MODELING the AVERAGE SHEAR RATE IN A CO‐ROTATING TWIN SCREW EXTRUDER

Mohamed, Ibrahim O.; Ofoli, Robert Y.; Morgan, Ronnie G.

doi:10.1111/j.1745-4530.1990.tb00052.x

Cited by 22 publications

(23 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Yousfi et al observed brittle behavior of the nanofilled polyethylene terephthalate/polyethylene (PET/PE) blends processed in TSE compared to the neat blend as a result of thermal degradation of the clay organomodifier during compounding [11]. Mohamed et al [12], Eise et al [13], and Altomare et al [14] all predicted that screw speed and throughput are the main variables affecting degradation.…”

Section: Introductionmentioning

confidence: 99%

Kinetic and process modeling of thermal and mechanical degradation in ultrahigh speed twin screw extrusion

Farahanchi

Sobkowicz

2017

Polymer Degradation and Stability

View full text Add to dashboard Cite

In this article, a kinetic model is introduced in conjunction with experimental extrusion results to predict the evolution of depolymerization reaction at various operating conditions during ultra-high speed twin screw extrusion (TSE). A commercially available flow simulation software (LUDOVIC ®) was used to calculate thermomechanical flow parameters for various screw profiles. The simulated local material temperature and mechanical shear rate were used as inputs to develop a kinetic model that separately describes the effects of temperature and shear on the extent of degradation reaction due to extruding at very high speeds. The model is validated through comparison with experimental gel permeation chromatography (GPC) results on extruded samples. A good agreement was found between theoretical and experimental results. This validation makes the model practically useful for processing optimization, which is a considerable challenge for realizing compounding benefits in ultra-high speed TSE.

show abstract

Section: Introductionmentioning

confidence: 99%

Kinetic and process modeling of thermal and mechanical degradation in ultrahigh speed twin screw extrusion

Farahanchi

Sobkowicz

2017

Polymer Degradation and Stability

View full text Add to dashboard Cite

show abstract

“…Shear rate in an extruder can be used to evaluate viscous dissipation, which is a source of energy to cook the material in the extruder (Mohamed et al. 1990).…”

Section: Introductionmentioning

confidence: 99%

Average Shear Rate in a Twin‐screw Extruder as a Function of Degree of Fill, Flow Behavior Index, Screw Speed and Screw Configuration

Suparno¹,

Dolan²,

Ng³

et al. 2010

J Food Process Engineering

View full text Add to dashboard Cite

Mixer viscometry assumptions were used to model average shear rate in a co-rotating twin-screw extruder. Screw speed was varied at 50, 100, 200, 300 and 400 rpm in an MPF-19APV twin-screw extruder for Newtonian and non-Newtonian fluids with different flow behavior indices (n). A composite screw configuration was used. Degree of fill was varied from 0.4 to 1.0. Also, for three separate all-one-type screw configurations, screw speed was varied from 50 to 400 rpm to estimate the average shear rate for 30°forwarding paddles, single-lead, and twin-lead screws individually for 1.0°fill. A modified matching viscosity technique was used to estimate average shear rate for all conditions.Average shear rate was modeled as a function of extruder constant (k′), screw speed and an empirical parameter a. The k′ increased as a power-law and a decreased linearly with degree of fill. The k′ ranged from 5.7 to 45.1 s a-1 rev -a and was independent of screw speed and flow behavior index. Alpha increased with n. Average shear rates for the composite screw configuration ranged from 10.5 to 404 s -1 for fluids with flow behavior indexes of 0.24, 0.60 and 0.67, respectively. For the separate screw configurations at fill = 1.0, average shear rate at a constant screw speed was highest for 30 forwarding paddles, followed by single-lead and twin-lead screws. Corresponding PRACTICAL APPLICATIONSPractical applications include providing a convenient method to estimate average shear rate for composite screw configurations under partial-fill conditions. Also, the study provides the basis for follow-up studies where the influence of shear on food product quality and nutritional value can be examined. 962 M. SUPARNO ET AL. AVERAGE SHEAR RATE IN EXTRUDER 963 1 6 10 15 11 100 1 . , e T n 970 M. SUPARNO ET AL.

show abstract

“…A model was presented for estimating the average shear rate in corotating twin-screw extruder [56]. Newtonian and non-Newtonian fluids were used to estimate the average shear rate for three screw configurations of Baker Perkins (MPF-500) twin-screw extruder section with a range of screw speed (100-400 r/min).…”

Section: Food Extruder Heat Transfer Modelingmentioning

confidence: 99%

Engineering Review Food Extrusion Technology and Its Applications

Adekola¹

2016

JFSE

View full text Add to dashboard Cite

An extensive technical review of studies on food extrusion processes which involves forcing mixed food ingredients through a die to produce food snacks has been carried out in this paper. This technical review includes some historical development, food extruder types, extrusion principles and applications, flow simulation and heat transfer modeling in extruders, process parameters and product quality, extruder die and extrudate expansion among others. The research and application of extrusion in food industry was mainly based on the adaptation of plastic extrusion technology which has been in existence for over hundred years. Studies show that twin-screw extruder are more efficient than single-screw extruders because of better mixing and better handling of different combinations of food ingredients. A thorough knowledge of the flow and heat behavior inside an extruder provide an insight into the mechanism of mixing and facilitates estimation of RTD, flow rate, pressure drop, heat transfer mechanism and power consumption. Until recently, very little work has been published on the mechanism of material flow and energy transfer in intermeshing co-rotating extruder mainly due to the complexity of the geometry and the flow behavior. A more recent approach to research in modeling of food extrusion is the 2D or 3D flow modeling using finite element computer package. This research area is gaining recognition in modeling different sections of food extruder. This work also points out some of the achievements and shortcomings of the reviewed works and where necessary, possible solutions are suggested. Areas needing further research have been highlighted. This study will reveal that understanding and application of extrusion technology in developing countries of Asia and Africa are still far from being satisfactory and this work would serve as a good reference material for researchers and operators in food extrusion technology.

show abstract

MODELING the AVERAGE SHEAR RATE IN A CO‐ROTATING TWIN SCREW EXTRUDER

Cited by 22 publications

References 8 publications

Kinetic and process modeling of thermal and mechanical degradation in ultrahigh speed twin screw extrusion

Kinetic and process modeling of thermal and mechanical degradation in ultrahigh speed twin screw extrusion

Average Shear Rate in a Twin‐screw Extruder as a Function of Degree of Fill, Flow Behavior Index, Screw Speed and Screw Configuration

Engineering Review Food Extrusion Technology and Its Applications

Contact Info

Product

Resources

About