Performance Evaluation Simulation for a Water Turbine
A 2D computational fluid dynamics evaluation of the performance of a water Darrieus turbine, composed of three NACA0020 straight blades rotating vertically, has been performed. This evaluation, using the k-ε EARSM and k-ε Standard turbulence models, allowed us to determine which of these two turbulence model better predicts the performance of this turbine. The computational fluid dynamics (CFD) was done four different RPM (125, 150, 190, 220 and 265 rpm) in a closed duct with water flowing at V = 0.67 m/s. A grid analysis for three different grid sizes has been performed to determine the minimum grid size required giving a good and acceptable prediction of the performance of this turbine. The numerical forces results determined by these two turbulence models were used to calculate the torque, power and torque and power coefficients. The numerical and experimental results comparison has shown that the k-ε Standard turbulence model gives a better performance prediction for this Darrieus turbine model for these particular flow velocity.
Keywords - Renewable Energy, Darrieus Turbine, CFD, Torque, Power.