Vortex Generators for Wind Turbine Blades: A Combined Wind Tunnel and Wind Turbine Parametric Study

2012 ◽  
Author(s):  
Hanns Mueller-Vahl ◽  
Georgios Pechlivanoglou ◽  
C. N. Nayeri ◽  
C. O. Paschereit
Keyword(s):  
Wind Turbine ◽  
Turbine Blades ◽  
Aerodynamic Performance ◽  
Force Balance ◽  
Vortex Generators ◽  
Wind Turbine Blades ◽  
Passive Flow Control ◽  
Flow Control Devices ◽  
Performance Curves ◽  
Stall Angle

Vortex generators (VGs) are passive flow control devices commonly employed to prevent flow separation on wind turbine blades. They mitigate the damaging fatigue loads resulting from stall while increasing lift and consequently lead to rotor torque increase. This work summarizes a research project aimed at optimizing the sectional as well as the full rotor-blade aerodynamics using VGs. The effects of chordwise position, spanwise spacing and VG size were studied with force balance measurements of a 2D wing section. Reducing the distance between adjacent VGs produced large increases in the static stall angle and maximum lift, but also resulted in a significant increase in drag as well as sharp lift excursions at angles exceeding the static stall angle. The optimal chordwise position of the vortex generators was found to be in the range of x/c = 15%–20%, where a comparatively low parasitic drag and a smooth post-stall lift curve were achieved. Particle Image Velocimetry measurements were conducted at various chordwise positions to provide insight into the interaction between adjacent streamwise vortices. The experimental aerodynamic performance curves of the optimal VG configuration were used to project their effect on wind turbine blade aerodynamics. Three different rotorblades were designed and several stall and pitch regulated wind turbine models were simulated by means of a Blade Element Momentum (BEM) code (QBlade) developed by Smart Blade GmbH. The performance of the rotorblades with and without VGs was simulated in order to assess their effect on the aerodynamic performance and loads. Finally, previously measured steady state performance curves under high-roughness conditions were used to simulate the detrimental effect of surface roughness on the performance of the aforementioned rotorblades. This allows for an estimate of the potential of the VGs to be employed as retrofit elements for performance recovery of blades with a contaminated surface.

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.

scholarly journals Experimental study of the effect of a slat on the aerodynamic performance of a thick base airfoil

2021 ◽  
Author(s):  
Axelle Viré ◽  
Bruce LeBlanc ◽  
Julia Steiner ◽  
Nando Timmer
Keyword(s):  
Experimental Study ◽  
Wind Turbine ◽  
Turbine Blades ◽  
Aerodynamic Performance ◽  
Vortex Generators ◽  
Wind Turbine Blades ◽  
Simulation Tools ◽  
Thick Airfoil ◽  
Drag Ratio ◽  
Lift To Drag Ratio

Abstract. There is continuous effort to try and improve the aerodynamic performance of wind turbine blades. This experimental study focusses on the addition of a passive slat on a thick airfoil typically used in the inboard part of commercial wind turbine blades. Nine different slat configurations are considered, with both a clean and tripped main airfoil. The results are compared with the performances of the airfoil without slat, as well as the airfoil equipped with vortex generators. It is found that, when the airfoil is clean, the increase in lift-to-drag ratio due to the presence of a slat is larger than when vortex generators are used. This is also true for the tripped airfoil, but only at small angles of attack. As expected, in all configurations, the presence of the slat delays flow separation and stall. Finally, for a clean airfoil and small angles of attack, the slat decreases the lift-to-drag ratio of the main airfoil only. By contrast, as the angle of attack increases, it seems that the slat changes the flow field around the main airfoil in such a way that its lift-to-drag ratio becomes larger than for the airfoil without slat. These effects are less pronounced when the airfoil is tripped. This work helps to better understand the role of slat in improving the aerodynamics of blade sections. It can also be used to validate simulation tools in the field.

scholarly journals Numerical Simulation of Aerodynamic Performance of Off-grid Small Vertical Axis Wind Turbine

2018 ◽  
Vol 53 ◽  
pp. 02004
Author(s):  
Qiuyun Mo ◽  
Jiabei Yin ◽  
Lin Chen ◽  
Weihao Liu ◽  
Li Jiang ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Turbine Blades ◽  
Vertical Axis ◽  
Aerodynamic Performance ◽  
Velocity Fields ◽  
Compact Model ◽  
Vertical Axis Wind Turbine ◽  
Wind Turbine Blades ◽  
Rotation Domain ◽  
Rng Turbulence Model

