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.

Computer simulation of three-dimensional transport during moistened defatted soy flour processing in the metering section of a single-screw extruder

2000 ◽  
Vol 214 (2) ◽  
pp. 335-349 ◽  
Author(s):  
P S Ghoshdastidar ◽  
G Ghai ◽  
R P Chhabra
Keyword(s):  
Power Law ◽  
Plug Flow ◽  
Three Dimensional ◽  
Soy Flour ◽  
Viscous Drag ◽  
Three Dimensional Model ◽  
Screw Extruder ◽  
Defatted Soy Flour ◽  
Single Screw ◽  
Single Screw Extruder

A quasi-three-dimensional steady state finite-volume-based computer model for a power-law fluid is used to describe the three-dimensional transport during the processing of defatted soy flour with 25, 28 and 33 per cent moisture contents by weight in the metering section of a single-screw extruder. The numerical results have been compared with the earlier experimental results of Fong. The results are found to be reliable only for the highest moisture content dough (33 per cent by weight). The conclusion is that the quasi-three-dimensional model showing a viscous drag flow mechanism using a power-law equation for viscosity may be effectively used for predicting the behaviour of moist doughs during the extrusion process while the same model may not be very reliable for drier doughs which show plug flow behaviour during processing.

Numerical analysis of mixing performance of mixing section in pin-barrel single-screw extruder

2011 ◽  
Vol 31 (1) ◽  
Author(s):  
Jinnan Chen ◽  
Pan Dai ◽  
Hui Yao ◽  
Tung Chan
Keyword(s):  
Numerical Analysis ◽  
Finite Elements ◽  
Flow Field ◽  
Residence Time ◽  
Particle Tracking ◽  
Mixing Efficiency ◽  
Screw Extruder ◽  
Mixing Performance ◽  
Single Screw ◽  
Single Screw Extruder

Abstract Using the finite elements method, numerical simulations of the flow field of a rubber melt in the mixing sections of a conventional full-flight single-screw extruder and a pin-barrel single-screw extruder were carried out. Particle tracking analysis was used to statistically analyze the mixing state of the rubber melt in the mixing section with pin and that without pin. The mixing performance of both types of mixing section was quantitatively evaluated. The results show that the pins partially disorganize the particle trajectories, change the particle moving directions, and enhance the mixing performance. The particle residence time is longer in the mixing section with pins than in the mixing section with no pin, leading to better mixing in the former. The distributive mixing of particles in both types of mixing section was statistically analyzed. The pins increase the efficiency of stretching and the time-averaged efficiency of stretching, and hence the mixing efficiency. However, further increase in the number of pins does not necessarily enhance the mixing performance.

Chaotic mixing analysis of a novel single-screw extruder with a perturbation baffle by the finite-time Lyapunov exponent method

2019 ◽  
Vol 39 (3) ◽  
pp. 287-299 ◽  
Author(s):  
Jian Liu ◽  
Xiangzhe Zhu
Keyword(s):  
Lyapunov Exponent ◽  
Finite Time ◽  
Polymer Processing ◽  
Chaotic Mixing ◽  
Mixing Efficiency ◽  
Screw Extruder ◽  
Screw Channel ◽  
Single Screw ◽  
Single Screw Extruder ◽  
Finite Time Lyapunov Exponent

Abstract The single-screw extruder with a perturbation baffle is a novel piece of equipment for polymer processing, in which the polymer melts undergo complex chaotic mixing. In this paper, from a new Lagrangian perspective, the fluid transporting mechanism in chaotic flow of the unwound screw channel was analyzed based on the finite element method. Firstly, two-dimensional velocity distributions in the unwound screw channel were calculated based on the mesh superposition technique. Fluid particle evolution processes in the extruder were tracked based on the fourth-order Runge-Kutta scheme. The numerical method used in this paper was validated by grid independence and experiments obtained from literature. Moreover, the finite-time Lyapunov exponent (FTLE) and Poincaré sections were adopted to discuss the chaotic mixing in the novel single-screw extruder. The effects of baffle width and height on the manifold structures in the flow dynamic system were analyzed. The results show that the homoclinic point of the manifold structure can give rise to chaotic mixing in the single-screw extruder. The height of the baffle is an important parameter to control the chaotic strength. In a way, increasing the height of the baffle can enlarge the kink scale and increase the stretching and folding actions, which results in the decrease of regular regions and an increase of the mixing efficiency in the single-screw extruder.

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.

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