Numerical Simulation Of Glass Melting Process For Large Tonnage TFT-LCD Substrate Glass

The rapid development of electronic information technology drives the growing market of ultra-thin electronic glass for photoelectric display.The ultra-thin electronic glass trends to be larger,thinner,multi-functionalized and flexible.Substrate glass is one of the important ultra-thin electronic glasses,and the increased melting capacity of glass furnace is required for the efficient production of large-size substrate glass.However,there are many difficulties for the melting of electronic substrate glass,for example,the high melting temperature,high viscosity,and difficult clarification of glass melt.The design of large-tonnage electronic glass furnace which could improve the melting quality of electronic glass is the premise of realizing the large-scale and stable production of high-quality electronic glass.In this work,numerical modeling was used to study the operating condition of large-tonnage electronic glass furnace,which adopted oxygen-fuel combustion and electric boosting melting technology.The influences of different electric boosting energy supply ratio and different tank structure design,including shallow clarification tank/deep clarification tank and extended clarification zone,on the heat transfer of glass furnace,electric current field,temperature field and velocity field of glass melt was studied.Furthermore,the mechanism of temperature/flow fields on the melting,primary clarification and homogenization quality of glass melt was discussed by using particle tracking method.Based on the results of various physical fields,the stability of working condition and service lifetime of glass furnace under different conditions were discussed.The main conclusions were as follows.(1)Based on the constant energy supply of glass tank,the increased electric energy and decreased natural gas supply could result in the decreased temperature of combustion space,which reduced the heat transfer efficiency of combustion space.It became more difficult to maintain the high temperature state at glass surface,and the temperature difference between the glass surface and tank bottom was reduced.The better glass melting quality was obtained with the optimized proportion of electric energy and natural gas supply,which could also realize the efficient and stable operating condition of substrate glass furnace in its service period.(2)With the application of shallow clarification zone,the higher temperature and stronger convection flow of glass melt were achieved,which would promote the glass clarification and homogenization process.Moreover,the glass convection flow in the tank was stable,and the particles number of glass tracer with short residence time was significantly reduced.The obtained melting,fining and homogenizing indexes of glass melt showed that the glass melting quality was better with the adoption of shallow clarification tank.(3)Stable flow of glass melts could be obtained with the application of shallow and extending clarification zone,and the number of glass fast particles in the tank was obviously reduced.The molten glass with better melting quality can be obtained since the increased electric power was adopted to compensate the heat dissipation of glass furnace and maintain the stable temperature of molten glass.The efficient and stable operating condition of substrate glass furnace could be realized.However,the greater extension of clarification zone would greatly increase the energy dissipation of glass furnace,which would result in the increased energy consumption and pollution emission.