Accuracy analysis of SPH for flow in a model extruder with a kneading element

Wittek, Patrick; Pereira, Gerald G.; Emin, M. Azad; Lemiale, Vincent; Cleary, Paul W.

doi:10.1016/j.ces.2018.05.007

Cited by 28 publications

(27 citation statements)

References 31 publications

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“…The calculation of the numerical equations was performed with ANSYS POLYFLOW ® (Version: 2020 R2, Ansys Inc., Canonsburg, PA, USA) , a computational fluid dynamics program that has previously been applied for comparable analyses in extrusion processes, mainly focusing on the screw section [34][35][36][37]50]. The simulated domain was modelled to correspond to the real die section from the extrusion trials as close as possible (a three-dimensional overview can be seen in the Appendix).…”

Section: Numerical Simulationmentioning

confidence: 99%

Morphology Development and Flow Characteristics during High Moisture Extrusion of a Plant-Based Meat Analogue

Wittek

Ellwanger

Karbstein

et al. 2021

Foods

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Plant-based meat analogues that mimic the characteristic structure and texture of meat are becoming increasingly popular. They can be produced by means of high moisture extrusion (HME), in which protein-rich raw materials are subjected to thermomechanical stresses in the extruder at high water content (>40%) and then forced through a cooling die. The cooling die, or generally the die section, is known to have a large influence on the products’ anisotropic structures, which are determined by the morphology of the underlying multi-phase system. However, the morphology development in the process and its relationship with the flow characteristics are not yet well understood and, therefore, investigated in this work. The results show that the underlying multi-phase system is already present in the screw section of the extruder. The morphology development mainly takes place in the tapered transition zone and the non-cooled zone, while the cooled zone only has a minor influence. The cross-sectional contraction and the cooling generate elongational flows and tensile stresses in the die section, whereas the highest tensile stresses are generated in the transition zone and are assumed to be the main factor for structure formation. Cooling also has an influence on the velocity gradients and, therefore, the shear stresses; the highest shear stresses are generated towards the die exit. The results further show that morphology development in the die section is mainly governed by deformation and orientation, while the breakup of phases appears to play a minor role. The size of the dispersed phase, i.e., size of individual particles, is presumably determined in the screw section and then stays the same over the die length. Overall, this study reveals that morphology development and flow characteristics need to be understood and controlled for a successful product design in HME, which, in turn, could be achieved by a targeted design of the extruders die section.

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Section: Numerical Simulationmentioning

confidence: 99%

Morphology Development and Flow Characteristics during High Moisture Extrusion of a Plant-Based Meat Analogue

Wittek

Ellwanger

Karbstein

et al. 2021

Foods

View full text Add to dashboard Cite

show abstract

“…Knowledge of the rheological properties thus helps understand the process and control the product properties [1,15]. Accurate rheological data input is also indispensable for analysis of the flow characteristics using numerical methods (CFD) [16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Analysis of the complex rheological properties of highly concentrated proteins with a closed cavity rheometer

et al. 2020

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Highly concentrated biopolymers are used in food extrusion processing. It is well known that rheo-logical properties of biopolymers influence considerably both process conditions and product properties. Therefore, characterization of rheological properties under extrusion-relevant conditions is crucial to process and product design. Since conventional rheological methods are still lacking for this purpose, a novel approach is presented. A closed cavity rheometer known in the rubber industry was used to systematically characterize a highly concentrated soy protein, a very relevant protein in extruded meat analogues. Rheological properties were first determined and discussed in the linear viscoelastic range (SAOS). Rheo-logical analysis was then carried out in the non-linear viscoelastic range (LAOS), as high deformations in extrusion demand for measurements at process-relevant high strains. The protein showed gel behavior in the linear range, while liquid behavior was observed in the nonlinear range. An expected increase in elasticity through addition of methylcellulose was detected. The measurements in the non-linear range reveal significant changes of material behavior with increasing strain. As another tool for rheological characterization, a stress relaxation test was carried out which confirmed the increase of elastic behavior after methylcellulose addition.

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“…Our approach uses smoothed particle hydrodynamics (SPH), a relatively new numerical method for simulating complex free surface flows occurring inside the rotating screws. SPH is a Lagrangian-based fluid dynamics model, with the fluid flow represented as a continuum of moving fluid parcels that can adjust naturally to the complex intermeshing movement of twin screw extruders without a numerical mesh (88)(89)(90)(91)(92)(93)(94)(95). The Lagrangian nature of the method also allows for a straightforward investigation of the flow in partially filled screw elements, as well as, a detailed investigation of the distributive mixing action of the screw geometry selected.…”

Section: Process Development and Control Process Setup And Scale-up Vmentioning

confidence: 99%

Developing HME-Based Drug Products Using Emerging Science: a Fast-Track Roadmap from Concept to Clinical Batch

et al. 2020

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This paper presents a rational workflow for developing enabling formulations, such as amorphous solid dispersions, via hot-melt extrusion in less than a year. First, our approach to an integrated product and process development framework is described, including state-ofthe-art theoretical concepts, modeling, and experimental characterization described in the literature and developed by us. Next, lab-scale extruder setups are designed (processing conditions and screw design) based on a rational, model-based framework that takes into account the thermal load required, the mixing capabilities, and the thermo-mechanical degradation. The predicted optimal process setup can be validated quickly in the pilot plant. Lastly, a transfer of the process to any GMP-certified manufacturing site can be performed in silico for any extruder based on our validated computational framework. In summary, the proposed workflow massively reduces the risk in product and process development and shortens the drug-to-market time for enabling formulations.

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Accuracy analysis of SPH for flow in a model extruder with a kneading element

Cited by 28 publications

References 31 publications

Morphology Development and Flow Characteristics during High Moisture Extrusion of a Plant-Based Meat Analogue

Morphology Development and Flow Characteristics during High Moisture Extrusion of a Plant-Based Meat Analogue

Analysis of the complex rheological properties of highly concentrated proteins with a closed cavity rheometer

Developing HME-Based Drug Products Using Emerging Science: a Fast-Track Roadmap from Concept to Clinical Batch

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