Documents disponibles écrits par cet auteur

Dynamic simulation of mixing - limited symmetric and asymmetric patterns in homogeneous autocatalytic reactors / Anwesha Chaudhury 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) . - pp. 10517-10523 Titre : Dynamic simulation of mixing - limited symmetric and asymmetric patterns in homogeneous autocatalytic reactors Type de document : texte imprimé Auteurs : Anwesha Chaudhury, Auteur ; Chakraborty Saikat, Auteur Année de publication : 2011 Article en page(s) : pp. 10517-10523 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Modeling  Reactor  Autocatalysis  Mixing  Dynamic  model Résumé : In this paper, we study the dynamic evolution of mixing-limited patterns in homogeneous autocatalytic reactors. Using a regularized low-dimensional model derived through the spatial averaging of the 3-D convection-diffusion-reaction equation using Liapunov-Schmidt technique of the classical bifurcation theory, we simulate the process of formation of asymmetric patterns that develop from differences in mixing and reaction time scales, and are widely observed in experimental studies. We also perform a detailed parametric analysis in order to quantify the effects of the parameters Pe, p, and Da on the formation, evolution and stability of patterns. Our nonlinear dynamic simulations show that increased transverse mixing limitations in the reactor help excite a broad spectrum of eigen modes that produce patterns of various length scales and axes of symmetry. These patterns coexist and superimpose to generate asymmetric patterns that are more stable than the symmetric ones formed from lower eigen modes. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23447944 [article] Dynamic simulation of mixing - limited symmetric and asymmetric patterns in homogeneous autocatalytic reactors [texte imprimé] / Anwesha Chaudhury, Auteur ; Chakraborty Saikat, Auteur . - 2011 . - pp. 10517-10523. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10517-10523 Mots-clés : Modeling  Reactor  Autocatalysis  Mixing  Dynamic  model Résumé : In this paper, we study the dynamic evolution of mixing-limited patterns in homogeneous autocatalytic reactors. Using a regularized low-dimensional model derived through the spatial averaging of the 3-D convection-diffusion-reaction equation using Liapunov-Schmidt technique of the classical bifurcation theory, we simulate the process of formation of asymmetric patterns that develop from differences in mixing and reaction time scales, and are widely observed in experimental studies. We also perform a detailed parametric analysis in order to quantify the effects of the parameters Pe, p, and Da on the formation, evolution and stability of patterns. Our nonlinear dynamic simulations show that increased transverse mixing limitations in the reactor help excite a broad spectrum of eigen modes that produce patterns of various length scales and axes of symmetry. These patterns coexist and superimpose to generate asymmetric patterns that are more stable than the symmetric ones formed from lower eigen modes. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23447944

Dynamics of mixing-limited pattern formation in nonisothermal homogeneous autocatalytic reactors / Anwesha Chaudhury in Industrial & engineering chemistry research, Vol. 50 N° 8 (Avril 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4335–4344 Titre : Dynamics of mixing-limited pattern formation in nonisothermal homogeneous autocatalytic reactors : a low-dimensional computational analysis Type de document : texte imprimé Auteurs : Anwesha Chaudhury, Auteur ; Saikat Chakraborty, Auteur Année de publication : 2011 Article en page(s) : pp. 4335–4344 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Dynamics  Homogeneous  autocatalytic  reactors Résumé : This work studies the temporal evolution of concentration and temperature patterns in fast, homogeneous, nonisothermal, autocatalytic, adiabatic tubular reactors. Transverse patterns are simulated using a two-dimensional unsteady-state model, called the regularized model, obtained by averaging the 3-D convection−diffusion−reaction equations axially using a Liapunov−Schmidt based averaging technique, followed by regularization. Steady state bifurcation and linear stability analysis show that the patterns emerge from the unstable middle branch of the S-shaped steady state bifurcation diagrams of concentration/temperature versus reactor Damkohler number. This unstable steady state is then slightly perturbed to analyze the evolution dynamics of various symmetric and asymmetric concentration and temperature patterns. Our simulations show how zones with slightly differing concentrations and temperature evolve over time into intensely segregated patterns that slowly diffuse into the homogeneous ignited branch of the steady state curve. Our parametric analysis quantifies the effects of process parameters such as transverse and axial Peclet numbers, Damkohler number, Zeldovich number, and Lewis number on the dynamics and intensity of pattern formation and dissolution. Interesting differences between the mechanics of pattern formation in isothermal and nonisothermal autocatalysis are also discussed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101861x [article] Dynamics of mixing-limited pattern formation in nonisothermal homogeneous autocatalytic reactors : a low-dimensional computational analysis [texte imprimé] / Anwesha Chaudhury, Auteur ; Saikat Chakraborty, Auteur . - 2011 . - pp. 4335–4344. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 8 (Avril 2011) . - pp. 4335–4344 Mots-clés : Dynamics  Homogeneous  autocatalytic  reactors Résumé : This work studies the temporal evolution of concentration and temperature patterns in fast, homogeneous, nonisothermal, autocatalytic, adiabatic tubular reactors. Transverse patterns are simulated using a two-dimensional unsteady-state model, called the regularized model, obtained by averaging the 3-D convection−diffusion−reaction equations axially using a Liapunov−Schmidt based averaging technique, followed by regularization. Steady state bifurcation and linear stability analysis show that the patterns emerge from the unstable middle branch of the S-shaped steady state bifurcation diagrams of concentration/temperature versus reactor Damkohler number. This unstable steady state is then slightly perturbed to analyze the evolution dynamics of various symmetric and asymmetric concentration and temperature patterns. Our simulations show how zones with slightly differing concentrations and temperature evolve over time into intensely segregated patterns that slowly diffuse into the homogeneous ignited branch of the steady state curve. Our parametric analysis quantifies the effects of process parameters such as transverse and axial Peclet numbers, Damkohler number, Zeldovich number, and Lewis number on the dynamics and intensity of pattern formation and dissolution. Interesting differences between the mechanics of pattern formation in isothermal and nonisothermal autocatalysis are also discussed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101861x