Conductive and Radiative Properties of Soda‐Lime Silicate Glassmelts with Different Iron Contents from 1100°C to 1500°C

This paper presents an inverse method for retrieving (i) the true thermal conductivity, and (ii) the two‐band absorption coefficient of soda‐lime silicate glassmelts between 1100°C and 1550°C from measured steady‐state temperature profiles. This was achieved by combining (i) a forward method solving combined conductive and radiative heat transfer accounting for temperature‐dependent thermal conductivity and spectral absorption coefficient and (ii) an inverse method based on genetic algorithm ( GA ) optimization. Four glassmelt compositions from ultraclear to gray glasses with iron content ranging from 0.008 to 1.1 wt% were investigated. First, it was established that the steady‐state temperature in glassmelt can be predicted accurately by averaging the spectral absorption coefficient over two bands from 0 to 2.8 μm and 2.8 to 5.0 μm. The inverse method showed that the true thermal conductivity was independent of the iron content and given by k c ( T ) = 1.31 + 5.90 × 10 −4 T , where T is given in °C. In addition, the band absorption coefficient between 0 and 2.8 μm strongly increased with increasing iron content, while the band absorption coefficient between 2.8–5.0 μm was independent of iron content.