Effect of an Electrically-Conducting Wall on Transient Magnetohydrodynamic Flow in a Continuous-Casting Mold with an Electromagnetic Brake
Abstract
:1. Introduction
2. Mini-LIMMCAST Experiments
3. Computational Model
3.1. Fluid Flow Field
3.2. Electromagnetic Field
3.3. Numerical Details
4. Results and Discussion
4.1. Comparison between Simulations and Measurements
4.2. Instantaneous Flow Characteristics
4.3. Time-Averaged Velocity and Electromagnetic Field Characteristics
5. Conclusions
- (1)
- Both the transient and time-averaged horizontal velocities predicted by the LES model agreed well with the measurements of the UDV probes. The transient fluctuation and time-averaged behaviors of the MHD flow in the mold was well captured by the current LES model.
- (2)
- The Q-criterion was used to visualize the characteristics of the three-dimensional turbulent eddy structure. Many pronounced large-scale vortex structures could be clearly seen inside the mold, containing various small-scale vortices between them. The highly turbulent nature of the flow could be suppressed by both configurations of the mold (electrically-insulated and conducting walls). The shedding of small-scale vortices due to the Kelvin–Helmholtz instability of the shear at the jet boundary was observed.
- (3)
- For the configuration of the EMBr with electrically-insulated walls, the flow was more unstable and changed with low-frequency oscillations. The phenomenon of alternating peaks and valleys in the velocity represents the oscillation of the jets as a kind of periodical motion. The time interval for the changeover was flexible.
- (4)
- For the configuration of EMBr with electrically-conducting walls, the low-frequency oscillations of the jets were well suppressed. Consequently, a stable double-roll flow pattern was generated.
- (5)
- The influence of different conductive boundary conditions on the electromagnetic field was studied. Electrically-conducting walls can dramatically increase the density of the induced electrical current and electromagnetic force, and can have a stabilizing effect on the MHD turbulent flow. This conclusion indicates that in order to design EMBr for real CC processes, the consideration of the growing solid shell of steel is of crucial importance.
Author Contributions
Funding
Acknowledgments
Conflicts of Interest
References
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Parameter | Value |
---|---|
Mold width/thickness | 140 mm/35 mm |
Mold length | 330 mm |
Nozzle diameter | 10 mm |
Nozzle port angle | 0° |
Nozzle port height/width | 18 mm/8 mm |
Submergence depth of nozzle | 72 mm |
Casting speed | 1.35 m/min |
Velocity at nozzle inlet | 1.4 m/s |
Dynamic viscosity of GaInSn | 0.00216 kg/m·s |
Density of GaInSn | 6360 kg/m3 |
Electrical conductivity of GaInSn | 3.2 × 106 1/Ω·m |
Magnetic permeability of GaInSn | 1.257 × 10−6 H/m |
Wall thickness at wide face (brass) | 0.5 mm |
Electrical conductivity of brass | 15 × 106 1/Ω·m |
Maximum magnetic field strength | 310 mT |
41,222 | |
417 | |
Stuart number, N | 5 |
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Liu, Z.; Vakhrushev, A.; Wu, M.; Karimi-Sibaki, E.; Kharicha, A.; Ludwig, A.; Li, B. Effect of an Electrically-Conducting Wall on Transient Magnetohydrodynamic Flow in a Continuous-Casting Mold with an Electromagnetic Brake. Metals 2018, 8, 609. https://doi.org/10.3390/met8080609
Liu Z, Vakhrushev A, Wu M, Karimi-Sibaki E, Kharicha A, Ludwig A, Li B. Effect of an Electrically-Conducting Wall on Transient Magnetohydrodynamic Flow in a Continuous-Casting Mold with an Electromagnetic Brake. Metals. 2018; 8(8):609. https://doi.org/10.3390/met8080609
Chicago/Turabian StyleLiu, Zhongqiu, Alexander Vakhrushev, Menghuai Wu, Ebrahim Karimi-Sibaki, Abdellah Kharicha, Andreas Ludwig, and Baokuan Li. 2018. "Effect of an Electrically-Conducting Wall on Transient Magnetohydrodynamic Flow in a Continuous-Casting Mold with an Electromagnetic Brake" Metals 8, no. 8: 609. https://doi.org/10.3390/met8080609