CFD Modelling of H-Darrieus Vertical Axis Wind Turbine

Abstract

With the progress of time, as fossil fuel is being exhausted, renewable energy resources are getting more attention for their promising impact on the environment and its capability to replenish and sustainability. Wind energy is one of the most important renewable energy sources. A study shows that installed wind capacity increases by more than 30% every year. Design improvement of wind turbines has many parameters to consider for optimization. Experimental analysis is complex and not always feasible. But numerical simulation has the ability to analyze different parameters with less complexity. In this thesis, a 2D CFD simulation of an H-Darrieus vertical axis wind turbine is done. Prior to the simulation, mesh independent and time independent study was done not only to validate the result but also to reduce the computational effort. Sliding Mesh model approach was used for simulation which takes into account the vortices generated by the blades passing upwind on the blades downstream unlike over-simplified Moving Reference Frame (MRF) model. The transition SST model was used as the turbulence model which utilizes the advantages of both k-ε and k-ω models, providing better simulation results. From the simulation results, a Power co-efficient (Cp) vs Tip speed ratio λ curve was obtained and was validated against existing experimental data available in the literature. The knowledge obtained from this thesis can lead to the development of improved 2D simulations and ultimately 3D simulations in the future. This can also be used for design optimization and performance study of wind turbines.