The matching of 3D Rolie-Poly viscoelastic numerical simulations with experimental polymer melt flow within a slit and a cross-slot geometry

Lord, T. D.; Scelsi, Lino; Hassell, David; Mackley, M. R.; Embery, John; Auhl, Dietmar; Harlen, Oliver G.; Tenchev, Rosen T.; Jimack, Peter K.; Walkley, Mark A.

doi:10.1122/1.3306572

Cited by 22 publications

(18 citation statements)

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“…ópticos [15,17,28,29] . Tal modificação consistiu em trocar a geometria padrão (capilar) por uma geometria slit (tipo fenda) equipada com janelas de quartzo em ambos os lados, que permitem a visualização do escoamento.…”

Section: Farias T M Et Al -Utilização Da Técnica De Birrefringêncunclassified

“…Tal modificação consistiu em trocar a geometria padrão (capilar) por uma geometria slit (tipo fenda) equipada com janelas de quartzo em ambos os lados, que permitem a visualização do escoamento. A fenda, que é caracterizada por uma contração/expansão (Figura 1b), possui cantos arrendondados na entrada e saída para melhorar as observações experimentais e facilitar a simulação numérica [29] . Nesse escoamento, existem regiões de cisalhamento e uma região com características elongacionais perto das regiões de entrada e saída da fenda.…”

Section: Farias T M Et Al -Utilização Da Técnica De Birrefringêncunclassified

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Utilização da técnica de birrefringência em reômetro multipasse para a diferenciação de grades de poliestireno cristal

et al. 2014

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Resumo: O entendimento de como as propriedades reológicas afetam o comportamento dos polímeros nas operações de processamento, por meio de diferentes técnicas experimentais, é de fundamental importância para ser possível prever e avaliar a estrutura final destes materiais. Neste contexto, o objetivo deste trabalho é aplicar a técnica de birrefringência para diferenciar dois grades de poliestireno cristal. Foram realizados experimentos em um reômetro multipasse que permitiram a aquisição de imagens de birrefringência, que representam o campo de tensão do escoamento, e obteve-se a queda de pressão durante os experimentos. Ao se compararem os padrões de birrefringência dos dois poliestirenos foi possível distinguir os materiais e verificar que o escoamento da amostra de maior massa molar é mais complexo, com maior birrefringência e tensão mais elevada. Os resultados obtidos, além de contribuírem para a caracterização reológica, podem ser empregados no estudo comparativo de modelos constitutivos e desenvolvimento de códigos computacionais. Palavras-chave:Birrefringência, reômetro multipasse, poliestireno. The Use of Birefringence Technique in a Multipass Rheometer for the Differentiation of General Purpose Polystyrene GradesAbstract: Polymers must go through processes that transform raw materials in a final product for consumption, and therefore it is crucial to understand how their rheological properties affect processability and final product quality. This study is aimed at applying the birefringence technique to differentiate two grades of general purpose polystyrene. Flow experiments were carried out using a multi-pass rheometer and flow-induced birefringence images and pressure profile were obtained. It was possible to distinguish between the different materials by examining their birefringence patterns. The flow of the higher molecular weight sample is more complex, with higher birefringence and tension. These data are important for the rheological characterization of the material and can be used in the validation of constitutive models in computational fluid dynamics. Universitária, Fundão, Av. Horácio Macedo, 2030, CEP 21941-914, Rio de Janeiro, RJ, Brasil, e-mail: arge@peq.coppe.ufrj.br Introdução O conhecimento do comportamento reológico de polímeros fundidos é de suma importância nas operações que transformam a matéria-prima em produto final para o consumo. Polímeros, tais como polietileno, polipropileno, policarbonato e poliestireno, são processados em elevadas temperaturas e, durante as operações como extrusão e moldagem por injeção, o material é submetido a altas taxas de deformação, causando a orientação e alongamento das cadeias. O processamento de polímeros é diretamente afetado pelas propriedades reológicas em estado fundido, sendo necessário conhecer o comportamento desses materiais nas condições práticas de escoamento para ser possível prever e avaliar a estrutura final do material [1] . Assim, com o intuito de evitar ou diminuir a necessidade de procedimentos de tentativa e erro, que represe...

