A 2‐d numerical study of intermeshing self‐wiping screws in biopolymer extrusion

Lai-Fook, R. A.; Li, Y.; Smith, Andrew C.

doi:10.1002/pen.760311513

Cited by 10 publications

(8 citation statements)

References 25 publications

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“…The presence of moving boundaries in the [6][7][8][9][10][11][12][13][14][15][16] twin screw extruder is ideal for mixing but makes analysis with numerical methods very difficult. When using numerical techniques such as finite differences or finite elements to compute the flow field, the domain of the process must be completely remeshed between time steps -thus requiring large amounts of user interaction to generate several meshes and possibly a supercomputer for the analysis of a complete cycle.…”

mentioning

confidence: 99%

Comparative study of mixing in corotating twin screw extruders using computer simulation

Rios¹,

Gramann²,

Osswald³

1998

Adv. Polym. Technol.

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Twin screw extruders are common for mixing and compounding of different polymers and additives in the production of materials with enhanced properties. However, the flow field and resulting mixing that occur inside these extruders are not well understood. For gaining a better understanding of the flow phenomena that take place during these operations, computer simulation can be used; however, due to the complexity of the moving boundaries in the twin screw extruder this is not an easy task. Using the boundary element method (BEM), which is the method of choice for moving boundary problems, the flow field, pressures, stress, and strains can be computed at every time step. With this information, the quality of mixing can be determined quantitatively and allows the engineer to modify the geometry of the screws for optimal mixing conditions. In this article, the boundary element method is used to analyze and compare mixing effectiveness of various geometries of the twin screw extruder.

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mentioning

confidence: 99%

Comparative study of mixing in corotating twin screw extruders using computer simulation

Rios¹,

Gramann²,

Osswald³

1998

Adv. Polym. Technol.

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“…There have been many efforts directed towards modeling flow, both in individual modules [103][104][105] and in composite modular machines [103,[106][107][108][109]. The latter models can predict fill factor and pressure and temperature profiles along the screws.…”

Section: Co-rotating Twin-screw Extrusionmentioning

confidence: 99%

Polymer Blend Compounding and Processing

White

Bumm

2011

Encyclopedia of Polymer Blends

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Humankind has been mixing together different materials since the dawn of written history to produce products with improved engineering properties. The term Bronze Age (which began around 3000 BC) indicated the blending of tin into copper to improve its mechanical performance. Concrete was also introduced by the ancients with similar purposes in mind.The polymer industry as we know it dates only from the first part of the nineteenth century, where the major industrial polymers aside from wood were natural rubber ( -1,4-polyisoprene) from Brazil, gutta-percha ( -1,4-polyisoprene) from Singapore and Malaya from the 1840s, and natural fibers, including cellulose (cotton, linen) and protein (wool) fibers and leather. Many of the earliest patents involved coating fabrics and leather with natural rubber [1-6]. There was a gradual realization in this period of the usefulness, in terms of improving the properties or rubber, of introducing solid particulates [7-10] or chemicals such as sulfur and its compounds [10-13], which caused vulcanization/crosslinking. It was only with the commercial appearance of gutta-percha in about 1845 [14-17] that there were investigations of polymer blends (gutta-percha with natural rubber). These were reported in patents of C. Hancock [17,18], A. Parkes [13] and W. Brockedon and T. Hancock [19] in 1846. All of these inventors knew each other, Two were brothers (C. Hancock and T. Hancock) and two others (Brockedon and Parkes) were at the time business colleagues of the above T. Hancock. The patents cited above generally cite one or more of the others. This all took place in or near London, England.The mixing processes are usually not critically discussed in these early patents. Brockedon and Hancock [19] indicate they used the single rotor masticating machine discussed in T. Hancocks earlier patents [6,7]. One can conclude by reading their patents that C. Hancock and Parkes used the same or similar machines. Parkes [13] mentioned using rollers, perhaps similar to the machine of Chaffees patent [5]. In addition, significant amounts of solvents derived from coal tar were used. First Edition. Edited by Avraam I. Isayev.

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“…The results are given along the flow direction, although these do not permit the observation of detailed flow patterns which are of great importance to the mixing analysis [45,46]. Two-dimensional models [47,48] provide less restrictive simplifications which can offer a somewhat more precise local information of the flow behaviour in the case of TSE analysis. A more sophisticated numerical approach to the complex geometry of TSE is taken by using the finite element method (FEM) [49].…”

Section: Simulation Approachmentioning

confidence: 99%

Fluid flow aspects of twin-screw extruder process: numerical simulations of TSE rheomixing

Tang

Wrobel

Fan

2003

Modelling Simul. Mater. Sci. Eng.

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This paper presents a brief review of the twin-screw extruder (TSE) process, analyses the fluid flow aspects of a new application of TSE in rheomixing casting, and simulates fundamental micro-mechanisms of the rheological behaviour of metallurgical alloys. The TSE is widely used as a mixing tool in the polymer industry. The numerical simulation of the TSE process is complex and there are only few simulation packages to provide an insight into TSE processing for viscoelastic flows. This study involves the systematic analysis of flow features of immiscible alloys in the TSE rheomixing process, the establishment of a simplified flow field, and simulation of the microstructure of immiscible alloy drops by the piecewise linear interface construction/volumeof-fluid method. It is noted that the microstructure of immiscible alloys is strongly influenced by the viscosity of the system, which dominates the interaction between droplets. The numerical results show good qualitative agreement with experimental results, and are useful for further optimization design of prototypical rheomixing processes.

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A 2‐d numerical study of intermeshing self‐wiping screws in biopolymer extrusion

Cited by 10 publications

References 25 publications

Comparative study of mixing in corotating twin screw extruders using computer simulation

Comparative study of mixing in corotating twin screw extruders using computer simulation

Polymer Blend Compounding and Processing

Fluid flow aspects of twin-screw extruder process: numerical simulations of TSE rheomixing

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