Research on the Power Capture and Wake Characteristics of a Wind Turbine Based on a Modified Actuator Line Model

Feifei Xue,Xingxing Han,Chang Xu,Yanqing Shangguan,Zhefei Fen,Tongtong Li,Heping Duan

doi:10.3390/en15010282

Abstract

On a wind farm, the wake has an important impact on the performance of the wind turbines. For example, the wake of an upstream wind turbine affects the blade load and output power of the downstream wind turbine. In this paper, a modified actuator line model with blade tips, root loss, and an airfoil three-dimensional delayed stall was revised. This full-scale modified actuator line model with blades, nacelles, and towers, was combined with a Large Eddy Simulation, and then applied and validated based on an analysis of wind turbine wakes in wind farms. The modified actuator line model was verified using an experimental wind turbine. Subsequently, numerical simulations were conducted on two NREL 5 MW wind turbines with different staggered spacing to study the effect of the staggered spacing on the characteristics of wind turbines. The results show that the output power of the upstream turbine stabilized at 5.9 MW, and the output power of the downstream turbine increased. When the staggered spacing is R and 1.5R, both the power and thrust of the downstream turbine are severely reduced. However, the length of the peaks was significantly longer, which resulted in a long-term unstable power output. As the staggered spacing increased, the velocity in the central near wake of the downstream turbine also increased, and the recovery speed at the threshold of the wake slowed down. The modified actuator line model described herein can be used for the numerical simulation of wakes in wind farms.

Highlights

Wind power is an important renewable energy source with great development and utilization value [1]
The wake characteristics of two National Renewable Energy Laboratory (NREL) 5MW wind turbines (WT-1 and WT-2) with different staggered arrangements ∆y were individually simulated to explore the influence of the upstream wind turbine wake and the working state on the downstream wind turbine output power and wake vortex structure
The thrust coefficient, power coefficient, and wake velocity of the wind turbine were all consistent with the experimental values

Summary

Introduction

Wind power is an important renewable energy source with great development and utilization value [1]. Shen et al [7,8] used an AL/NS-LES coupling model to numerically study the MEXICO experimental wind turbine Their results showed that the model could precisely predict the wake expansion, vortex radius, circulation, and the axial and tangential wind speed distribution of the MEXICO wind turbine. F. Baratchi et al [10] applied a grid-based distribution of the blade elements and used the local chord length as the length scale for the projection factor to modify the standard ALM. Baratchi et al [10] applied a grid-based distribution of the blade elements and used the local chord length as the length scale for the projection factor to modify the standard ALM They studied the influence of the turbulence model on the prediction of the actuator line method

Methods

Results

Conclusion