Comprehensive and numerically efficient CFD model for bubbling in an industrial glass tank

In the present paper, a novel method for numerically calculating the process of forced bubbling in an industrial-scale glass furnace was developed. The bubble chain in the glass tank was substituted with a locally acting buoyancy source. Unlike the few previously presented models, the following improvements were included: 1) Bubble characteristics were determined by running separate Eulerian multiphase simulations. Specific coupling to the actual tank model was integrated so that the induced buoyancy was calculated directly on the basis of the practical application. 2) Changes of the bubble properties and the induced buoyancy in vertical direction were analyzed. 3) The practical gas input per bubbler nozzle was used as the single input parameter. All essential model quantities could thus be expressed as direct functions of this variable. A detailed investigation of the induced buoyancy force revealed its linear dependency on the gas flow rate. A high degree of convective mixing as well as a local reduction of surface temperatures of up to 200 K could be demonstrated with the glass tank simulation results. In total, the presented models can be effectively applied in practical furnace dimensioning processes to determine both the ideal bubbler placement and the optimal mode of operation.