Numerical simulation study on the floating of inclusions of different shapes in steel in a supergravity field

Abstract

Supergravity is a noncontact volumetric force; when there is a density difference between the two phases, supergravity can strengthen their separation. The removal of nonmetallic inclusions in steel by supergravity technology not only does not cause molten steel to stir back to the mixing but also promotes the rapid floating of inclusions and shortens their floating time in the molten steel. Small inclusions that are difficult to remove can be removed using a supergravity field. The shape of the inclusions affects their floating behavior in molten steel. To study this effect, this study uses the fluid–structure interaction method to track the computational fluid–solid interface state, constructs three inclusions with different aspect ratios in a two-dimensional longitudinal section, and performs simulation studies of the floating behavior of the inclusions in a supergravity field. The effects of the different initial angles of the inclusions on their floating behavior were also compared. The simulation results show that the floating velocity of the inclusions is related to their shape and floating angle, and the faster the floating velocity, the closer the aspect ratio is to 1, or the floating angle is too vertical. For a given length, inclusions with a larger equivalent diameter float faster. In the supergravity field of G = 1000, the inclusions with a length of 1 μm did not undergo rotation; the inclusions with lengths of 10 and 20 μm rotated from the initial angle (45°, 90°) to the horizontal and then floated steadily. The floating velocity of inclusions is related to the real-time angle of inclusions. The rotational state of the inclusions gradually decreases as the gravity coefficient decreases. When G = 50, the inclusions with a length of 20 μm (initial angle of 90°) fail to rotate completely, which also proves that the inclusions are more likely to rotate when initially inclined instead of vertically. In addition, it was concluded that supergravity does not cause anisotropy in steel properties and that the method of removing inclusions from steel by supergravity does not have a substantial negative effect on steel properties. Finally, this study noted that the prediction of the supergravity treatment time using this model should be based on the floating velocity of the inclusions in the horizontal state, and an approximate time for the floating removal of the inclusions is provided based on this conclusion.

Keywords

• inclusions
• shape
• supergravity
• numerical simulation
• fluid–solid interaction