effect of the slag layer on the flow patterns. The flow patterns were evaluated for a single injector located at the center of the ladle bottom with a gas flow rate of 2.85 l/min, with the presence of a slag phase with a thickness of 0.0066 m. The experimental results obtained in this work are in excellent agreement with the trends reported in the literature for these gas-stirred ladles. Additionally, a mathematical model was developed in a 2D gas-stirred ladle considering the three-phase system built in the physical model. The model was based on the Eulerian approach in which the continuity and the Navier Stokes equations are solved for each phase. Therefore, there were three continuity and six Navier-Stokes equations in the system. Additionally, turbulence in the ladle was computed by using the standard k-epsilon turbulent model. The agreement between numerical simulations and experiments was excellent with respect to velocity fields and turbulent structure, which sets the basis for future works on process analysis with the developed mathematical model, since there are only a few three-phase models reported so far in the literature to predict fluid dynamics in gas-stirred steel ladles.

scholarly journals Three Phase Resolution Transmitarray Element for Electronically Reconfigurable Transmitarrays

2019 ◽  
Vol 2019 (2) ◽  
pp. 106-113
Author(s):  
Nguyễn Minh Thiện ◽  
Nguyễn Hữu Minh ◽  
Nguyễn Bình Dương
Keyword(s):  
Phase Change ◽  
Phase State ◽  
Main Beam ◽  
System A ◽  
Full Wave ◽  
Three Phase ◽  
Phase Resolution ◽  
Waveguide System ◽  
Em Simulation ◽  
And Performance

Electrical beam scanning is a feature enabling an antenna array to electrically control its main beam toward a desired direction. In this paper, a three-phase state element for electronically reconfigurable transmitarrays is presented. The element is made up of C-patches and modified ring slots loaded rectangular gaps. By controlling the bias state of four p-i-n diodes, three phase states are obtained. The dimension of the element is optimized by using full-wave EM simulation and performance of the element is validated by both simulation and an experimental waveguide system. A transmitarrayconsistingof12×12elementshasbeensimulated to validate the steering capabilities. Experimental results indicate the element has good characteristics and excellent phase change capabilities.

Mathematical Modeling of Transient Flow and Heat Transfer in Gas Stirred Molten Steel

2001 ◽  
Author(s):  
J. L. Xia ◽  
T. Ahokainen
Keyword(s):  
Heat Transfer ◽  
Molten Steel ◽  
Thermal Stratification ◽  
Transient Flow ◽  
Liquid Interface ◽  
Turbulent Dispersion ◽  
Steel Ladle ◽  
Bubble Liquid ◽  
Flow And Heat Transfer ◽  
Heat Transfer Correlations

Abstract Transient two phase flow and heat transfer in a gas-stirred steel ladle are numerically investigated. An Eulerian two fluid approach is used. The drag, lift and turbulent dispersion forces are taken into account for the interface interactions. Different interface heat transfer correlations such as Ranz-Marshall and Hughmark relations are used to examine the influence of heat transfer between gas-liquid interface on the flow. The flow pattern, the histories of both gas and molten steel temperatures, and the thermal stratification history are presented. Results show that gas injection can homogenize thermal field and result in a thermal stratification of about 2 °C only (not complete homogenization). The different heat transfer correlations examined for the bubble-liquid interface have negligible impact on the flow and thermal fields. Predictions are compared with experimental data measured in an industrial ladle and a reasonable agreement is achieved.

Discussion on Clustering Effects in Vertical Gas-Particle Flows

2000 ◽  
Author(s):  
Eivind Helland ◽  
Rene Occelli ◽  
Lounes Tadrist
Keyword(s):  
Gas Phase ◽  
Stokes Equations ◽  
Lagrangian Approach ◽  
Inelastic Collisions ◽  
Navier Stokes ◽  
Coupling Term ◽  
Two Phase ◽  
Navier Stokes Equations ◽  
Drag Forces ◽  
Particle Flows

Abstract Simulations of 2D gas-particle flows in a vertical riser using a mixed Eulerian-Lagrangian approach are addressed. The model for the interstitial gas phase is based on the Navier-Stokes equations for two-phase flow with a coupling term between the gas and solid phases due to drag forces. The motion of particles is treated by a Lagrangian approach and the particles are assumed to interact through binary, instantaneous, non-frontal, inelastic collisions with friction. In this paper different particle clustering effects in the gas-particle flow is investigated.

Transmission Line Theories for the Analysis of Electromagnetic Transients in Coil Windings

2013 ◽  
pp. 1-44
Author(s):  
Akihiro Ametani ◽  
Teruo Ohno
Keyword(s):  
Transmission Line ◽  
Propagation Constant ◽  
Characteristic Impedance ◽  
Electromagnetic Transients ◽  
Distributed Parameter ◽  
System A ◽  
Three Phase ◽  
Distributed Parameter Circuit ◽  
Transformer Winding ◽  
Phase Transmission

The chapter contains the basic theory of a distributed-parameter circuit for a single overhead conductor and for a multi-conductor system, which corresponds to a three-phase transmission line and a transformer winding. Starting from a partial differential equation of a single conductor, solutions of a voltage and a current on the conductor are derived as a function of the distance from the sending end. The characteristics of the voltage and the current are explained, and the propagation constant (attenuation and propagation velocity) and the characteristic impedance are described. For a multi-conductor system, a modal theory is introduced, and it is shown that the multi-conductor system is handled as a combination of independent single conductors. Finally, a modeling method of a coil is explained by applying the theories described in the chapter.