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Section: Farias T M Et Al -Utilização Da Técnica De Birrefringêncunclassified

Utilização da técnica de birrefringência em reômetro multipasse para a diferenciação de grades de poliestireno cristal

et al. 2014

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“…The simulated results were in good agreement with the experimental results, which illustrate the efficiency of Rolie-Poly constitutive equation. Lord et al (2010) further investigated the flow behavior of polydisperse polystyrene for threedimensional case in a similar way, and the multi-mode Rolie-Poly constitutive equation was used in simulation. Hassell et al (2008b) presented the experimental studies of flow instability of the monodisperse linear polystyrenes, and the formation and development of the instability phenomenon are observed.…”

Section: Introductionmentioning

confidence: 99%

Finite volume simulations of behavior for polystyrene in a cross-slot flow based on Rolie-Poly model

et al. 2016

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The flow behavior of polystyrenes is investigated numerically for a cross-slot geometry using Rolie-Poly model with finite extensibility, and governing equations for the polystyrene melts are solved by finite volume method with domain extension technique on the collocated grid. The effect of molecular weight, flow rate, and two kinds of Weissenberg numbers on the principal stress difference (PSD) profiles are discussed detailedly. The microstructures of polymer melts, including molecular orientation, extension, and deformation, are also investigated and presented in this paper. We found that the orientation of Weissenberg number is the major factor affecting the PSD profiles and the performance of the RoliePoly model has been improved greatly by introducing finite extensibility at high extension rate. The numerical results are consistent with the available experiment results, which demonstrate the capabilities of single-mode Rolie-Poly model with finite extensibility to simulate the flow behavior of polystyrenes and the numerical method developed in this paper.

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“…This generates a pure and controllable elongational deformation in the neighborhood of the stagnation line along the middle section of the centreaxis of the cross, but essentially simple shear near the outer walls, e.g., Coventry and Mackley (2008) and . Full three-dimensional flow simulations and experiments have been performed for both linear polystyrene [Lord et al (2010)] and LCB-polyethylenes 298 HOYLE et al…”

Section: B Cross-slot Extensional Rheologymentioning

confidence: 99%

“…Details of the numerical scheme are given in the references [Tenchev et al (2008); Lord et al (2010)]. Due to symmetry, only one quarter of the cross-slot domain was calculated.…”

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Transient overshoot extensional rheology of long-chain branched polyethylenes: Experimental and numerical comparisons between filament stretching and cross-slot flow

Hoyle

Huang²,

Auhl

et al. 2013

Journal of Rheology

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Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. SynopsisThis work analyses the high-strain extensional behavior of long-chain branched polyethylenes, employing two novel extensional rheometer devices, the filament stretching rheometer and the crossslot extensional rheometer. The filament stretching rheometer uses an active feedback loop to control the imposed strain rate on a filament, allowing Hencky strains of around 7 to be reached. The cross-slot extensional rheometer uses optical birefringence patterns to determine the steady-state extensional viscosity from planar stagnation point flow. The two methods probe different strain-rate regimes and in this paper we demonstrate the agreement when the operating regimes overlap and explore the steadystate extensional viscosity in the full strain-rate regime that these two complimentary techniques offer. For long-chain branched materials, the cross-slot birefringence images show a double cusp pattern around the outflow centre line (named W-cusps). Using constitutive modeling of the observed transient overshoot in extension seen in the filament stretching rheometer and using finite element simulations we show that the overshoot explains the W-cusps seen in the cross-slot extensional rheometer, further confirming the agreement between the two experimental techniques. V C 2013 The Society of Rheology.[http://dx

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The matching of 3D Rolie-Poly viscoelastic numerical simulations with experimental polymer melt flow within a slit and a cross-slot geometry

Cited by 22 publications

References 40 publications

Utilização da técnica de birrefringência em reômetro multipasse para a diferenciação de grades de poliestireno cristal

Utilização da técnica de birrefringência em reômetro multipasse para a diferenciação de grades de poliestireno cristal

Finite volume simulations of behavior for polystyrene in a cross-slot flow based on Rolie-Poly model

Transient overshoot extensional rheology of long-chain branched polyethylenes: Experimental and numerical comparisons between filament stretching and cross-slot flow

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