In this paper 3D simulations of four different
horizontal axis wind turbine (HAWT) blade shapes with the same
radius (0.65m) and airfoil profile (NACA4418) are presented.
The first blade shape is optimal twist and tapered (OPT); this
blade is designed using blade element momentum (BEM) theory.
The second is un-tapered and optimal twist (UOT), this blade has
the same twist distribution as the (OPT) but with a constant
chord. The third is tapered un-twisted (TUT), this blade has the
same chord variations as the OPT blade. The fourth is untapered
un-twisted (UUT). The effect of nacelle, shaft and tower
existence on the performance of the four designs has been
investigated also in the present work.
All simulations are performed by using shear stress transport
(SST) k-ω turbulence model. The power coefficient of OPT blade
reach to 0.317 at TSR = 5. Meanwhile, the maximum power
coefficient (Cp=0.3348 at TSR=4) has been recorded in the UOT
blade. The TUT and UUT blade recorded a lower power
coefficient, this is due to their always operations in stall and
turbulence conditions. |
