Computational fluid dynamics modeling of real scale slab reheating furnace

Abstract

Understanding the complex transient flow and heat transfer characteristics inside the furnace is a precondition to optimize furnace operation while maintaining high standard steel products. In the industrial furnaces often hot spots have been observed inside the slabs due to the current alignment of the burners. The control of the slab heating uses surface temperature as boundary condition, and it is thus important to predict this as accurate as possible. Transient flow behavior and interactions between the burners make it challenging to find an optimal burner arrangement. However, Computational Fluid Dynamics (CFD) is one of the robust methods which can be used to simulate the flow and perceive the complexity in combustion and radiation associated with the furnace. The scope of this work is to simulate the slab reheating furnace to understand the flow pattern and provide the results as input to simplified zonal radiation method to use it in online control system in real plant. In this paper we present the CFD simulation results for a real scale slab reheating furnace in 3D and compare them with measurements. The simulation predicts the gas temperature similar to the measurement points. However, the slab surface and average temperature deviate from continuous curve generated from the interpolation based on measurements from few thermocouples. The flow pattern and temperature distribution suggests the interpolation method to improve using the results from the simulation.