Mathematical Modeling of Transport Processes in Funnel Shaped Mold of Steel Thin Slab Continuous Caster

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
A. Hajari ◽  
S. H. Seyedein ◽  
M. R. Aboutalebi
Keyword(s):  
Flow Pattern ◽  
Casting Speed ◽  
Continuous Caster ◽  
Transport Processes ◽  
Inlet Temperature ◽  
High Heat Flux ◽  
Thin Slab ◽  
Surface Turbulence ◽  
Submergence Depth ◽  
Slab Continuous Caster

In this work a three-dimensional fluid flow and heat transfer model was developed to predict the flow pattern and superheat dissipation in funnel shaped mold of a thin slab continuous caster with a novel tetrafurcated design for the submerged entry nozzle. Low Reynolds k−ε turbulent model was adopted to account for the turbulent effect. The transport equations were solved numerically using finite volume method. The results were compared with a full scale water model of the caster. Good agreement between mathematical and physical models was obtained. Parametric studies were carried out to evaluate the effect of casting speed, nozzle submergence depth, and inlet temperature on the superheat dissipation, flow pattern, and surface turbulence in the mold region. The results indicate a special flow pattern and heat distribution in the caster while using a tetrafurcated nozzle. Aiming to achieve more product capacity, in the case of casting with lower superheat temperature, a higher casting speed, together with higher submergence depth, is recommended in order to avoid surface turbulence and high heat flux across the narrow face.

scholarly journals Combined Effects of EMBr and SEMS on Melt Flow and Solidification in a Thin Slab Continuous Caster

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 948
Author(s):  
Changjun Wang ◽  
Zhongqiu Liu ◽  
Baokuan Li
Keyword(s):  
Continuous Caster ◽  
Solidification Rate ◽  
Potential Method ◽  
Suppressive Effect ◽  
Thin Slab ◽  
Dispersion Effect ◽  
Melt Flow ◽  
Simultaneous Application ◽  
Iron And Steel ◽  
Slab Continuous Caster

Electromagnetic fields have emerged as powerful tools for addressing current problems in thin slab continuous casting processes in the iron and steel industry. Substantial studies have been undertaken on the fundamental effects of electromagnetic brakes (EMBr) and strand electromagnetic stirring (SEMS). However, little attention has been focused on melt flow and solidification in a thin slab continuous caster with the simultaneous application of an EMBr and SEMS. The present study aimed to predict transient fields in the caster using a large eddy simulation and an enthalpy-porosity method. The electric potential method was applied in the braking process, and the conductivity change with solidification was considered. The suppressive effect on the intensity of the nozzle jet, the balance effect on the mold flow, and a dispersion effect could be observed. The dispersion effect was a novel finding and was beneficial to a flatter nozzle jet. In contrast, SEMS caused a highly turbulent flow in the strand. A large vortex could be observed in the casting direction. The solidified shell became more uniform, and the solidification rate became obviously slower. These findings supported the view that a high-quality thin slab can be produced by the application of an EMBr and SEMS.

Investigation on New Submersed Entry Nozzle in Slab Caster

2011 ◽  
Vol 287-290 ◽  
pp. 2768-2771
Author(s):  
Yu Ma ◽  
Jing She Li ◽  
Xiao Chuan Lin ◽  
Li Yuan Sun
Keyword(s):  
Penetration Depth ◽  
Continuous Caster ◽  
Surface Velocity ◽  
Slab Caster ◽  
Slab Continuous Casting ◽  
Outlet Angle ◽  
Surface Turbulence ◽  
Continuous Casting Mould ◽  
Better Than ◽  
Slab Continuous Caster

The fluid flow in the mould of slab continuous caster was investigated by 1:1 ratio water modeling simulation system. The effects of outlet angle of Bilateral and quadripuntal SEN on surface turbulence, penetration depth and surface velocity were discussed and the regularity of the flow field for change of outlet angle in slab continuous casting mould was obtained. The results show that the case C (both α and β are downward angle and α<β) is better than the usual SEN, for this kind of SEN can stabilize surface turbulence and reduce penetration depth and get moderate velocity.

scholarly journals Optimal Design of the Submerged Entry Nozzle for Thin Slab Continuous Casting Molds

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1223
Author(s):  
Mingtao Xuan ◽  
Min Chen
Keyword(s):  
Temperature Distribution ◽  
Wave Height ◽  
Casting Speed ◽  
Continuous Caster ◽  
Submerged Entry Nozzle ◽  
Thin Slab ◽  
Recirculation Flow ◽  
Defect Rate ◽  
Port Area ◽  
The Mean

