Definition of a 5MW/61.5m wind turbine blade reference model.

Abstract

A basic structural concept of the blade design that is associated with the frequently utilized "NREL offshore 5-MW baseline wind turbine" is needed for studies involving blade structural design and blade structural design tools. The blade structural design documented in this report represents a concept that meets basic design criteria set forth by IEC standards for the onshore turbine. The design documented in this report is not a fully vetted blade design which is ready for manufacture. The intent of the structural concept described by this report is to provide a good starting point for more detailed and targeted investigations such as blade design optimization, blade design tool verification, blade materials and structures investigations, and blade design standards evaluation. This report documents the information used to create the current model as well as the analyses used to verify that the blade structural performance meets reasonable blade design criteria. 5 CONTENTS

Momentum balance in a fully developed boundary layer over a staggered array of NREL 5MW rotors

“…Geometry and mesh An 'infinitely large' array of NREL 5MW rotors is considered in this paper. The 126m diameter (D) turbine is based on the initial design by NREL [13] and takes into account the modifications suggested by Sandia National Laboratories [14] (i.e. a smoother blade thickness distribution and a smoother root/blade transition compared to the initial design).…”

“…This turbine concept has been widely used [15,16,17]. The tip shape, not included in the reference designs [13,14], is defined as a simple 'rounded' tip and the hub diameter has been increased to 5.4m in this study (to simplify the generation of the structured mesh). The center of the hub is located 90m above the ground which gives a ground clearance of 0.21D.…”

Design of the OffWindChina 5 MW Wind Turbine Rotor

“…Beside the design variables listed in Table 2, other less important distributions are shown in Figure 12, such as the number of UD-glass plies of LEP and TEP, and the thickness of the foam at the leading-(web1) and trailing-edge webs (web2). The weight of the constructed FE blade model is 17,787 kg, which is close to the 17,700 kg of the 61.5 m 5 MW reference wind turbine blade [51]. The maximum out-of-plane tip displacement is 7.0876 m, which nearly reaches the maximum allowable tip deflection of 7.1 m. The Tsai-Wu failure factors, f tsw , are smaller than one.…”

“…Airfoils are modeled with a blunt trailing-edge. The element size is set to be no bigger than 0.1 m [51] in order to adequately capture the structural performance. The mesh near the tip is dense to avoid a large aspect ratio, which can cause numerical difficulties to FEM calculations.…”

Uniform Decomposition and Positive-Gradient Differential Evolution for Multi-Objective Design of Wind Turbine Blade

“…It is important to point out that the determination of the extreme loads acting on the wind turbine, prerequisite for structural design, is a complicated and complex task involved in nonlinear simulations of aero-elastic-hydro-servo interactions in thousands of design load cases. In this study, the extreme loads are evaluated using the FAST [24], which is widely-used software packages for wind turbine dynamic performance analysis, and have been tested and validated by several kinds of wind turbines [25][26][27][28]. The wind class and design load conditions are set in terms of the International Electrotechnical Commission standard IEC 61400-1 [29].…”