Average sodium vapor concentrations were measured along lines-of-sight through the combustion space in an oxygen-natural-gas-fired soda-lime-silicate glass container furnace using the emission and absorption of light by the atomic sodium D-lines. The total concentration of sodium species was estimated by assuming that they were in equilibrium. The measurements showed that sodium was roughly uniformly distributed through the combustion space, except over the batch blanket, where the combustion products are sometimes diluted by in-leaking air. The presence of a uniform sodium concentration permits a convenient approximate description of sodium vaporisation and deposition, without the need for detailed knowledge of velocity and temperature distributions.