For the purpose of increasing the capacity of an Angang Strip Production (ASP) continuous caster and the surface quality of a medium-thin slab with mold sections of 150 × (1020–1540) mm2, the present work investigated the influences of the submerged entry nozzle (SEN) structure and main operating parameters on the flow characteristic and temperature distribution in the mold by physical and numerical simulations. The results showed that the typical “double-roll” flow and a central jet were formed through the three-port SEN. With the original SEN, the mean wave height exceeded the critical value of 5.0 mm after the casting speed was increased due to the strong upper recirculation flow. By the slight increment of the bottom port area and the side port angle of SEN, the mean wave height was obviously decreased below 4.4 mm due to the depressing of the upper recirculation flow after the casting speed increased. Meanwhile, the temperature distribution was slightly changed by using the optimized SEN. The practical application showed that the breakout rate decreased from 0.349% to 0.107% and the surface defect rate decreased from 0.54% to 0.19% by using the optimized SEN, while throughput reached the new level of 3.96 t/min.

scholarly journals Physical simulation of liquid steel motion in a thin-slab continuous caster mold

2019 ◽  
Vol 75 (4) ◽  
pp. 454-459
Author(s):  
V. M. Safonov ◽  
V. G. Borisevich ◽  
V. V. Kislitsa ◽  
D. V. Morov
Keyword(s):  
Liquid Steel ◽  
Steel Casting ◽  
Physical Simulation ◽  
Continuous Caster ◽  
Dead Volume ◽  
Mold Surface ◽  
Thin Slab ◽  
Direct Flow ◽  
Deep Layers ◽  
Slab Continuous Caster

Industrial experience of steel casting at the thin-slab continuous caster (CC) revealed processes, having negative effect on the quality of internal structure and surface of CC thin slab. The main problems are as follows: flat streams of liquid steel, flowing through submerged snorkel into restricted dead volume, form circulating flows of extremely high velocity in both liquid core and on the slab surface. This circumstance makes specific requirements to the design and parameters of the submerged snorkel to supply the metal into the thin-slab CC mold. Despite the more than 25 years’ experience of the snorkel form and geometric parameters development, there is no single opinion on its optimal design. Results of physical simulation of the liquid motion processes in a thinslab Caster mold presented (for slab maximum width 1800 mm, thickness – 90 mm) of JSC “Vyksa Steel-works” casting and rolling complex. Description of the physical model facility quoted, as well as description of the experiment methodology and its results. The speed was measured and structure of liquid steel flows revealed in depth and sub-surface layers, as well as in slag-forming mixture at the mold surface. The comparison of two principally different variants of liquid steel feeding into the mold made. The two variants were as follows: by a flat down-directed stream with a narrow central divider (direct-flow submerged snorkel) and by four streams , two of them directed down under an angle relating the vertical axe, and the other (about 20% of total liquid consumption) – directed upward to the bath mirror (the snorkel of “hammer” type). It was determined, that steel casting with technological speed through the direct-flow snorkel was most effective into the slab of 1400 mm width and less, since in this case the sub-surface flows speed did not resulted in the intensive waves formation, constant whirls formation and slag particles dragging into deep layers of the slab. For steel casting into slab of width more than 1400 mm, it is reasonable to use a snorkel of the “hammer” type, which enables to create a favorable stable structure of circulation and decrease the tendency of slag particles dragging in the deep layers of the slab.

Numerical analysis of local heat flux and thin-slab solidification in a CSP funnel-type mold with electromagnetic braking

2020 ◽  
Vol 117 (6) ◽  
pp. 602
Author(s):  
Heping Liu ◽  
Jianjun Zhang ◽  
Hongbiao Tao ◽  
Hui Zhang
Keyword(s):  
Heat Flux ◽  
Casting Speed ◽  
Shell Growth ◽  
Local Heat ◽  
Operating Conditions ◽  
Thin Slab ◽  
Wide Face ◽  
Slab Width ◽  
Steel Grades ◽  
Local Heat Flux

