連鋳注入ノズル内の介在物挙動に及ぼす濡れ性の影響

抄録

Molten steel flow in the submerged entry nozzle (SEN) largely affects the cast steel quality. However, it wasn’t clarified how non-metallic inclusions behave at the front of nozzle wall in the SEN. One of the reasons is that the contact angle of inclusions with molten steel is bigger than 90 degree and the effect of wettability of the inclusions and nozzle wall on the multi-phase flow behavior in SEN has not been fully clarified. In this study, water model to simulate the multi-phase flow in the SEN has been constructed to investigate the effect of wettability of particles and the nozzle wall on the fluid flow by changing the contact angle of the surface of particles and the nozzle wall. Additionally, an endoscope has been installed into the stopper in order to directly observe the behavior of particles in the SEN. As a result, it was found that particles coated with hydrophobic agent are swept away as if they hit on the nozzle wall and changed the flow direction in the air. This is why the air film was surrounded around the particle by the hydrophobic treatment and cavity bridge was formed between the hydrophobic treated particles in the water. The adhesion force acting between the hydrophobic treated particles was calculated by theoretical analysis and the aforementioned adhesion force could not be ignored compared to the buoyancy force and the drag force in the water.