scholarly journals Mixing Phenomenon and Flow Field in Ladle of RH Process

Metals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 886 ◽  
Author(s):  
Kaitian Zhang ◽  
Heng Cui ◽  
Rudong Wang ◽  
Yang Liu
Keyword(s):  
Flow Field ◽  
Vacuum Chamber ◽  
Mixing Time ◽  
Mixing Layer ◽  
Water Model ◽  
Utilization Rate ◽  
Rh Process ◽  
Depth Increase ◽  
The One ◽  
Gas Blowing

Particle image velocimetry (PIV) system was adopted to investigate the relationship between the mixing phenomenon and the flow field of a 210 t RH degasser by a 1:4 scale water model. The results of mixing simulation experiments indicated that the mixing time decreased with the increase of gas blowing rate. However, with the increase of Snorkel immersion depth (SID), the mixing time presented a decreasing rend firstly and then increased. The measurement of flow fields of RH ladle by PIV system can explain the phenomenon above. According to the characteristics of the flow field in RH ladle, the flow field can be divided into the mixing layer, the transition layer, and the inactive layer. On the one hand, the stirring power in RH ladle and vacuum chamber both increases with more gas blowing rate, leading to the decrease of mixing time. On the other hand, with SID increases from 400 mm to 480 mm, the gas blowing depth increase results in the mixing power increases, and the mixing time decreases at the beginning. Because of too much-molten steel in the vacuum chamber and the expanding of the inactive layer in RH ladle, however, the utilization rate of the gas driving force begins to decrease. Therefore, the mixing time started to increases with the increase of SID.

Research on Flow Field of Double-Nozzles Bottom Blowing CAS Process with Properties of Liquid Metal through Numerical Simulation

2013 ◽  
Vol 675 ◽  
pp. 129-134
Author(s):  
Meng Zhou
Keyword(s):  
Numerical Simulation ◽  
Liquid Metal ◽  
Flow Field ◽  
Mixing Time ◽  
Simulation Method ◽  
Refining Process ◽  
Transmission Process ◽  
Dimensionless Analysis ◽  
Bottom Blowing ◽  
Gas Blowing

The Fluid Flow of Liquid Metal in Ladles of CAS-OB Refining Process Is a Complicated Turbulent Transmission Process. it Behaves much More Complicated than in Traditional Ladle because of Immersion Snorkel. this Paper Describes Properties of Liquid Metal Based on Full Buoyancy Model. the Author Analyzes the Characteristics of Flow Field in Single and Double-nozzles Bottom Blowing Condition through Numerical Simulation Method. Double-nozzles Bottom Blowing Could Improve Blending Effect in the Region where Is Weak Mixing. this Paper Also Draws an Empirical Formula which Tells how Gas Blowing and Immersion Depth Influence Mixing Time in CAS-OB Ladle through Dimensionless Analysis.

Mass Transfer Coefficients during Steel Decarburization in a RH Degasser

2008 ◽  
Vol 273-276 ◽  
pp. 679-684
Author(s):  
Roberto Parreiras Tavares ◽  
André Afonso Nascimento ◽  
Henrique Loures Vale Pujatti
Keyword(s):  
Mass Transfer ◽  
Reynolds Number ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Gas Flow ◽  
Vacuum Chamber ◽  
Volumetric Mass Transfer Coefficient ◽  
Gas Flow Rate ◽  
Rh Process ◽  
Kinetics Of

The RH process is a secondary refining process that can simultaneously attain significant levels of removal of interstitial elements, such as carbon, nitrogen and hydrogen, from liquid steel. In the RH process, the decarburization rate plays a very important role in determining the productivity of the equipment. The kinetics of this reaction is controlled by mass transfer in the liquid phase. In the present work, a physical model of a RH degasser has been built and used in the study of the kinetics of decarburization. The effects of the gas flow rate and of the configurations of the nozzles used in the injection of the gas have been analyzed. The decarburization reaction of liquid steel was simulated using a reaction involving CO2 and caustic solutions. The concentration of CO2 in the solution was evaluated using pH measurements. Based on the experimental results, it was possible to estimate the reaction rate constant. A volumetric mass transfer coefficient was then calculated based on these rate constants and on the circulation rate of the liquid. The logarithm of the mass transfer coefficient showed a linear relationship with the logarithm of the gas flow rate. The slope of the line was found to vary according to the relevance of the reaction at the free surface in the vacuum chamber. A linear relationship between the volumetric mass transfer coefficient and the nozzle Reynolds number was also observed. The slopes of the lines changed according to the relative importance of the two reaction sites, gas-liquid interface in the upleg snorkel and in the vacuum. At higher Reynolds number, the reaction in the vacuum chamber tends to be more significant.

