Design of a Boundary-Layer Suction System for Trailing-Edge Noise Reduction of an Industrial Wind Turbine

摘要

Distributed boundary-layer suction has numerically and experimentally shown impressive potential to reduce flow-induced trailing-edge noise, further proven with the transfer of this potential to a generic full-size wind turbine by means of a dedicated suction system design. The present work is meant to point out whether the predicted improvements carry over to industrial turbines represented by the N117, not hitherto in liaison with active flow control. Guidance is given through the different design steps involving the suction-followed blowing of the fluid and being continually dictated by industrial constraints and requirements. Since the processes of trailing-edge noise reduction and effective power alteration are intimately bound together, great emphasis is put on an accurate prediction of pump power requirement, the latter being based on a detailed suction hardware system implying pressure losses across each component. Exploiting the maximum installation space, a total trailing-edge noise reduction of 2 dB is coupled with an enhancement of total rotor power of 1.5 %. As of a cross-over noise reduction level of 2.8 dB, the enhancement of aerodynamic power no longer compensates for the pump power requirement and, hence, aeroacoustic demands are implemented to the detriment of aerodynamic performance. Striving for ac-cessability of the pump, additional pressure losses are introduced slightly weakening the overall potential of the suction system. An in-depth analysis of the associated designs shall reveal the major shares of pump power.