Investigation of an Eppler 423 Style Wind Turbine Blade

Author(s):  
David M. McStravick ◽  
Brent C. Houchens ◽  
David C. Garland ◽  
Kenneth E. Davis

Due to the increasing demand for alternative energy sources and the reliability of wind turbines, the performance of different horizontal-axis wind turbine blade designs were investigated and compared through computational fluid dynamics (CFD) modeling and wind tunnel testing. The Eppler 423 airfoil was of particular interest. In avionics the blade has been associated with high lift and a low tendency to stall, yet little is known about its performance in wind turbines. In both physical testing and ANSYS CFX 11.0 analysis, the airfoil significantly outperformed a Nordtank 41/500 turbine blade. Wind tunnel tests were performed on 12-inch diameter ABS polymer prototypes, created with a 3D printer. To exaggerate the features of each prototype and obtain more measureable differences in turbine performance, the blades are scaled down more in the radial direction than in the profile section directions. The Eppler 423 airfoil design was tested at different blade base angles. The testing identified an optimum power production for a blade base angle of 25°. In the ANSYS CFX computer simulations, the moments on to the turbine blade due to the incoming air allowed for the power generated and the coefficient of power (Cp) to be determined and compared. The Eppler profile outperformed the Nordtank blade profile in these simulations.

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):  
Fouad Mohammad ◽  
Emmanuel Ayorinde

The aerodynamic loadings that act on the blade of a horizontal axis wind turbine change as a function of time due to the instantaneous change of the wind speed, the wind direction and the blade position. The new contribution in this study is the introduction of a simplified non CFD based procedure for the calculation of all the aerodynamic loadings acting on a wind turbine blade. The premise of the current simplified model is that (a) the forces can be modeled by a set of point loads rather than distributed pressures, and (b) the magnitudes of these point loads can be estimated using the below load formulas, (c) an interpolation scheme needed to have all computed forces and moments as a function of the blade lengthwise x. Considering a 14m blade length and utilizing a time dependent set of parameters such as angle of attack, material and air density, wind and blade speed, flow angle, yaw, pitch angles, the centrifugal forces (along x-direction of the blade length), the cross-sectional forces (Fy and Fz) and the twisting moment of the blade (about the x-direction) were calculated for each of all the given time steps. After that the authors explain how to interpolate the calculated loadings (forces and twisting moment) and the right formulas to compute the aerodynamic load vector (the right side of the dynamic equations of motion).


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.


2014 ◽  
Vol 1014 ◽  
pp. 124-127
Author(s):  
Zhi Qiang Xu ◽  
Jian Huang

Wind turbines consists of three key parts, namely, wind wheels (including blades, hub, etc.), cabin (including gearboxes, motors, controls, etc.) and the tower and Foundation. Wind turbine wheel is the most important part ,which is made up of blades and hubs. Blade has a good aerodynamic shape, which will produce aerodynamic in the airflow rotation, converting wind energy into mechanical energy, and then, driving the generator into electrical energy by gearbox pace. Wind turbine operates in the natural environment, their load wind turbine blades are more complex. Therefore load calculations and strength analysis for wind turbine design is very important. Wind turbine blades are core components of wind turbines, so understanding of their loads and dynamics by which the load on the wind turbine blade design is of great significance.


2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Rui Zhu ◽  
Da-duo Chen ◽  
Shi-wei Wu

A 1.5 MW horizontal-axis wind turbine blade and fluid field model are established to study the difference in the unsteady flow field and structural vibration of the wind turbine blade under one- and two-way fluid-structure interactions. The governing equations in fluid field and the motion equations in structural were developed, and the corresponding equations were discretized with the Galerkin method. Based on ANSYS CFX fluid dynamics and mechanical structural dynamics calculation software, the effects of couplings on the aerodynamic and vibration characteristics of the blade are compared and analyzed in detail. Results show that pressure distributions at different sections of the blade are concentrated near the leading edge, and the leeward side of two-way coupling is slightly higher than that of one-way coupling. Deformation along the blade span shows a nonlinear change under the coupling effect. The degree of amplitude attenuation in two-way coupling is significantly greater than that in one-way coupling because of the existence of aerodynamic damping. However, the final amplitude is still higher than the one-way coupling. The Mises stress fluctuation in the windward and leeward sides is more obvious than one-way coupling, and the discrepancy must not be ignored.


2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Ki-Hak Lee ◽  
Kyu-Hong Kim ◽  
Dong-Ho Lee ◽  
Kyung-Tae Lee ◽  
Jong-Po Park

A horizontal-axis wind turbine blade is designed using two step optimization procedures with probability approach. For the efficient management of the multiple design variables required for the blade design, the design procedure is divided into two optimization steps. In step 1, the diameter and rotating speed of a blade are determined and design points are extracted from the design space. In step 2-1, blade shapes are optimized by using the strip theory with the minimum energy loss method. The capacity factor and the cost model for each optimized blade shape are calculated in steps 2-2 and 2-3, respectively. To find the global optimum point in the design space, the space is modified into a highly possible region through the use of the probability approach.


2015 ◽  
Author(s):  
Juan Garate ◽  
Stephen A. Solovitz ◽  
Dave Kim

Today a large-scale wind turbine blade can be 70 m long and 5 m in root chord length, and it is fabricated in a single piece. This feature leads to high initial costs, as transportation of a large blade requires special trucks, escorts, and road adaptations. These constraints can account for approximately 6–7% of the total investment for the blade. In addition, the manufacturing process commonly used is a hand lay-up configuration of thermoset composite sheets. These materials are not reusable after fabrication, which is a non-renewable feature of existing systems. The project consists of manufacturing thermoplastic composite blades in segments, which are joined before installation at the turbine site. This paper addresses the preliminary research results when conducting design and fabrication of a small blade with this innovative approach. Three segmented blades are manufactured for a horizontal-axis wind turbine, with each blade having a 50 cm span and a 4 cm tip chord length. The blade size and profile are designed based on the idealized Betz limit condition. The material used for manufacturing is a glass fiber reinforced thermoplastic composite system with a polypropylene matrix that melts at 200 °C. Each blade is fabricated in 4 independently manufactured pieces, consisting of top/bottom, and tip/root segments, via a vacuum assisted thermoforming technique. The parts will be assembled afterwards by a joining process, forming the final part for site testing.


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