Numerical study of forced convection of a power-law fluid in a porous channel
- Stevens Inst. of Technology, Hoboken, NJ (United States). Dept. of Mechanical Engineering
Thermal convection in porous media has been the subject of many recent studies because of its importance in many engineering applications such as geothermal systems, thermal insulation, solid-matrix compact heat exchangers, and packed bed chemical reactors. A detailed numerical study of laminar forced convection in a porous channel saturated with a power-law fluid was performed. Hydrodynamic and heat transfer results are reported for the configuration in which the channel was heated symmetrically at the walls. The flow in the porous medium was modeled using the Brinkman-Forchheimer extended Darcy model. Parametric studies were conducted to evaluate the effects of Darcy number, power law index, and Prandtl number. The results indicate that when the power law index is increased, the velocity gradient near the walls decreases and the fully developed centerline velocity increases. These effects are reduced gradually as the Darcy number decreases until the Darcy regime (Da {le} 10{sup {minus}6}) is reached in which the effects of power law index are negligible. As the power law index is increased, the thermal boundary layer thickness increases and the wall temperature increases but these effects are only important in the non-Darcy regime. Consequently, as the power law index increases, the average Nusselt number decreases significantly in the non-Darcy regime whereas in the Darcy regime the change in Nusselt number is very small. As the Prandtl number increases, the average Nusselt number increases and this effect is more significant for shear-thinning fluids (power law index less than 1.0). As the power law index decreases, the pressure drop decreases suggesting that shear-thinning fluids are more attractive for heat transfer enhancement.
- OSTI ID:
- 435696
- Report Number(s):
- CONF-950828--; ISBN 0-7918-1708-3
- Country of Publication:
- United States
- Language:
- English
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