Numerical Simulation On Structure Optimization Of Combustion Space In Oxy-Fuel Glass Furnace

Glass furnace is not only a key heat equipment in glass industry,but also a high energy consumer.In China,traditional air-fuel technology was used in combustion space of glass furnace for a long time.Oxy-fuel technology is an advanced combustion technology that make pure oxygen instead of air react with fuel.which can greatly speed up the burning process and make the fuel completely combusted in the process of glass melting system.In addition,fuel consumption significantly reduced pollution reduced and flue emissions and nitrogen oxides formation decreasing.In this paper,the combustion space stucture of an oxy-fuel glass furnace which can product 200 tons of glass per day is designed and calculated,working up three-dimensional geometric model and meshing for combustion space of the glass furnace,using commercial CFD software FLUENT to simulate.In the simulation,the following mathematical model are used:the standard k-e model(using standard wall function to simplify the flow near the wall),the simplified PDF model,the Discrete Ordinates model(using the WSGGM-cell-based to calculate the gray gas absorption coefficient).The finite volume method is used to discrete the differential equations, using SIMPLE(Semi-Implicit Method for Pressure-Linked Equations) to couple the pressure and velocity.Three-diagonal matrix algorithm(TDMA)is used to carry out iteration in solving with the low-relaxation process of strategy.On the oxy-fuel combustion conditions,numerical simulation and optimization analysis are carded out from perspectives of crown height,flue location,installation height and arrangement of burners.The main conclusions are as follows:(1) Increasing the crown height by 0.16m is good for protecting crown and improving the melting rate of glass batch,but it can not make the volatilization rate of alkali vapors reduce.(2)When the flue is away from the feeding,the gas flow near the crown is relatively slow,flame coverage increases,the average temperature in the furnace increases and becomes more uniform,which is benefit for the melting of glass batch.(3)In oxy-fuel float glass furnace,increasing the installation height of burners, temperature becomes more uniform on the surface of glass melting.When the burners installed at the height of 0.3m,the gas flow tends to wash out the melted glass and hige temperature zone appears on the crown.When the burners installed at the height of 0.4 m or 0.5m,the average temperature of combustion space is higher,the gas flow near the melted glass surface has lower velocity,which result in less disturbances on the melted glass surface and less alkali vapor,can avoid damag on the crown owing to the high temperature.Therefore,the reasonable installation height of burners should be between 0.4 m and 0.5 m.(4)The impact which the arrangement of burners has on the combustion space of oxy-fuel float glass furnace shows as following:When there are fourteen burners installed,the gas flow washes out the part of crown near the flue seriously and the concentration of alkali vapor is great near the crown,which make the erosion of the crown more serious.The arrangement of ten burners is better than the arrangement of fourteen burners,When there are ten burners installed,the high-temperature zone is large and the gas flow has low velocity near the melted glass surface,which is benefical for melting and clarification,but in this case, high-temperature zone on the crown is larger and gas flow washes out the walls and the crown more seriously.Therefore,the width of furnace and the height of the crown should be increased appropriately in order to protect the walls and the crown.