Multiphase Reactions and Reactors

2001 ◽  
Author(s):  
L. K. Doraiswamy
Keyword(s):  
Liquid Phase ◽  
Solid Phase ◽  
Complete Classification ◽  
Catalytic Reactions ◽  
Two Phase ◽  
Multiphase Reactions ◽  
Liquid Phases ◽  
Three Phase ◽  
Solid Form

The first three chapters of this part dealt with two-phase reactions. Although catalysts are not generally present in these systems, they can be used in dissolved form in the liquid phase. This, however, does not increase the number of phases. On the other hand, there are innumerable instances of gas-liquid reactions in which the catalyst is present in solid form. A popular example of this is the slurry reactor so extensively employed in reactions such as hydrogenation and oxidation. There are also situations where the solid is a reactant or where a phasetransfer catalyst is immobilized on a solid support that gives rise to a third phase. A broad classification of three-phase reactions and reactors is presented in Table 17.1 (not all of which are considered here). This is not a complete classification, but it includes most of the important (and potentially important) types of reactions and reactors. The thrust of this chapter is on reactions and reactors involving a gas phase, a liquid phase, and a solid phase which can be either a catalyst (but not a phasetransfer catalyst) or a reactant, with greater emphasis on the former. The book by Ramachandran and Chaudhari (1983) on three-phase catalytic reactions is particularly valuable. Other books and reviews include those of Shah (1979), Chaudhari and Ramachandran (1980), Villermaux (1981), Shah et al. (1982), Hofmann (1983), Crine and L’Homme (1983), Doraiswamy and Sharma (1984), Tarmy et al. (1984), Shah and Deckwer (1985), Chaudhari and Shah (1986), Kohler (1986), Chaudhari et al. (1986), Hanika and Stanek (1986), Joshi et al. (1988), Concordia (1990), Mills et al. (1992), Beenackers and Van Swaaij (1993), and Mills and Chaudhari (1997). Doraiswamy and Sharma (1984) also present a discussion of gas-liquid-solid noncatalytic reactions in which the solid is a reactant. In Chapter 7 we saw how Langmuir-Hinshelwood-Hougen-Watson (LHHW) models are normally used to describe the kinetics of gas-solid (catalytic) or liquid-solid (catalytic) reactions, and in Chapters 14 to 16 we saw how mass transfer between gas and liquid phases can significantly alter the rates and regimes of these two-phase reactions.

scholarly journals Dimerization of Acetic Acid in the Gas Phase—NMR Experiments and Quantum-Chemical Calculations

Molecules ◽  
2020 ◽  
Vol 25 (9) ◽  
pp. 2150 ◽  
Author(s):  
Ondřej Socha ◽  
Martin Dračínský
Keyword(s):  
Acetic Acid ◽  
Gas Phase ◽  
Low Temperatures ◽  
Variable Temperature ◽  
Glass Tube ◽  
Variable Pressure ◽  
Liquid Phases ◽  
Donor And Acceptor ◽  
Moller Plesset ◽  
Triple Excitation

Due to the nature of the carboxylic group, acetic acid can serve as both a donor and acceptor of a hydrogen bond. Gaseous acetic acid is known to form cyclic dimers with two strong hydrogen bonds. However, trimeric and various oligomeric structures have also been hypothesized to exist in both the gas and liquid phases of acetic acid. In this work, a combination of gas-phase NMR experiments and advanced computational approaches were employed in order to validate the basic dimerization model of gaseous acetic acid. The gas-phase experiments performed in a glass tube revealed interactions of acetic acid with the glass surface. On the other hand, variable-temperature and variable-pressure NMR parameters obtained for acetic acid in a polymer insert provided thermodynamic parameters that were in excellent agreement with the MP2 (the second order Møller–Plesset perturbation theory) and CCSD(T) (coupled cluster with single, double and perturbative triple excitation) calculations based on the basic dimerization model. A slight disparity between the theoretical dimerization model and the experimental data was revealed only at low temperatures. This observation might indicate the presence of other, entropically disfavored, supramolecular structures at low temperatures.

The Feasibility of a Helmet-Mounted Sight as a Control Device

1966 ◽  
Vol 8 (5) ◽  
pp. 417-425 ◽  
Author(s):  
Robert M. Nicholson
Keyword(s):  
High Speed ◽  
Angular Rate ◽  
Control Device ◽  
Experimental Program ◽  
Moving Targets ◽  
Human Capabilities ◽  
Laboratory Environment ◽  
System A ◽  
Three Phase ◽  
Low Altitude

The purpose of this research was to investigate the practicality of a helmet-mounted sight as an operational element in a quick-reaction bore-sighting system. A three-phase experimental program was conducted to determine the human capabilities with the helmet-mounted sight. In a laboratory environment sighting accuracies were obtained on both static and moving targets. Field test data were obtained during high-speed, low-altitude flights. The series of tests indicated that the accuracy of the sighting process can be expected to vary between a fraction of a degree and four degrees depending on target angular rate and the target sighting angle.

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