Effect of Temperature and Multi‐Channeled Stopper Rod on Bubbles in Water Model of a Steel Continuous Caster

2021 ◽  
Author(s):  
Fenggang Liu ◽  
Haichen Zhou ◽  
Lifeng Zhang ◽  
Changyu Ren ◽  
Ji Zhang ◽  
...  
Keyword(s):  
Continuous Caster ◽  
Water Model ◽  
Effect Of Temperature

Large eddy simulation modelling of asymmetrical flow structures in a vertical-bending continuous caster

2019 ◽  
Vol 116 (6) ◽  
pp. 636
Author(s):  
Peng Zhao ◽  
Yinhe Lin ◽  
Bin Yang ◽  
Kegao Liu ◽  
Jingrui Zhao ◽  
...  
Keyword(s):  
Power Spectrum ◽  
Large Eddy Simulation ◽  
Casting Speed ◽  
Oscillation Frequency ◽  
Continuous Caster ◽  
Water Model ◽  
Flow Structures ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Coherent Vortices

Transient asymmetric circulations in the vertical-bending section of a continuous caster were simulated using a large eddy simulation (LES) model. The accuracy of the modelling was verified by comparing the jet behaviours, asymmetrical flow structures in the water model, and velocities reported in the literature. Coherent structures play an essential role in the circulations motion in the vertical-bending caster. A classical Q-criterion was introduced to detect and identify coherent vortices to investigate flow structures. The results indicate that coherent vortices in the lower circulation exhibit asymmetrical features, which further reveal the nature of the turbulence behind the flow structures in the caster. Monitoring points were then selected to investigate the motions of the “strong” and “weak” circulatory vortices and corresponding velocity variations at the interface between the vertical and bending section of the caster. The alternative variations show the periodic behaviours of asymmetrical circulations at both sides of the vertical-bending caster. Besides these circulations were interrelated and interacted, they were also affected by the curved section of the caster, which resulted in the asymmetrical flow structures in the vertical-bending caster. Finally, the effects of casting speed and SEN immersion depths on the oscillation frequency of circulations during a continuous casting process were analysed. As the casting speed increased, the oscillation frequency and power spectrum increased accordingly; as the SEN immersion depth increased, the oscillation frequency and power spectrum thereof decreased accordingly.

MODELING OF FLOW FIELD AND SLAG/LIQUID INTERFACE IN THE CRYSTALLIZER SYSTEM OF A THIN SLAB STEEL CONTINUOUS CASTING

2012 ◽  
Vol 01 (01) ◽  
pp. 1250009
Author(s):  
S. MAHMODI ◽  
A. H. MEISAMI ◽  
M. MAZAR ATABAKI ◽  
M. R. ABOUTALEBI
Keyword(s):  
Flow Field ◽  
Continuous Caster ◽  
Three Dimensional ◽  
Liquid Pool ◽  
Liquid Interface ◽  
Water Model ◽  
Wave Flow ◽  
Main Concern ◽  
Thin Slab ◽  
Thin Slab Casting

In the present investigation, a three dimensional steady flow field model inside crystallizer system of a thin slab steel continuous caster is presented using real geometrical dimension starting from the inlet port of the nozzle. The nozzle flow was modeled considering the minimum casting defects. In addition, a new numerical model is developed for a thin slab casting mold. The velocity of the liquid from the inlet and outlet of the nozzle was considered as the boundary condition. The liquid flow field was computed with main concern on the velocities exiting the nozzle ports for the flow in the liquid pool. It was shown that the fluid pattern in the liquid pool has four main fluid rings including two fluid rings provided by the outer fluid coming from the bottom outlets into the liquid pool and two small fluid rings prepared by the fluid coming from the upper inlets into the liquid pool. The flow pattern agrees well with real measurements obtained by water model. The pool simulation shows asymmetries between two sides of the flow, mainly in the lower recirculation zone. The predictions of slag/liquid interface at the top side of the nozzle and its fluctuations show good agreement with the experimental results. The maximum upward wave flow occurred because of the liquid contact to the upper ports. Hence, a maximum upward flow wave was defined to prevent any unsteady state at the highest casting speed and lowest submergence depth.

