Aerodynamics Simulation Method for Swept Wind Turbine Blades Based on Improved Vortex Lattice Method

2016 ◽  
Author(s):  
Guangxing Wu ◽  
Lei Zhang
Keyword(s):  
Wind Turbine ◽  
Vortex Lattice ◽  
Aerodynamic Force ◽  
Turbine Blades ◽  
Simulation Method ◽  
Experimental Results ◽  
Wind Turbine Blades ◽  
Lattice Method ◽  
Correction Model ◽  
Vortex Lattice Method

Recent advances in blade design involve the development of backward swept blades, which can increase energy capture that minimizes an increase in the turbine loads by bend-twist coupling deformation. Most of the aerodynamics simulation modules in aeroelastic analyses are based on Blade Element Momentum Theory, which is limited to straight blades and does not account for sweep. The goal of this work is to develop higher fidelity aerodynamic simulation method for swept wind turbine. The vortex lattice method (VLM) with lower computational cost can consider the effects of spanwise flow, dynamic inflow and wake. A VLM code was obtained and validated for an elliptical planform wing with analytical solutions. Unfortunately, the VLM dose not consider viscous effects such as skin friction and form drag due to inherently assumption of potential flow; therefore, it is limited to be applied to wind turbine blades with thick airfoils. A numerical methodology named viscous correction method (VCM) considering viscosity was developed for predicting the aerodynamic force of wind turbine blades. Experimental results that include viscous terms are brought in the iteration of VLM to modify the vortex strength of all the vortex lattices, so that skin friction and form drag can be included. Lots of wind tunnel experimental results on NREL phase VI rotor with two straight blades have been published, which were chosen to validate the VCM. Good qualitative agreement is obtained between computated and experimental results when VCM is introduced into VLM. To apply VCM to swept blade, it is still high-cost work to conduct lots of experiments on the swept blade strips with different sweep angles and airfoils. Furthermore, one correction model was also developed to compute the aerodynamic force of swept blade from experimental results of straight blade, which is named sweep correction model (SCM). The SCM is obtained by theoretical derivation and validated by CFD method. Finally, the vortex lattice method with VCM and SCM was applied to NREL 5MW rotor with two swept blade designs and baseline blade. The effects of sweep on power and load are minor if the effects of structure deformation are not involved.

scholarly journals Stochastic Model for Aerodynamic Force Dynamics on Wind Turbine Blades in Unsteady Wind Inflow

2015 ◽  
Vol 10 (4) ◽  
Author(s):  
M. R. Luhur ◽  
J. Peinke ◽  
M. Kühn ◽  
M. Wächter
Keyword(s):  
Stochastic Model ◽  
Wind Turbine ◽  
Aerodynamic Force ◽  
Turbine Blades ◽  
Stochastic Approach ◽  
Simulation Software ◽  
Dynamic Stall ◽  
Wind Turbine Blades ◽  
Full Field ◽  
Blade Element

The paper presents a stochastic approach to estimate the aerodynamic forces with local dynamics on wind turbine blades in unsteady wind inflow. This is done by integrating a stochastic model of lift and drag dynamics for an airfoil into the aerodynamic simulation software AeroDyn. The model is added as an alternative to the static table lookup approach in blade element momentum (BEM) wake model used by AeroDyn. The stochastic forces are obtained for a rotor blade element using full field turbulence simulated wind data input and compared with the classical BEM and dynamic stall models for identical conditions. The comparison shows that the stochastic model generates additional extended dynamic response in terms of local force fluctuations. Further, the comparison of statistics between the classical BEM, dynamic stall, and stochastic models' results in terms of their increment probability density functions (PDFs) gives consistent results.

Effects of shallow angle on static strength and fatigue life of multi-directional laminates for wind turbine blades

2016 ◽  
Vol 51 (18) ◽  
pp. 2549-2563 ◽  
Author(s):  
Sung Kyu Ha ◽  
Alvaro Gorostidi Martinez de Lece ◽  
Carlos Donazar Moriones ◽  
Carlos Alberto Cimini Junior ◽  
Chengzhu Jin
Keyword(s):  
Fatigue Life ◽  
Wind Turbine ◽  
Turbine Blades ◽  
Failure Criteria ◽  
Static Strength ◽  
Experimental Results ◽  
Multiscale Approach ◽  
Wind Turbine Blades ◽  
Static Tests ◽  
Angle Effect

