Calculation of average residence time in a ko-kneader / Bruno Vergnes in INTERNATIONAL POLYMER PROCESSING, Vol. XXVI, N° 5 (11/2011)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXVI, N° 5 (11/2011) . - p. 587-589 Titre : Calculation of average residence time in a ko-kneader Type de document : texte imprimé Auteurs : Bruno Vergnes, Auteur Année de publication : 2011 Article en page(s) : p. 587-589 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Distribution de temps de séjour Malaxeurs et mélangeurs Mélange Index. décimale : 668.9 Polymères Résumé : We propose in this short note a rapid and efficient way to calculate the average residence time in a ko-kneader. Two experiments are enough to define the two parameters of the model. The proposed expression has been thoroughly validated by comparison with numerous experimental results obtained in various conditions of screw speed, feed rate and screw profile. Note de contenu : - Estimation of average residence time - Experimental validation DOI : 10.3139/217.2528 En ligne : https://drive.google.com/file/d/1rS-2hGOW6poT7Vf3dPPaKFhUKMFJ9nmv/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=12481 [article]

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Dispersive mixing performance evaluation of special rotor segments in an intermeshing co-rotating twin-screw extruder by using weighted probability distributions / S. Yamada in INTERNATIONAL POLYMER PROCESSING, Vol. XXX, N° 4 (08/2015)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXX, N° 4 (08/2015) . - p. 451-459 Titre : Dispersive mixing performance evaluation of special rotor segments in an intermeshing co-rotating twin-screw extruder by using weighted probability distributions Type de document : texte imprimé Auteurs : S. Yamada, Auteur ; K. Fukutani, Auteur ; K. Yamaguchi, Auteur ; H. Funahashi, Auteur ; K. Ebata, Auteur ; Hideyuki Uematsu, Auteur ; S. Tanoue, Auteur Année de publication : 2015 Article en page(s) : p. 451-459 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Alliages polymères Analyse numérique Calcul Distribution de temps de séjour Extrudeuse bi-vis Extrudeuse rotative Matières plastiques -- Extrusion Index. décimale : 668.4 Plastiques, vinyles Résumé : An intermeshing co-rotating twin-screw extruder is widely used for producing polymer composites. In order to satisfy properties of the composites, it is important to understand mixing performance of segments. In this study, we discussed mixing performance of special rotor segments commercially named VCMT (various clearance mixing technology) by using a numerical analysis method. The several tip clearances of VCMT work for achievement of both self-cleaning and effective mixing. We adopted a particle tracking method to obtain the following two evaluation indices; 1) residence time for the evaluation of its uniformity and 2) maximum 1st principal stress for the evaluation of dispersive mixing. And we evaluated mixing performance of VCMT by using probability distributions of each index. Moreover, we proposed weighted probability distributions as theoretically better evaluation. The probability distributions of VCMT were compared with those of two kinds of kneading disk segments (KDs). From the comparison, it was found that the probability of VCMT in large 1st principal stress region is higher than those of KDs. As a conclusion, VCMT has better mixing performance than KDs for the geometries and operating conditions that were investigated. Note de contenu : - ANALYSIS METHOD AND CONDITIONS : Fundamental equations and properties - Analysis conditions - Particle tracking method - Mixing evaluation indices - PREPARATION FOR NUMERICAL ANALYSIS-DETERMINATION OF COMPUTATIONAL MODEL - RESULTS AND DISCUSSION : Characteristics of residence time distribution - Dispersive mixing performance DOI : 10.3139/217.2972 En ligne : https://drive.google.com/file/d/1XgEHKyQAVgA3w-I0u05dph3hj0nadr47/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=24854 [article]

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Experimental flow visualization and residence time distributions in a co-kneader / M. Brito-Bazan in INTERNATIONAL POLYMER PROCESSING, Vol. XXVII, N° 4 (08/2012)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXVII, N° 4 (08/2012) . - p. 414-426 Titre : Experimental flow visualization and residence time distributions in a co-kneader Type de document : texte imprimé Auteurs : M. Brito-Bazan, Auteur ; L. Fradette, Auteur ; P. A. Tanguy, Auteur Année de publication : 2012 Article en page(s) : p. 414-426 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Distribution de temps de séjour Ecoulement visqueux Fluides, Mécanique des Malaxeurs et mélangeurs Mesures optiques Polymères Polyméthacrylate de méthyle Le poly(méthacrylate de méthyle) (souvent abrégé en PMMA, de l'anglais Poly(methyl methacrylate)) est un polymère thermoplastique transparent obtenu par polyaddition dont le monomère est le méthacrylate de méthyle (MMA). Ce polymère est plus connu sous son premier nom commercial de Plexiglas (nom déposé), même si le leader global du PMMA est Altuglas International9 du groupe Arkema, sous le nom commercial Altuglas. Il est également vendu sous les noms commerciaux Lucite, Crystalite, Perspex ou Nudec. Rhéologie Index. décimale : 668.9 Polymères Résumé : Flow patterns and residence time distributions have been investigated in a transparent laboratory-scale Co-Kneader with a viscous fluid and different combinations of operating conditions. An image analysis technique, already successfully applied in stirred tanks, has been applied here for the first time in a continuous system. The flow visualization results are presented as mixing curves, which show quantitatively the evolution of the macromixing along the Co-Kneader. It has been found that the image analysis technique gives new insight into the mixing mechanism of the Co-Kneader and may be used as a simple experimental method to quantify the degree of backmixing. Residence time distributions have been used to obtain axial dispersion coefficients. A comparison of the cumulative distribution functions between different systems is also presented. DOI : 10.3139/217.2470 En ligne : https://drive.google.com/file/d/1QDd_qJo-AG4_adm605j8fU35pRbPAhd8/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=15755 [article]

