Morphing Blades

This project is funded by the Engineering and Physical Sciences Research Council via the grant EP/V009443/1

The project "Morphing Blades: New-Concept Tidal (and Wind) Turbine Blades for Unsteady Load Mitigation" aims to demonstrate, at model-scale, a novel technology to reduce unsteady-loading for tidal and wind turbines, improving resilience and reliability and decreasing the levelised cost of energy. Within this project we have first demonstrated a new morphing technology based on a passively pitching rigid blade for tidal turbines. We now focus on providing further evidence on the effectiveness of this morphing technology, as well as demonstrating a new morphing concept based on fixed pitch blade with a flexible trailing edge. Furthermore, we aim to demonstrate these two concepts for both wind and tidal energy. 
 
Tidal energy is a promising renewable energy source that can contribute to providing energy security for the UK. The world’s first arrays of tidal turbines have recently been deployed in Scotland, confirming the UK as a world leader in this emerging energy sector. One of the main technical challenges of harvesting energy from tidal currents is the large load fluctuations experienced by the blades. These can result in fatigue failures of the blades and in power fluctuations at the generator, and thus in a lower mean power when load peaks correspond to rated power. The aim of this project is to develop a technology that cancels the unsteady loading at its source, while adding minimal complexity to the turbine, to ensure high resilience and reliability of the overall system. Furthermore, morphing blades might entirely replace active pitch, ensuring high fluid mechanics efficiency while substantially decreasing the system complexity and the costs. 
 
We showed that almost complete cancellation of the torque, or thrust fluctuations is possible through blades that passively and elastically adapt their camber and angle of attack. First, we show that, for a 1 MW turbine operating in shear flow, more than 80\% of the unsteady loading is mitigated by using a rigid blade with a passive pitch mechanism. Secondly, for a blade that is rigid near the leading edge and flexible near the trailing edge, we showed that the unsteady load mitigation is proportional to the ratio between the length of the flexible and rigid parts of the blade. For example, for a blade section where the flexibility is concentrated in a hinge at 3/4 of the chord, the amplitude of the fluctuations is 3/4 of the original amplitude. 
 
The project, whic is funded by the EPSRC (EP/V009443/1), is led by Prof. Ignazio Maria Viola, Dr Eddie McCarthy, Dr Anna Young (University of Bath), and Dr Riccardo Broglia (Centro Nazionale delle Ricerche, Italy), as well as VOILAb members Dr Stefano Gambuzza, Dr Shūji Ōtomo, Dr Yabin Liu, Kuba Frankowski. Together with key tidal and wind energy technology companies such as SIMEC Atlantis Energy, Orbital Marine Power, Nova Innovation, Schottel Hydro, ACT Blades and the Wood Group, we aim to investigate the applicability of morphing blades to different tidal and wind technologies. 
Detached eddy simulation of a tidal turbine (with Riccardo Broglia and Antonio Posa)
Detached eddy simulation of a tidal turbine (with Riccardo Broglia and Antonio Posa)