CFD Analysis of Multiphase Flow in a Slab Continuous Caster Mold

2006 ◽  
Author(s):  
Miguel A. Barron ◽  
Jesus Gonzalez ◽  
Raul Miranda ◽  
Gabriel Plascencia ◽  
Isai´as Hilerio
Keyword(s):  
Free Surface ◽  
Multiphase Flow ◽  
Numerical Simulations ◽  
Continuous Caster ◽  
Surface Profile ◽  
Submerged Entry Nozzle ◽  
Water Model ◽  
The Third ◽  
Third Phase ◽  
Free Surface Profile

In order to analyze the influence of a third phase in the behaviour of the free surface profile in the mould of a slab steel continuous caster, multiphase flow in a mould water model is physically and numerically investigated. A one third scale mould water model was constructed in accordance with the Froude similarity criterion. The free surface profile in the experimental air-water system was tracked using ultrasonic level sensors which were located at six different positions along a line between the submerged entry nozzle and the mould narrow wall. Volumetric flow rates of water from 3.5×10-4 to 5.83×10-4 m3/s were employed in the physical experiments. Three submergence depths of the nozzle, namely 0.05, 0.07 and 0.09 m, were considered. On the other hand, two and three phase transient and steady state numerical simulations were carried out by means of computational fluid dynamics software. Oil engine was employed as the third phase in the numerical simulations. A comparison between the experimental results and the numerical ones with three phases suggests significant changes in the steel-slag interface due to the presence of the third phase, particularly in the neighbourhood of the discharge of the submerged entry nozzle.

Nucleation of Disorder in Fe3Al Alloys

1967 ◽  
Vol 25 ◽  
pp. 312-313
Author(s):  
P. R. Swann ◽  
W. R. Duff ◽  
R. M. Fisher
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Annealing Temperature ◽  
Antiphase Domain ◽  
Effect Of Temperature ◽  
Domain Structures ◽  
Transmission Electron ◽  
Domain Boundaries ◽  
Higher Temperature ◽  
The One

Recently we have investigated the phase equilibria and antiphase domain structures of Fe-Al alloys containing from 18 to 50 at.% Al by transmission electron microscopy and Mössbauer techniques. This study has revealed that none of the published phase diagrams are correct, although the one proposed by Rimlinger agrees most closely with our results to be published separately. In this paper observations by transmission electron microscopy relating to the nucleation of disorder in Fe-24% Al will be described. Figure 1 shows the structure after heating this alloy to 776.6°C and quenching. The white areas are B2 micro-domains corresponding to regions of disorder which form at the annealing temperature and re-order during the quench. By examining specimens heated in a temperature gradient of 2°C/cm it is possible to determine the effect of temperature on the disordering reaction very precisely. It was found that disorder begins at existing antiphase domain boundaries but that at a slightly higher temperature (1°C) it also occurs by homogeneous nucleation within the domains. A small (∼ .01°C) further increase in temperature caused these micro-domains to completely fill the specimen.

The effect of temperature on high-resolution TEM image contrast

1995 ◽  
Vol 53 ◽  
pp. 640-641
Author(s):  
T. Geipel ◽  
W. Mader ◽  
P. Pirouz
Keyword(s):  
Form Factor ◽  
Inelastic Scattering ◽  
Accurate Method ◽  
Waller Factor ◽  
Effect Of Temperature ◽  
Specimen Thickness ◽  
Influence Of Temperature ◽  
Debye Waller Factor ◽  
Influence Of Temperature On ◽  
Atomic Form Factor

Temperature affects both elastic and inelastic scattering of electrons in a crystal. The Debye-Waller factor, B, describes the influence of temperature on the elastic scattering of electrons, whereas the imaginary part of the (complex) atomic form factor, fc = fr + ifi, describes the influence of temperature on the inelastic scattering of electrons (i.e. absorption). In HRTEM simulations, two possible ways to include absorption are: (i) an approximate method in which absorption is described by a phenomenological constant, μ, i.e. fi; - μfr, with the real part of the atomic form factor, fr, obtained from Hartree-Fock calculations, (ii) a more accurate method in which the absorptive components, fi of the atomic form factor are explicitly calculated. In this contribution, the inclusion of both the Debye-Waller factor and absorption on HRTEM images of a (Oll)-oriented GaAs crystal are presented (using the EMS software.Fig. 1 shows the the amplitudes and phases of the dominant 111 beams as a function of the specimen thickness, t, for the cases when μ = 0 (i.e. no absorption, solid line) and μ = 0.1 (with absorption, dashed line).

