Investigation of applying CFD models to 3D wind turbine simulation

Abstract

CFD simulation is becoming a more and more popular tool for analyzing wind turbine performance. This thesis studies the effect of various CFD models on 3D wind turbine simulation by conducting simulations on the NREL PHASE VI wind turbine which is linearly taped and non-linearly twisted. The configuration of NREL PHASE VI in this thesis is 10 meters long in diameter, 𝟎 ° yaw angle, 𝟑 ° pitch angle at the tip and rotating at a constant angular velocity of 72 RPM. An accurate 3D model of NREL Phase VI turbine is created to which various CFD models with different mesh configurations, including structured and unstructured mesh, and turbulence models are applied to study their ability to capture flow behaviors, such as flow separation, and measure flow quantity such as wind turbine torque. Unstructured mesh with SST turbulence model was found to output results which have the best agreement with the experiment results in terms of generated shaft torque and the intensity of flow separation at various wind speed. Intense flow separation at a wind speed of 10m/s was observed in both structured and unstructured mesh model. It was also found that over-prediction of flow separation will lead to the under-prediction of shaft torque for every turbulence model tested in this thesis.