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Effects of particle diameter and position on hydrodynamics around a confined sphere / Suresh Krishnan in Industrial & engineering chemistry research, Vol. 50 N° 23 (Décembre 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13137–13160 Titre : Effects of particle diameter and position on hydrodynamics around a confined sphere Type de document : texte imprimé Auteurs : Suresh Krishnan, Auteur ; Kannan Aravamudan, Auteur Année de publication : 2012 Article en page(s) : pp. 13137–13160 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Hydrodynamics Résumé : The effect of confinement of a sphere within a tube on the hydrodynamics of Newtonian fluid flow around the solid surface is investigated. The ratio of particle diameter to tube diameter (blockage ratio), the ratio of sphere distance from the tube axis to the tube diameter (eccentricity), and the fluid flow rate were the parameters of this study. Computational fluid dynamics (CFD) simulations were carried out to obtain the flow field around the sphere from which the angle of boundary layer separations, as well as drag and lift coefficients, were obtained. The pressure distributions and friction factor along the sphere surface are also reported. To estimate the effect of confinement and eccentricity in position of the particle, with respect to the tube axis, the results are compared with the classical case involving the flow of an unbounded fluid over the sphere. The drag coefficient diminished when the particle was positioned eccentrically with respect to the tube axis at very low particle Reynolds number (Rep). However, the drag coefficient increased with increasing eccentric positions at higher Rep. At eccentric particle positions, boundary layer separation occurred earlier from the upper hemisphere while, depending on the eccentricity, it was delayed or nonexistent in the lower hemisphere. The difference in pressure between the lower and upper hemisphere regions led to incursion of fluid into the upper hemispherical region. Correlations are proposed for the drag and lift coefficients in the range of 0.1≤ Rep ≤ 500 for different possible eccentricities and blockage ratios. The results from this work will be of relevance in applications such as fluidization and aseptic food processing. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2000852 [article] Effects of particle diameter and position on hydrodynamics around a confined sphere [texte imprimé] / Suresh Krishnan, Auteur ; Kannan Aravamudan, Auteur . - 2012 . - pp. 13137–13160. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 13137–13160 Mots-clés : Hydrodynamics Résumé : The effect of confinement of a sphere within a tube on the hydrodynamics of Newtonian fluid flow around the solid surface is investigated. The ratio of particle diameter to tube diameter (blockage ratio), the ratio of sphere distance from the tube axis to the tube diameter (eccentricity), and the fluid flow rate were the parameters of this study. Computational fluid dynamics (CFD) simulations were carried out to obtain the flow field around the sphere from which the angle of boundary layer separations, as well as drag and lift coefficients, were obtained. The pressure distributions and friction factor along the sphere surface are also reported. To estimate the effect of confinement and eccentricity in position of the particle, with respect to the tube axis, the results are compared with the classical case involving the flow of an unbounded fluid over the sphere. The drag coefficient diminished when the particle was positioned eccentrically with respect to the tube axis at very low particle Reynolds number (Rep). However, the drag coefficient increased with increasing eccentric positions at higher Rep. At eccentric particle positions, boundary layer separation occurred earlier from the upper hemisphere while, depending on the eccentricity, it was delayed or nonexistent in the lower hemisphere. The difference in pressure between the lower and upper hemisphere regions led to incursion of fluid into the upper hemispherical region. Correlations are proposed for the drag and lift coefficients in the range of 0.1≤ Rep ≤ 500 for different possible eccentricities and blockage ratios. The results from this work will be of relevance in applications such as fluidization and aseptic food processing. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2000852