Documents disponibles écrits par cet auteur

Novel features of aerosol coagulation in nonisothermal environments / Daniel E. Rosner 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. 8932–8940 Titre : Novel features of aerosol coagulation in nonisothermal environments Type de document : texte imprimé Auteurs : Daniel E. Rosner, Auteur ; Manuel Arias-Zugasti, Auteur Année de publication : 2011 Article en page(s) : pp. 8932–8940 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Aerosol  coagulation Résumé : Local supersaturations and the rapid homogeneous nucleation of often subcooled nanometric particles occur when vapors from a high-temperature source diffuse into adjacent regions of much lower temperature. While earlier experimental and theoretical studies were focused on the macroscopic mass transfer rate consequences of such localized condensation (Turkdogan and Mills (1964), Epstein and Rosner (1970)), we identify and describe here, from a broader perspective, several expected novel features of aerosol coagulation dynamics in nonisothermal environments, including the expected particle size “spectra”. In the simplest (limiting) case, differential thermal particle drift down the local temperature gradient dominates the Brownian diffusion-controlled collision rate, and, for a population of thermally conductive mist droplets coagulating by this mechanism, we have calculated and displayed (e.g., Rosner, D. E.; Arias-Zugasti, M. Thermophoretically-dominated aerosol coagulation. Phys. Rev. Lett.2011, 106, 015502.) the expected coagulation-aged “self-preserving” droplet size distribution. However, in most applications the more familiar Brownian diffusion contribution to the coagulation rate must also be included, and we summarize here our recent analysis of this combined case, which enables another test of the frequently made assumption of “additive rate constants” and leads to quasi-self-preserving droplet size distributions. Because fully miscible mist droplets may also be distributed with respect to composition (and, hence, thermal conductivity) we take this opportunity to outline how these, and more general phoretic mechanisms (including thermocapillary flow), can be incorporated into the present formulation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102444e [article] Novel features of aerosol coagulation in nonisothermal environments [texte imprimé] / Daniel E. Rosner, Auteur ; Manuel Arias-Zugasti, Auteur . - 2011 . - pp. 8932–8940. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 8932–8940 Mots-clés : Aerosol  coagulation Résumé : Local supersaturations and the rapid homogeneous nucleation of often subcooled nanometric particles occur when vapors from a high-temperature source diffuse into adjacent regions of much lower temperature. While earlier experimental and theoretical studies were focused on the macroscopic mass transfer rate consequences of such localized condensation (Turkdogan and Mills (1964), Epstein and Rosner (1970)), we identify and describe here, from a broader perspective, several expected novel features of aerosol coagulation dynamics in nonisothermal environments, including the expected particle size “spectra”. In the simplest (limiting) case, differential thermal particle drift down the local temperature gradient dominates the Brownian diffusion-controlled collision rate, and, for a population of thermally conductive mist droplets coagulating by this mechanism, we have calculated and displayed (e.g., Rosner, D. E.; Arias-Zugasti, M. Thermophoretically-dominated aerosol coagulation. Phys. Rev. Lett.2011, 106, 015502.) the expected coagulation-aged “self-preserving” droplet size distribution. However, in most applications the more familiar Brownian diffusion contribution to the coagulation rate must also be included, and we summarize here our recent analysis of this combined case, which enables another test of the frequently made assumption of “additive rate constants” and leads to quasi-self-preserving droplet size distributions. Because fully miscible mist droplets may also be distributed with respect to composition (and, hence, thermal conductivity) we take this opportunity to outline how these, and more general phoretic mechanisms (including thermocapillary flow), can be incorporated into the present formulation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102444e

