Research on Optimization of Tundish Flow Distrbution

2012 ◽  
Vol 542-543 ◽  
pp. 1132-1138
Author(s):  
Wen Fang Gao ◽  
Jian Jun Zhang ◽  
Zhu Gang Peng ◽  
Wei Li ◽  
Jiang Peng Wu ◽  
...  
Keyword(s):  
Time Distribution ◽  
Flow Behavior ◽  
Plug Flow ◽  
Oxide Inclusion ◽  
Pulse Response ◽  
Dead Volume ◽  
Water Model ◽  
Control Solution ◽  
Minimum Residence Time ◽  
Turbulence Inhibitor

Research was made on the flow behavior of the 45t single strand tundish by means of water model. The model was 1:3 in size of the real tundish. Experiment conditions satisfied Froude number similarity. Minimum residence time distribution (RTD) curves were determined by pulse response. The proportion of the plug flow, mixed flow and dead volume were calculated. An optimized solution was made of a combination of turbulence inhibitor, dam and weir to decrease the dead volume (Vd) in the tundish to 11.36%, 67.8% lower than before. Production contrast tests showed that, with the optimized flow control solution, removal of oxide inclusion in slab is improved by 35.3%.

Dispersion Number Studies in ChemicalMechanical Planarization

2003 ◽  
Vol 767 ◽  
Author(s):  
Ara Philipossian ◽  
Erin Mitchell
Keyword(s):  
Fluid Dynamics ◽  
Residence Time ◽  
Time Distribution ◽  
Residence Time Distribution ◽  
Dispersion Model ◽  
Flow Behavior ◽  
Plug Flow ◽  
Operating Conditions ◽  
The Coefficient Of Friction ◽  
Dispersion Number

AbstractThis study explores aspects of the fluid dynamics of CMP processes. The residence time distribution of slurry under the wafer is experimentally determined and used to calculate the Dispersion Number (Δ) of the fluid in the wafer-pad region based on a dispersion model for non-ideal reactors. Furthermore, lubrication theory is used to explain flow behaviors at various operating conditions. Results indicate that at low wafer pressure and high relative pad-wafer velocity, the slurry exhibits nearly ideal plug flow behavior. As pressure increases and velocity decreases, flow begins to deviate from ideality and the slurry becomes increasingly more mixed beneath the wafer. These phenomena are confirmed to be the result of variable slurry film thicknesses between the pad and the wafer, as measured by changes in the coefficient of friction (COF) in the pad-wafer interface.

scholarly journals Application of Tanks-in-Series Model to Characterize Non-Ideal Flow Regimes in Continuous Casting Tundish

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 208
Author(s):  
Dong-Yuan Sheng ◽  
Zongshu Zou
Keyword(s):  
Model Experiment ◽  
Plug Flow ◽  
Flow Regimes ◽  
Dead Volume ◽  
Water Model ◽  
Flow Volume ◽  
Mixed Flow ◽  
Inclusion Removal ◽  
Ideal Flow ◽  
In Series

This study describes a new tanks-in-series model for analyzing non-ideal flow regimes in a single-strand tundish. The tundish was divided into two interconnected tanks, namely an inlet tank and an outlet tank. A water model experiment was carried out to separately measure the residence-time distribution (RTD) of the two tanks. Drift beads were adopted in the water model experiment to simulate the non-metallic inclusions in molten steel. Dead volume fraction was evaluated by analyzing measured RTD curves. The ratio between mixed flow volume and plug flow volume was proposed as a new criterion to evaluate the inclusion removal. In the inlet tank, a higher mixed flow fraction was preferred to effectively release turbulent kinetic energy and enhance inclusion collision growth. In the outlet tank, a higher plug flow fraction was preferred to facilitate inclusion removal by flotation. The optimal positions of the weir were recommended based on the RTD analysis and the inclusion removal from the results of water model experiments. A theoretical equation was derived based on the tanks-in-series model, providing a good fitting function to analyze the experimental data. The confirmation test was performed by applying computational fluid dynamics simulations of liquid steel flow in the real tundish.

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.

