Natural convection in a glass melting furnace is driven mainly by the temperature difference between the cold batch and the mirror zone as they are heated by the combustion space above. Numerical analysis has been performed to examine the effects of the glass Prandtl number, the surface temperature difference, the length-to-depth aspect ratio and the batch length on the heat transfer and flow of the glass melt. Calculations ave focused on the flow patterns of natural convection cells since the intrinsic functions of the glass melting tank are melting and refining.