Fluid dynamic optimization of internal flow in a wind turbine nacelle

The wind turbine design has been always affected by an intensive use of the numerical flow simulation for the optimization of the wings profiles for the maximization of the power generation efficiency. Another design issue in this field is the optimization of the heat exchange on the magnetic polar generator. Due to the environmental condition the heat produced by the magnetic polar generator can be greater than the heat dissipation causing the safety arrest of the wind turbine. The magnetic polar generator is placed in the back side of the ogive that usually is closed. In the present work the numerical fluid dynamics has been adopted for the optimization of the flow to increase the heat exchange on the magnetic polar generator. The first case studied is the ogive geometry with a simple orthogonal section of the front side to guarantee the entrainment of the flow. The numerical experiments have been suggested a modified ogive geometry to avoid ricirculation zones that reduce the cooling air flow rate towards the magnetic polar generator. The innovative geometry of the ogive has multiple channels with helical profile to follow the flow streamlines due to the rotation of the turbine. The mass flow rate with the modified ogive has been increased three times with respect to the simple section.