A novel adaptive blade concept for large-scale wind turbines. Part Ⅱ: Structural design and power performance

摘要

This two-part body of work considers wind turbines that increase annual energy production on account of an enhanced aeroelastic behaviour. In Part Ⅰ, an aerodynamic analysis was performed to identify the theoretically ideal aeroelastic response of a reference blade. By so doing, the distributions of twist that maximise the power yielded at different wind speeds were obtained. Then, noting that the total twist is the sum of pre-twist, elastically-induced twist and pitch angle, a distribution of elastic twist was identified, that adaptively varies the blade's total twist to align with the ideal aeroelastic response, while also providing gust load alleviation capability. In Part Ⅱ, the required elastically-induced twist is analysed from a structural point of view and adapted accordingly. In addition, a blade concept that realises the desired adaptive behaviour is proposed and the increase of power harvested is assessed by a provisional structural design.