Research on Optimization of Flow Field in 60t Tow-Strand Tundish by Hydraulic Model

2012 ◽  
Vol 605-607 ◽  
pp. 1311-1316
Author(s):  
Jian Jun Zhang ◽  
Wen Fang Gao ◽  
Zhu Gang Peng
Keyword(s):  
Flow Field ◽  
Residence Time ◽  
Time Distribution ◽  
Residence Time Distribution ◽  
Flow Behavior ◽  
Hydraulic Model ◽  
Dead Volume ◽  
Average Residence Time ◽  
Original Scheme ◽  
The Dead

The original scheme flow behavior of WISCO 60t two-strand tundish was investigated by means of hydraulic model. Optimized scheme was selected by flow field Character analyzing and residence time distribution (RTD) curves analyzing of each scheme. The results show that the dead volume Vd of optimized scheme decreases to 5.33%, reduced by 77.4% compared with the original scheme. The average residence time Ta of optimized scheme increases to 364.5s, increased by 70.5s compared with the original scheme. The optimized scheme favors more reasonable flow field and inclusions removing in the tundish. It is more adaptive than the original scheme for the tow-strand tundish.

scholarly journals Numerical Modeling of the Fluid Flow in Continuous Casting Tundish with Different Control Devices

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Zhu He ◽  
Kun Zhou ◽  
Shuang Liu ◽  
Wei Xiong ◽  
Baokuan Li
Keyword(s):  
Fluid Dynamics ◽  
Fluid Flow ◽  
Plug Flow ◽  
Flow Characteristics ◽  
The Other ◽  
Dead Volume ◽  
Continuous Casting Tundish ◽  
Control Devices ◽  
Fluid Flow Characteristics ◽  
Turbulence Inhibitor

Numerical simulations were conducted to study the melt flow under the influence of control devices in a T-type two-strand bloom caster tundish via the open source Computational Fluid Dynamics software OpenFOAM. Three different cases were studied: a bare tundish, a tundish with two pairs of baffles, and a tundish equipped with a turbulence inhibitor and a pair of baffles. Turbulence inhibitor and baffles arrangement showed an improvement of the fluid flow characteristics, yielding lower values of dead volume and higher values of plug flow. With a turbulence inhibitor, the velocity of metal which flows directly toward the tundish floor is smaller and the turbulence kinetic energy of the melt top surface is lower than the other two arrangements.

Modeling of Vortex-Flow Solar Reactor via Ideal Reactors in Series Approach

2010 ◽  
Author(s):  
Nesrin Ozalp ◽  
Vidyasagar Shilapuram ◽  
D. Jayakrishna
Keyword(s):  
Residence Time ◽  
Time Distribution ◽  
Residence Time Distribution ◽  
Vortex Flow ◽  
Flow Reactor ◽  
Flow Behavior ◽  
Plug Flow ◽  
Flow Reactors ◽  
In Series ◽  
Sweeping Gas

In this work, we present a thorough reaction engineering analysis on the modeling of a vortex-flow reactor to show that commonly practiced one-plug reactor approach is not sufficient to explain the flow behavior inside the reactor. Our study shows that N-plug flow reactors in series is the best approach in predicting the flow dynamics based on the computational fluid dynamics (CFD) simulations. We have studied the residence time distribution using CFD by two different methods. The residence time distribution characteristics are calculated by approximating the real reactor as N-ideal reactors in series, and then estimated the number of ideal reactors in series for the model. We have validated our CFD model by comparing the simulation results with experimental results. Finally, we have done a parametric study with a different sweeping gas to identify the best screening gas to avoid carbon deposition inside the vortex-flow reactor. Our results have shown that hydrogen is a better screening gas than argon.

