Non‐<scp>I</scp>sothermal Modeling of a Non‐<scp>N</scp>ewtonian Fluid Flow in a Twin Screw Extruder Using the Fictitious Domain Method

Sobhani, Hadi; Anderson, Patrick Patrick; Meijer, H.E.H.; Ghoreishy, Mir Hamid Reza; Razavi‐Nouri, Mohammad

doi:10.1002/mats.201300110

Cited by 20 publications

(16 citation statements)

References 33 publications

(53 reference statements)

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“…For first principles simulations of the flow in co-rotating twinscrew extruders, mainly mesh-based CFD (computational fluid dynamics) methods, such as the FEM (finite element method) and FVM (finite volume method), have been used (e.g., Ishikawa, 2001;Bertrand et al, 2003;Malik and Kalyon, 2005;Ficarella et al, 2006a;Ficarella et al, 2006b;Kalyon and Malik, 2007;Barrera et al, 2008;Bierdel, 2008;Conzen, 2008;Rodríguez, 2009;Haghayeghi et al, 2010;Vyakaranam et al, 2012;Sarhangi Fard et al, 2012a;Sarhangi Fard et al, 2012b;Sarhangi Fard and Anderson, 2013;Hétu and Ilinca, 2013;Rathod and Kokini, 2013;Sobhani et al, 2013;Durin et al, 2014). FEM was also used to simulate complex fluids in extruders including wall slip phenomena, (e.g., Kalyon et al, 1999;Lawal et al, 1999;Malik et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Co-rotating twin-screw extruders: Detailed analysis of conveying elements based on smoothed particle hydrodynamics. Part 1: Hydrodynamics

Eitzlmayr

Khinast

2015

Chemical Engineering Science

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We applied SPH to study the flow in a co-rotating twin-screw extruder. A new model which accounts for the flow in unresolved clearances was presented. We showed detailed results for pressure drop, flow rate and power consumption. We achieved excellent agreement with CFD data for the completely filled state. Detailed results for the partially filled state are included. a b s t r a c tDue to the complex geometry of the rotating screws and, typically, free surface flows in partially filled screw sections, first principles simulations of the flow in co-rotating intermeshing twin-screw extruders using the well-established, mesh-based CFD (computational fluid dynamics) approaches are highly challenging. These issues can be resolved via the smoothed particle hydrodynamics (SPH) method thanks to its meshless nature and the inherent capability to simulate free surface flows. In our previous work, we developed a novel method for modeling the boundary conditions with complex wall geometries, under which SPH could be efficiently applied to complex surfaces of typical screw geometries of extruders. In this work, we employed SPH and our boundary method to study the flow in a conveying element in detail. To address unresolved clearances, we developed a new model that is coupled to SPH and can correctly account for the flow through unresolved clearances. A validation of our approach using CFD data from the literature for a completely filled conveying element indicated excellent agreement. Consequently, we studied the flow in a partially filled conveying element and obtained results for the flow rate, the power input and the axial force with variable filling ratio. A detailed analysis of the corresponding mixing phenomena is presented in Part 2. Our results show that the proposed method is a comprehensive approach to study the flow in different types of screw elements in detail, providing an excellent basis for further development of simplified models of entire extrusion processes.

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Section: Introductionmentioning

confidence: 99%

Co-rotating twin-screw extruders: Detailed analysis of conveying elements based on smoothed particle hydrodynamics. Part 1: Hydrodynamics

Eitzlmayr

Khinast

2015

Chemical Engineering Science

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“…[ 30,31 ] on the distributive mixing in twin‐screw extruders. The fluid flow simulations of the twin‐screw extruder are expensive in terms of computation time, but these simulations enabled the group to introduce methods like the fictitious domain method [ 32 ] or the diffuse mapping method. [ 33 ] Grosse et al.…”

Section: Introductionmentioning

confidence: 99%

“…Eventually, the fluid is discharged through the outflow channel due to the intermeshing of the teeth. The inter-teeth volumes are in theory perfectly sealed, simulations enabled the group to introduce methods like the fictitious domain method [32] or the diffuse mapping method. [33] Grosse et al [34] quite recently used fluid flow simulations to analyze cavity transfer mixers.…”

Section: Introductionmentioning

confidence: 99%

Finite Element Modeling of a Viscous Fluid Flowing through an External Gear Pump

Bie

Hulsen

Anderson

2020

Macro Theory & Simulations

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Gear pumps are frequently used for the transport of high‐viscosity fluids, for instance, for the extrusion of polymers. The flow rate of this extrusion process is regularly controlled by an external gear pump. In this work, the 2D flow of a viscous fluid through such an external gear pump is studied using the finite element method. Local mesh refinement based on the respective distance between moving boundaries is essential to capture the relatively narrow clearances in the pump. The gear pump works against the pressure driven flow, therefore its performance is strongly dependent on material and processing parameters. The flow of Newtonian and shear‐thinning fluids through the external gear pump is studied for a range of processing conditions. Pump curves are obtained that display the volumetric efficiency against the Hersey number, which is defined as viscosity times rotation speed divided by pressure difference over the pump. Analysis of the residence time of the fluid in the pump, shows that vortices are present in the inflow channel causing material to remain in the pump for longer times.

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“…In the simulation, the flow was assumed to be fully developed at the outlet . No slip condition was imposed on the screw and barrel surface .…”

Section: Numerical Simulationmentioning

confidence: 99%

3‐D numerical simulations for polycondensation of poly(p‐phenylene terephthalamide) in twin screw extruder

Zong

Tang

Zhao

2017

Polymer Engineering & Sci

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Poly(p-phenylene terephthalamide) (PPTA) is a typical high-performance fiber and usually synthesized by low temperature solution polycondensation in twin screw extruder. During the reactive extrusion, flow behavior, rheokinetics, and temperature are highly coupled, which makes it difficult to ensure the quality of product. In the present work, the rheokinetics of the PPTA solution is established by experiments and its reactive extrusion is investigated via 3-D numerical simulation. The flow pattern, molecular weight distribution and temperature have been investigated for the extruders with three different elements, i.e., full flight screw (FF), kneading block (KB), and screw mixing element (SME). The results indicate that the unique flow characteristic of different screw elements affects mixing experience of the reactants and further the PPTA qualities. By numerical simulation, it shows the temperature increase within the tested extrusion stage is 7 K and reaction heat is found the main energy source for extrusion stage. Furthermore, heat removal method is verified with consideration of industrial production process. The numerical simulation work also discusses the reaction and mixing process in the extruders with three combined screws. The results show the introduction of more reverse FF and KB elements can lead to higher quality of FIG. 2. Rheokinetics of PPTA during polycondensation: (a) effect of shear rate on viscosity. (b) Effect of M w on consistency index. [Color figure can be viewed at wileyonlinelibrary.com]

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Non‐Isothermal Modeling of a Non‐Newtonian Fluid Flow in a Twin Screw Extruder Using the Fictitious Domain Method

Cited by 20 publications

References 33 publications

Co-rotating twin-screw extruders: Detailed analysis of conveying elements based on smoothed particle hydrodynamics. Part 1: Hydrodynamics

Co-rotating twin-screw extruders: Detailed analysis of conveying elements based on smoothed particle hydrodynamics. Part 1: Hydrodynamics

Finite Element Modeling of a Viscous Fluid Flowing through an External Gear Pump

3‐D numerical simulations for polycondensation of poly(p‐phenylene terephthalamide) in twin screw extruder

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