Investigation of leading-edge slat on aerodynamic performance of wind turbine blade

Author(s):  
Tao Chen ◽  
Xiao Jiang ◽  
Haipeng Wang ◽  
Qian Li ◽  
Mingzhou Li ◽  
...  

In this paper, the numerical simulation was used to investigate the effects of the leading-edge slat installation angles ( β for airfoils from 0° to 40° and β1 for blades from −20° to 40°) on the aerodynamic characteristics of the airfoil and the wind turbine blade. The chord length of the leading-edge slat is 0.1c (the chord length of the clean airfoil). The horizontal and vertical distances from its center to the leading edge of the clean airfoil are 0.005c and 0.009c, respectively. The results indicated that the lift coefficient could be significantly improved by the leading-edge slat (except β = 40°) when the attack angle exceeded 10.2°. For β = 0°, the lift coefficient increased the most. The trailing vortex of the leading-edge slat played an important role at the process of flow control. It could transfer kinetic energy from the bounder layer to its out-flow region. Furthermore, the vorticities of trailing vortex generated by the leading-edge slat with different installation angles were different, promoting several effects on the airfoil at the different cases. The torque of the blade with leading-edge slat (except β1 = −20°) was improved significantly as the leading-edge slat trailing-vortices became stronger with the higher wind-speeds.

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Weijun Tian ◽  
Zhen Yang ◽  
Qi Zhang ◽  
Jiyue Wang ◽  
Ming Li ◽  
...  

The main purpose of this paper is to demonstrate a bionic design for the airfoil of wind turbines inspired by the morphology of Long-eared Owl’s wings. Glauert Model was adopted to design the standard blade and the bionic blade, respectively. Numerical analysis method was utilized to study the aerodynamic characteristics of the airfoils as well as the blades. Results show that the bionic airfoil inspired by the airfoil at the 50% aspect ratio of the Long-eared Owl’s wing gives rise to a superior lift coefficient and stalling performance and thus can be beneficial to improving the performance of the wind turbine blade. Also, the efficiency of the bionic blade in wind turbine blades tests increases by 12% or above (up to 44%) compared to that of the standard blade. The reason lies in the bigger pressure difference between the upper and lower surface which can provide stronger lift.


Author(s):  
Abdul Wahab Malik ◽  
Naseem Uddin ◽  
Syed M. Hameed Ul Haq ◽  
M. Faizyab Uddin Khan ◽  
Sikandar Hayat

Wind turbines are subjected to variable wind speeds and flow patterns, this can result in variable power output from the wind turbine. A common practice to counter this problem is to create a twisted wind turbine blade, which can produce optimum output when subjected to different velocities and angle of attack. The research paper discusses the performance characteristics of the same. The research paper presents CFD modeling of a twisted blade. The strategy used for the modeling was to divide the research in two parts. In the first part CFD simulations for 2-D Airfoils were carried-out and the aerodynamic characteristics were examined. In the second part, for more realistic results, a complete 3-D Wind turbine 3 blades rotor with nacelle was examined. For both parts GAMBIT was used for geometry and grid creation (pre-processing), whereas ANSYS FLUENT was used for performing simulations and obtaining the contour plots (Processing and Post Processing).


Author(s):  
GholamHossein Maleki ◽  
Ali Reza Davari ◽  
Mohammad Reza Soltani

An extensive experimental investigation was conducted to study the effects of Dielectric Barrier Discharge (DBD), on the flow field of an airfoil at low Reynolds number. The DBD was mounted near the leading edge of a section of a wind turbine blade. It is believed that DBD can postpone the separation point on the airfoil by injecting momentum to the flow. The effects of steady actuations on the velocity profiles in the wake region have been investigated. The tests were performed at α = 4 to 36 degrees i.e. from low to deep stall angles of attack regions. Both surface pressure distribution and wake profile show remarkable improvement at high angles of attack, beyond the static stall angle of the airfoil when the plasma actuation was implemented. The drag calculated from the wake momentum deficit has further shown the favorable role of the plasma actuators to control the flow over the airfoil at incidences beyond the static stall angle of attack of this airfoil. The results demonstrated that DBD has been able to postpone the stall onset significantly. It has been observed that the best performance for the plasma actuation for this airfoil is in the deep stall angles of attack range. However, below and near the static stall angles of attack, plasma augmentation was pointed out to have a negligible improvement in the aerodynamic behavior.