In this paper, a 2D off-grid small compact model of vertical axis wind turbine was established. The sliding grid technology, the RNG turbulence model and the Coupld algorithm was applied to simulate the unsteady value of the model's aerodynamic performance. Through the analysis on the flow field at difference moments, the rules about velocity fields, vortices distributions and the wind turbine's total torque were obtained. The results show that: the speed around wind turbine blades have obvious gradient, and the velocity distribution at different times show large differences in the computional domain. In the rotating domain vorticity is large. With away from the rotation domain, vorticity reduced quickly. In the process of rotating for vertical axis wind turbine, the wind turbine's total torque showed alternating positive and negative changes.

Optimization of Aerodynamic Performance of Wind Turbine Blades

2013 ◽  
Vol 284-287 ◽  
pp. 518-522
Author(s):  
Hua Wei Chi ◽  
Pey Shey Wu ◽  
Kami Ru Chen ◽  
Yue Hua Jhuo ◽  
Hung Yun Wu
Keyword(s):  
Power Generation ◽  
Wind Turbine ◽  
Turbine Blades ◽  
Three Dimensional ◽  
Aerodynamic Performance ◽  
Wind Power Generation ◽  
Generation System ◽  
Wind Turbine Blades ◽  
Rotor Design ◽  
Power Generation System

A wind-power generation system uses wind turbine blades to convert the kinetic energy of wind to drive a generator which in turn yields electricity, the aerodynamic performance of the wind turbine blades has decisive effect on the cost benefit of the whole system. The aerodynamic analysis and the optimization of design parameters for the wind turbine blades are key techniques in the early stage of the development of a wind-power generation system. It influences the size selection of connecting mechanisms and the specification of parts in the design steps that follows. A computational procedure and method for aerodynamics optimization was established in this study for three-dimensional blades and the rotor design of a wind turbine. The procedure was applied to improving a previously studied 25kW wind turbine rotor design. Results show that the aerodynamic performance of the new three-dimensional blades has remarkable improvement after optimization.

Wind Tunnel Experimental Study of Wind Turbine Airfoil Aerodynamic Characteristics

2012 ◽  
Vol 260-261 ◽  
pp. 125-129
Author(s):  
Xin Zi Tang ◽  
Xu Zhang ◽  
Rui Tao Peng ◽  
Xiong Wei Liu
Keyword(s):  
Wind Tunnel ◽  
Wind Turbine ◽  
Lift Coefficient ◽  
Turbine Blades ◽  
Aerodynamic Characteristics ◽  
Wind Turbine Blades ◽  
High Lift ◽  
Minimum Drag ◽  
Stall Angle ◽  
High Reynolds

High lift and low drag are desirable for wind turbine blade airfoils. The performance of a high lift airfoil at high Reynolds number (Re) for large wind turbine blades is different from that at low Re number for small wind turbine blades. This paper investigates the performance of a high lift airfoil DU93-W-210 at high Re number in low Re number flows through wind tunnel testing. A series of low speed wind tunnel tests were conducted in a subsonic low turbulence closed return wind tunnel at the Re number from 2×105to 5×105. The results show that the maximum lift, minimum drag and stall angle differ at different Re numbers. Prior to the onset of stall, the lift coefficient increases linearly and the slope of the lift coefficient curve is larger at a higher Re number, the drag coefficient goes up gradually as angle of attack increases for these low Re numbers, meanwhile the stall angle moves from 14° to 12° while the Re number changes from 2×105to 5×105.

Seagull in Wind Turbine Airfoil Blade Design Application Bionic

2013 ◽  
Vol 380-384 ◽  
pp. 4336-4339
Author(s):  
Hua Xin ◽  
Chun Hua Zhang ◽  
Qing Guo Zhang ◽  
Ping Wang
Keyword(s):  
Wind Energy ◽  
Wind Turbine ◽  
Simulation Analysis ◽  
Turbine Blades ◽  
Clean Energy ◽  
Aerodynamic Performance ◽  
Blade Design ◽  
Wind Turbine Blades ◽  
Bionic Blade ◽  
Turbine Blade Design