Spray combustor design/performance / Daniel E. Rosner in Industrial & engineering chemistry research, Vol. 48 N° 14 (Juillet 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 14 (Juillet 2009) . - pp. 6453–6464 Titre : Spray combustor design/performance : chemical engineering contributions and the emergence of an “interacting population-balance” perspective Type de document : texte imprimé Auteurs : Daniel E. Rosner, Auteur Année de publication : 2009 Article en page(s) : pp. 6453–6464 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Spray  combustors  Chemical  engineering  contributions Résumé : Spray combustors are now widely used in many technologies, spanning commodity chemical synthesis (combustion of molten sulfur en route to sulfuric acid (H2SO4) and phosphorus en route to phosphoric acid (H3PO4), ...), and nanoparticle synthesis (eg., via “spray pyrolysis”), to energy conversion (oil-fired furnaces or boilers) and chemical propulsion (aircraft gas turbines and liquid-propellant rocket motors). While important space, weight, and pollutant constraints inevitably differ from application to application, spray-“fuel”-fed combustors share certain common performance characteristics, and there is a considerable economic incentive to develop rational yet tractable design methods for them. While this intrinsically interdisciplinary subject continues to evolve, here, we briefly review some of the principal contributions to these challenging goals published by chemical engineers since the inception of Industrial and Engineering Chemistry (I&EC). Not surprisingly, the earliest contributions focused on some of the important “unit processes” (e.g., isolated droplet evaporation rates, vapor micromixing rates in spatially homogeneous turbulent flows, and steady vapor-phase laminar diffusion flames). Chemical engineers introduced “continuous mixture theory” to economically address not only phase/chemical equilibria in multicomponent mixtures, but also spatially nonuniform (nonequilibrium) flows. More-recent studies have introduced diffusion “flamelet” concepts for vapor-phase nonpremixed combustion and statistical population-balance concepts to address evolving turbulence characteristics and/or droplet size distributions. Because of the wide range of operative (length and time) scales in the full problem, in the foreseeable future, clever asymptotic methods will continue to be required to capture the essential physicochemical phenomena but still make the associated numerical simulations manageable. In this regard, a fruitful unified perspective is now emerging—one quite natural to chemical engineers. This can perhaps be best described as an interacting “multi-phase, multi-environment” approach—or simply an “interacting multivariable population balance” approach. While much remains to be done, it is hoped that this 2008/2009 perspective, and highly selective “review” of but one class of multiphase chemical reactors, will stimulate further activity along this promising path. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900167h [article] Spray combustor design/performance : chemical engineering contributions and the emergence of an “interacting population-balance” perspective [texte imprimé] / Daniel E. Rosner, Auteur . - 2009 . - pp. 6453–6464. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 14 (Juillet 2009) . - pp. 6453–6464 Mots-clés : Spray  combustors  Chemical  engineering  contributions Résumé : Spray combustors are now widely used in many technologies, spanning commodity chemical synthesis (combustion of molten sulfur en route to sulfuric acid (H2SO4) and phosphorus en route to phosphoric acid (H3PO4), ...), and nanoparticle synthesis (eg., via “spray pyrolysis”), to energy conversion (oil-fired furnaces or boilers) and chemical propulsion (aircraft gas turbines and liquid-propellant rocket motors). While important space, weight, and pollutant constraints inevitably differ from application to application, spray-“fuel”-fed combustors share certain common performance characteristics, and there is a considerable economic incentive to develop rational yet tractable design methods for them. While this intrinsically interdisciplinary subject continues to evolve, here, we briefly review some of the principal contributions to these challenging goals published by chemical engineers since the inception of Industrial and Engineering Chemistry (I&EC). Not surprisingly, the earliest contributions focused on some of the important “unit processes” (e.g., isolated droplet evaporation rates, vapor micromixing rates in spatially homogeneous turbulent flows, and steady vapor-phase laminar diffusion flames). Chemical engineers introduced “continuous mixture theory” to economically address not only phase/chemical equilibria in multicomponent mixtures, but also spatially nonuniform (nonequilibrium) flows. More-recent studies have introduced diffusion “flamelet” concepts for vapor-phase nonpremixed combustion and statistical population-balance concepts to address evolving turbulence characteristics and/or droplet size distributions. Because of the wide range of operative (length and time) scales in the full problem, in the foreseeable future, clever asymptotic methods will continue to be required to capture the essential physicochemical phenomena but still make the associated numerical simulations manageable. In this regard, a fruitful unified perspective is now emerging—one quite natural to chemical engineers. This can perhaps be best described as an interacting “multi-phase, multi-environment” approach—or simply an “interacting multivariable population balance” approach. While much remains to be done, it is hoped that this 2008/2009 perspective, and highly selective “review” of but one class of multiphase chemical reactors, will stimulate further activity along this promising path. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900167h