Thermal analysis of a tunnel kiln used to produce roof tiles

This paper presents a thermal analysis of a tunnel kiln used for the production of roof tiles, fueled by firewood and shale oil. A tridimensional numerical model based on the finite volume method is presented and applied to model the thermal behavior of the kiln. The fuel combustion was treated as a one-step complete reaction. Surface to surface radiation between the kiln walls and load surfaces with non-participating media was considered. A prescribed flow of flue gas and air was used to surpass the obstacle of high computational cost due to the large dimensions of the numerical domain. Experimental measurements for an operating tunnel kiln were compared with numerical results and a good agreement was observed. Temperature profiles and heat fluxes for the walls and load are reported and discussed.