The development of dormancy in bulblets of Lilium speciosum generated in vitro. II. The effect of temperature

1990 ◽  
Vol 80 (3) ◽  
pp. 431-436 ◽  
Author(s):  
Isabelle Delvallee ◽  
Annie Paffen ◽  
Geert-Jan De Klerk
Keyword(s):  
Effect Of Temperature ◽  
Lilium Speciosum

Effect of Temperature on ADP-Induced Platelet Aggregation

1973 ◽  
Vol 29 (01) ◽  
pp. 183-189
Author(s):  
C. A Praga ◽  
E. M Pogliani
Keyword(s):  
Platelet Aggregation ◽  
Incubation Period ◽  
Room Temperature ◽  
Important Variable ◽  
Practical Significance ◽  
Effect Of Temperature ◽  
Induce Platelet Aggregation ◽  
Cuvette Holder ◽  
Exact Temperature

SummaryTemperature represents a very important variable in ADP-induced platelet aggregation.When low doses of ADP ( < 1 (μM) are used to induce platelet aggregation, the length of the incubation period of PRP in the cuvette holder of the aggregometer, thermostatted at 37° C, is very critical. Samples of the same PRP previously kept at room temperature, were incubated for increasing periods of time in the cuvette of the aggregometer before adding ADP, and a significant decrease of aggregation, proportional to the length of incubation, was observed. Stirring of the PRP during the incubation period made these changes more evident.To measure the exact temperature of the PRP during incubation in the aggre- gometer, a thermocouple device was used. While the temperature of the cuvette holder was stable at 37° C, the PRP temperature itself increased exponentially, taking about ten minutes from the beginning of the incubation to reach the value of 37° C. The above results have a practical significance in the reproducibility of the platelet aggregation test in vitro and acquire particular value when the effect of inhibitors of ADP induced platelet aggregation is studied.Experiments carried out with three anti-aggregating agents (acetyl salicyclic acid, dipyridamole and metergoline) have shown that the incubation conditions which influence both the effect of the drugs on platelets and the ADP breakdown in plasma must be strictly controlled.

Effect of Temperature, Velocity Gradient and I.V. Heparin on in Vitro Blood Coagulation and Platelet Aggregation

1967 ◽  
Vol 17 (01/02) ◽  
pp. 112-119 ◽  
Author(s):  
L Dintenfass ◽  
M. C Rozenberg
Keyword(s):  
Blood Coagulation ◽  
Velocity Gradient ◽  
Elevated Temperatures ◽  
Morphological Changes ◽  
Effect Of Temperature ◽  
Clotting Time ◽  
Progressive Change ◽  
Aggregation Of Platelets ◽  
Microscopic Techniques

SummaryA study of blood coagulation was carried out by observing changes in the blood viscosity of blood coagulating in the cone-in-cone viscometer. The clots were investigated by microscopic techniques.Immediately after blood is obtained by venepuncture, viscosity of blood remains constant for a certain “latent” period. The duration of this period depends not only on the intrinsic properties of the blood sample, but also on temperature and rate of shear used during blood storage. An increase of temperature decreases the clotting time ; also, an increase in the rate of shear decreases the clotting time.It is confirmed that morphological changes take place in blood coagula as a function of the velocity gradient at which such coagulation takes place. There is a progressive change from the red clot to white thrombus as the rates of shear increase. Aggregation of platelets increases as the rate of shear increases.This pattern is maintained with changes of temperature, although aggregation of platelets appears to be increased at elevated temperatures.Intravenously added heparin affects the clotting time and the aggregation of platelets in in vitro coagulation.

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