Wind energy is an inexhaustible, an inexhaustible source of renewable and clean energy. Present due to the energy crisis and environmental protection and other issues, the use of wind more and more world attention. The wind turbine is the best form of wind energy conversion. Wind turbine wind turbine blades to capture wind energy is the core component of the blade in a natural environment to run directly in contact with air, with seagulls wings generate lift conditions are similar, so the gull wings airfoil and excellent conformation, with wind turbine blade design designed by combining the bionic blades. Through numerical simulation analysis found bionic blade aerodynamic performance than the standard blade aerodynamic performance has improved.

scholarly journals Detailed analysis of the blade root flow of a horizontal axis wind turbine

2016 ◽  
Vol 1 (2) ◽  
pp. 89-100 ◽  
Author(s):  
Iván Herráez ◽  
Buşra Akay ◽  
Gerard J. W. van Bussel ◽  
Joachim Peinke ◽  
Bernhard Stoevesandt
Keyword(s):  
Wind Turbine ◽  
Turbine Blades ◽  
Aerodynamic Performance ◽  
Negative Influence ◽  
Navier Stokes ◽  
Wind Turbine Blades ◽  
Force Coefficient ◽  
Horizontal Axis Wind Turbine ◽  
Blade Root ◽  
Root Region

Abstract. The root flow of wind turbine blades is subjected to complex physical mechanisms that influence significantly the rotor aerodynamic performance. Spanwise flows, the Himmelskamp effect, and the formation of the root vortex are examples of interrelated aerodynamic phenomena that take place in the blade root region. In this study we address those phenomena by means of particle image velocimetry (PIV) measurements and Reynolds-averaged Navier–Stokes (RANS) simulations. The numerical results obtained in this study are in very good agreement with the experiments and unveil the details of the intricate root flow. The Himmelskamp effect is shown to delay the stall onset and to enhance the lift force coefficient Cl even at moderate angles of attack. This improvement in the aerodynamic performance occurs in spite of the negative influence of the mentioned effect on the suction peak of the involved blade sections. The results also show that the vortex emanating from the spanwise position of maximum chord length rotates in the opposite direction to the root vortex, which affects the wake evolution. Furthermore, the aerodynamic losses in the root region are demonstrated to take place much more gradually than at the tip.

scholarly journals Parametric slat design study for thick base airfoils at high Reynolds numbers

2019 ◽  
Author(s):  
Julia Steiner ◽  
Axelle Viré ◽  
Francesco Benetti ◽  
Nando Timmer ◽  
Richard Dwight
Keyword(s):  
Turbine Blades ◽  
Design Procedure ◽  
Leading Edge ◽  
Optimization Procedure ◽  
Point Of View ◽  
Main Element ◽  
Single Element ◽  
Wind Turbine Blades ◽  
Flow Control Devices ◽  
Stall Angle

Abstract. Standard passive aerodynamic flow control devices such as vortex generators and gurney flaps have a working principle that is well understood. They increase the stall angle and the lift below stall and are mainly applied at the inboard part of wind turbine blades. However, the potential of applying a rigidly fixed leading edge slat element at inboard blade stations is less well understood but has received some attention in the past decade. This solution may offer advantages not only under steady conditions but also under unsteady inflow conditions such as yaw. This article aims at further clarifying what an optimal two-element configuration with a thick main element would look like, and what kind of performance characteristics can be expected from a purely aerodynamic point of view. To accomplish this an aerodynamic shape optimization procedure is used to derive optimal profile designs for different optimization boundary conditions including the optimization of both the slat and the main element. The performance of the optimized designs shows several positive characteristics as compared to single element airfoils, such as a high stall angle, high lift below stall, low roughness sensitivity and higher aerodynamic efficiency. Furthermore, the results highlight the benefits of an integral design procedure, where both slat and main element are optimized, over an auxiliary one. Nevertheless, the designs also have two caveats, namely a steep drop in lift post-stall and high positive pitching moments.

On the role of surface roughness in the aerodynamic performance and energy conversion of horizontal wind turbine blades: a review

2016 ◽  
Vol 40 (15) ◽  
pp. 2054-2077 ◽  
Author(s):  
Iham F. Zidane ◽  
Khalid M. Saqr ◽  
Greg Swadener ◽  
Xianghong Ma ◽  
Mohamed F. Shehadeh
Keyword(s):  
Surface Roughness ◽  
Energy Conversion ◽  
Wind Turbine ◽  
Turbine Blades ◽  
Aerodynamic Performance ◽  
Horizontal Wind ◽  
Wind Turbine Blades
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