Analysis of the conjugate heat transfer in a multi-layer wall including an air layer

Analysis of the conjugate heat transfer in a multi-layer furnace wall including an air layer, using computational fluid dynamics (CFD), is presented. The analysis consists of the study of the heat transfer in the air layer to determine the heat flow that passes through the wall of the furnace. In the study, the natural convection effect on the insulating capacity of the wall was determined. The multi-layer wall is found in industrial furnaces used in the baking process of ceramics. In this study a critical thickness of the air layer was determined, identifying the beginning of natural convection, which represents a reduction in the insulating effect of the wall. In addition, different combinations of air layer thickness with vertical partitions were analyzed in order to increase the total thickness of the multi-layer wall and to improve the insulating capacity of the wall. An air layer with 10 cm of thickness and four parallel partitions presents the best insulating capacity, reducing by 44% the heat losses through the multi-layer wall.