Laminar boundary layer development around a circular cylinder / A. Alper Ozalp in Journal of heat transfer, Vol. 132 N° 12 (Décembre 2010)  

Public ISBD [article]  inJournal of heat transfer > Vol. 132 N° 12 (Décembre 2010) . - pp. [121703-1/17] Titre : Laminar boundary layer development around a circular cylinder : fluid flow and heat-mass transfer characteristics Type de document : texte imprimé Auteurs : A. Alper Ozalp, Auteur ; Ibrahim Dincer, Auteur Année de publication : 2010 Article en page(s) : pp. [121703-1/17] Note générale : Physique Langues : Anglais (eng) Mots-clés : Heat transfer Fluid flow Mass Confined Friction coefficient Moisture diffusivity Moisure Coefficient Drying Index. décimale : 536 Chaleur. Thermodynamique Résumé : This paper presents a comprehensive computational work on the hydrodynamic, thermal, and mass transfer characteristics of a circular cylinder, subjected to confined flow at the cylinder Reynolds number of Red=40. As the two-dimensional, steady and incompressible momentum and energy equations are solved using ANSYS-CFX (version 11.0), the moisture distributions are computed by a new alternating direction implicit method based software. The significant results, highlighting the influence of blockage (beta=0.200–0.800) on the flow and heat transfer mechanism and clarifying the combined roles of beta and moisture diffusivity (D=1×10−8–1×10−5 m2/s) on the mass transfer behavior, are obtained for practical applications. It is shown that the blockage augments the friction coefficients (Cf) and Nusselt numbers (Nu) on the complete cylinder surface, where the average Nu are evaluated as Nuave=3.66, 4.05, 4.97, and 6.51 for beta=0.200, 0.333, 0.571, and 0.800. Moreover, the blockage shifts separation (thetas) and maximum Cf locations (thetaCf−max) downstream to the positions of thetas=54.10, 50.20, 41.98, and 37.30 deg and thetaCf−max=51.5, 53.4, 74.9, and 85.4 deg. The highest blockage of beta=0.800 encourages the downstream backward velocity values, which as a consequence disturbs the boundary layer and weakens the fluid-solid contact. The center and average moisture contents differ significantly at the beginning of drying process, but in the last 5% of the drying period they vary only by 1.6%. Additionally, higher blockage augments mass transfer coefficients (hm) on the overall cylinder surface; however, the growing rate of back face mass transfer coefficients (hm−bf) is dominant to that of the front face values (hm−ff), with the interpreting ratios of [overline h]m−bf/[overline h]m=0.50 and 0.57 and [overline h]m−ff/[overline h]m=1.50 and 1.43 for beta=0.200 and 0.800. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...] [article] Laminar boundary layer development around a circular cylinder : fluid flow and heat-mass transfer characteristics [texte imprimé] / A. Alper Ozalp, Auteur ; Ibrahim Dincer, Auteur . - 2010 . - pp. [121703-1/17]. Physique Langues : Anglais (eng) in Journal of heat transfer > Vol. 132 N° 12 (Décembre 2010) . - pp. [121703-1/17] Mots-clés : Heat transfer Fluid flow Mass Confined Friction coefficient Moisture diffusivity Moisure Coefficient Drying Index. décimale : 536 Chaleur. Thermodynamique Résumé : This paper presents a comprehensive computational work on the hydrodynamic, thermal, and mass transfer characteristics of a circular cylinder, subjected to confined flow at the cylinder Reynolds number of Red=40. As the two-dimensional, steady and incompressible momentum and energy equations are solved using ANSYS-CFX (version 11.0), the moisture distributions are computed by a new alternating direction implicit method based software. The significant results, highlighting the influence of blockage (beta=0.200–0.800) on the flow and heat transfer mechanism and clarifying the combined roles of beta and moisture diffusivity (D=1×10−8–1×10−5 m2/s) on the mass transfer behavior, are obtained for practical applications. It is shown that the blockage augments the friction coefficients (Cf) and Nusselt numbers (Nu) on the complete cylinder surface, where the average Nu are evaluated as Nuave=3.66, 4.05, 4.97, and 6.51 for beta=0.200, 0.333, 0.571, and 0.800. Moreover, the blockage shifts separation (thetas) and maximum Cf locations (thetaCf−max) downstream to the positions of thetas=54.10, 50.20, 41.98, and 37.30 deg and thetaCf−max=51.5, 53.4, 74.9, and 85.4 deg. The highest blockage of beta=0.800 encourages the downstream backward velocity values, which as a consequence disturbs the boundary layer and weakens the fluid-solid contact. The center and average moisture contents differ significantly at the beginning of drying process, but in the last 5% of the drying period they vary only by 1.6%. Additionally, higher blockage augments mass transfer coefficients (hm) on the overall cylinder surface; however, the growing rate of back face mass transfer coefficients (hm−bf) is dominant to that of the front face values (hm−ff), with the interpreting ratios of [overline h]m−bf/[overline h]m=0.50 and 0.57 and [overline h]m−ff/[overline h]m=1.50 and 1.43 for beta=0.200 and 0.800. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...]

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