Numerical Investigation of Industrial Glass Melting Furnace: Effect of Foam Layer on Glass Bath Temperature and Flow Kinematics

Abstract In glass furnaces, gas bubbles within the glass melt play a critical role due to their detrimental impact on heat transfer, particularly on radiation. Therefore, understanding bubble migration and addressing bubble accumulation at the melt surface is essential. To this end, a numerical model was developed to simulate an operational industrial glass melting furnace. The combustion and glass bath zones were solved separately and coupled with an iterative scheme. The model was validated using temperature measurements at the furnace bottom wall. The gas bubbles were modelled using a Eulerian multiphase model alongside with a new foam potential model. Gas release rates from the batch and gas discharge from the foam were controlled by user-defined parameters. A parametric study on the effect of the gas release rates from the batch and gas discharge rates from the melt surface was conducted. Results show that the foam layer thickness is largely affected by the gas release rate but very weakly by the gas discharge rate from the foam layer. The accumulated foam layer also affected the temperature distribution inside the glass bath and the resulting convective currents. In all cases, bubbles led to lower average temperatures at the tank bottom and outlet. To determine whether the radiation extinction caused by bubbles increases or decreases convective effects, an additional analytical study was performed based on the Grashof number. Simultaneously considering these physical mechanisms marks a substantial step forward in the realization of truly predictive and realistic modelling of glass furnaces.