Documents disponibles écrits par cet auteur

Direct simulations of mixing of liquids with density and viscosity differences / J. J. Derksen in Industrial & engineering chemistry research, Vol. 51 N° 19 (Mai 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6948-6957 Titre : Direct simulations of mixing of liquids with density and viscosity differences Type de document : texte imprimé Auteurs : J. J. Derksen, Auteur Année de publication : 2012 Article en page(s) : pp. 6948-6957 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Viscosity  Density  Mixing Résumé : Simulations of flow and scalar transport in stirred tanks operated in transitional and mildly turbulent regimes (Re = 3000―12000) are presented. The moderate Reynolds numbers allow the flow to be simulated directly, without the use of turbulence closure or subgrid-scale models. The Newtonian liquids that are blended have different densities and/or viscosities, and the emphasis is on how these differences affect mixing times. The density difference is characterized by a Richardson number (Ri) that varies in the range of 0―0.5. The kinematic viscosity ratio is between 1 and 4. The results show that mixing times increase steeply with increasing Ri and that changing the tank layout can partly mitigate this effect. The viscosity ratio has a much weaker influence on the mixing time. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25900249 [article] Direct simulations of mixing of liquids with density and viscosity differences [texte imprimé] / J. J. Derksen, Auteur . - 2012 . - pp. 6948-6957. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 19 (Mai 2012) . - pp. 6948-6957 Mots-clés : Viscosity  Density  Mixing Résumé : Simulations of flow and scalar transport in stirred tanks operated in transitional and mildly turbulent regimes (Re = 3000―12000) are presented. The moderate Reynolds numbers allow the flow to be simulated directly, without the use of turbulence closure or subgrid-scale models. The Newtonian liquids that are blended have different densities and/or viscosities, and the emphasis is on how these differences affect mixing times. The density difference is characterized by a Richardson number (Ri) that varies in the range of 0―0.5. The kinematic viscosity ratio is between 1 and 4. The results show that mixing times increase steeply with increasing Ri and that changing the tank layout can partly mitigate this effect. The viscosity ratio has a much weaker influence on the mixing time. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25900249

Potential of Microchannel Flow for Agglomerate Breakage / J. J. Derksen in Industrial & engineering chemistry research, Vol. 49 N° 21 (Novembre 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) Titre : Potential of Microchannel Flow for Agglomerate Breakage Type de document : texte imprimé Auteurs : J. J. Derksen, Auteur ; Dmitry Eskin, Auteur Année de publication : 2011 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Microchannel  flow Résumé : Direct simulations of laminar solid−liquid flow in microchannels with full resolution of the solid−liquid interfaces have been performed. The solids phase consists of simple agglomerates, assembled of monosized, spherical particles. The flow of the interstitial liquid is solved with the lattice-Boltzmann method. Solids and fluid dynamics are two-way coupled. The simulations keep track of the flow-induced forces in the agglomerates. The effects of agglomerate type (doublets, triplets, and quadruplets), solids loading, and channel geometry on (the statistics of the) flow and collision-induced forces has been investigated. By comparing these forces with agglomerate strength, we would be able to assess the potential of microchannels as agglomerate breakage devices. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100442e [article] Potential of Microchannel Flow for Agglomerate Breakage [texte imprimé] / J. J. Derksen, Auteur ; Dmitry Eskin, Auteur . - 2011. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) Mots-clés : Microchannel  flow Résumé : Direct simulations of laminar solid−liquid flow in microchannels with full resolution of the solid−liquid interfaces have been performed. The solids phase consists of simple agglomerates, assembled of monosized, spherical particles. The flow of the interstitial liquid is solved with the lattice-Boltzmann method. Solids and fluid dynamics are two-way coupled. The simulations keep track of the flow-induced forces in the agglomerates. The effects of agglomerate type (doublets, triplets, and quadruplets), solids loading, and channel geometry on (the statistics of the) flow and collision-induced forces has been investigated. By comparing these forces with agglomerate strength, we would be able to assess the potential of microchannels as agglomerate breakage devices. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100442e

