Documents disponibles écrits par cet auteur

Modeling the turbulent flow of pulp suspensions / Carla A.F. Ventura in Industrial & engineering chemistry research, Vol. 50 N° 16 (Août 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9735-9742 Titre : Modeling the turbulent flow of pulp suspensions Type de document : texte imprimé Auteurs : Carla A.F. Ventura, Auteur ; Fernando A.P. Garcia, Auteur ; Paulo J. Ferreira, Auteur Année de publication : 2011 Article en page(s) : pp. 9735-9742 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Turbulent  flow  Modeling Résumé : Pulp fiber suspensions are complex systems because the components present singular and complex interactions between them. A mechanistic model for the turbulent flow regime of industrial pulp suspensions was developed on the basis of a CFD code, using the chemical engineering module of COMSOL Multiphysics software. The standard k-ε turbulence model, chosen to simulate turbulence, was tested and validated using four different industrial pulp suspensions previously characterized experimentally. The modeled pressure drop profiles agree very well with the experimental results obtained in a pilot rig. Therefore, the k-ε turbulence model for the simulation of pulp fiber suspension flows, associated with experimental rheological data, proved to be a prompt strategy to attain good prediction of pressure drop for fiber suspension flows. Moreover, the adjustment of the turbulence parameters confirmed previous studies, where it was concluded that the existence of particles, such as fibers, in a fluid flow induces a turbulence damping. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425218 [article] Modeling the turbulent flow of pulp suspensions [texte imprimé] / Carla A.F. Ventura, Auteur ; Fernando A.P. Garcia, Auteur ; Paulo J. Ferreira, Auteur . - 2011 . - pp. 9735-9742. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 16 (Août 2011) . - pp. 9735-9742 Mots-clés : Turbulent  flow  Modeling Résumé : Pulp fiber suspensions are complex systems because the components present singular and complex interactions between them. A mechanistic model for the turbulent flow regime of industrial pulp suspensions was developed on the basis of a CFD code, using the chemical engineering module of COMSOL Multiphysics software. The standard k-ε turbulence model, chosen to simulate turbulence, was tested and validated using four different industrial pulp suspensions previously characterized experimentally. The modeled pressure drop profiles agree very well with the experimental results obtained in a pilot rig. Therefore, the k-ε turbulence model for the simulation of pulp fiber suspension flows, associated with experimental rheological data, proved to be a prompt strategy to attain good prediction of pressure drop for fiber suspension flows. Moreover, the adjustment of the turbulence parameters confirmed previous studies, where it was concluded that the existence of particles, such as fibers, in a fluid flow induces a turbulence damping. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24425218

Use of new branched cationic polyacrylamides to improve retention and drainage in papermaking / Elisabete Antunes in Industrial & engineering chemistry research, Vol. 47 N° 23 (Décembre 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 N° 23 (Décembre 2008) . - p. 9370–9375 Titre : Use of new branched cationic polyacrylamides to improve retention and drainage in papermaking Type de document : texte imprimé Auteurs : Elisabete Antunes, Auteur ; Fernando A.P. Garcia, Auteur ; Paulo Ferreira, Auteur Année de publication : 2009 Article en page(s) : p. 9370–9375 Note générale : Chemistry engineering Langues : Anglais (eng) Mots-clés : Polyacrylamides  Improve  retention  Papermaking Résumé : Cationic polyacrylamides of very high molecular weight and with different charge densities and degrees of branching have been investigated as retention aids for papermaking. The effects of polymer charge density and polymer branching on drainage and retention of a suspension containing fibers and precipitated calcium carbonate have been correlated with flocs properties. Additionally, the effects of flocculant dosage and contact time with the furnish were investigated. Results show that polymers of medium charge density are more adequate to be used as retention aids since lower drainage time and higher filler retention are obtained at short contact time and low flocculant dosage. The branched polymers exhibited better performance than the linear polymers: drainage performance is significantly improved because highly branched polymers produce small flocs with a more open structure. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801216t [article] Use of new branched cationic polyacrylamides to improve retention and drainage in papermaking [texte imprimé] / Elisabete Antunes, Auteur ; Fernando A.P. Garcia, Auteur ; Paulo Ferreira, Auteur . - 2009 . - p. 9370–9375. Chemistry engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 N° 23 (Décembre 2008) . - p. 9370–9375 Mots-clés : Polyacrylamides  Improve  retention  Papermaking Résumé : Cationic polyacrylamides of very high molecular weight and with different charge densities and degrees of branching have been investigated as retention aids for papermaking. The effects of polymer charge density and polymer branching on drainage and retention of a suspension containing fibers and precipitated calcium carbonate have been correlated with flocs properties. Additionally, the effects of flocculant dosage and contact time with the furnish were investigated. Results show that polymers of medium charge density are more adequate to be used as retention aids since lower drainage time and higher filler retention are obtained at short contact time and low flocculant dosage. The branched polymers exhibited better performance than the linear polymers: drainage performance is significantly improved because highly branched polymers produce small flocs with a more open structure. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801216t