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Numerical Modeling of Cooling Stage of Glass Molding Process Assisted by CFD and Measurement of Residual Birefringence
Published in Blackwell Publishing Inc.
2016
Volume: 99
   
Issue: 2
Pages: 470 - 483
Abstract
Process parameters of Precision Glass Molding (PGM) are often sought by Finite Element (FE) simulation. Mechanical as well as thermal boundary conditions (BCs) are necessary for FE simulation in which mechanical BCs are usually known or easily determinable. However, most of the thermal BCs are generally assumed in the FE simulation as they cannot be measured directly. The focus of this article is to propose a novel method for evaluating the thermal BC of glass-N2 gas. FE simulations as well as thermal cycling experiments are carried out for a glass disk specimen for three different cooling rates. CFD analysis of N2 flow in the PGM machine is performed to understand the heat extraction mechanism. Based on this, adhoc values for equivalent heat transfer coefficient (heqv) are obtained by lumped system analysis. A novel methodology is then proposed for obtaining accurate heqv values by measurement of integrated residual birefringence in glass using digital photoelasticity. FE simulation is repeated for different values of heqv until the integrated birefringence based on simulation matches with that of the experiment. For the same cooling rates, two aspherical glass lenses are molded and their residual birefringence is measured and compared with the glass disk specimen. © 2015 The American Ceramic Society.
About the journal
JournalJournal of the American Ceramic Society
PublisherBlackwell Publishing Inc.
ISSN00027820
Open AccessNo
Concepts (15)
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    Birefringence
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    Computational fluid dynamics
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    Cooling
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    Glass
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    Heat transfer
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    Molding
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    ASPHERICAL GLASS LENS
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    DIGITAL PHOTOELASTICITY
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    EQUIVALENT HEAT TRANSFER COEFFICIENT
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    Finite element simulations
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    PRECISION GLASS MOLDINGS
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    Process parameters
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    RESIDUAL BIREFRINGENCE
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    Thermal boundary conditions
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    Finite element method