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Flow visualisation in co-rotating twin screw extruders : positron emission particle tracking and numerical particle trajectories / J. Diemer in INTERNATIONAL POLYMER PROCESSING, Vol. XXVI, N° 5 (11/2011)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXVI, N° 5 (11/2011) . - p. 540-550 Titre : Flow visualisation in co-rotating twin screw extruders : positron emission particle tracking and numerical particle trajectories Type de document : texte imprimé Auteurs : J. Diemer, Auteur ; C. Chilles, Auteur ; J. Colbert, Auteur ; T. Miri, Auteur ; A. Ingram, Auteur ; P. David, Auteur ; A. Sarhangi Fard, Auteur ; P. D. Anderson, Auteur Année de publication : 2011 Article en page(s) : p. 540-550 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Distribution de temps de séjour Eléments finis, Méthode des Extrudeuse bi-vis Fluides, Mécanique des Matières plastiques -- Extrusion Tomographie par émission Index. décimale : 668.4 Plastiques, vinyles Résumé : Co-rotating twin-screw extruders are widely used compounding machines. They are mainly configured based on extensive experience and iterative approaches to optimise output and composite quality. The visualisation technology developed in the EU-project PEPTFlow allows visualisation of composite flow in twin-screw extruders under realistic processing conditions by tracking radioactive tracer particles in the polymer melt, using a specially developed camera system. This new approach allows polymer flow to be studied in different screw elements and screw configurations under realistic compounding conditions at normal temperatures and melt pressures. The paper presents the latest developments in the camera systems as well as the different ways to use and interpret the results. Detailed analysis of residence times and residence time distributions for standard compound screw elements, like kneading discs, conveying elements and reverse elements are presented. In addition for a better understanding of the flow field inside twin-screw extruders, numerical particle tracking is done. The Stokes equation, using XFEM method, are solved and the numerical RTD’s (residence time distribution) are compared for various screw designs. DOI : 10.3139/217.2475 En ligne : https://drive.google.com/file/d/1sX_ReWY3dj2OVw72SnKHLCHwrLL2eT9M/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=12470 [article]

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Residence time distribution in a high shear twin screw extruder / E. Fel in INTERNATIONAL POLYMER PROCESSING, Vol. XXIX, N° 1 (03/2014)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXIX, N° 1 (03/2014) . - p. 71-80 Titre : Residence time distribution in a high shear twin screw extruder Type de document : texte imprimé Auteurs : E. Fel, Auteur ; Valérie Massardier, Auteur ; F. Melis, Auteur ; Bruno Vergnes, Auteur Année de publication : 2014 Article en page(s) : p. 71-80 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cisaillement (mécanique) Distribution de temps de séjour Extrudeuse bi-vis Polypropylène Simulation par ordinateur Index. décimale : 668.4 Plastiques, vinyles Résumé : The residence time distributions (RTD) of a high shear twin screw extruder were measured by an on–line UV fluorescence device. First, by increasing throughput (Q) and screw speed (N), a decrease of the complex viscosity of the studied polypropylene (PP) was observed, revealing chain scissions. It was associated to high viscous dissipation taking place during extrusion, and more particularly under high shear conditions. Then the impact of these experimental conditions on the RTD was carried out. As expected, an increase of usual throughputs and screw speeds decrease mostly the RTD characteristic data. In this study industrial rate have been studied: throughput varied from 1.5 up to 22 kg h?1 and screw speed varied from 200 min?1 up to 1 200 min?1. However, by increasing the screw speed over usual values (from 500 up to 1 200 min?1), the variation of some experimental RTD characteristics were unexpected. Indeed, the slope of the shape of the experimental RTD function E(t) changed significantly. This phenomenon will be called lag or delay time. This result was only observed at low throughputs and high screw rotation speeds. To finish, a modeling software of twin screw extrusion process was used to compare experimental and calculated results. For usual processing conditions (up to 700 min?1), the simulation predicts nicely the experimental RTDs. However, at high screw speed (N > 800 min?1) and moderate throughput (Q = 4 kg h?1), the simulation fails to predict the RDT delay time. Hence, some side effects apparently occurred during high shear extrusion at low throughputs. Note de contenu : - THEORETICAL ASPECTS : Residence time distribution (RTD) - MATERIALS AND METHODS : Material - Twin screw extruder - UV tracer and UV-fluorescence device - Bulk temperature - RESULTS AND DISCUSSION : Experimental results - Simulation from Ludovic software DOI : 10.3139/217.2805 En ligne : https://drive.google.com/file/d/1o_Iuqwuk5vId94nbqcSHDVbikBJ84ssh/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=20577 [article]

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