Flow birefringence and computational studies of a shear thinning polymer solution in axisymmetric stagnation flow

Li, Ji Ming; Burghardt, Wesley R.; Yang, Bin; Khomami, Bamin

doi:10.1016/s0377-0257(97)00058-x

Cited by 41 publications

(32 citation statements)

References 38 publications

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“…Particularly simple expressions are obtained in the limit of small retardation and the methodology is demonstrated for a Newtonian fluid in [122] and for viscoelastic fluids in [140]. The attractiveness of the axisymmetric stagnation flows studied in this work is that both uni-and bi-axial elongational properties of the fluid may be examined.…”

Section: Comparison With Experimentsmentioning

confidence: 97%

“…For axi-symmetric flows, Li and Burghardt [122] and Li et al [140], show that rather than decomposing optical signals into stress data, optical properties can be used for comparison purposes. Particularly simple expressions are obtained in the limit of small retardation and the methodology is demonstrated for a Newtonian fluid in [122] and for viscoelastic fluids in [140].…”

Section: Comparison With Experimentsmentioning

confidence: 99%

See 1 more Smart Citation

Mixed finite element methods for viscoelastic flow analysis: a review

Baaijens

1998

Journal of Non-Newtonian Fluid Mechanics

273

150

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The progress made during the past decade in the application of mixed finite element methods to solve viscoelastic flow problems using differential constitutive equations is reviewed. The algorithmic developments are discussed in detail. Starting with the classical mixed formulation, the elastic viscous stress splitting (EVSS) method as well as the related discrete EVSS and the so-called EVSS-G method are discussed among others. Furthermore, stabilization techniques such as the streamline upwind PetrovGalerkin (SUPG) and the discontinuous Galerkin (DG) are reviewed. The performance of the numerical schemes for both smooth and non-smooth benchmark problems is discussed. Finally, the capabilities of viscoelastic flow solvers to predict experimental observations are reviewed.

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Section: Comparison With Experimentsmentioning

confidence: 97%

Section: Comparison With Experimentsmentioning

confidence: 99%

Mixed finite element methods for viscoelastic flow analysis: a review

Baaijens

1998

Journal of Non-Newtonian Fluid Mechanics

273

150

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“…The Giesekus model can fit both linear and nonlinear shear rheology of most concentrated polymeric solutions, and is commonly employed to represent weakly strainhardening fluids. For example in this respect, the Giesekus model has already been employed by various authors, such as Li et al [2] and Yao et al [3]. In their work, Li et al utilised a higher-order-discrete-elastic-viscous-stress (hp-DEVSS) finite element method to solve an axisymmetric stagnation flow.…”

Section: Introductionmentioning

confidence: 99%

Modelling filament stretching flows with strain-hardening models and sub-cell approximations

Matallah

Banaai

Sujatha

et al. 2006

Journal of Non-Newtonian Fluid Mechanics

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This article analyses the transient viscoelastic response of strain-hardening fluids in filament stretching flows. We utilise an Arbitrary Lagrangian/Eulerian temporal approach (ALE), coupled with a particle-tracking procedure for free-surface movement and a hybrid finite volume/element method upon the domain. We are able to contrast findings between Oldroyd, Giesekus and linear Phan-Thien/Tanner models, and distinguish between single and multi-mode implementations. In this manner, we identify the impact that greater severe strainhardening has in this transient flow context. Contributions from shear-thinning rheology may be gathered in particular by comparing single-mode solution response between a shearthinning Giesekus and a constant shear viscosity Oldroyd-B model. A parameter study on inertial and surface tension effects has been undertaken, where we isolate the occurrence of asymmetries in the flow under certain conditions, leading to the onset and formulation of bead-like structures. This elucidates the specific localised influence that surface tension and gravitational forces have upon some stretching filament flows.

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“…There are many reports on viscoelastic flow birefringence phenomenon [5][6][7][8][9], while not many studies treat welding flows. Baaijens et al [10] studied viscoelastic flows past a cylinder by both flow birefringence experiments using low density polyethylene melts and a numerical simulation.…”

Section: Introductionmentioning

confidence: 99%

Welding Flow of Low Density Polyethylene Melt

Mitsuhashi

Nishimura

Yamamoto

et al. 2003

Journal of Textile Engineering

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Weld-lines degrade the mechanical and optical properties of products. This is because the polymer molecules near the weld-line highly orient owing to the elongational flow and the molecular orientation is fixed by solidification of the polymer melts before it returns to a random condition. Birefringence experiments were, therefore, carried out for welding flows of a low density polyethylene (LDPE) past a spider supporting a mandrel. The die used in the present study has a glass window to observe the birefringence pattern. The birefringence in the polymer melts was measured by the photoelastic method. The purpose of the present study is to elucidate the effect of the die temperature, spider shapes and a viscoelastic property of polymer melts on the anisotropy of the molecular orientation in the stress relaxation process downstream of the spider. The birefringence pattern in the welding flow of LDPE was measured at the die temperature T190, 205 °C and the polymer melts temperature 719O °C for flow rates of 0.7, 1.0, 2.2, 2.9, 4.6 cm3ls. The results showed that complete relaxation of birefringence depended on the flow rate. For high die temperature (205 °C), the distance necessary for the relaxation of molecular orientation was short. Moreover, the birefringence pattern in the welding flow was numerically calculated using the single-mode Giesekus model as a constitutive equation, and the results were compared with the experimental data. The numerical predictions agreed with the experimental results.

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Flow birefringence and computational studies of a shear thinning polymer solution in axisymmetric stagnation flow

Cited by 41 publications

References 38 publications

Mixed finite element methods for viscoelastic flow analysis: a review

Mixed finite element methods for viscoelastic flow analysis: a review

Modelling filament stretching flows with strain-hardening models and sub-cell approximations

Welding Flow of Low Density Polyethylene Melt

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