Documents disponibles écrits par cet auteur

Next - generation modeling of melt blowing / Brent R. Shambaugh in Industrial & engineering chemistry research, Vol. 50 N° 21 (Novembre 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 21 (Novembre 2011) . - pp. 12233-12245 Titre : Next - generation modeling of melt blowing Type de document : texte imprimé Auteurs : Brent R. Shambaugh, Auteur ; Dimitrios V. Papavassiliou, Auteur ; Robert L. Shambaugh, Auteur Année de publication : 2011 Article en page(s) : pp. 12233-12245 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Modeling Résumé : An advanced model has been developed for predicting the behavior of a fiber as it is formed in the melt blowing process. The model involves the simultaneous solution of the momentum, energy, and continuity equations. Crystallization effects are included. The model equations are solved numerically. As a bottom boundary condition in this solution, a "stop point" is assumed. The stop point is the point where (a) the fiber stress is zero, and (b) the air velocity and fiber velocity are equal. Predicted parameters include fiber diameter, velocity, temperature, stress, and crystallinity. The predicted results show that very little online crystallization takes place under typical melt blowing conditions. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24697542 [article] Next - generation modeling of melt blowing [texte imprimé] / Brent R. Shambaugh, Auteur ; Dimitrios V. Papavassiliou, Auteur ; Robert L. Shambaugh, Auteur . - 2011 . - pp. 12233-12245. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 21 (Novembre 2011) . - pp. 12233-12245 Mots-clés : Modeling Résumé : An advanced model has been developed for predicting the behavior of a fiber as it is formed in the melt blowing process. The model involves the simultaneous solution of the momentum, energy, and continuity equations. Crystallization effects are included. The model equations are solved numerically. As a bottom boundary condition in this solution, a "stop point" is assumed. The stop point is the point where (a) the fiber stress is zero, and (b) the air velocity and fiber velocity are equal. Predicted parameters include fiber diameter, velocity, temperature, stress, and crystallinity. The predicted results show that very little online crystallization takes place under typical melt blowing conditions. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24697542

Online measurement of fiber diameter and temperature in the melt-spinning and melt-blowing processes / Vishnu T. Marla in Industrial & engineering chemistry research, Vol. 48 N° 18 (Septembre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 18 (Septembre 2009) . - pp. 8736–8744 Titre : Online measurement of fiber diameter and temperature in the melt-spinning and melt-blowing processes Type de document : texte imprimé Auteurs : Vishnu T. Marla, Auteur ; Robert L. Shambaugh, Auteur ; Dimitrios V. Papavassiliou, Auteur Année de publication : 2010 Article en page(s) : pp. 8736–8744 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Fiber  temperature  Fiber  diameter  Melt-spinning  processe  Melt-blowing  processe Résumé : Online measurements of fiber temperature and diameter were made for both the melt-spinning and the melt-blowing processes. The fiber temperature was determined by infrared thermography, and the fiber diameter was determined by high-speed photography. These measurements were then compared with predictions made with mathematical models for melt spinning and melt blowing. There was good agreement between the models and the experimental results, and the agreement was best when heat-transfer correlations developed specifically for fine fibers (cylinders) were used. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900615n [article] Online measurement of fiber diameter and temperature in the melt-spinning and melt-blowing processes [texte imprimé] / Vishnu T. Marla, Auteur ; Robert L. Shambaugh, Auteur ; Dimitrios V. Papavassiliou, Auteur . - 2010 . - pp. 8736–8744. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 18 (Septembre 2009) . - pp. 8736–8744 Mots-clés : Fiber  temperature  Fiber  diameter  Melt-spinning  processe  Melt-blowing  processe Résumé : Online measurements of fiber temperature and diameter were made for both the melt-spinning and the melt-blowing processes. The fiber temperature was determined by infrared thermography, and the fiber diameter was determined by high-speed photography. These measurements were then compared with predictions made with mathematical models for melt spinning and melt blowing. There was good agreement between the models and the experimental results, and the agreement was best when heat-transfer correlations developed specifically for fine fibers (cylinders) were used. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900615n