On the Flow Fields of Inertial Impactors

1974 ◽  
Vol 96 (4) ◽  
pp. 394-400 ◽  
Author(s):  
V. A. Marple ◽  
B. Y. H. Liu ◽  
K. T. Whitby
Keyword(s):  
Flow Field ◽  
Stokes Equations ◽  
Relaxation Method ◽  
Water Model ◽  
Navier Stokes ◽  
Visualization Technique ◽  
Navier Stokes Equations ◽  
Theoretical Results ◽  
Plate Distance ◽  
Good Agreement

The flow field in an inertial impactor was studied experimentally with a water model by means of a flow visualization technique. The influence of such parameters as Reynolds number and jet-to-plate distance on the flow field was determined. The Navier-Stokes equations describing the laminar flow field in the impactor were solved numerically by means of a finite difference relaxation method. The theoretical results were found to be in good agreement with the empirical observations made with the water model.

scholarly journals Growth Rate Exponents of Richtmyer-Meshkov Mixing Layers

2005 ◽  
Vol 73 (3) ◽  
pp. 461-468 ◽  
Author(s):  
Timothy T. Clark ◽  
Ye Zhou
Keyword(s):  
Flow Field ◽  
Power Law ◽  
Mixing Layer ◽  
Power Laws ◽  
Mixing Layers ◽  
Spatial Gradients ◽  
Power Law Exponent ◽  
Virtual Time ◽  
Time Origin ◽  
Density Ratios

The Richtmyer-Meshkov mixing layer is initiated by the passing of a shock over an interface between fluid of differing densities. The energy deposited during the shock passage undergoes a relaxation process during which the fluctuational energy in the flow field decays and the spatial gradients of the flow field decrease in time. This late stage of Richtmyer-Meshkov mixing layers is studied from the viewpoint of self-similarity. Analogies with weakly anisotropic turbulence suggest that both the bubble-side and spike-side widths of the mixing layer should evolve as power-laws in time, with the same power-law exponent and virtual time origin for both sides. The analogy also bounds the power-law exponent between 2∕7 and 1∕2. It is then shown that the assumption of identical power-law exponents for bubbles and spikes yields fits that are in good agreement with experiment at modest density ratios.

Contrast Study on the Radial Velocity of the Flow Field of the Hydrocyclones with Different Inlet Structures

2011 ◽  
Vol 339 ◽  
pp. 624-629
Author(s):  
Lian Cheng Ren ◽  
Zheng Liang ◽  
Jiang Meng ◽  
Lin Yang ◽  
Jia Lin Tian
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Radial Velocity ◽  
Axial Symmetry ◽  
Separation Efficiency ◽  
Great Influence ◽  
The Other ◽  
Contrast Study ◽  
The One ◽  
Tangential Inlet

On the base of numerical simulation and theoretical analysis, the flow field of a conventional single-tangential-inlet Hydrocyclone and a newly put forward axial-symmetry double-tangential-inlet hydrocyclone were contrasted. The study shows that the inlet structure of the Hydrocylone has a great influence on the radial velocity of the flow field in the hydrocyclone and that the radial velocity in the hydrocyclone with single-tangential-inlet is not symmetry about the axis of the hydrocyclone; and on the other hand the radial velocity in the hydrocyclone with axial-symmetry double-tangential-inlet is symmetry about the axis of the hydrocyclone. The magnitude of the radial velocity of the flow in the hydrocyclone with single-tangential-inlet is greater than that in the hydrocyclone with axial-symmetry double-tangential-inlet hydrocyclone, which means the hydrocyclone with axial-symmetry double-tangential-inlet has greater capability than the rival one with single-tangential inlet. The symmetry about the axis of the hydrocyclone of the radial velocity means the radial velocities in the place where the radio is the same are constant, which means the hydrocyclone has a great separation efficiency. The conclusion is that changing the conventional hydrocyclone into the one with axial-symmetry double-tangential-inlet structure can offer greater separation capability and efficiency.

