Numerical comparison of bubbling in a waste glass melter

Guillen, Donna Post; Cambareri, Joseph J.; Abboud, Alexander W.; Bolotnov, Igor A.

doi:10.1016/j.anucene.2017.11.044

Cited by 21 publications

(14 citation statements)

References 40 publications

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“…Fundamental studies on bubble deformation and break-up could help reveal the underneath mechanisms and produce improved predictive models. This in turn will lead to optimized engineering designs (e.g., nuclear, thermal, and chemical reactors) and industrial processes (e.g., purification of polluted water, and the charging of plasma bubbles) where bubble deformation and break-up play a pivotal role (Yamatake et al, 2007;Guillen et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Complex bubble deformation and break-up dynamics studies using interface capturing approach

Fan

Fang

Bolotnov

2020

Exp. Comput. Multiph. Flow

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The dynamics of bubble deformation has significant impacts on two-phase flow fundamentals such as bubble induced turbulence and flow regime transition. Despite the significant progress achieved by experimental studies on bubble deformation, certain limitations still exist especially for wide-range datasets. To significantly expand the flow conditions available from experiments, direct numerical simulation (DNS) is utilized to study the bubble-liquid interactions using finiteelement solver with level-set interface capturing method. Different from conventional investigations of bubble rising and deforming in stagnant liquids, a proportional-integral-derivative (PID) bubble controller is leveraged to maintain the bubble location in uniform liquid flow. This paper evaluates the reliability and reproducibility of the PID bubble controller for complex bubble deformation studies through a comprehensive set of verification and validation studies. An improved bubble deformation map is developed, based on Weber number and bubble Reynolds number, showing six zones for different deformation and break-up mechanisms. This research aims at producing virtual experiment level data source using interface resolved DNS and shedding light into the physics of interface dynamics. The insights obtained can be further incorporated in improved multiphase CFD models to guide the engineering designs and industrial processes where bubble deformation and break-up play a pivotal role.

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Section: Introductionmentioning

confidence: 99%

Complex bubble deformation and break-up dynamics studies using interface capturing approach

Fan

Fang

Bolotnov

2020

Exp. Comput. Multiph. Flow

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“…The Waste Treatment and Immobilization Plant, currently being constructed at the Hanford site in Washington State, US, will vitrify nuclear waste in joule‐heated melters equipped with bubblers. Boosting melt circulation by bubbling, that is, injecting gas to the melt, brings hot melt from the melt pool to the cold‐cap vicinity, thus compressing the TBL. A high glass viscosity in the melt pool ( η M ) limits the effectiveness of bubbling in promoting forced convection, thereby reducing the convective heat transfer to the cold cap and, as a result, the glass production rate (melting rate).…”

Section: Discussionmentioning

confidence: 99%

“…The Waste Treatment and Immobilization Plant, currently being constructed at the Hanford site in Washington State, US, will vitrify nuclear waste in joule-heated melters equipped with bubblers. Boosting melt circulation by bubbling, that is, injecting gas to the melt, 13,14,33,58 brings hot melt from the melt pool to the cold-cap vicinity, thus compressing the TBL.…”

Section: Discussionmentioning

confidence: 99%

Viscosity of glass‐forming melt at the bottom of high‐level waste melter‐feed cold caps: Effects of temperature and incorporation of solid components

et al. 2019

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During the final stages of conversion of melter feed (glass batch) to molten glass, the glass‐forming melt becomes a continuous liquid phase that encapsulates dissolving solid particles and gas bubbles that produce primary foam at the bottom of the cold cap (the reacting melter feed in an electric glass‐melting furnace). The glass‐forming melt viscosity plays a dominant role in primary foam formation, stability, and eventual collapse, thus affecting the rate of melting (the glass production rate per cold‐cap area). We have traced the glass‐forming melt viscosity during the final stages of feed‐to‐glass conversion as it changes in response to changing temperature and composition (resulting from dissolving solid particles). For this study, we used high‐level waste melter feeds—taking advantage of the large amount of data available to us—and a variety of experimental techniques (feed expansion test, evolved gas analysis, thermogravimetric analyzer‐differential scanning calorimetry, X‐ray diffraction, and viscometer). Starting with a relatively low value at the moment when the melt connects, melt viscosity reached maximum within the primary foam layer and then decreased to its final melter operating temperature value. At the cold‐cap bottom—the boundary between the primary foam layer and the thermal boundary layer—where physicochemical reactions of a melter feed influence the driving force of the heat transfer from the melt to the cold cap, the melt viscosity affects the rate of melting predominantly through its effect on the temperature at which primary foam is collapsing.

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“…In the second part, the CFD model is used to investigate the effect of cold cap coverage and emissivity on the plenum space temperature. The CFD model is based upon the computational framework developed by Abboud and Guillen as an extension of Abboud et al The multiphase flow methodology employs a volume of fluid (VOF) approach that has been well established in the previous studies of free surface and bubbling flows, including highly viscous fluids . This study is part of a larger validation hierarchy for modeling the multiphysics of the vitrification process .…”

Section: Introductionmentioning

confidence: 99%

“…The CFD model is based upon the computational framework developed by Abboud and Guillen 9 as an extension of Abboud et al 10 The multiphase flow methodology employs a volume of fluid (VOF) approach that has been well established in the previous studies of free surface and bubbling flows, including highly viscous fluids. [11][12][13][14][15] This study is part of a larger validation hierarchy for modeling the multiphysics of the vitrification process. 16 Validation of the modeling for the multiphysics and cold cap dynamics which occur in the WTP can improve the control protocols.…”

Section: Introductionmentioning

confidence: 99%

Effect of cold cap coverage and emissivity on the plenum temperature in a pilot‐scale waste vitrification melter

Abboud

Guillen

Pokorný

2020

Int J of Appl Glass Sci

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Integrated computational fluid dynamics (CFD) models are being developed to model the complex physics occurring within the high‐level waste melter for vitrification of legacy tank waste at the Hanford site. This study presents a validation of the integrated CFD model by using data from two experimental runs in a pilot‐scale melter. While the model uses several simplifying assumptions (such as constant heat sinks from a cooling jacket and inleakage of ambient air, steady state feed‐to‐batch conversion heat, and a cold cap model with a simplified shape), it closely predicts the molten glass (1150°C and 1175°C) and plenum temperatures (550°C) obtained from thermocouples during two pilot‐scale tests, with an average cold cap coverage of 80%. Additional simulations were performed to explore the sensitivity of the predicted plenum temperatures to variations in cold cap coverage (fraction of melt surface covered by the glass batch) and batch emissivity. The plenum temperature was found to be in the range of 606°C when cold cap coverage decreased from 95% to 70%. Cold cap emissivity had a smaller effect, increasing the plenum temperature by as much as 179°C when cold cap emissivity increased from 0.2 to 0.8. Maintaining a high cold cap coverage without overfeeding is important for a sustained melter operation with high glass throughput. This work provides a tool for achieving that goal in terms of correlating the plenum temperature with the cold cap coverage.

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Numerical comparison of bubbling in a waste glass melter

Cited by 21 publications

References 40 publications

Complex bubble deformation and break-up dynamics studies using interface capturing approach

Complex bubble deformation and break-up dynamics studies using interface capturing approach

Viscosity of glass‐forming melt at the bottom of high‐level waste melter‐feed cold caps: Effects of temperature and incorporation of solid components

Effect of cold cap coverage and emissivity on the plenum temperature in a pilot‐scale waste vitrification melter

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