Abonnement à la biblothèque: Guest
Portail numérique Bibliothèque numérique eBooks Revues Références et comptes rendus Collections
Computational Thermal Sciences: An International Journal
ESCI SJR: 0.249 SNIP: 0.434 CiteScore™: 1.4

ISSN Imprimer: 1940-2503
ISSN En ligne: 1940-2554

Computational Thermal Sciences: An International Journal

DOI: 10.1615/ComputThermalScien.2015014174
pages 261-282

NUMERICAL INVESTIGATION OF BOUNDARY CONDITION EFFECTS ON LAMINAR NATURAL CONVECTION OF POWER LAW FLUIDS IN SQUARE CROSS-SECTIONAL CYLINDRICAL ANNULAR SPACE WITH DIFFERENTIALLY HEATED VERTICAL WALLS

Sahin Yigit
School of Mechanical and Systems Engineering, Newcastle University, Newcastle-Upon-Tyne, United Kingdom
Joseph Ford
School of Mechanical and Systems Engineering, Newcastle University, Newcastle-Upon-Tyne, United Kingdom
Robert J. Poole
School of Engineering, University of Liverpool, Brownlow Hill, Liverpool, L69 3GH, UK
Nilanjan Chakraborty
School of Mechanical and Systems Engineering, Newcastle University, Newcastle-Upon-Tyne, NE17RU, United Kingdom

RÉSUMÉ

Axisymmetric numerical simulations have been conducted to analyse steady-state convection of power law fluids in square cross-sectional cylindrical annular space with differentially heated vertical walls for nominal Rayleigh number range 103 ≤ Ra ≤ 106, nominal Prandtl number range 102 ≤ Pr ≤ 104, and power law exponent range 0.6 ≤ n ≤ 1.8 for both constant wall temperature (CWT) and constant wall heat flux (CWHF) boundary conditions. It has been shown that the mean Nusselt number based on the inner periphery Nui increases with decreasing (increasing) power law exponent (nominal Rayleigh number) due to strengthening of thermal advection. However, Nui has been found to be insensitive to the change in nominal Prandtl number. It has been demonstrated that Nui decreases with increasing internal cylinder radius (normalized by its height ri /L) before approaching the mean Nusselt number for a square enclosure in the limit at ri /L → ∞. By contrast, the mean Nusselt number normalized by the corresponding Nusselt number for pure conductive transport (i.e., Nui /Nucond) increases with increasing ri /L. It has been found that Nui assumes smaller values for the CWHF boundary condition than in the CWT boundary condition for the same set of values of nominal Rayleigh and Prandtl numbers, and power law exponent for large values of Ra. Detailed physical explanations have been provided for the observed behavior, and correlations for Nut have been proposed based on scaling arguments, which satisfactorily capture the mean Nusselt number obtained from these steady-state simulations.


Articles with similar content:

NATURAL CONVECTION OF POWER-LAW FLUIDS IN RECTANGULAR CROSSSECTIONAL CYLINDRICAL ANNULAR ENCLOSURES WITH DIFFERENTIALLY HEATED VERTICAL WALLS
ICHMT DIGITAL LIBRARY ONLINE, Vol.0, 2017, issue
Osman Turan, Sahin Yigit, Nilanjan Chakraborty
BOUNDARY CONDITION EFFECTS ON NATURAL CONVECTION OF BINGHAM FLUIDS IN A SQUARE ENCLOSURE WITH DIFFERENTIALLY HEATED HORIZONTAL WALLS
Computational Thermal Sciences: An International Journal, Vol.4, 2012, issue 1
Osman Turan, Robert J. Poole, Nilanjan Chakraborty
THE COMPARISION OF THE EFFECTS OF TOP AND BOTTOM WALL HEATING ON MIXED CONVECTION OF YIELD STRESS FLUIDS IN A CYLINDRICAL CONTAINER WITH ROTATING END WALL
ICHMT DIGITAL LIBRARY ONLINE, Vol.0, 2017, issue
Osman Turan, Nilanjan Chakraborty
ASPECT RATIO EFFECTS ON LAMINAR RAYLEIGH-BENARD CONVECTION OF POWER-LAW FLUIDS IN RECTANGULAR ENCLOSURES: A NUMERICAL INVESTIGATION
ICHMT DIGITAL LIBRARY ONLINE, Vol.0, 2015, issue
Sahin Yigit, Robert J. Poole, Nilanjan Chakraborty
EFFECTS OF ASPECT RATIO ON NATURAL CONVECTION OF BINGHAM FLUIDS IN RECTANGULAR ENCLOSURES WITH DIFFERENTIALLY HEATED HORIZONTAL WALLS HEATED FROM BELOW
ICHMT DIGITAL LIBRARY ONLINE, Vol.0, 2014, issue
Sahin Yigit, Robert J. Poole, Nilanjan Chakraborty