MMC-LES of a syngas mixing layer using an anisotropic mixing time scale model

2018 ◽  
Vol 189 ◽  
pp. 311-314 ◽  
Author(s):  
Son Vo ◽  
Andreas Kronenburg ◽  
Oliver T. Stein ◽  
Matthew J. Cleary
Keyword(s):  
Time Scale ◽  
Mixing Time ◽  
Mixing Layer ◽  
Scale Model ◽  
Mixing Time Scale

The Model Analysis of Inclusion Moving in the Swirl Flow Zone Sourcing from the Inner-Swirl-Type Turbulence Controller in Tundish

2017 ◽  
Vol 36 (5) ◽  
pp. 541-550 ◽  
Author(s):  
Yan Jin ◽  
Chen Ye ◽  
Xiao Luo ◽  
Hui Yuan ◽  
Changgui Cheng
Keyword(s):  
Flow Field ◽  
Swirling Flow ◽  
Mathematic Model ◽  
Swirl Flow ◽  
Water Model ◽  
Medium Size ◽  
Force Analysis ◽  
Inclusion Removal ◽  
Flow Band ◽  
Turbulence Inhibitor

AbstractIn order to improve the inclusion removal property of the tundish, the mathematic model for simulation of the flow field sourced from inner-swirl-type turbulence controller (ISTTC) was developed, in which there were six blades arranged with an eccentric angle (θ) counterclockwise. Based on the mathematical and water model, the effect of inclusion removal in the swirling flow field formed by ISTTC was analyzed. It was found that ISTTC had got the better effect of inhibiting turbulence in tundish than traditional turbulence inhibitor (TI). As the blades eccentric angle (θ) of ISTTC increasing, the intensity of swirling flow above it increased. The maximum rotate speed of fluid in swirling flow band driven by ISTTC (θ=45°) was equal to 25 rmp. Based on the force analysis of inclusion in swirling flow sourced from ISTTC, the removal effect of medium size inclusion by ISTTC was attributed to the centripetal force (Fct) of swirling flow, but removal effect of ISTTC to small size inclusion was more depend on its better turbulence depression behavior.

scholarly journals Study of the Effect of a Plug with Torsion Channels on the Mixing Time in a Continuous Casting Ladle Water Model

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1942
Author(s):  
Gerardo Aguilar ◽  
Gildardo Solorio-Diaz ◽  
Alicia Aguilar-Corona ◽  
José Angel Ramos-Banderas ◽  
Constantin A. Hernández ◽  
...  
Keyword(s):  
Continuous Casting ◽  
Mixing Time ◽  
Tangential Velocity ◽  
Water Model ◽  
Mixing Times ◽  
Low Velocity ◽  
Velocity Magnitude ◽  
Image Velocimetry ◽  
Casting Ladle ◽  
Upward Direction

The use of porous plugs in injecting gas through the bottom of a ladle forms vertical plumes in a very similar way to a truncated cone. The gas plume when exiting the plug has a smaller diameter compared to that formed in the upper zone of the ladle because inertial forces predominate over buoyancy forces in this zone. In addition, the magnitude of the plume velocity is concentrated in an upward direction, which increases the likelihood of low velocity zones forming near the bottom of the ladle, especially in lower corners. In this work, a plug with spiral-shaped channels with different torsion angles is proposed, with the objective that the gas, when passing through them, has a tangential velocity gain or that the velocity magnitude is distributed in the three axes and does not just focus on the upward direction, helping to decrease low velocity zones near the bottom of the ladle for better mixing times. For the experimentation, we worked in a continuous casting ladle water model with two configuration injections, which in previous works were reported as the most efficient in mixing the steel in this ladle. The results obtained using the PIV technique (particle image velocimetry) and conductimetry technique indicate that the plugs with the torsion channels at angles of 60° and 120° improve the mixing times for the two injection configurations.

Time resolved flow-field measurements of a turbulent mixing layer over a rectangular cavity

2010 ◽  
Vol 51 (1) ◽  
pp. 51-63 ◽  
Author(s):  
Shiyao Bian ◽  
James F. Driscoll ◽  
Brian R. Elbing ◽  
Steven L. Ceccio
Keyword(s):  
Flow Field ◽  
Turbulent Mixing ◽  
Mixing Layer ◽  
Field Measurements ◽  
Rectangular Cavity ◽  
Time Resolved ◽  
Turbulent Mixing Layer

scholarly journals Core overshooting under the light of fluid dynamics

2019 ◽  
Vol 82 ◽  
pp. 153-165
Author(s):  
M. Rieutord
Keyword(s):  
Fluid Dynamics ◽  
Viscous Dissipation ◽  
Mixing Layer ◽  
Mechanical Analysis ◽  
Scale Height ◽  
Early Type ◽  
Pressure Scale ◽  
Early Type Stars ◽  
The One

We discuss the possible contraints that are brought about by a fluid mechanical analysis of the overshooting phenomenon at the interface of convective cores and radiative envelopes of early-type stars. We investigate an improvement of Roxburgh’s criterion by taking into account the viscous dissipation but show that this criterion remains not stringent enough to be predictive. We then discuss the thickness of the overshooting layer and show that all estimates, including the one of Zahn (1991), lead to a very thin mixing layer typically less than a percent of the pressure scale height.

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