Solid particle mobility in agitated bingham liquids / J. J. Derksen in Industrial & engineering chemistry research, Vol. 48 N°4 (Février 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2266–2274 Titre : Solid particle mobility in agitated bingham liquids Type de document : texte imprimé Auteurs : J. J. Derksen, Auteur Année de publication : 2009 Article en page(s) : p. 2266–2274 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Combined  flow  Yield-stress  liquids  Mixing  tank  Lattice-Boltzmann  scheme Résumé : Motivated by applications in oil sands processing, numerical simulations of the combined flow of yield-stress (Bingham) liquids and solid particles in a mixing tank have been performed. The conditions were such that, generally, the flow systems were in a transitional regime, between laminar and developed turbulence. The fluid flow was simulated according to a lattice-Boltzmann scheme, with the yield stress being mimicked as a highly viscous fluid for low deformation rates. Particles were assumed to move under the influence of drag, gravity, and particle−wall and particle−particle collisions. Agitation formed a cavity (active volume) around the impeller, with the rest of the tank being virtually inactive. This mobilized the particles in the cavity. In their ability to suspend and mobilize particles, agitated Bingham liquids behave markedly different from Newtonian liquids. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801296q [article] Solid particle mobility in agitated bingham liquids [texte imprimé] / J. J. Derksen, Auteur . - 2009 . - p. 2266–2274. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2266–2274 Mots-clés : Combined  flow  Yield-stress  liquids  Mixing  tank  Lattice-Boltzmann  scheme Résumé : Motivated by applications in oil sands processing, numerical simulations of the combined flow of yield-stress (Bingham) liquids and solid particles in a mixing tank have been performed. The conditions were such that, generally, the flow systems were in a transitional regime, between laminar and developed turbulence. The fluid flow was simulated according to a lattice-Boltzmann scheme, with the yield stress being mimicked as a highly viscous fluid for low deformation rates. Particles were assumed to move under the influence of drag, gravity, and particle−wall and particle−particle collisions. Agitation formed a cavity (active volume) around the impeller, with the rest of the tank being virtually inactive. This mobilized the particles in the cavity. In their ability to suspend and mobilize particles, agitated Bingham liquids behave markedly different from Newtonian liquids. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801296q

Solid particle mobility in agitated bingham liquids / J. J. Derksen in Industrial & engineering chemistry research, Vol. 48 N°4 (Février 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2266–2274 Titre : Solid particle mobility in agitated bingham liquids Type de document : texte imprimé Auteurs : J. J. Derksen, Auteur Année de publication : 2009 Article en page(s) : p. 2266–2274 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Combined  flow  Yield-stress  liquids  Mixing  tank  Lattice-Boltzmann  scheme Résumé : Motivated by applications in oil sands processing, numerical simulations of the combined flow of yield-stress (Bingham) liquids and solid particles in a mixing tank have been performed. The conditions were such that, generally, the flow systems were in a transitional regime, between laminar and developed turbulence. The fluid flow was simulated according to a lattice-Boltzmann scheme, with the yield stress being mimicked as a highly viscous fluid for low deformation rates. Particles were assumed to move under the influence of drag, gravity, and particle−wall and particle−particle collisions. Agitation formed a cavity (active volume) around the impeller, with the rest of the tank being virtually inactive. This mobilized the particles in the cavity. In their ability to suspend and mobilize particles, agitated Bingham liquids behave markedly different from Newtonian liquids. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801296q [article] Solid particle mobility in agitated bingham liquids [texte imprimé] / J. J. Derksen, Auteur . - 2009 . - p. 2266–2274. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°4 (Février 2009) . - p. 2266–2274 Mots-clés : Combined  flow  Yield-stress  liquids  Mixing  tank  Lattice-Boltzmann  scheme Résumé : Motivated by applications in oil sands processing, numerical simulations of the combined flow of yield-stress (Bingham) liquids and solid particles in a mixing tank have been performed. The conditions were such that, generally, the flow systems were in a transitional regime, between laminar and developed turbulence. The fluid flow was simulated according to a lattice-Boltzmann scheme, with the yield stress being mimicked as a highly viscous fluid for low deformation rates. Particles were assumed to move under the influence of drag, gravity, and particle−wall and particle−particle collisions. Agitation formed a cavity (active volume) around the impeller, with the rest of the tank being virtually inactive. This mobilized the particles in the cavity. In their ability to suspend and mobilize particles, agitated Bingham liquids behave markedly different from Newtonian liquids. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801296q