Structural Design Analysis of a Sustainable Energy Wave Rotor

The growth in the market of ocean energy turbines has lead to the design of a prototype that is able to convert both tidal and wave energy into electrical energy. In this research, a finite element (FE) model of the combined Wells and Darrieus water turbine is developed. This model is verified with strain gauge measurements of the prototype that is running in open sea conditions. The results of the finite element analysis are discussed and used to analyse the performance and the structural design of the prototype. In 2020, an expected 3 GW of ocean energy turbines will be installed worldwide. Several studies have already focused on the conversion of tidal or wave energy into electrical energy. In the beginning of 2009, a unique prototype water turbine called the CEnergyWave Rotor was built and installed in theWesterschelde River, The Netherlands. This vertical axis water turbine is able to convert both tidal and wave energy into electrical energy, using a rotor that consists of Darrieus and Wells blades. The Darrieus blades are powered by tidal currents and waves (water particles that move back and forth), whereas theWells blades are powered by the up and down moving water particles. The Wave Rotor can be attached to offshore wind turbine support structures where it increases the total power production using the same grid. In order to be competitive with other renewable energy systems, cost reduction should be the objective of the design. In this research a hydrodynamic force model is used which is based on the blade element momentum theory and verified with the results of a prototype rotor in laboratory environment. Using this verified model, forces are applied to the developed FE model of the rotor. Strain gauge measurements from the running wave rotor in open sea conditions are then used to verify the correctness of the combination of both theoretical models. After verification, the models are used as a simulation tool to estimate the fatigue life of the rotor blades for different scenarios. It turns out that the combination of the two models gives reliable estimates for the occurring stresses. With this result, the structural design of the Wave Rotor blades can be optimized for any site condition and expected life time.Aerospace EngineeringAerodynamics & Wind EnergySustainable Energy Technolog