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Determination of Heat Conductivity and Thermal Diffusivity of Waste Glass Melter Feed: Extension to High Temperatures
Author(s) -
Rice Jarrett A.,
Pokorny Richard,
Schweiger Michael J.,
Hrma Pavel
Publication year - 2014
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.12971
Subject(s) - thermal diffusivity , thermal conductivity , thermocouple , materials science , crucible (geodemography) , solar furnace , thermodynamics , heat flux , work (physics) , heat transfer , composite material , volume (thermodynamics) , metallurgy , chemistry , solar energy , physics , computational chemistry , ecology , biology
The heat conductivity (λ) and the thermal diffusivity ( a ) of reacting glass batch, or melter feed, control the heat flux into and within the cold cap, a layer of reacting material floating on the pool of molten glass in an all‐electric continuous waste glass melter. After previously estimating λ of melter feed at temperatures up to 680°C, we focus in this work on the λ( T ) function at T > 680°C, at which the feed material becomes foamy. We used a customized experimental setup consisting of a large cylindrical crucible with an assembly of thermocouples, which monitored the evolution of the temperature field while the crucible with feed was heated at a constant rate from room temperature up to 1100°C. Approximating measured temperature profiles by polynomial functions, we used the energy equation to estimate the λ( T ) approximation function, which we subsequently optimized using the finite‐volume method combined with least‐squares analysis. The heat conductivity increased as the temperature increased until the feed began to expand into foam, at which point the conductivity dropped. It began to increase again as the foam turned into a bubble‐free glassmelt. We discuss the implications of this behavior for the mathematical modeling of the cold cap.