Modeling the Heat Transfer in a Ring Furnace

The ring furnace and its overall model have been presented in an accompanying article. The aspect of heat transfer which in itself requires an elaborate model is considered here. Taken into account are the convection and radiation between gas and brick wall, and the conduction from bricks to packing coke then on to the anodes. A global heat transfer coefficient profile along the furnace hG(x) is determined, and it serves as one of the most important and sensitive parameters in the overall furnace model. The model of heat transfer also yields another important parameter for the overall model, namely, the nuc, group where ms are the "mass flows" of each solid (brick, coke, anodes) and cs their specific heats. The difficulty in determining this group comes from the fact that due to the transient nature of the process, all mass flows are not affected equally, and cs are temperature-dependent. Finally, the model also gives axial and transversal temperature profiles for each of the three solids; in other words, it gives a complete micropicture of the furnace. Using Schenck's explicit method, the model is first built for a given gas temperature profile, then generalized to any profile by adding a heat balance on the gas, thus resulting in a closed-loop algorithm.