Unsteady Aeroelastic Coupling Model and Dynamic Response Analysis of Back-swept Blade on Wind Turbines

doi:10.3901/JME.2022.04.174

Abstract

Abstract: The elastic shaft of back-swept blade is separated from the torsion shaft which resulting in the nonlinear deformation of blade structure, three-dimensional flow. It significantly enhances aero-elastic coupling characteristics of rotating blade. In order to accurately analyse the coupling relationship between the structure and aerodynamics of the back-swept blade, the helicoidal wake vortex lift line method combined with the modified B-L dynamic stall model is used to calculate the unsteady aerodynamic load. And, the influence of instantaneous deformation of the stack line on the induction speed is also token into account. To model the structure of blade with nonlinear deformation, the super-element is adopted to discretize the back-swept blade into a multi-body system, and the multi-body recursive formulation is used to conduct the efficient assembly of dynamic equations and numerical solution of the rotating blade. The effectiveness and accuracy of the simulation model are verified by analysing the steady-state response of NREL 5 MW straight blades. Then, the unsteady response of 5 MW back-swept blade with pitch and no pitch is also analysed. Numerical results show that the proposed method can effectively simulate the nonlinear deformation and unsteady aerodynamic characteristics of the back-swept blade and it can provide an effective numerical analysis method for the aerodynamic performance simulation, fatigue load spectrum analysis and structural optimization design of back-swept blade with the load-alleviating function.

Key words: wind turbines, back-swept blade, lift line, B-L model, aeroelastic coupling

CLC Number:

TK83

GUO Kunxiang, XIA Hongjian, LI Deyuan, HUANG Jundong. Unsteady Aeroelastic Coupling Model and Dynamic Response Analysis of Back-swept Blade on Wind Turbines[J]. Journal of Mechanical Engineering, 2022, 58(4): 174-182.

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