Online measurement of fiber diameter and temperature in the melt-spinning and melt-blowing processes / Vishnu T. Marla in Industrial & engineering chemistry research, Vol. 48 N° 18 (Septembre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 18 (Septembre 2009) . - pp. 8736–8744 Titre : Online measurement of fiber diameter and temperature in the melt-spinning and melt-blowing processes Type de document : texte imprimé Auteurs : Vishnu T. Marla, Auteur ; Robert L. Shambaugh, Auteur ; Dimitrios V. Papavassiliou, Auteur Année de publication : 2010 Article en page(s) : pp. 8736–8744 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Fiber  temperature  Fiber  diameter  Melt-spinning  processe  Melt-blowing  processe Résumé : Online measurements of fiber temperature and diameter were made for both the melt-spinning and the melt-blowing processes. The fiber temperature was determined by infrared thermography, and the fiber diameter was determined by high-speed photography. These measurements were then compared with predictions made with mathematical models for melt spinning and melt blowing. There was good agreement between the models and the experimental results, and the agreement was best when heat-transfer correlations developed specifically for fine fibers (cylinders) were used. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900615n [article] Online measurement of fiber diameter and temperature in the melt-spinning and melt-blowing processes [texte imprimé] / Vishnu T. Marla, Auteur ; Robert L. Shambaugh, Auteur ; Dimitrios V. Papavassiliou, Auteur . - 2010 . - pp. 8736–8744. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 18 (Septembre 2009) . - pp. 8736–8744 Mots-clés : Fiber  temperature  Fiber  diameter  Melt-spinning  processe  Melt-blowing  processe Résumé : Online measurements of fiber temperature and diameter were made for both the melt-spinning and the melt-blowing processes. The fiber temperature was determined by infrared thermography, and the fiber diameter was determined by high-speed photography. These measurements were then compared with predictions made with mathematical models for melt spinning and melt blowing. There was good agreement between the models and the experimental results, and the agreement was best when heat-transfer correlations developed specifically for fine fibers (cylinders) were used. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900615n

Online measurement of fiber diameter and temperature in the melt-spinning and melt-blowing processes / Vishnu T. Marla in Industrial & engineering chemistry research, Vol. 48 N° 18 (Septembre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 18 (Septembre 2009) . - pp. 8736–8744 Titre : Online measurement of fiber diameter and temperature in the melt-spinning and melt-blowing processes Type de document : texte imprimé Auteurs : Vishnu T. Marla, Auteur ; Robert L. Shambaugh, Auteur ; Dimitrios V. Papavassiliou, Auteur Année de publication : 2010 Article en page(s) : pp. 8736–8744 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Fiber  temperature  Fiber  diameter  Melt-spinning  processe  Melt-blowing  processe Résumé : Online measurements of fiber temperature and diameter were made for both the melt-spinning and the melt-blowing processes. The fiber temperature was determined by infrared thermography, and the fiber diameter was determined by high-speed photography. These measurements were then compared with predictions made with mathematical models for melt spinning and melt blowing. There was good agreement between the models and the experimental results, and the agreement was best when heat-transfer correlations developed specifically for fine fibers (cylinders) were used. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900615n [article] Online measurement of fiber diameter and temperature in the melt-spinning and melt-blowing processes [texte imprimé] / Vishnu T. Marla, Auteur ; Robert L. Shambaugh, Auteur ; Dimitrios V. Papavassiliou, Auteur . - 2010 . - pp. 8736–8744. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 18 (Septembre 2009) . - pp. 8736–8744 Mots-clés : Fiber  temperature  Fiber  diameter  Melt-spinning  processe  Melt-blowing  processe Résumé : Online measurements of fiber temperature and diameter were made for both the melt-spinning and the melt-blowing processes. The fiber temperature was determined by infrared thermography, and the fiber diameter was determined by high-speed photography. These measurements were then compared with predictions made with mathematical models for melt spinning and melt blowing. There was good agreement between the models and the experimental results, and the agreement was best when heat-transfer correlations developed specifically for fine fibers (cylinders) were used. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900615n

