A New Optimisation Framework for Investigating Wind Turbine Blade Designs

Abstract

We propose a new optimisation framework developed for the investigation of innovative wind turbine blade designs. The design of wind turbines has progressively evolved over recent decades as part of an ongoing effort to provide economically competitive solutions for wind energy production. In particular, rotors have increased in size so as to capture more wind energy while limiting installation costs. At the same time blade designers have had to continually improve the structural efficiency of blades in order to accommodate higher extreme and fatigue loads resulting from growing rotor diameters. Modern wind turbine designs are the result of these incremental improvements, limiting financial risks but also confining the design space and effectively reducing opportunities for more radical innovation. In this paper, we enable the wider exploration of the wind turbine blade design space by means of a new optimisation framework. For that purpose we develop and combine state-of-the-art tools for the aero-servo-elastic analysis and optimisation of wind turbines aiming to explore the uncharted design space resulting from decades of incremental changes. Our framework relies on the use of B-spline surfaces and lamination parameters to provide a compact and continuous means of describing blade structures, also enabling the use of gradient-based optimisers. This structural parameterisation is further combined with beam and shell finite element models to provide further confidence in preliminary structural designs. The proposed framework is presented and verified herein. Validation results show good agreement with the modern large scale DTU 10 MW blade design. Additionally, the coupled bend-twist behaviour of the beam model is found to agree well with higher fidelity finite element model predictions.

Finite Beam Elements for Variable Stiffness Structures

“…We start by generating a benchmark set of displacements and strains obtained with 200 prismatic Euler-Bernoulli beam elements, each with 2 nodes and 1 cross-section. The blade is subjected to a representative force distribution obtained via a static aeroelastic analysis at the turbine rated wind speed [16] . The blade cross-sectional properties, displacements, and strains are presented in Figure 5.…”

Aero-structural design and optimization of 50 MW wind turbine with over 250-m blades

“…Macquart et al (2017) developed a new framework to optimize the blade design, such framework utilized the B-spline surfaces and lamination parameters to describe the blade structure. Their work showed a significant design time reduction by applying an effective gradient-based optimizer, and their method was validated by the DTU 10 MW blade design.…”