On the Influence of Viscoelastic Modeling in Fluid Flow Simulations of Gum Acrylonitrile Butadiene Rubber

Stieger, Sebastian; Mitsoulis, Evan; Walluch, Matthias; Ebner, Christian; Kerschbaumer, Roman Christopher; Haselmann, Matthias; Mostafaiyan, Mehdi; Kämpfe, Markus; Kuehnert, Ines; Wießner, Sven; Friesenbichler, Walter

doi:10.3390/polym13142323

Cited by 10 publications

(9 citation statements)

References 35 publications

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“…With the advent of numerical simulation, polymer processing has become a precise and highly technological industrial step. Before actual rubber injection moulding, for example, the process can be computer-aided simulated, in order to establish the most suitable processing conditions for a specific application [ 8 , 9 ]. During simulation, several models are applied to describe the injection moulding process, from the filling phase to the crosslinking phase of the product [ 10 , 11 ].…”

Section: Introductionmentioning

confidence: 99%

Peroxide-Based Crosslinking of Solid Silicone Rubber, Part I: Insights into the Influence of Dicumylperoxide Concentration on the Curing Kinetics and Thermodynamics Determined by a Rheological Approach

et al. 2022

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Predicting the curing behaviour of industrially employed elastomeric compounds under typical processing conditions in a reliable and scientifically driven way is important for rubber processing simulation routines, such as injection moulding. Herein, a rubber process analyser was employed to study the crosslinking kinetics of solid silicone rubber based on the concentration of dicumylperoxide. A model was proposed to describe the optimal cure time variation with peroxide concentration and temperature, based on the analysis of processing parameters applying kinetic and thermodynamic judgments. Additionally, the conversion rate was described with the aid of a phenomenological model, and the effect of dicumylperoxide concentration on the final crosslink state was investigated using kinetic and thermodynamic explanations. Optimal curing time was affected both by temperature and dicumylperoxide concentration. However, the effects were less pronounced for high temperatures (>170 ∘C) and high concentrations (>0.70 phr). A limit on the crosslink state was detected, meaning that the dicumylperoxide capacity to crosslink the silicone network is restricted by the curing mechanism. Curing restrictions were presumed to be primarily thermodynamic, based on the proton abstraction mechanism that drives the crosslinking reaction. In addition to providing more realistic crosslinking models for rubber injection moulding simulation routines, the results of this study may also explain the chemical behaviour of organic peroxides widely used for silicone crosslinking.

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Section: Introductionmentioning

confidence: 99%

Peroxide-Based Crosslinking of Solid Silicone Rubber, Part I: Insights into the Influence of Dicumylperoxide Concentration on the Curing Kinetics and Thermodynamics Determined by a Rheological Approach

et al. 2022

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“…We began the nonisothermal capillary flow simulations with the viscous Cross-WLF model for the orifice die depicted in Figure 1 a (

), based on the shear viscosities with and without temperature correction. It is known that the contraction flow has an elongational character along the centerline [ 35 , 37 , 46 ] and that a purely viscous model has a much lower elongational viscosity than a viscoelastic model, therefore it is not surprising to see that the viscous Cross-WLF model severely underpredicted the entrance pressure drop

[ 35 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 ]. This is illustrated for GPPS in Figure 6 a, where

were measured using the 0.2-mm-long orifice die.…”

Section: Resultsmentioning

confidence: 99%

Retrieving Equivalent Shear Viscosity for Molten Polymers from 3-D Nonisothermal Capillary Flow Simulation

