scholarly journals Numerical Simulation of Polymer Solutions in a Single-Screw Extruder

2019 ◽  
Vol 9 (24) ◽  
pp. 5423
Author(s):  
Aidar Kadyirov ◽  
Rustem Gataullin ◽  
Julia Karaeva
Keyword(s):  
Polymer Solutions ◽  
Three Dimensional ◽  
Extrusion Process ◽  
Working Fluid ◽  
Screw Extruder ◽  
Single Screw ◽  
Single Screw Extruder ◽  
Single Screw Extruders ◽  
Speed Rotation ◽  
Screw Extruders

Single-screw extruders are the most common equipment used for polymer extrusion. The study of the hydrodynamics of a polymer melts flow in the extruder channel is the basis for modeling and understanding the extrusion process. In general form, the extruder includes a straight section with a screw installed in it. In this study, the three-dimensional mathematical modeling of the polymer solutions flow in the metering zone of a single-screw extruder is performed. The influences of the screw geometry (L/D2 = 1…3) on the flow structure and the pressure drop are analyzed under a speed rotation up to 60 rpm. Aqueous solutions of 0.5% polyacrylamide (0.5% PAA) and 1.5% sodium salt of carboxymethyl cellulose (1.5% CMC) are considered as the working fluid.

Plasticating Single-Screw Extrusion

2006 ◽  
Author(s):  
Chang Dae Han
Keyword(s):  
Solid Polymer ◽  
Heat Of Fusion ◽  
Screw Extruder ◽  
Twin Screw Extruders ◽  
Single Screw ◽  
Single Screw Extrusion ◽  
Single Screw Extruder ◽  
Single Screw Extruders ◽  
Twin Screw ◽  
Screw Extruders

There are two types of extruder: (1) single-screw extruders and (2) twin-screw extruders. The single-screw extruder is one of the most important pieces of equipment in the processing of thermoplastic polymers. Accordingly, during the past three decades, many attempts have been made to analyze the performance of single-screw extruders using different degrees of mathematical sophistication (Cox and Fenner 1980; Donovan 1971; Edmondson and Fenner 1975; Elbirli et al. 1983, 1984; Halmos et al. 1978; Han et al. 1991a, 1991b, 1996; Lee and Han 1990; Lindt 1976; Lindt and Elbirli 1985; Shapiro et al. 1976; Tadmor 1966; Tadmor and Klein 1970; Tadmor et al. 1967). There are two types of single-screw extruders: (a) plasticating and (b) melt-conveying. The plasticating single-screw extruder conveys a solid polymer from the feed section to the melting section, where most of the melting (or softening) occurs, and then transports the melted or softened polymer to a shaping device (e.g., dies and molds). The meltconveying extruder does not include a melting section; it simply transports an already softened polymer to a shaping device (e.g., rubber extruder). Single-screw extruders are used for various purposes, such as melting and pumping, compounding with an additive(s) or filler, cooling and mixing, removing residual monomers or solvents in polymer (i.e., polymer devolatilization), and cross-linking reactions. Single-screw extruders are simple to operate and relatively inexpensive as compared with twin-screw extruders. However, there are situations where a single-screw extruder cannot function as effectively as a twin-screw extruder. In the design of plasticating single-screw extruders, one needs information on (1) the physical and thermal properties of polymers (e.g., friction coefficient between the solid polymer and barrel wall, thermal conductivity of polymer, specific heat as a function of temperature, melting point of polymer, and heat of fusion of polymer) and (2) rheological properties of polymers as functions of shear rate and temperature. Due to the complexity involved in the design of extruders, it is highly desirable for one to establish relationships between material variables and processing variables.

Investigation of Mixing Performance in the Extruder with Embedded Planetary-Screws

2013 ◽  
Vol 781-784 ◽  
pp. 2809-2816
Author(s):  
Liang He ◽  
Bai Ping Xu ◽  
Hui Wen Yu ◽  
Xiao Long Wang ◽  
Gang Xue
Keyword(s):  
The Novel ◽  
Screw Extruder ◽  
Mixing Performance ◽  
Single Screw ◽  
Single Screw Extruder ◽  
Laminar Mixing ◽  
Single Screw Extruders ◽  
Twin Screw ◽  
Screw Extruders

The novel geometrical configuration of embedded planetary-screws is proposed in the paper. The corresponding numerical simulation and the experimental investigation are carried out to characterize the mixing performance. Adopting commercial software FLUENT, the simplified physical model is presented with the boundary conditions imposed by UDF codes which are developed by us. Compared with the traditional single screw extruder, the flow and mixing are primarily investigated by using particle tracking technology. The sensitivity to initial positions is found in the novel screw configuration, which is caused by the periodic perturbation of planetary-screws. In contrast, the traditional laminar mixing occurs in single screw extruders. Compared with the traditional twin screw extruder, the experimental characterization of filled system of adding active nanometer CaCO3 into LLDPE matrix is conducted. No obvious difference in dispersion of CaCO3 is found when the extrusion samples are observed through scanning electron microscopy (SEM), on the condition that the both extrusion outputs are equal. The shear rate in the novel screw configuration is relatively smaller, and the extrusion characteristic is more excellent.

