Abstract
Driven by economics-of-scale factors, wind-turbine rotor sizes have increased formidably in recent years. Larger rotors with lighter blades of increased flexibility will experiment substantially higher levels of deformation. Future turbines will also incorporate advanced control strategies to widen the range of wind velocities over which energy is captured. These factors will extend turbine operational regimes, including flow states with high interference factors. In this paper we derive a new empirical relation to both improve and extend the range of Blade Element Momentum (BEM) models, when applied to high interference-factor regimes. In most BEM models, these flow regimes are modeled using empirical relations derived from experimental data. However, an empirical relation that best represents these flow states is still missing. The new relation presented in this paper is based on data from numerical experiments performed on an actuator disk model, and implemented in the context of a novel model of the BEM family called the DRD-BEM (Dynamic Rotor Deformation—BEM), recently introduced in Ponta, et al., 2016. A detailed description of the numerical experiments is presented, followed by DRD-BEM simulation results for the case of the benchmark NREL-5MW Reference Wind Turbine with this new polynomial curve incorporated.
Highlights
As wind energy penetration continues to grow, there is a need to improve both quality and quantity of power being generated by wind turbines [1,2]
In an innovative approach to this problem, flow across sections that have entered these high induction factor regimes, is instead, numerically simulated as flow across an actuator disk using turbulence models. By using such sophisticated Computational Fluid Dynamics (CFD) tools, in this paper, we aim at a better representation of these high-interference flow states, implemented in the context of a novel model of the Blade Element Momentum (BEM) family called the DRD-BEM (Dynamic Rotor Deformation—BEM), recently introduced by Ponta et al [6]
Among the various approaches used to model the aerodynamics of a horizontal axis wind turbine, the stream tube approach known as the Blade element momentum (BEM) theory is the most widely used aerodynamic model
Summary
As wind energy penetration continues to grow, there is a need to improve both quality and quantity of power being generated by wind turbines [1,2]. Energies 2019, 12, 1148 likely undergo greater levels of deformation during operational regimes over a wide range of wind velocities These factors can lead to rotor blade sections operating at flow states characterized by high axial induction factors. In an innovative approach to this problem, flow across sections that have entered these high induction factor regimes, is instead, numerically simulated as flow across an actuator disk using turbulence models By using such sophisticated Computational Fluid Dynamics (CFD) tools, in this paper, we aim at a better representation of these high-interference flow states, implemented in the context of a novel model of the BEM family called the DRD-BEM (Dynamic Rotor Deformation—BEM), recently introduced by Ponta et al [6]. Results will be presented for characteristic scenarios where the turbine enters into flow states with high interference factors
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