2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Alvaro Gonzalez ◽  
Xabier Munduate

This work undertakes an aerodynamic analysis over the parked and the rotating NREL Phase VI wind turbine blade. The experimental sequences from NASA Ames wind tunnel selected for this study respond to the parked blade and the rotating configuration, both for the upwind, two-bladed wind turbine operating at nonyawed conditions. The objective is to bring some light into the nature of the flow field and especially the type of stall behavior observed when 2D aerofoil steady measurements are compared to the parked blade and the latter to the rotating one. From averaged pressure coefficients together with their standard deviation values, trailing and leading edge separated flow regions have been found, with the limitations of the repeatability of the flow encountered on the blade. Results for the parked blade show the progressive delay from tip to root of the trailing edge separation process, with respect to the 2D profile, and also reveal a local region of leading edge separated flow or bubble at the inner, 30% and 47% of the blade. For the rotating blade, results at inboard 30% and 47% stations show a dramatic suppression of the trailing edge separation, and the development of a leading edge separation structure connected with the extra lift.


Author(s):  
Alka Gupta ◽  
Abdulrahman Alsultan ◽  
R. S. Amano ◽  
Sourabh Kumar ◽  
Andrew D. Welsh

Energy is the heart of today’s civilization and the demand seems to be increasing with our growing population. Alternative energy solutions are the future of energy, whereas the fossil-based fuels are finite and deemed to become extinct. The design of the wind turbine blade is the main governing factor that affects power generation from the wind turbine. Different airfoils, angle of twist and blade dimensions are the parameters that control the efficiency of the wind turbine. This study is aimed at investigating the aerodynamic performance of the wind turbine blade. In the present paper, we discuss innovative blade designs using the NACA 4412 airfoil, comparing them with a straight swept blade. The wake region was measured in the lab with a straight blade. All the results with different designs of blades were compared for their performance. A complete three-dimensional computational analysis was carried out to compare the power generation in each case for different wind speeds. It was found from the numerical analysis that the slotted blade yielded the most power generation among the other blade designs.


2021 ◽  
Vol 25 (6 Part B) ◽  
pp. 4643-4650
Author(s):  
Yan Li ◽  
Lei Shi ◽  
Wen-Feng Guo ◽  
Kotaro Tagawa ◽  
Bin Zhao

Icing accretion on wind turbine will degrade its performance, resulting in reduction of output power and even leading to accidents. For solving this problem, it is necessary to predict the icing type and shape on wind turbine blade, and evaluate the variation of aerodynamic characteristics. In this paper the icing types and shapes in presence of airfoil, selected from blade of 1.5 MW horizontal-axis wind turbine, are simulated under different ambient temperatures and icing time lengths. Based on the icing simulation results, the aerodynamic characteristics of icing airfoils are simulated, including lift and drag coefficient, lift-drag ratio, etc. The simulation results show that the glaze ice with two horns presents on airfoil under high ambient temperature such as -5?C. When ambient temperatures are low, such as -10?C and -15?C, the rime ices with streamline profiles present on the airfoil. With increase in icing time the lift forces and coefficients decrease, and the drag ones increase. According to the variations of lift-drag ratios of icing airfoil, the aerodynamic performance of airfoil deteriorates in the presence of icing. The glaze ice has great effect on aerodynamic characteristics of airfoil. The research findings lay theoretical foundation for icing wind tunnel experiment.


Energies ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 3330 ◽  
Author(s):  
Jianhua Xu ◽  
Zhonghua Han ◽  
Xiaochao Yan ◽  
Wenping Song

A new airfoil family, called NPU-MWA (Northwestern Polytechnical University Multi-megawatt Wind-turbine A-series) airfoils, was designed to improve both aerodynamic and structural performance, with the outboard airfoils being designed at high design lift coefficient and high Reynolds number, and the inboard airfoils being designed as flat-back airfoils. This article aims to design a multi-megawatt wind turbine blade in order to demonstrate the advantages of the NPU-MWA airfoils in improving wind energy capturing and structural weight reduction. The distributions of chord length and twist angle for a 5 MW wind turbine blade are optimized by a Kriging surrogate model-based optimizer, with aerodynamic performance being evaluated by blade element-momentum theory. The Reynolds-averaged Navier–Stokes equations solver was used to validate the improvement in aerodynamic performance. Results show that compared with an existing NREL (National Renewable Energy Laboratory) 5 MW blade, the maximum power coefficient of the optimized NPU 5 MW blade is larger, and the chord lengths at all span-wise sections are dramatically smaller, resulting in a significant structural weight reduction (9%). It is shown that the NPU-MWA airfoils feature excellent aerodynamic and structural performance for the design of multi-megawatt wind turbine blades.


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