Numerical Simulation of a Large-Scale Industrial Billet Heating Furnace with Direct Flame Impingement

Numerical simulations of a billet heating furnace with direct flame impingement operating in a metallurgical plant were carried out and the results compared to measurements obtained in an industrial environment. The transport equations for mass, momentum, energy and mass of chemical species in reactive flow were computed with the use of ANSYS FLUENT. Turbulence, combustion and radiation were modeled using, respectively, the realizable k-ε model, the finite-rate/eddy-dissipation model and the finite volume scheme. The model was used to simulate the furnace operating under the conditions that occurred during an energy audit carried out at an industrial facility (413 kW firing rate and 80% excess air). The predicted furnace efficiency, 72.5%, is in very good agreement with the one obtained in the energy audit (0.4% difference). The flue gas temperature at the end of the second preheating zone was measured during the energy audit and its value compared to the one predicted. In this case, the agreement between measurements and simulation is not so satisfactory (23% difference). This paper presents the validation of a CFD model of a direct-flame impingement furnace for billet heating in a full-scale industrial situation, which was not previously published, and opens the way for more simulations and detailed studies of the phenomena that occur inside this type of furnace