Mathematical Modeling of Flaws In the Coke-free Layer of a Blast Furnace Hearth

摘要

Due to the very hostile environment inside a blast furnace hearth, direct measurements of flow and temperature distributions that impact hearth wear is fundamentally precluded. Consequently, one resorts to physical and mathematical modeling of the process. In the current study, a mathematical model of fluid flow inside the hearth during the tapping process is presented. This model, at the current stage of an ongoing program at McMaster University, is two-dimensional and under unsteady state conditions. The study is performed using Fluent 6.1, a commercial computational fluid dynamics (CFD) software package. The results presented in the current paper are focused on the flow patterns in the cock-free layer and their impact on the wear of the hearth refractory. These flow patterns and the accompanied shear stress distributions on the hearth bottom and side walls are presented for cases of different thicknesses of the cock-free layer and different sump depths. In the absence of the energy equation in the mathematical model at the current stage, shear stress distribution does not only represent the mechanical force acting on the bottom and wall of the hearth but also can be used in a qualitative sense as a measure of the heat transfer rate as well (based on Reynolds analogy). Shear stress (mechanical force) and heat transfer rate on the floor and wall of the hearth are considered to be major factors affecting the life of the lining of the hearth. Also, a tracking method or the ability to track liquids originated from different regions of the hearth during the drainage (taping) process is introduced for the first time.