The effects of the shallow angle on the static strength and the fatigue life of the multi-directional glass fiber-reinforced plastics for wind turbine blades were presented based on experimental results and predictions. The static tests and the tension–tension fatigue tests under cyclic fatigue loads with a stress ratio of 0.1 were performed on bi-axial (BX, [±θ]), tri-axial 1 (TA, [0/±θ2]), and tri-axial 2 (TX, [02/±θ]) laminates with ply angles θ of 25°, 35°, and 45°. A multiscale approach was applied to predict the static tensile and compressive strengths and the S–N curves of BX, TA, and TX laminates based on the constituents: fiber, matrix, and interface. Three ply-based failure criteria (Hashin, Puck, and Tsai–Wu) were also employed to predict the static strength and compare with the experimental results. The predictions and the experimental results show that the tensile strength increases as θ becomes shallower, while laminates with a shallow ply angle of 35° showed similar or even lower compressive strengths, especially for TA and TX laminates. The laminate fatigue life increases as θ becomes shallower. The shallow angle effect on strength and fatigue life is greater for BX than TA and TX laminates since the ply angle θ plays a more important role in BX. By using the multiscale approach, the shallow angle effect on the laminate static and fatigue behaviors were also explained based on the ply stresses as well as the constitutive micro stresses.

Investigate aerodynamic performance of wind turbine blades with vortex generators at the transition area

2021 ◽  
pp. 0309524X2110385
Author(s):  
Zhou Wu ◽  
Tao Chen ◽  
Haipeng Wang ◽  
Hongwei Shi ◽  
Mingzhou Li
Keyword(s):  
Wind Turbine ◽  
Flow Separation ◽  
Turbine Blades ◽  
Simulation Method ◽  
High Energy ◽  
Aerodynamic Performance ◽  
Vortex Generators ◽  
Geometrical Parameters ◽  
Wind Turbine Blades ◽  
Transition Area

The transition area of the blade had a large relative thickness of airfoil, which was prone to the flow separation. The vortex generators (VGs) could restrain the flow separation. In this paper, the VGs were installed at the transition area of the WindPACT 1.5 MW wind turbine blades. The numerical simulation method was used to investigate the effects of the VGs on the aerodynamic performance of the blade. The high-energy vortexes were generated at the tail by the VG. It could change the energy distribution and flow characteristics of the airflow in the boundary layer. There were influences by the geometric parameters of the VGs. The VGs could change the aerodynamic performance at the transition area of the blade. A satisfactory result was obtained for reasonable geometrical parameters of the VGs. It also could restrain the flow separation of the blade surface and improve the torque.

Fluid-Structure Coupled Analyses of Composite Wind Turbine Blades

2007 ◽  
Vol 26-28 ◽  
pp. 41-44
Author(s):  
Tai Hong Cheng ◽  
Il Kwon Oh
Keyword(s):  
Wind Turbine ◽  
Aerodynamic Force ◽  
Interaction Analysis ◽  
Turbine Blades ◽  
Fluid Structure Interaction ◽  
Rotor Blades ◽  
Arbitrary Lagrangian Eulerian ◽  
Wind Turbine Blades ◽  
Fluid Structure ◽  
Structure Interaction

The composite rotor blades have been widely used as an important part of the wind power generation systems because the strength, stiffness, durability and vibration of composite materials are all excellent. In composite laminated blades, the static and dynamic aeroelasticity tailoring can be performed by controlling laminate angle or stacking sequence. In this paper, the fluid-structure coupled analyses of 10kW wind turbine blades has been performed by means of the full coupling between CFD and CSD based finite element methods. Fiber enforced composites fabricated with three types of stacking sequences were also studied. First the centrifugal force was considered for the nonlinear static analyses of the wind turbine so as to predict the deformation of tip point in the length direction and maximum stress in the root of a wind turbine. And then, the aeroelastic static deformation was taken into account with fluid-structure interaction analysis of the wind turbine. The Arbitrary Lagrangian Eulerian Coordinate was used to compute fluid structure interaction analysis of the wind turbine by using ADINA program. The displacement and stress increased apparently with the increment of aerodynamic force, but under the condition of maximum rotation speed 140RPM of the wind turbine, the displacement and stress were in the range of safety.

Aeroservoelastic state-space vortex lattice modeling and load alleviation of wind turbine blades

Wind Energy ◽  
2014 ◽  
Vol 18 (7) ◽  
pp. 1317-1331 ◽  
Author(s):  
Bing Feng Ng ◽  
Henrik Hesse ◽  
Rafael Palacios ◽  
J.Michael R. Graham ◽  
Eric C. Kerrigan
Keyword(s):  
Wind Turbine ◽  
State Space ◽  
Vortex Lattice ◽  
Turbine Blades ◽  
Wind Turbine Blades
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