| Summary: | 碩士 === 國立成功大學 === 材料科學(工程)學系 === 86 === Abstract The fluid flow phenomena during the initial filling of
a tundish in the continuous casting process is closely related
to the entrapment of gas and slag in the molten steel as well as
the erosion of the refractory. The purpose of this study is to
develop a mathematical model to simulate this fluid flow
phenomena .The information provided by the analysis has proven
to be useful to optimize the tundish design to reduce the
entrapment of gas in the molten steel as well as the erosion of
the refractory and to be consulted to eliminate the second steel
during the end of initial tundish filling .In the initial stage
of developing the mathematical system﹐the basis and reliability
of the mathematical model is verified by conducting water model
experiments and comparing the numerically simulated flow
patterns with the water model observations. The mathematical
model is based on a computational fluid dynamics technique;
named SOLA-MAC, which has the capabilities of handing transient
fluid flow phenomena with highly and quickly distorted free
surfaces. An air particle technique is also incorporated to
clearly and explicitly reveal the extent of gas entrapment . For
water model experiments , high speed photography is employed to
record the quick changes of the free surface during the tundish
filling . The main result of the study is to develop a
mathematical model to simulate the fluid pattern of initial
tundish filling. For the filling operation of tundish , We also
study the effects of the inlet velocity and volume of the
second steel before formal casting . The fluid pattern and the
entrapment of gas on the initial tundish filling can control by
the inlet velocity conditions. Lower the filling rates on the
open timing of the outlet are ,more the reducing rates of the
second steel are. The results of the study show the optimal
operating conditions of the initial tundish filling can obtain
cleaner continuous casting steel.
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