Paper presented at the 6th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 30 June - 2 July, 2008.
This paper reports an increase in the heat transfer rate density
by using wrinkled entrance regions in ducts with laminar flow.
The heat transfer rate density is increased by taking advantage
of the presence of relatively isothermal fluid in the entrance
regions. In order to stimulate a more complete thermal
interaction between walls and fluid, the square entrances are
wrinkled on the perimeter, at the one-third and the two-third
positions. The new structure has two degrees of freedom. The
fluid flow through the ducts is forced by the imposed pressure
difference across the duct. Numerical simulations document the
effects of the dimensionless pressure drop on the optimized
configurations and show a fifteen percent enhancement in heat
transfer rate density.