Development of Transient Mathematical Models for a Large-scale Reheating Furnace using Hybrid- Zone-CFD Methods

While providing an accurate means of simulating radiative heat transfer within a furnace, the major limitation of the classical zone method of radiation analysis has been the difficulty of incorporating furnace flow patterns within the model. This aspect is of particular importance in furnaces where the flow pattern may be highly complex due to the burner arrangement and variations in the flow pattern may be significant during transient furnace operation. This paper is concerned with the development of a hybrid modelling approach to simulate transient thermal performances of a large scale reheating furnace. In particular, this new modelling approach combines the advantages of the zone method and Computational Fluid Dynamics (CFD) in a robust manner. The hybrid model has been validated using comprehensive experimental data collected during an instrumented bloom trial period that includes a long production delay. The results suggest that the model predictions are in good agreement with actual measurements, and that the model is able to respond correctly with respect to the production delay. Furthermore, the hybrid approach has a relatively modest computing demand so that it may be used efficiently for off-line (or near real-time) simulations to investigate problems related to furnace optimisation and control.