The friction factor at laminar flow in vertical parallel plate ducts with uniform heat flux has been determined as function of Reynolds number and Rayleigh number using a numerical model. The velocity field and the wall shear stress are modified as compared to forced convection due to buoyancy effects when the Rayleigh number is increased, and for sufficiently large Rayleigh numbers the friction factor becomes increased. The duct height to width ratio has been 10, 20, and 50, and combinations of Reynolds number and Rayleigh number have been chosen in order to study mixed convection situations when the Reynolds number is larger as well as smaller as compared to free convection. The Prandtl number has been set to 0.72 corresponding to e.g. air and to 70 which is typical for e.g. some transformer oils, which are fluids that are frequently applied in buoyancy driven cooling applications.
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2010 14th International Heat Transfer Conference
August 8–13, 2010
Washington, DC, USA
Conference Sponsors:
- Heat Transfer Division
ISBN:
978-0-7918-4942-2
PROCEEDINGS PAPER
Laminar Mixed Convection Pressure Drop in Vertical Ducts
Carl-Olof Olsson
Carl-Olof Olsson
ABB AB, Va¨stera˚s, Sweden
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Carl-Olof Olsson
ABB AB, Va¨stera˚s, Sweden
Paper No:
IHTC14-22923, pp. 259-267; 9 pages
Published Online:
March 1, 2011
Citation
Olsson, C. "Laminar Mixed Convection Pressure Drop in Vertical Ducts." Proceedings of the 2010 14th International Heat Transfer Conference. 2010 14th International Heat Transfer Conference, Volume 7. Washington, DC, USA. August 8–13, 2010. pp. 259-267. ASME. https://doi.org/10.1115/IHTC14-22923
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