Lubricated cross-slot flow of a low density polyethylene melt

Soulages, Johannes; Schweizer, Th.; Venerus, David C.; Kröger, Martin; Öttinger, Hans Christian

doi:10.1016/j.jnnfm.2008.02.007

Cited by 17 publications

(6 citation statements)

References 40 publications

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“…Larger devices with typical channel width w $O(1-10 mm) have been constructed that are suitable for extensional measurements with high viscosity elastic fluids such as polymer melts. 125,127,129,130 The simplicity of the cross-slots geometry also makes it amenable for fabrication at the microscale. The strain rate in the cross-slot scales with the inverse of the channel dimension (_ e % 2U=w, where U is the average flow velocity), while inertial effects, as quantified by the Reynolds number, scale linearly with the channel dimension (Re ¼ qUw=g).…”

Section: Stagnation Point Flowsmentioning

confidence: 99%

Microfluidic extensional rheometry using stagnation point flow

Haward

2016

Biomicrofluidics

102

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Characterization of the extensional rheometry of fluids with complex microstructures is of great relevance to the optimization of a wide range of industrial applications and for understanding various natural processes, biological functions, and diseases. However, quantitative measurement of the extensional properties of complex fluids has proven elusive to researchers, particularly in the case of low viscosity, weakly elastic fluids. For some time, microfluidic platforms have been recognized as having the potential to fill this gap and various approaches have been proposed. This review begins with a general discussion of extensional viscosity and the requirements of an extensional rheometer, before various types of extensional rheometers (particularly those of microfluidic design) are critically discussed. A specific focus is placed on microfluidic stagnation point extensional flows generated by cross-slot type devices, for which some important developments have been reported during the last 10 years. Additional emphasis is placed on measurements made on relevant biological fluids. Finally, the operating limits of the cross-slot extensional rheometer (chiefly imposed by the onset of elastic and inertial flow instabilities) are discussed.

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Section: Stagnation Point Flowsmentioning

confidence: 99%

Microfluidic extensional rheometry using stagnation point flow

Haward

2016

Biomicrofluidics

102

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“…ize the presence of a lag between chain orientation and the inducing flow due to slip. 45,46 Finally, we highlight that having a method to discriminate independently the different sources of non-Newtonian rheological behaviour through the eigendynamics of the conformation tensor will help produce better data-driven constitutive equations for polymer solutions, where non-affine motion and entropic contributions are clearly separated. Following our method, once the slip parameter is obtained, we can infer σ -the entropic contribution to the evolution of c -by using Eq.…”

Section: Discussionmentioning

confidence: 99%

Non-affine motion and selection of slip coefficient in constitutive modeling of polymeric solutions using a mixed derivative

Simavilla

Español

Ellero

2022

Journal of Rheology

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Constitutive models for the dynamics of polymer solutions traditionally rely on closure relations for the extra stress or related microstructural variables (e.g., conformation tensor) linking them to flow history. In this work, we study the eigendynamics of the conformation tensor within the GENERIC framework in mesoscopic computer simulations of polymer solutions to separate the effects of nonaffine motion from other sources of non-Newtonian behavior. We observe that nonaffine motion or slip increases with both the polymer concentration and the polymer chain length. Our analysis allows to uniquely calibrate a mixed derivative of the Gordon–Schowalter type in macroscopic models based on a micro-macromapping of the dynamics of the polymeric system. The presented approach paves the way for better polymer constitutive modeling in multiscale simulations of polymer solutions, where different sources of non-Newtonian behavior are modelled independently.

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“…IV B and IV C. The matrix L defining the coarse-grained Poisson bracket ( 7) is obtained by inserting the definitions (12-15) of the coarsegrained variables into Eq. (7). Details of the straightforward calculations are presented in Ref.…”

Section: A Generic Coarse-graining Applied To Unentangled Melts: Foun...mentioning

confidence: 99%

“…Understanding relaxation processes and structure development occurring over these multiple scales is a prerequisite for deriving reliable constitutive equations connecting the stresses developing in these materials in terms of the imposed flow kinematics and certain molecular parameters or functions, and for computing polymer flows [3,4,5,6,7,8,9,10]. It is only through a comprehensive understanding across scales that one can hope to build the relationship between polymer molecular structure, conformation and architecture and macroscopic rheological response.…”

mentioning

confidence: 99%

Multiscale Modeling and Coarse Graining of Polymer Dynamics: Simulations Guided by Statistical Beyond-Equilibrium Thermodynamics

Ilg,

Mavrantzas,

Öttinger

2009

Preprint

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Lubricated cross-slot flow of a low density polyethylene melt

Cited by 17 publications

References 40 publications

Microfluidic extensional rheometry using stagnation point flow

Microfluidic extensional rheometry using stagnation point flow

Non-affine motion and selection of slip coefficient in constitutive modeling of polymeric solutions using a mixed derivative

Multiscale Modeling and Coarse Graining of Polymer Dynamics: Simulations Guided by Statistical Beyond-Equilibrium Thermodynamics

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