Numerical Simulation of Melted Glass Flow Structures inside a Glass Furnace with Different Heat Release Profiles from Combustion

A glass production furnace requires a considerable amount of energy to allow the correct glass melting process. In this work, a CFD model has been developed in order to simulate the convective flow movements within the molten glass bath of the glass furnace. A heat flux profile has been assigned to the glass free surface to model the combustion process, and the glass has been modelled with thermophysical properties variable with temperature based on its chemical composition. The model has been validated by comparing the flow structure and temperature with a reference work. Subsequently, a flow analysis has been carried out by using different shapes for the heat flux profile and by varying its main parameters. The above heat release profiles are representative of different settings of the combustion operating points and can be useful to understand the effects of different flames (i.e., from different fuels also) on the glass flow structure. It has been demonstrated that only the thermal distribution with a maximum generates two convective macro-cells: the first is necessary for the glass melting, the second for its homogenization. It has also been observed that the length of these vortices is related to the flame length. However, a portion of the flow exits directly from the throat (furnace exit port) without entering into the second cell; a low-quality product will be generated in this case.