On the combined effects of slip, compressibility, and inertia on the Newtonian extrudate-swell flow problem

Kountouriotis, Zacharias; Georgiou, Georgios C.; Mitsoulis, Evan

doi:10.1016/j.compfluid.2012.09.026

Cited by 12 publications

(5 citation statements)

References 25 publications

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“…For this purpose, the simulations were carried out at the same Re and Bn numbers as those presented in Section 4.2, but with a flow index exponent representative of shear-thinning, n = 0.5, and shear-thickening, n = 1.5, behaviors. As shown in Figure 5, the extrudate swell ratio obtained by the newly developed solver is again very close to the results presented by Kountouriotis et al [41] for both n = 0.5 and n = 1.5 at Re = 1, 5, and 10. The general trend of the shear-thinning extrudate swell ratio (see Figure 5a) at the different Re numbers is similar to the behavior shown for the Bingham flow (n = 1) in Figure 2.…”

Section: The Effects Of Inertia and Yield-stress In The Extrudate Swell Of Herschel-bulkley Fluidssupporting

confidence: 88%

“…The swell ratio is defined as the height of the free-surface away from the die exit, where the plug flow has been established, divided by the die radius, i.e., χ = h 0 /R. As shown in Figure 2, the extrudate swell ratio obtained by the newly developed solver is very close to the results presented by Kountouriotis et al [41] at Re = 1, 5, and 10. For the lowest Reynolds number (Re = 1), as the yield stress effect is enhanced (i.e., increase of the Bn number), the extrudate swell shrinks steeply for Bn > 0.1, and above a critical value of Bn > 5, the swell contracts and becomes smaller than unity.…”

Section: The Effects Of Inertia and Yield-stress In The Extrudate Swell Of Bingham Fluidssupporting

confidence: 79%

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Non-Isothermal Free-Surface Viscous Flow of Polymer Melts in Pipe Extrusion Using an Open-Source Interface Tracking Finite Volume Method

2021

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Polymer extrudate swelling is a rheological phenomenon that occurs after polymer melt flow emerges at the die exit of extrusion equipment due to molecular stress relaxations and flow redistributions. Specifically, with the growing demand for large scale and high productivity, polymer pipes have recently been produced by extrusion. This study reports the development of a new incompressible non-isothermal finite volume method, based on the Arbitrary Lagrangian–Eulerian (ALE) formulation, to compute the viscous flow of polymer melts obeying the Herschel–Bulkley constitutive equation. The Papanastasiou-regularized version of the constitutive equation is employed. The influence of the temperature on the rheological behavior of the material is controlled by the Williams–Landel–Ferry (WLF) function. The new method is validated by comparing the extrudate swell ratio obtained for Bingham and Herschel–Bulkley flows (shear-thinning and shear-thickening) with reference data found in the scientific literature. Additionally, the essential flow characteristics including yield-stress, inertia and non-isothermal effects were investigated.

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Section: The Effects Of Inertia and Yield-stress In The Extrudate Swell Of Herschel-bulkley Fluidssupporting

confidence: 88%

Section: The Effects Of Inertia and Yield-stress In The Extrudate Swell Of Bingham Fluidssupporting

confidence: 79%

Non-Isothermal Free-Surface Viscous Flow of Polymer Melts in Pipe Extrusion Using an Open-Source Interface Tracking Finite Volume Method

2021

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“…Computer modeling of fluid extrusion is not just used for EBM, it is also valuable for different industrial applications such as ink-jet printing and cable coating [21]. Fluid forced out of a die undergoes complex behavior that is dependent on a wide variety of factors [70,54,99,73]. The extrusion modeling and simulation is usually referred to as the die swell or extrusion swell problem.…”

Section: Modeling and Simulation Of Polymer Extrusionmentioning

confidence: 99%

“…In [70], the fluid passes through a chamber without any contractions before exiting into free space. This configuration is typically used in literature addressing die swell where the fluid passes through a long chamber and forms a Poiseuille flow [93,86,54,78,79,21]. In this work, the die acts as a sudden contraction.…”