The Impact of Different Screw Edge Width on Extrusion Quality of the Single-Screw Extruder

2014 ◽  
Vol 926-930 ◽  
pp. 833-837
Author(s):  
Yuan Lou Gao ◽  
Xin Wang ◽  
Li Zhou
Keyword(s):  
Extrusion Process ◽  
Phase Flow ◽  
Screw Extruder ◽  
Single Screw ◽  
Single Screw Extruder ◽  
Multi Phase Flow ◽  
Multi Phase ◽  
The Impact ◽  
Screw Extruders

The screw edge width is usually selected based on experience when designing screw extruders, and it is difficult to get the best extrusion quality. The extrusion process of screw extruder is a process of multi-phase flow, which includes gas, liquid and solid. Making it simplified to single-phase flow process can cause relatively large error. This paper adopts the method of multi-phase flow to simulate the extrusion process of single-screw extruder based on different screw edge width by using the finite element analysis software, and get the conclusion that increasing the screw edge width appropriately under the condition that the production efficiency is acceptable is helpful to improve the extrusion quality of single-screw extruders.

Melting of PP/PA6 Polymer Blends in Single Screw Extruders – An Experimental Study

2008 ◽  
Vol 587-588 ◽  
pp. 505-509 ◽  
Author(s):  
S.M. Cunha ◽  
António Gaspar-Cunha ◽  
José A. Covas
Keyword(s):  
Experimental Study ◽  
Polymer Blends ◽  
Polymer Blend ◽  
Screw Extruder ◽  
Immiscible Polymer Blend ◽  
Single Screw ◽  
Single Screw Extruder ◽  
Single Screw Extruders ◽  
Melting Mechanism ◽  
Screw Extruders

A prototype modular single screw extruder fitted with a screw extracting device is used to monitor melting of an immiscible polymer blend (PP/PA6, with different weight ratios) in this widely used processing equipment. As anticipated, the phenomena observed are much more complex than those involved in extruding PP or PA6, when the well known Maddock/Tadmor mechanism is valid. Consequently a hybrid melting mechanism, involving Maddock/Tadmor and Dispersive melting sequences, is proposed.

scholarly journals Characteristics of nanoclay reinforced starch biocomposites through the extrusion process

2018 ◽  
Vol 204 ◽  
pp. 00008
Author(s):  
Heru Suryanto ◽  
Alfian Widi Rahmawan ◽  
Solichin ◽  
Sahana Rizki Tata ◽  
Uun Yanuhar
Keyword(s):  
Tensile Strength ◽  
Functional Group ◽  
Extrusion Process ◽  
Cassava Starch ◽  
Diffraction Peak ◽  
Screw Extruder ◽  
Materials Engineering ◽  
Single Screw ◽  
Single Screw Extruder ◽  
Composite Properties

The development of materials engineering has led to many significant discoveries one of which is biocomposite with its diverse applications. The addition of reinforcing materials in biopolymers improves the composite properties. This study aimed at investigating the effect of adding nanoclay on the tensile strength, morphology, functional group, and structure of extruded biocomposites with cassava starch matrix. This experimental research involved different concentrations of nanoclay i.e. 0%, 2.5%, 5%, 7.5%. The extrusion process was performed using a single screw extruder at 120°C. The samples were characterized by tensile testing, XRD, and SEM. The biocomposite reinforced with 5% nanoclay had the highest tensile strength of 10.8 MPa. The highest diffraction peak at 2θ of 19.4° appeared in the sample added with 5% nanoclay. The addition of excessive amounts of nanoclay can hinder the formation of exfoliated structures.

Analysis of Mixing Efficiency in a Multi-Cut Transfermix

1995 ◽  
Vol 68 (5) ◽  
pp. 773-782 ◽  
Author(s):  
Tao Li ◽  
Hongfei Cheng ◽  
Ica Manas-Zloczower
Keyword(s):  
Three Dimensional ◽  
Mixing Efficiency ◽  
Power Law Model ◽  
Screw Extruder ◽  
Axial Pressure ◽  
Three Dimensional Flow ◽  
Single Screw ◽  
Single Screw Extruder ◽  
Model Fluid ◽  
Constant Output

Abstract Three-dimensional flow patterns of a power-law model fluid in a Multi-Cut Transfermix were calculated. A particle tracking algorithm was used to study the dynamics of mixing. Distributive mixing efficiency was quantified in terms of length stretch distributions and average values. The influence of rotational speed and axial pressure difference on mixing efficiency, under constant output was analyzed. The mixing performances in the MCT was also compared with that in a single screw extruder with the same dimensions as the entrance region of MCT and operating at the same flow rate.

The Effect of Screw Speed on Extrusion Quality of the Single-Screw Extruder

2014 ◽  
Vol 941-944 ◽  
pp. 1715-1719
Author(s):  
Yuan Lou Gao ◽  
Xin Wang ◽  
Li Zhou
Keyword(s):  
Extrusion Process ◽  
Screw Extruder ◽  
Screw Speed ◽  
Element Analysis ◽  
Outlet Pressure ◽  
Single Screw ◽  
Single Screw Extruder ◽  
Multi Phase Flow ◽  
Multi Phase

This paper adopts the method of multi-phase flow to simulate the extrusion process of single-screw extruder based on different screw speed by using the finite element analysis software, and get the conclusion that the screw speed has a significant effect on the extrusion quality and outlet pressure of the single-screw extruder. With the increase of the screw speed, the extrusion quality of the single-screw extruder gets worse and the outlet pressure of the single-screw extruder increases.

Sign in / Sign up

Export Citation Format

Share Document