Thermal optimization of induction-heated pulling-down furnace for quartz glass rod fabrication

Ma, Qianli; Liu, Zhongyi; Zhong, Ya; Lang, Yudong; Liu, Xiaozhou; Fang, Haisheng

doi:10.1016/j.applthermaleng.2018.05.103

Cited by 11 publications

(3 citation statements)

References 13 publications

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“…The physical properties of solid skeleton, including density, specific heat capacity, and thermal conductivity is selected the same as those of silica glass 4,26 . Density of the gas mixture is calculated by ideal gas law:

ρ_{normalg} = \frac{p M_{normalm}}{italicRT},

where the mean molar mass of gas mixture is calculated by

\frac{1}{M_{m}} = \frac{ω_{Air}}{M_{Air}} + \frac{ω_{H_{2} normalO}}{M_{H_{2} normalO}},

…”

Section: Numerical Modelmentioning

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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ρ_{normalg} = \frac{p M_{normalm}}{italicRT},

where the mean molar mass of gas mixture is calculated by

\frac{1}{M_{m}} = \frac{ω_{Air}}{M_{Air}} + \frac{ω_{H_{2} normalO}}{M_{H_{2} normalO}},

…”

Section: Numerical Modelmentioning

confidence: 99%

“…The physical properties of solid skeleton, including density, specific heat capacity, and thermal conductivity is selected the same as those of silica glass. 4,26 Density of the gas mixture is calculated by ideal gas law:…”

Section: Physical Propertiesmentioning

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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“…Wang et al organized the power allocation during the cooling process of sapphire [7]. Ma et al optimized the induction-heated pulling-down furnace [8], and the melting process of the porous silica ingot [9]. Xiao et al optimized thermal stress of the laser glass by controlling the point, line, and surface of the ingot [10].…”

Section: Introductionmentioning

confidence: 99%

Optimizing the Cooling Process of the Quartz Glass in an Electric Furnace

Jing¹,

Ma²,

Zhang³

2019

dtcse

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The thermal stress in the quartz ingot, generated by nonlinear temperature gradients during cooling process, and stress-related defects critically degrade its optical performance. Precise control of the cooling process is an emergent task in the production. This paper proposed a transient model to investigate changes of temperature and stress in the ingot during cooling. Also we examined the influences of the heater power profile on the stress evolution. The results show that a step function not only can notably reduce the maximum stress, but also cool down the ingot in a shorter period. The proposed cooling strategies provide a valuable direction for improving quality and productivity of the quartz glass in industry.

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Transverse Thermal Behavior of a Hot‐Rolled Strip During the Edge‐Induction‐Heating Process

Wen

Zhang

et al. 2023

steel research int.

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To obtain the transverse temperature distribution of running strips under C‐type edge induction heaters during the hot‐rolling process, a coupled electromagnetic–thermal finite‐element model is established using COMSOL, in which the electromagnetic and temperature distributions regularity with various process parameters are systematically obtained. It is shown in the results that the temperature increase is directly proportional to the frequency and current and inversely proportional to the thickness. Meanwhile, the edge temperature drop can be rapidly compensated for using an edge heater, but it also leads to the appearance of a “cat‐ear” high‐temperature zone at the edge; thus, the transverse temperature uniformity cannot be guaranteed. To improve the temperature uniformity of the running strip, a magnetic shield plate is designed to weaken the effect of the cat ear, and the effects of the size and installation position of the shielding plate on the temperature distribution are analyzed. The standard deviation and uniformity of the temperature are used to determine the uniformity of the transverse temperature, and the optimal parameter combination mode of the magnetic shielding amounts is obtained, which can provide a reference for optimizing the heating process at the edge of the strip under moving conditions.

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Thermal optimization of induction-heated pulling-down furnace for quartz glass rod fabrication

Cited by 11 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

Optimizing the Cooling Process of the Quartz Glass in an Electric Furnace

Transverse Thermal Behavior of a Hot‐Rolled Strip During the Edge‐Induction‐Heating Process

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