In this article, based on the actual monitored temperature data from mold copper plate with a dense thermocouple layout and the measured magnetic flux density values in a CSP thin-slab mold, the local heat flux and thin-slab solidification features in the funnel-type mold with electromagnetic braking are analyzed. The differences of local heat flux, fluid flow and solidified shell growth features between two steel grades of Q235B with carbon content of 0.19%C and DC01 of 0.03%C under varying operation conditions are discussed. The results show the maximum transverse local heat flux is near the meniscus region of over 0.3 m away from the center of the wide face, which corresponds to the upper flow circulation and the large turbulent kinetic energy in a CSP funnel-type mold. The increased slab width and low casting speed can reduce the fluctuation of the transverse local heat flux near the meniscus. There is a decreased transverse local heat flux in the center of the wide face after the solidified shell is pulled through the transition zone from the funnel-curve to the parallel-cure zone. In order to achieve similar metallurgical effects, the braking strength should increase with the increase of casting speed and slab width. Using the strong EMBr field in a lower casting speed might reverse the desired effects. There exist some differences of solidified shell thinning features for different steel grades in the range of the funnel opening region under the measured operating conditions, which may affect the optimization of the casting process in a CSP caster.

Natural-Ventilation Flow in a 3-D Room Fitted With Solar Chimney

2012 ◽  
Author(s):  
B. P. Huynh
Keyword(s):  
Heat Flux ◽  
Flow Pattern ◽  
Natural Ventilation ◽  
Air Flow ◽  
Ventilation Rate ◽  
High Heat Flux ◽  
Solar Chimney ◽  
Solar Heat ◽  
Solar Heat Flux ◽  
Inlet Opening

Natural-ventilation flow induced in a real-sized rectangular-box room fitted with a solar chimney on its roof is investigated numerically, using a commercial CFD (Computational Fluid Dynamics) software package. The chimney in turn is in the form of a parallel channel with one plate being subjected to uniform solar heat flux. Ventilation rate and air-flow pattern through the room are considered in terms of the heat flux for two different locations of the room’s inlet opening. Chien’s turbulence model of low-Reynolds-number K-ε is used in a Reynolds-Averaged Navier-Stokes (RANS) formulation. It is found that ventilation flow rate increases quickly with solar heat flux when this flux is low, but more gradually at higher flux. At low heat flux, ventilation rate is not significantly affected by location of the inlet opening to the room. On the other hand, at high heat flux, ventilation rate varies substantially with the opening’s location. Location of the inlet opening to the room also affects strongly the air-flow pattern. In any case, ample ventilation rate is readily induced by the chimney.

Heat Transfer Characteristics and Flow Pattern Visualization for Flow Boiling in a Vertical Narrow Microchannel

2018 ◽  
Author(s):  
Kan Zhou ◽  
Junye Li ◽  
Zhao-zan Feng ◽  
Wei Li ◽  
Hua Zhu ◽  
...  
Keyword(s):  
Heat Flux ◽  
Flow Pattern ◽  
Flow Boiling ◽  
Nucleate Boiling ◽  
Working Fluid ◽  
Inlet Temperature ◽  
Lower Mass ◽  
Subcooled Flow Boiling ◽  
Mass Fluxes ◽  
Subcooled Flow

For improving the functionality and signal speed of electronic devices, electronic components have been miniaturized and an increasing number of elements have been packaged in the device. As a result there has been a steady rise in the amount of heat necessitated to be dissipated from the electronic device. Recently microchannel heat sinks have been emerged as a kind of high performance cooling scheme to meet the heat dissipation requirement of electronics packaging, In the present study an experimental study of subcooled flow boiling in a high-aspect-ratio, one-sided heating rectangular microchannel with gap depth of 0.52 mm and width of 5 mm was conducted with deionized water as the working fluid. In the experimental operations, the mass flux was varied from 200 to 400 kg/m2s and imposed heat flux from 3 to 20 W/cm2 while the fluid inlet temperature was regulated constantly at 90 °C. The boiling curves, flow pattern and onset of nucleate boiling of subcooled flow boiling were investigated through instrumental measurements and a high speed camera. It was found that the slope of the boiling curves increased sharply once the superheat needed to initiate the onset of nucleate boiling was attained, and the slope was greater for lower mass fluxes, with lower superheat required for boiling incipience. As for the visualization images, for relatively lower mass fluxes the bubbles generated were larger and not easy to depart from the vertical upward placed narrow microchannel wall, giving elongated bubbly flow and reverse backflow. The thin film evaporation mechanism dominated the entire test section due to the elongated bubbles and transient local dryout as well as rewetting occurred. Meanwhile the initiative superheat and heat flux of onset of nucleate boiling were compared with existing correlations in the literature with good agreement.

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