Mathematical analysis of the reaction–diffusion of water in glass tubes

Mazumder, Prantik

doi:10.1016/s0022-3093(02)01574-0

Cited by 6 publications

(4 citation statements)

References 13 publications

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“…As temperature increases, the dehydroxylation reaction begins to happen, in which hydroxyls react to form hydrogen or water vapor 21,22 . Gas generation leads to local pressure increase, which results in gas flow in porous silica preform under pressure difference.…”

Section: Process Descriptionmentioning

confidence: 99%

“…As temperature increases, the dehydroxylation reaction begins to happen, in which hydroxyls react to form hydrogen or water vapor. 21,22 Gas generation leads to local pressure increase, which results in gas flow in porous silica preform under pressure difference. However, according to our previous results, the convection is very weak because the amount of generated gases is very small, and most of the gases are expelled by diffusion.…”

Section: Introductionmentioning

confidence: 99%

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Effects of thermal environment on dehydroxylation of porous silica preform in two‐step CVD synthesis

Shang³

et al. 2021

J. Am. Ceram. Soc.

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Hydroxyl (-OH) is one of the main impurities in silica glass which has strong optical absorption near the infrared spectral region and greatly weakens the glass's optical performance. 1 To eliminate the hydroxyl impurities in silica glass, a two-step chemical vapor deposition (CVD) method is developed for fabricating silica glass ingot with low or controllable hydroxyl concentrations, which has drawn wide attentions in recent years. 2,3,4 The CVD synthesis of silica glass is mainly based on flame hydrolysis reaction, in which silicon-containing compounds (e.g., SiCl 4 , organosilicone, etc.) react in an oxygen-hydrogen flame to form SiO 2 particles. 5 In direct CVD method, the flame hydrolysis reaction works at high temperatures, and the melted SiO 2 particles deposit on the substrate to form silica glass directly after cooling. 6 By contrast, in two-step CVD method the flame hydrolysis reaction works at lower

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Section: Process Descriptionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effects of thermal environment on dehydroxylation of porous silica preform in two‐step CVD synthesis

Shang³

et al. 2021

J. Am. Ceram. Soc.

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“…The OH group in silica glass exists mainly in the form of ≡Si‐OH, which is relatively immobile in the silica glass owning to the strong bonding of OH with Si and the high activation energy barrier for molecular diffusion 10 . Consequently, convection arising from the large deformation of the glass ingot becomes the dominant mechanism for the OH group to transport during the sagging process, and predicting the deformation behavior of the glass ingot becomes the most critical part of the simulation.…”

Section: Introductionmentioning

confidence: 99%

“…The OH group in silica glass exists mainly in the form of ≡Si-OH, which is relatively immobile in the silica glass owning to the strong bonding of OH with Si and the high activation energy barrier for molecular diffusion. 10 Consequently, convection arising from the large deformation of the glass ingot becomes the dominant mechanism for the OH group to transport during the sagging process, and predicting the deformation behavior of the glass ingot becomes the most critical part of the simulation. To solve this problem, the solid mechanical method is widely used in the prediction of glass deformation during the slumping process, where the glass is considered to be a material having viscoelastic behaviors and characterized by a glass transition temperature, and the corresponding stress-strain equations are solved for the volume deformation rate.…”

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confidence: 99%

Modeling and optimization of the sagging process for large‐size and high‐purity silica glass synthesis

Li,

Yin,

et al. 2023

Int J of Appl Glass Sci

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Glass sagging is a subsequent process to the CVD process used for large‐size and high‐purity silica glass synthesis. Physical phenomena taking place in this process are complicated which need an in‐depth understanding for better control. In this paper, a comprehensive study is conducted for the sagging process using a level‐set and enthalpy‐porosity coupled model. With this model, the deforming behavior of glass ingot and evolution of OH uniformly distributed region are well predicted. Then, two performance indices (the effective yield rate and maximum extension radius of OH uniformly distributed region) are proposed based on different applications, and important factors, including geometrical parameters (the ingot initial length, crucible diameter and pedestal height) and operating parameter (the heater power allocation scheme), are explored for their effects on the two indices. The orthogonal test design method is adopted to further determine the collective effects of the four factors. According to the range analysis results, the initial ingot length has the greatest effect, while the crucible diameter has the least effect on the effective yield rate; and for the maximum extension radius, the crucible diameter becomes the major factor, while the pedestal height is the most insensitive factor. The corresponding optimal schemes are proposed for the two indices finally, which are believed to provide useful guidance for improving the sagging process.

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Diffusion of methylene blue in glass fibers – Application of the shrinking core model

Sarkar

Chakrabarti

Dutta

2009

Applied Mathematical Modelling

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Mathematical analysis of the reaction–diffusion of water in glass tubes

Cited by 6 publications

References 13 publications

Effects of thermal environment on dehydroxylation of porous silica preform in two‐step CVD synthesis

Effects of thermal environment on dehydroxylation of porous silica preform in two‐step CVD synthesis

Modeling and optimization of the sagging process for large‐size and high‐purity silica glass synthesis

Diffusion of methylene blue in glass fibers – Application of the shrinking core model

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