New Understanding on Relationship Between RTD Curve and Inclusion Behavior in the Tundish

The inclusion behavior depends on the turbulent flow in the tundish. To make a deep understanding on the relation between flow field and inclusion behavior, the residence time distribution (RTD) curve is applied to analyze the flow field, the inclusion mass/population conservation model is applied to explore the inclusion behavior, and Pearson correlation is introduced to investigate the relation of RTD curve and the inclusion coalescence-removal. The numerical flow field and the number density confirm well with the measured data. Among plug volume fraction, well-mixed volume fraction and dead volume fraction, dead volume fraction is the most important factor to affect the inclusion removal rate and the dimensionless inclusion characteristic radius. For the same control devices in a tundish, structure parameters (distance from dam/baffle to tundish exit, the diameter of the hole in the baffle) can be optimized to obtained the maximum inclusion removal rate. Such a critical state can be expressed by the ratio of plug volume fraction to well-mixed volume fraction. But the dimensionless characteristic radius may be the maximum or the minimum at this critical state.