NUMERICAL SIMULATION OF A DIRECT FIRED PREHEATING FURNACE

摘要

ArcelorMittal Indiana Harbor operates a continuous coating aluminized line. The process involves preheating steel strip in an annealing furnace prior to coating it with aluminum. A problem occasionally encountered in continuous coating lines is the deformation of the strip prior to entry into the molten aluminum pot. A potential contributing cause of such deformations is an uneven heating profile within the furnace. However, it is exceedingly difficult to directly measure and examine the transient temperature distribution within a furnace as well as that of the strip. The elimination of strip deformation and effective optimization of the preheating furnace performance with increased efficiency and higher product quality requires a better understanding of the flow characteristics and temperature distributions inside the furnace. Computational Fluid Dynamics (CFD) was employed to model the fluid mechanics coupled with combustion and conjugate heat transfer in the direct-fired furnace (DFF). In the present work, simulation of the whole heating process with natural gas combustion was conducted. The temperature distribution in the steel strip was estimated throughout the simulated heating process. These results present flow characteristics and temperature gradients, within both the DFF and the strip. Future work may include the use of these results to enable an estimation of deformation forces imposed on the strip, and a parametric study to provide insight into the optimization of heating performance and the improvement of product quality.