Numerical model of vertical axis wind turbine performance in realistic gusty wind conditions

Abstract

The goal of this study is to implement a numerical strategy to estimate the performance of a Vertical Axis Wind Turbine (VAWT) in response to realistic winds typical of an urban/suburban area over a full year of operation, and to predict the Levelized Cost of Energy (LCOE) produced by that VAWT in comparison to the national electricity price. Wind speed data from sensors located in Oklahoma City were used as input. Three numerical models were implemented, including Computational Fluid Dynamics (CFD), Blade Element Momentum (BEM), and a transient response model based on conservation of angular momentum of the VAWT. Here, CFD is utilized to simulate the flow around an isolated turbine blade in order to obtain the dynamic lift and drag coefficients as a function of azimuth angle, wind speed, and rotational speed. In total, 86 CFD simulations were performed over a range of wind speeds from 3 to 15 m/s and tip speed ratios from 2.5 to 4.5. These results are then used as input to the BEM and transient response models. Results show that the LCOE price for the VAWT is equal to or less than the average national electricity price at four locations where annual average wind speed measures ≥4.3 m/s.