A simplified analysis of thermal performance for oxy-fuel glass melting furnaces

Calculations of thermal performance parameters for oxy-fuel glass melting furnaces have been carried out by applying the modified well-stirred model of heat transfer in combustion space. The influences of breast wall height, flame temperature, and furnace wall thermal resistance have been studied. The calculated results show that with increasing breast wall height the total heat loss through furnace wall increases obviously, but the heat loss of unit furnace wall surface and the inner and outer surface temperatures of furnace wall change slightly. Under the condition of keeping the temperatures of flame and glass melt unchanged, the net heat transfer from flame to glass melt increases remarkably because of the decrease of view factor between the furnace wall and the glass melt and the increase of flame emissivity. The flame temperature has a substantial effect on thermal performance parameters. The net heat transfer increases by about 10% for 10°C increase of flame temperature at the flame temperature of about 1600°C. The heat loss decreases and the net heat transfer increases with increasing thermal resistance, and this is favorable to the furnace efficiency. Correspondingly, the inner surface temperature of furnace wall increases obviously.