Numerical simulation of the flow, solidification, and solute transport in a billet mold under electromagnetic stirring

2021 ◽  
Vol 118 (2) ◽  
pp. 221
Author(s):  
Yaoguang Li ◽  
Yanhui Sun ◽  
Xuesong Bai

In this study, a coupled three-dimensional model of the billet continuous casting mold process was developed to investigate the characteristics of the macroscopic transmission behaviors under different mold electromagnetic stirring (M-EMS) parameters. The mold curvature was also considered during the modeling of electromagnetic and flow fields. The results indicate that the macroscopic physical quantities had nonsymmetrical distributions in the mold because of the mold curvature. However, the influence of mold curvature on the electromagnetic force could be ignored. The horizontal swirling flow caused by the M-EMS became stronger as the current density increased, which enhanced the dissipation of the molten steel superheat and promoted the growth of the solidification shell. However, the flushing of the bias hot jet slowed the growth of the local solidified shell. Meanwhile, the washing effect of the melt flow on the solidification front caused the solute element content near the billet surface to fluctuate. In addition, the distribution of the solute element content became more uneven in the strand transverse direction as the current density increased.

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 516
Author(s):  
Lianwang Zhang ◽  
Changjun Xu ◽  
Jiazheng Zhang ◽  
Tao Wang ◽  
Jing Li ◽  
...  

The electromagnetic model of a large-bloom continuous casting was established to simulate the magnetic field. The model 3600 digital, high-precision, three-dimensional Gaussian meter was used to measure the internal magnetic field of mold electromagnetic stirring (M-EMS). The distribution of simulated magnetic field was basically consistent with that of the measured magnetic field; the accuracy of electromagnetic stirring model was verified. With the increase of current frequency, the electromagnetic force first increases and then decreases; when the current frequency is 9 Hz, the electromagnetic force reaches its maximum value. A bipolar electromagnetic stirring model is proposed; the influence of current intensity and distance were investigated. With the increase of current intensity of lower mold electromagnetic stirring (M-EMSB), the internal magnetic intensity of upper mold electromagnetic stirring (M-EMSA) gradually increases, and the middle region is gradually filled by magnetic field. With the increase of the distance, the range of the low-intensity magnetic field expands. When the current intensity of the M-EMSB is 320 A, and the distance is 400 mm, an 8 mT uniform magnetic field in the range of 1.2 m is formed. Compared with the traditional continuous casting electromagnetic agitator, the center equiaxial crystal of bipolar electromagnetic agitator increases from 30.3% to 49.5%.


Metals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 66 ◽  
Author(s):  
Wenjie Zhang ◽  
Sen Luo ◽  
Yao Chen ◽  
Weiling Wang ◽  
Miaoyong Zhu

Electromagnetic stirring in mold (M-EMS) has been widely used in continuous casting process to improve the solidification quality of the steel strand. In the present study, a 3D multi-physical-field mathematical model was developed to predict the macro transport phenomena in continuous casting mold with M-EMS using ANSYS commercial software, and was adopted to investigate the effect of current intensity (0, 150, 200, and 240 A) on the heat, momentum, and species transports in the billet continuous casting mold with a size of 160 mm × 160 mm. The results show that when the M-EMS is on, the horizontal swirling flow appears and shifts the high-temperature zone upward. With the increase of current intensity, two swirling flows form on the longitudinal section of continuous casting mold and become more intensive, and the flow velocity of the molten steel at the solidification front increases. Thus, the wash effects of the fluid flow on the initial solidified shell become intensive, resulting in a thinner shell thickness at the mold exit and a significant negative segregation of carbon at the billet subsurface.


Author(s):  
D. Jua´rez-Robles ◽  
A. Herna´ndez-Guerrero ◽  
C. E. Damia´n-Ascencio ◽  
C. Rubio-Arana

This work presents the analysis of a non-isothermal three-dimensional model in single phase of a PEM fuel cell with an innovative flow field path in the form of the Fermat spiral, i.e. two concentric spirals. The model is used to predict the current density contours and the water content in all of the zones of the fuel cell. The three-dimensional model includes: the gas flow channels with the shape of the new geometry proposed, the current collectors, gas diffusion layers, catalyst layers on both sides of the model, anode and cathode, and a proton exchange membrane in between. The model solves the energy equation, mass conservation, and species transport equations, including the source terms due the electrochemical effects occurring in the cell. The results show a higher average current density than the fuel cells with conventional flow paths, showing also that the current density attained is more uniform from the inlet to the outlet of the flow channels.


Skull Base ◽  
2008 ◽  
Vol 18 (S 01) ◽  
Author(s):  
Akio Morita ◽  
Toshikazu Kimura ◽  
Shigeo Sora ◽  
Kengo Nishimura ◽  
Hisayuki Sugiyama ◽  
...  

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