Wen¹,

Wang²,

Cyue³

et al. 2021

Polymers

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For highly viscous polymer melts, considerable fluid temperature rises produced by viscous heating can be a disturbing factor in viscosity measurements. By scrutinizing the experimental and simulated capillary pressure losses for polymeric liquids, we demonstrate the importance of applying a viscous heating correction to the shear viscosity, so as to correct for large errors introduced by the undesirable temperature rises. Specifically, on the basis of a theoretical derivation and 3-D nonisothermal flow simulation, an approach is developed for retrieving the equivalent shear viscosity in capillary rheometry, and we show that the shear viscosity can be evaluated by using the average fluid temperature at the wall, instead of the bulk temperature, as previously assumed. With the help of a viscous Cross model in analyzing the shear-dominated capillary flow, it is possible to extract the viscous heating contribution to capillary pressure loss, and the general validity of the methodology is assessed using the experiments on a series of thermoplastic melts, including polymers of amorphous, crystalline, and filler-reinforced types. The predictions of the viscous model based on the equivalent viscosity are found to be in good to excellent agreement with experimental pressure drops. For all the materials studied, a near material-independent scaling relation between the dimensionless temperature rise (Θ) and the Nahme number (Na) is found, Θ ~ Na0.72, from which the fluid temperature rise due to viscous heating as well as the resultant viscosity change can be predicted.

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“…In nature complex uids such as viscoelastic or micro uidic mixtures surround many important phenomena, and therefore, investigation of such uids can play an important role in the development of many industrial processes. ese industrial processes range from polymeric melting processes [1,2], pulp bers [3,4], mineral processing [5], food processing [6]; and references therein, cement pastes and cosmetics processing [7]; and reference therein, and biophysical processes [8][9][10]. Also, viscoelastic ows are seen to be generated in simple liquids by the vibration of nanostructures, see for instance [8], and references present therein.…”

Section: Introductionmentioning

confidence: 99%

“…Although many important applications [1][2][3][4][5][6][7][8][9][10] are realizing the investigation of viscoelastic flows, the effect of fluid relaxation time in these models has been rarely investigated. Among the existing literature only few studies are dealing with the study of fluid relaxation time but in different contexts.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Relaxation Time on Viscoelastic Two‐Dimensional Flow Characteristics Using FreeFem++

Khan

Memon

Bonyah³

2022

Journal of Mathematics

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Viscoelastic fluid flow models have shown promising scope in modeling the behavior of many industrial materials such as polymeric materials, microfluidics, biological liquids, gels, plastic melts, and geomaterials. The relaxation time in these models is of great physical significance. In this article, we study the impact of relaxation time on the viscoelastic flow characteristics in a two-dimensional baffled cavity. To the best of authors’ knowledge, relaxation time impact on the chosen flow characteristics in the present context has not been studied and presented in the literature before. The constitutive theory of upper convected Maxwell viscoelastic flow incorporating the viscosity ad relaxation time is taken into consideration. To this account, the flow governing PDEs are derived, and an unsteady variational numerical approach based on classical variational setting is presented. A numerical algorithm based on characteristic Galerkin finite elements method is designed and implemented using the programming language FreeFem++. Computations are carried out and drag and lift forces along with other parameters of interests are calculated. Impact of relaxation time on these flow characteristics are studied and analyzed. The relaxation time R f is assumed to be in the range of 0 ≤ R f ≤ 1 × 10 − 3. The flow simulations are carried out for large Reynolds number in the range of 200 ≤ Re ≤ 5000. In addition to the application of FreeFem++, some new and interesting features of the flow characteristics are presented and discussed.

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On the Influence of Viscoelastic Modeling in Fluid Flow Simulations of Gum Acrylonitrile Butadiene Rubber

Cited by 10 publications

References 35 publications

Peroxide-Based Crosslinking of Solid Silicone Rubber, Part I: Insights into the Influence of Dicumylperoxide Concentration on the Curing Kinetics and Thermodynamics Determined by a Rheological Approach

Peroxide-Based Crosslinking of Solid Silicone Rubber, Part I: Insights into the Influence of Dicumylperoxide Concentration on the Curing Kinetics and Thermodynamics Determined by a Rheological Approach

Retrieving Equivalent Shear Viscosity for Molten Polymers from 3-D Nonisothermal Capillary Flow Simulation

Investigation of Relaxation Time on Viscoelastic Two‐Dimensional Flow Characteristics Using FreeFem++

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