Analysis of Optimization Weights for Flow Field of Internal Rotation Stabilizer Coupled with Porous Retaining Wall
Abstract
:1. Introduction
- Stabilizing the flow field of molten steel, reducing liquid level fluctuations, and reducing endogenous inclusions caused by secondary oxidation of molten steel;
- Reducing the contamination of molten steel caused by foreign inclusions formed after the refractory material is eroded;
- Improving the operating conditions of the flow field, increasing the proportion of plug flow volume, reducing the proportion of the dead zone volume fraction, and avoiding short-circuit flow;
- Separating non-metallic inclusions and purifying molten steel;
- Ensuring precise control of the composition, temperature, and flow field of molten steel in the tundish.
2. Flow Control Device Structure
3. Governing Equations and Boundary Conditions
- The molten steel and the tracer indicator are both incompressible fluids, and the flow of molten steel is a turbulent motion with a Reynolds number greater than 2000;
- After the pouring stage is over, the flow field of the tundish is a steady-state process, and the smooth flow of molten steel will not cause slag level fluctuations;
- The movement of inclusions in the fluid conforms to the unidirectional fluid-solid coupling model. The change of the flow field movement mode will affect the entrapped particles, but the change of the movement trajectory of the inclusion solid has no obvious effect on the flow field flow;
- The simplified particle model of inclusions is spherical particles, and the particle motion of inclusions is coupled to the collision growth model based on the random motion model. UDF (user-defined function) is used to set the boundary adsorption conditions. When the particles move to the inner surface of the tundish wall and the speed drops below 0.01 m/s, it is determined that the particles are adsorbed by the wall and removed to terminate the calculation.
4. Results and Discussion
4.1. Orthogonal Experimental Design Results
4.2. Analysis of the Results of SCB Structure Convection Field Optimization
4.3. Analysis of the Influence of SCB Structure on the Removal of Fine Inclusions
5. Conclusions
- Compared with the original tundish, SCB’s flow control device combination can effectively improve the flow field operation state and increase the removal rate of fine inclusions. The flow control device makes the average residence time of molten steel extended by up to 106 s, the dead zone volume fraction is the highest decrease by 10.5%, and the dispersion of molten steel composition at the inner and outer outlets by 60.1%;
- The change of DPRW structure parameters has a significant effect on the average residence time, the volume fraction of dead space and the removal rate of fine inclusions, while the IRS structure only has a significant effect on the change of the volume fraction of dead space. However, the IRS structure has an important influence on the direction of movement of inclusions in the injection zone and the reduction in molten steel injection velocity, which makes the average velocity in the tundish drop by 22% compared to the original package;
- The diameter of the guide hole of the DPRW structure has the greatest influence on the change of the flow field state of the tundish, and the X-shaped opening method is most beneficial to the optimization of the flow field of the tundish. The X-shaped opening method causes the molten steel flow to form a large-area swirl and vortex in the outlet flow area of the tundish, and plans the best route for the subsequent flow field movement;
- The larger the diameter of the guide hole in the DPRW structure, the more beneficial it is to improve the flow field, increase the average residence time, and reduce the volume fraction of the dead zone. The volume fraction of the dead zone when the diameter is enlarged by 50 mm is reduced by 3.3%. Decreasing the diameter of the diversion hole is conducive to the removal of fine inclusions, and the removal rate of inclusions is increased by 13.6% when the diameter is reduced by 50 mm, which is conducive to improving the yield of high-quality steel;
- The trajectory of fine inclusions with a diameter of less than 20 μm is highly coincident with the flow field of the tundish. Therefore, it can be judged that the flowability is the most important factor affecting the removal rate. Changing the flow field can effectively affect the removal rate of fine inclusions. The relationship between the removal mechanism of fine inclusions and flowability needs to be studied further in the future.