Section: Mesh Convergence and Literature Validation At T =mentioning

confidence: 99%

Modeling and simulation for varying die gap fluid extrusion

Toukhtarian

2019

Preprint

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The analysis and the simulation of fluid extruded out of a die opening are of great importance in different industrial applications. Mathematical modeling and experimental studies of extrusion out of a constant die gap has been the subject of numerous publications in the literature. Extrusion Blow Molding is a polymer forming technique used to manufacture a wide range of large hollow parts such as fuel tanks used in the automotive industry. The die gap is varied during extrusion to adjust the manufactured product's final thickness and to compensate for uneven stretching during molding. In this work, mathematical modeling of varying die gap extrusion is introduced. Two models using different approaches are presented to model the time dependent effects of varying the die gap on the extrudate.In the first approach, physics based partial differential equations are used to simulate extrusion. The Navier Stokes equations are used as governing equations to simulate molten polymers. The governing equations are solved using Arbitrary Lagrangian Eulerian based Finite Element Method. A novel numerical method for defining the free surface of the extrudate is proposed. In addition, the effects of varying the die gap on the material velocity, pressure and extrudate shape are reported.In the second approach, a parameter identification scheme is used to obtain the parameters of a novel model with a predefined structure. The purpose of the proposed model is to replicate time dependent extrudate thickness of the physics based model. The parameters of the model are identified by minimizing the response error between the two models due to step inputs. The parameter identification based model provides a computationally low cost alternative to the physics based model. Moreover, the parameter identification based model has a transport Partial Differential Equation/Ordinary Differential Equation cascade structure that is suitable for designing feedback controllers for Extrusion Blow Molding.First, I would like to express sincere gratitude and appreciation to my supervisor Prof. Benoit Boulet for his great guidance and the intellectual freedom I was granted throughout this research. This work would not have been possible without his great dedication, constructive criticism and support. A special thanks to my co-supervisor Prof. Roni Khazaka for his mentorship and guidance. I also gratefully acknowledge Prof. Savvas Hatzikiriakos and Mr. Haile Atsbha for sharing with me their profound knowledge and expertise. I gratefully acknowledge the Natural Sciences and Engineering Research Council of Canada (Automotive Partnership Canada) for the financial support and giving me the opportunity to pursue my passion in science and engineering.Finally, I would like to thank my loving friends and family for their encouragement and support along my journey over the past five years. viii

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“…Fluid forced out of a die undergoes complex behaviour that is dependent on a wide variety of factors. [ 15–17 ] Extrusion is usually simulated using physics based governing equations that are commonly solved using a finite element method (FEM). Given that the computational domain boundaries include a free surface, the position of the boundaries is part of the intended unknowns besides other variables such as pressure and velocity.…”

Section: Introductionmentioning

confidence: 99%

Parameter identification of transport PDE/nonlinear ODE cascade model for polymer extrusion with varying die gap

et al. 2020

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A new transport PDE/nonlinear ODE cascade model is proposed to simulate extrudate thickness for polymer extrusion with varying die gap. The model is developed to simulate extrusion in extrusion blow moulding. A finite element method simulator is used as a reference for the proposed model to replicate its time dependent extrudate thickness profile. The parameters of the proposed model are identified by minimizing the response error between the proposed model and the finite element method simulator due to step inputs. The novel model is computationally cheap, suitable for controller design, and effective in simulating the extrudate thickness.

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On the combined effects of slip, compressibility, and inertia on the Newtonian extrudate-swell flow problem

Cited by 12 publications

References 25 publications

Non-Isothermal Free-Surface Viscous Flow of Polymer Melts in Pipe Extrusion Using an Open-Source Interface Tracking Finite Volume Method

Non-Isothermal Free-Surface Viscous Flow of Polymer Melts in Pipe Extrusion Using an Open-Source Interface Tracking Finite Volume Method

Modeling and simulation for varying die gap fluid extrusion

Parameter identification of transport PDE/nonlinear ODE cascade model for polymer extrusion with varying die gap

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