Effective Thermal Conductivity of Soda‐Lime Silicate Glassmelts with Different Iron Contents Between 1100°C and 1500°C

Abstract

This study presents a simple method for retrieving the effective thermal conductivity of semitransparent glassmelts from measured temperature profiles. Effective thermal conductivity of molten glass at high temperature is an important thermophysical property that affects the glassmelting and forming processes and thus the quality of the final glass products. In semitransparent glassmelts, heat is transferred by both conduction and radiation. In the limiting case of optically thick glassmelts, typically featuring high iron content, thermal radiation can be treated as a diffusion process. The total heat flux can be expressed as the sum of a phononic and a radiative heat fluxes based on Fourier's law. For weakly absorbing glassmelts, the temperature profile may be strongly nonlinear particularly neat container walls due to the contribution from emission and absorption. Steady-state measurement techniques, such as the linear heat flux method, have been developed to measure glassmelt effective thermal conductivity at high temperatures. However, they typically use only three temperatures measurements and assume linear temperature profile in the glassmelt. The new retrieval method addresses these drawbacks particularly for weakly absorbing glassmelts featuring nonlinear temperature profiles. It is demonstrated with experimental data collected for sodalime silicate glasses with iron content ranging from 0.008 to 1.1 wt% and temperatures between 1100°C and 1550°C.

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

“…[10]. The uncertainties for the measured temperatures were estimated to be DT = 5°C as discussed in our previous study.…”

“…The uncertainties for the measured temperatures were estimated to be DT = 5°C as discussed in our previous study. 10 Soda-lime silicate glass with the prescribed composition was crushed and melted in a high-alumina crucible of large cross section and heated from the top in a high-temperature furnace. The thickness L of the glassmelt varied between 14 and 17 cm depending on the glassmelts composition.…”

“…In addition, the furnace temperature T f was not measured accurately in the experiments described in Ref. [10]. However, the predicted temperature profile was very sensitive to T f as it directly affected the boundary condition at surface x = L [Eq.…”

“…[10] and need not be repeated. In brief, they can be divided into steady-state and transient methods.…”

Mechanical Properties of Soda-Lime-Silica Glasses with Variable Peanut Shell Contents

“…For example, so-called solar control glass is a type of SLS glass containing around 1 wt.% of iron, which is used in automotive windows [5]. Iron is added to absorb ultraviolet (UV) and infrared * corresponding author; e-mail: baktas@harran.edu.tr (IR) solar radiation to reduce the harmful effects of UV rays and vehicle thermal load, to increase passenger comfort [6]. SLS glasses have also been investigated to determine whether their mechanical properties (such as elastic modulus and fracture toughness) could be used to predict glass hardness.…”