Effect of gas flow rate, bubble size and inclusion size on inclusion removal under high throughput conditions using water model experiment

It is widely recognized that gas injecting into molten steel can be effective way to enhance inclusion removal. In this paper, bubble diameters from porous refractory nozzles, with different pore sizes, were measured, and the effect of gas flow, bubble size and inclusion size on inclusion removal ratio, was investigated by the water model experiments under high throughput conditions. It was found that tracer removal ratio by bubbles was increased with smaller bubble diameter, because of large collision frequency function between bubbles and tracers. When bubble size was the same conditions, tracer removal ratio by bubbles was increased with larger flow rate, because of higher bubble density. It can be concluded that the size and flow rate of bubbles were important for inclusion removal. Furthermore, it has been shown that Inclusion removal ratio by bubbles in high throughput conditions was expressed by the equation including bubble density, collision frequency function and Reynolds number.