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Conflicts of Interest
References
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IRS Mode | Parameter | DPRW Mode | Parameter |
---|---|---|---|
Angle of diversion hole/° | 30 | Angle of diversion hole/° | 30 |
Inner diameter of stabilizer/mm | 100 | Retaining wall thickness/mm | 90 |
Outer diameter of stabilizer/mm | 650 | Inner cavity thickness/mm | 200 |
Inner diameter of stop/mm | 220 | - | - |
Outer diameter of stop/mm | 300 | - | - |
Level | Factor | |||
---|---|---|---|---|
A | B | C | D | |
1 | 45 | With diversion holes | TIBO mode | 50 |
2 | 90 | No diversion hole | BITO mode | 100 |
3 | 135 | - | X mode | - |
Serial Number | Scheme | Outflow 1 | Outflow 2 | |||||
---|---|---|---|---|---|---|---|---|
0 | A0B0C0D0 | 655 | 558 | 10.46 | 19.69 | 675 | 25.88 | 13.44 |
1 | A1B1C1D1 | 613 | 658 | 38.82 | 12.40 | 697 | 38.74 | 12.44 |
2 | A3B2C3D1 | 614 | 650 | 39.07 | 11.04 | 698 | 45.82 | 11.66 |
3 | A3B1C2D2 | 613 | 622 | 38.33 | 9.12 | 719 | 46.32 | 10.01 |
4 | A2B1C2D1 | 613 | 627 | 32.46 | 11.14 | 686 | 42.49 | 11.44 |
5 | A1B2C2D1 | 613 | 640 | 34.66 | 11.77 | 688 | 39.47 | 12.03 |
6 | A2B1C3D1 | 613 | 639 | 41.83 | 10.92 | 691 | 42.24 | 11.14 |
7 | A1B1C3D2 | 615 | 682 | 49.20 | 9.36 | 674 | 33.26 | 10.30 |
8 | A3B1C1D1 | 613 | 647 | 32.46 | 11.94 | 688 | 39.96 | 12.21 |
9 | A2B2C1D2 | 614 | 701 | 48.75 | 9.39 | 625 | 36.46 | 11.75 |
Parameter | Average Residence Time (s) | Dead Zone Volume Fraction (%) | ||||||
---|---|---|---|---|---|---|---|---|
A | B | C | D | A | B | C | D | |
K1 | 660 | 646 | 669 | 644 | 11.18 | 10.81 | 11.24 | 11.54 |
K2 | 656 | 664 | 630 | 668 | 10.48 | 10.73 | 10.68 | 9.29 |
K3 | 640 | - | 657 | - | 10.70 | - | 10.44 | - |
square error | 344 | 636 | 1202 | 1233 | 0.37 | 0.01 | 0.5 | 10.1 |
Significance level | 0.26 | 0.149 | 0.091 | 0.086 | 0.001 | 0.016 | 0.0005 | 0.0001 |
Parameter | Inclusion Removal Rate (%) | |||
---|---|---|---|---|
A | B | C | D | |
K1 | 80.41 | 80.81 | 82.65 | 85.75 |
K2 | 82.77 | 82.06 | 81.64 | 72.18 |
K3 | 80.49 | - | 79.38 | - |
Mean square error | 5.37 | 3.16 | 8.43 | 368.20 |
Significance level | 0.127 | 0.182 | 0.085 | 0.002 |
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Liu, Z.; Jin, Y.; Gan, F.; Lin, P.; Huang, J.; Li, J. Analysis of Optimization Weights for Flow Field of Internal Rotation Stabilizer Coupled with Porous Retaining Wall. Metals 2021, 11, 1208. https://doi.org/10.3390/met11081208
Liu Z, Jin Y, Gan F, Lin P, Huang J, Li J. Analysis of Optimization Weights for Flow Field of Internal Rotation Stabilizer Coupled with Porous Retaining Wall. Metals. 2021; 11(8):1208. https://doi.org/10.3390/met11081208
Chicago/Turabian StyleLiu, Ziyu, Yan Jin, Feifang Gan, Peng Lin, Jingyu Huang, and Jun Li. 2021. "Analysis of Optimization Weights for Flow Field of Internal Rotation Stabilizer Coupled with Porous Retaining Wall" Metals 11, no. 8: 1208. https://doi.org/10.3390/met11081208