Numerical Modelling of Bubble Columns for High Temperature Glass Melting Applications

Bottom heating approach for glass melting offers potential benefits of higher efficiency and lower emissions compared to the conventional surface fired melters with burners above the bath surface. Recent advances in the enabling technologies such as burners, controls, heat recovery and refractive materials have led to successful demonstration of bottom heating Submerged Combustion Melting (SCM) of glass. In the proposed reactor, combustion products of natural gas oxy combustion are bubbled through the three phase re-circulating tank reactor. The turbulence generated by the rising bubble column would result in rapid heating and mixing of the charge resulting in fast melting and homogeneous composition of the product. Detailed understanding of such two-phase gas liquid flows is imperative for developing efficient multi-phase reactors through precise control of mixing and reaction kinetics. The bubble column, without any phase change and heating, is a good apparatus for an elementary experimental study and numerical modeling of such flows. In this study, the hydrodynamics of the bubble column are investigated using two different numerical approaches i) Using ANSYS FLUENT with an Eulerian-Eulerian approach to model the bubble and continuous phases and ii) Using a Navier-Stokes solver with the Eulerian-Lagrangian method with the Particle-in-Ball approach. The results thus obtained are discussed in detail in comparison with the experimental data available. Experiments have been conducted to gain a deeper understanding of the behaviour of the bubbles in very viscous media.