Influence of Hydrodynamic Structure on Mixing Time of Alloy Additions with Liquid Steel in One Strand Tundish

Abstract

The knowledge of the hydrodynamic pattern aids in designing new and modernizing existing tundishes. The device under examination is an one-strand tundish of a capacity of 30 Mg. Computer simulation of the liquid steel flow, tracer and alloy addition behaviour in turbulent motion conditions was done using the Ansys-Fluent®computer program. The hydrodynamic conditions of steel flow were determined based on the distribution of the characteristics of tundish liquid steel residence time distribution (RTD). The alloy addition was introduced to the liquid steel by the pulse-step method. Based on computer simulations carried out, steel flow fields and RTD and mixing curves were obtained, and the shares of stagnant volume flow and active flow and the mixing time were computed. Dispersion of the alloy addition in liquid steel during its flow through the tundish is a dynamic process which is determined by the hydrodynamic conditions occurring in the tundish working space.

Two-Phase Numerical Modeling of Grade Intermixing in a Steelmaking Tundish

“…Siddiqui and Jha [20] reported that the inflow rate has a significant impact on grade mixing in tundish during sequential castings. Cwudzinski [21] carried out a numerical investigation of flow control devices in tundish to modify the hydrodynamic pattern inside the tundish. It was reported that an adverse influence of stagnant volume could be compensated by active recycle zone.…”

“…It was concluded that 80% of the old steel grade in the tundish can come out in the first five-six min of the mixed grade slab casting process. In further quest of understanding the hydrodynamic patterns and implementing it to minimize the mixing in the tundish, Cwudziński [21] studied the dispersion of alloys in the melt. The numerical model was developed to find the distribution of the characteristics of tundish, residence time distribution (RTD) and dispersion of alloy in one strand tundish.…”