Investigation on the control of multiphase flow behavior in a continuous casting tundish during ladle change

2020 ◽  
Vol 117 (6) ◽  
pp. 619
Author(s):  
Rui Xu ◽  
Haitao Ling ◽  
Haijun Wang ◽  
Lizhong Chang ◽  
Shengtao Qiu
Keyword(s):  
Multiphase Flow ◽  
Flow Behavior ◽  
Rolled Strip ◽  
Impact Zone ◽  
Steel Cleanliness ◽  
Carry Over ◽  
Slag Carry Over ◽  
Hot Rolled ◽  
Turbulence Inhibitor ◽  
The Impact

The transient multiphase flow behavior in a single-strand tundish during ladle change was studied using physical modeling. The water and silicon oil were employed to simulate the liquid steel and slag. The effect of the turbulence inhibitor on the slag entrainment and the steel exposure during ladle change were evaluated and discussed. The effect of the slag carry-over on the water-oil-air flow was also analyzed. For the original tundish, the top oil phase in the impact zone was continuously dragged into the tundish bath and opened during ladle change, forming an emulsification phenomenon. By decreasing the liquid velocities in the upper part of the impact zone, the turbulence inhibitor decreased considerably the amount of entrained slag and the steel exposure during ladle change, thereby eliminating the emulsification phenomenon. Furthermore, the use of the TI-2 effectively lowered the effect of the slag carry-over on the steel cleanliness by controlling the movement of slag droplets. The results from industrial trials indicated that the application of the TI-2 reduced considerably the number of linear inclusions caused by ladle change in hot-rolled strip coils.

scholarly journals Integrated impedance sensing of liquid sample plug flow enables automated high throughput NMR spectroscopy

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Omar Nassar ◽  
Mazin Jouda ◽  
Michael Rapp ◽  
Dario Mager ◽  
Jan G. Korvink ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
High Throughput ◽  
Plug Flow ◽  
Microfluidic System ◽  
High Resolution Spectroscopy ◽  
Dead Volume ◽  
Absolute Difference ◽  
Immiscible Fluid ◽  
Flow Sensors ◽  
Novel Approach

AbstractA novel approach for automated high throughput NMR spectroscopy with improved mass-sensitivity is accomplished by integrating microfluidic technologies and micro-NMR resonators. A flow system is utilized to transport a sample of interest from outside the NMR magnet through the NMR detector, circumventing the relatively vast dead volume in the supplying tube by loading a series of individual sample plugs separated by an immiscible fluid. This dual-phase flow demands a real-time robust sensing system to track the sample position and velocities and synchronize the NMR acquisition. In this contribution, we describe an NMR probe head that possesses a microfluidic system featuring: (i) a micro saddle coil for NMR spectroscopy and (ii) a pair of interdigitated capacitive sensors flanking the NMR detector for continuous position and velocity monitoring of the plugs with respect to the NMR detector. The system was successfully tested for automating flow-based measurement in a 500 MHz NMR system, enabling high resolution spectroscopy and NMR sensitivity of 2.18 nmol s1/2 with the flow sensors in operation. The flow sensors featured sensitivity to an absolute difference of 0.2 in relative permittivity, enabling distinction between most common solvents. It was demonstrated that a fully automated NMR measurement of nine individual 120 μL samples could be done within 3.6 min or effectively 15.3 s per sample.

Effects of Nano-Nozzles Cross-Sectional Geometry on Fluid Flow: Molecular Dynamic Simulation

2017 ◽  
Vol 34 (5) ◽  
pp. 667-678 ◽  
Author(s):  
H. Nowruzi ◽  
H. Ghassemi
Keyword(s):  
Fluid Flow ◽  
Velocity Profile ◽  
Cross Sections ◽  
Md Simulation ◽  
Flow Behavior ◽  
Water Model ◽  
Physical Parameters ◽  
Cross Sectional ◽  
Behavior Characteristics ◽  
Fanning Friction Factor

AbstractNano-nozzles are an essential part of the nano electromechanical systems (NEMS). Cross-sectional geometry of nano-nozzles has a significant role on the fluid flow inside them. So, main purpose of the present study is related to the effects of different symmetrical cross-sections on the fluid flow behavior inside of nano-nozzles. To this accomplishment, five different cross-sectional geometries (equilateral triangle, square, regular hexagon, elliptical and circular) are investigated by using molecular dynamics (MD) simulation. In addition, TIP4P is used for atomistic water model. In order to evaluate the fluid flow behavior, non-dimensional physical parameters such as Fanning friction factor, velocity profile and density number are analyzed. Obtained results are shown that the flow behavior characteristics appreciably depend on the geometry of nano-nozzle's cross-section. Velocity profile and density number for five different cross sections of nano-nozzle at three various measurement gauges are presented and discussed.

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.

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