Modeling and simulation of ceramic tiles linear shrinkage variation during the sintering process

Abstract

Linear shrinkage (S_L) is utilized as a criterion to modify the size of the sintered ceramic tiles, and the sintering cycle affects the shrinkage variation. The exact sintering cycle associated with the S_L of ceramic tiles is difficult to verify experimentally, and it affects the quality of the final ceramic tiles. Production costs also increased due to the large amount of experimental work. This study investigated a powerful numeric model of the sintering process within ceramic tile, using computational fluid dynamics (CFD) to evaluate the variation of the S_L in ceramic tiles during the sintering process. The sintering process was simultaneous and integrated with energy and mass transport phenomena. Numerical formulas were developed for the sintering operation, and the S_L behavior of ceramic tiles during sintering was examined using a kinetic model. An unsteady 3D model was established, and simulation was performed using the CFD tool by varying the temperature profile. The results of CFD simulation can ascertain the temporal and spatial changes in the S_L of ceramic tiles through sintering. To validate the model, the green body mixture of ceramic tile was prepared and analyzed. Ceramic tiles were shaped by a powder pressing technique on a laboratory scale. Dried tiles were sintered in a laboratory furnace by adjusting the maximum sintering temperatures. The structure of sintered ceramic tiles was analyzed. The S_L variation of each sintered tile was determined and compared with the results of CFD simulations. The results of the CFD simulation were validated and concurred with experimental outcomes, and the R² value of the results was 0.9. The developed CFD model is capable of predicting the temporal and spatial changes in S_L of ceramic tiles through sintering, and it is a great help to find the exact sintering cycle associated with S_L. Finally, the quality of the tile is increased, and production costs are also reduced.