Prediction of the turbulent prandtl number in wall flows with lagrangian simulations / Chiranth Srinivasan in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8881-8891 Titre : Prediction of the turbulent prandtl number in wall flows with lagrangian simulations Type de document : texte imprimé Auteurs : Chiranth Srinivasan, Auteur ; Dimitrios V. Papavassiliou, Auteur Année de publication : 2011 Article en page(s) : pp. 8881-8891 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Prandtl  number  Prediction Résumé : The turbulent Prandtl number (Prt) is an important parameter in modeling turbulent transport, and a lot of effort has been placed in studying its behavior in wall turbulence. This work applied the Churchill model for turbulence scaling to determine the Prt. Two different computational approaches involving a direct numerical simulation in conjunction with Lagrangian techniques were utilized. In the first approach, the local fractions of shear stress and heat flux density, as defined using Churchill's scaling model and determined previously by Le and Papavassiliou [Le, P. M.; Papavassiliou, D. V. On temperature prediction at low Re turbulent flows using the Churchill turbulent heat flux correlation. Int. J. Heat Mass Transfer. 2006, 49, 3681-3690], were used to calculate the Prt. For Poiseuille channel flow, the Prt, at distances far away from the channel walls, was found to have a value between 0.8 and 0.9 irrespective of the molecular Prandtl number, while for plane Couette flow, it was found to be between 0.7 and 1.5. An alternative approach to determining the Pr, is to translate Churchill's physical interpretation of Pr, in a Lagrangian sense. Contributions of turbulent and molecular transport to momentum and heat transfer were calculated to find the local fractions of shear stress and heat flux density. For both Poiseuille channel and Couette flows, the Prt at Pr= 0.1 in regions near the center of the channel was higher than that at higher Pr. For Pr > 0.7, in the case of Poiseuille flow and plane Couette flow, the Prt started from values above 1 decreased and then followed a similar trend to that of the lower molecular Pr. The near-wall Prt increased with increasing Pr for both types of turbulent flow. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395833 [article] Prediction of the turbulent prandtl number in wall flows with lagrangian simulations [texte imprimé] / Chiranth Srinivasan, Auteur ; Dimitrios V. Papavassiliou, Auteur . - 2011 . - pp. 8881-8891. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8881-8891 Mots-clés : Prandtl  number  Prediction Résumé : The turbulent Prandtl number (Prt) is an important parameter in modeling turbulent transport, and a lot of effort has been placed in studying its behavior in wall turbulence. This work applied the Churchill model for turbulence scaling to determine the Prt. Two different computational approaches involving a direct numerical simulation in conjunction with Lagrangian techniques were utilized. In the first approach, the local fractions of shear stress and heat flux density, as defined using Churchill's scaling model and determined previously by Le and Papavassiliou [Le, P. M.; Papavassiliou, D. V. On temperature prediction at low Re turbulent flows using the Churchill turbulent heat flux correlation. Int. J. Heat Mass Transfer. 2006, 49, 3681-3690], were used to calculate the Prt. For Poiseuille channel flow, the Prt, at distances far away from the channel walls, was found to have a value between 0.8 and 0.9 irrespective of the molecular Prandtl number, while for plane Couette flow, it was found to be between 0.7 and 1.5. An alternative approach to determining the Pr, is to translate Churchill's physical interpretation of Pr, in a Lagrangian sense. Contributions of turbulent and molecular transport to momentum and heat transfer were calculated to find the local fractions of shear stress and heat flux density. For both Poiseuille channel and Couette flows, the Prt at Pr= 0.1 in regions near the center of the channel was higher than that at higher Pr. For Pr > 0.7, in the case of Poiseuille flow and plane Couette flow, the Prt started from values above 1 decreased and then followed a similar trend to that of the lower molecular Pr. The near-wall Prt increased with increasing Pr for both types of turbulent flow. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395833

Unsteady state heat transfer from cylinders to air in normal and parallel flow / Vishnu T. Marla in Industrial & engineering chemistry research, Vol. 48 N° 8 (Avril 2009) 

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