Role of Glass Melt Flow in Container Furnace Examined by Mathematical Modelling

Jebavá, Marcela; Nemec, Lubomir

doi:10.13168/cs.2017.0049

Cited by 10 publications

(12 citation statements)

References 12 publications

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“…Mathematical models have successfully simulated fluid flow and heat transfer in the melt pool and furnace atmosphere to address energy economy, glass product quality, and environmental pollution issues, [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] but the heat transfer from the melt pool to the cold cap has not been the main focus. Even though certain aspects of glass processing have been studied in minute detail, [23][24][25] the complexity of chemical and physical phenomena occurring in the batch blanket and at the batch-melt and batch-gas interfaces present formidable obstacles to executing realistic models. As a result, existing mathematical models of glass melting furnaces have paid little attention to the cold cap and its close proximity, where the heat transfer determines the rate of melting.…”

Section: Introductionmentioning

confidence: 99%

Glass production rate in electric furnaces for radioactive waste vitrification

et al. 2019

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Correlating the melting rates of feeds in electric melters with results of simple laboratory experiments can help evaluate melter feed additives and their effects on melting rate, and support the feed scheduling and plant operation. A recently proposed melting rate correlation (MRC) equation, relating the melting rate to melt viscosity, feed‐to‐glass conversion heat, and cold‐cap bottom temperature, was tested using data from experiments covering various feed compositions and melter operating parameters. The MRC equation is shown to reasonably represent the measured data and thus can be used to quantify how individual variables (melt viscosity, cold‐cap bottom temperature, conversion heat, melter operating temperature, and bubbling flux) affect the glass production rate.

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Section: Introductionmentioning

confidence: 99%

Glass production rate in electric furnaces for radioactive waste vitrification

et al. 2019

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“…The modeling of glass‐melting furnaces has focused on two main goals: minimizing heat loss and producing high quality glass, that is, avoiding blisters (bubbles), stones (undissolved solids), and striae (compositional inhomogeneities) . Accordingly, most attention has been paid to heat transfer from burning gases to the glass melt and glass batch, as well as the influence of gas bubbling and electric boosting, on the temperature and velocity fields in the melt . The adequacy of computed velocity and temperature fields was verified by round‐robin studies .…”

Section: Introductionmentioning

confidence: 99%

Heat transfer from glass melt to cold cap: Effect of heating rate

Lee

Hrma

Pokorný

et al. 2019

Int J of Appl Glass Sci

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Conversion of melter feed to glass occurs in the cold cap that floats on the melt pool in a nuclear waste glass melter. The conversion rate (the melting rate or the glass production rate) is controlled by the heat flux delivered to the cold cap from the molten glass. In an attempt to analyze the intricate relationship between the rate of heating, the feed foaming response, and the rate of melting, we measured the change in feed volume at different heating rates by using several melter feeds known to exhibit a wide range of melting rates under identical melter operating conditions. As expected, the maximum foam porosity increased as the heating rate increased.However, contrary to expectation, the temperature at which the foam reached maximum volume either decreased or increased with the heating rate, depending on the feed composition. A change in maximum foam temperature from the feed volume expansion test indicates a similar change of the cold-cap bottom temperature, which influences the heat flow to the cold cap, and thus the rate of melting. K E Y W O R D Sfeed-to-glass conversion, foaming, heat flux, melting rate 402 | LEE Et aL.

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“…Although a major portion of refractories dissolve in the batch blanket, only a handful of studies have focused on refractory dissolution within this layer . Most of the experimental and modeling studies address the effect of undissolved particles on fining and on the final product quality, investigating, for example, the dissolution of residual quartz particles in the bulk melt …”

Section: Kinetic Limited Modelsmentioning

confidence: 99%

“…Eventually, the foam collapses into cavities (larger, flat bubbles) that drift under the batch:melt interface with the convective flow of the melt. In a large fossil‐fired furnace, large bubbles burst at the batch edges directly into the atmosphere, while the rapid convective flow of melt can carry smaller bubbles from beneath the batch to the fining area and even all the way to the conditioning area . In electric melters where the batch blanket covers most of the melt surface, accumulated gases create occasional “volcanoes” through which they erupt to the atmosphere.…”

Section: Kinetic Limited Modelsmentioning

confidence: 99%

Modeling batch melting: Roles of heat transfer and reaction kinetics

et al. 2019

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Development of mathematical models of heat and mass transfer in glass‐melting furnaces began in the 1970s and progressed rapidly with advances in sophisticated experimental/numerical techniques and increasing computational power. Today, practically all newly built or rebuilt furnaces are optimized with these models to meet stringent quality requirements, reduce the unit costs of manufacturing, or control emissions. One remaining hurdle is to model the batch‐to‐glass conversion accurately enough to reliably assess the glass production rate. This article summarizes two key aspects of the batch‐conversion modeling—the heat transfer and the kinetics of conversion—and reviews the current state‐of‐the‐art approaches to simulating them. We critically examine the advantages of the commonly used heat transfer approach, but also explain that its predictive capabilities are significantly restricted by the dependence of batch thermal properties on the time‐temperature history. We argue that kinetic approaches to the batch‐conversion modeling would offer a significant improvement when coupled with the heat transfer approach. Finally, we summarize key areas requiring further research on the way toward a realistic model of the batch blanket.

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Role of Glass Melt Flow in Container Furnace Examined by Mathematical Modelling

Cited by 10 publications

References 12 publications

Glass production rate in electric furnaces for radioactive waste vitrification

Glass production rate in electric furnaces for radioactive waste vitrification

Heat transfer from glass melt to cold cap: Effect of heating rate

Modeling batch melting: Roles of heat transfer and reaction kinetics

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