scholarly journals Structural Performance of 14m HAWT blade through CFD

An alternative method used in generating energy is with the help of wind turbines utilizing power from the winds. The efficient extraction of energy hinges on the geometry and structure of the blade. The blade of wind turbine encounters high operational loads and undergoes fluctuating conditions of environment. The proposed work comprises of creating an exact model using CAD applications which includes the optimized geometry of the blade in addition with process verification of structural integrity, under several operating conditions by the means of finite element analysis. The prime motive of the proposed study is to check and evaluate the reliability of the blades by developing the entire geometry of the blade and performing failure analysis by altering load conditions. The construction of blade geometry is done by implementing the blade element momentum theory (BEMT) in order to retrieve the ultimate power coefficient at the required tip speed ratio of 7.05 by the means of optimization process. The NACA 63(4)-221 airfoil is used to create the primary design of blade. Blade with 14 m length has been taken for the present work for RRB V27-225 kW HAWT (horizontal axis wind turbine blade), which is an exclusive design of the blade. In order to perform analysis and modeling of the blade in presence and absence of shear web, two individual materials such as carbon fiber and glass fiber are taken in account. In the case of carbon fibre with shear web, the structural strength is improved which is shown in the results.

Author(s):  
Xiaomin Chen ◽  
Ramesh Agarwal

It is well established that the power generated by a Horizontal-Axis Wind Turbine (HAWT) is a function of the number of blades B, the tip speed ratio λr (blade tip speed/wind free-stream velocity) and the lift to drag ratio (CL/CD) of the airfoil sections of the blade. The previous studies have shown that Blade Element Momentum (BEM) theory is capable of evaluating the steady-state performance of wind turbines, in particular it can provide a reasonably good estimate of generated power at a given wind speed. However in more realistic applications, wind turbine operating conditions change from time to time due to variations in wind velocity and the aerodynamic forces change to new steady-state values after the wake settles to a new equilibrium whenever changes in operating conditions occur. The goal of this paper is to modify the quasi-steady BEM theory by including a simple dynamic inflow model to capture the unsteady behavior of wind turbines on a larger time scale. The output power of the wind turbines is calculated using the improved BEM method incorporating the inflow model. The computations are performed for the original NREL Phase II and Phase III turbines and the Risoe turbine all employing the S809 airfoil section for the turbine blades. It is shown by a simple example that the improved BEM theory is capable of evaluating the wind turbine performance in practical situations where operating conditions often vary in time.


Author(s):  
Ibtissem Barkat ◽  
Abdelouahab Benretem ◽  
Fawaz Massouh ◽  
Issam Meghlaoui ◽  
Ahlem Chebel

This article aims to study the forces applied to the rotors of horizontal axis wind turbines. The aerodynamics of a turbine are controlled by the flow around the rotor, or estimate of air charges on the rotor blades under various operating conditions and their relation to the structural dynamics of the rotor are critical for design. One of the major challenges in wind turbine aerodynamics is to predict the forces on the blade as various methods, including blade element moment theory (BEM), the approach that is naturally adapted to the simulation of the aerodynamics of wind turbines and the dynamic and models (CFD) that describes with fidelity the flow around the rotor. In our article we proposed a modeling method and a simulation of the forces applied to the horizontal axis wind rotors turbines using the application of the blade elements method to model the rotor and the vortex method of free wake modeling in order to develop a rotor model, which can be used to study wind farms. This model is intended to speed up the calculation, guaranteeing a good representation of the aerodynamic loads exerted by the wind.


Author(s):  
Manoj Kumar Chaudhary ◽  
◽  
S. Prakash ◽  

In this research work, the investigation and optimization of small horizontal axis wind turbine blade at low wind speed is pursued. The experimental blades were developed using the 3D printing additive manufacturing technique. The airfoils E210, NACA2412, S1223, SG6043, E216, NACA4415, SD7080, SD7033, S1210 and MAF were tested at the wind speed of 2-6 m/s. The airfoils and optimum blade geometry were investigated with the aid of the Xfoil software at Reynolds number of 100,000. The initial investigation range included tip speed ratios from 3 to 10, solidity from 0.0431 – 0.1181 and angle of attacks from 2o to 20o. Later on these parameters were varied in MATLAB and Xfoil software for optimization and investigation of the power coefficient, lift coefficient, drag coefficient and lift to drag ratio. The cut-in wind speed of the rotors was 2 and 2.5 m/s with the winglet-equipped blades and without winglets. It was found that the E210, SG6043, E216 NACA4415 and MAF airfoil displayed better performance than the NACA 2412, S1223, SD7080, S1210 & SD7003 for the geometry optimized for the operating conditions and manufacturing method described.


2019 ◽  
Vol 8 (3) ◽  
pp. 3390-3400

In the present study, Blade Element Momentum theory (BEMT) has been implemented to heuristically design a rotor blade for a 2kW Fixed Pitch Fixed Speed (FPFS) Small Scale Horizontal Axis Wind Turbine (SSHAWT). Critical geometrical properties viz. Sectional Chord ci and Twist distribution θTi for the idealized, optimized and linearized blades are analytically determined for various operating conditions. Results obtained from BEM theory demonstrate that the average sectional chord ci and twist distribution θTi of the idealized blade are 20.42% and 14.08% more in comparison with optimized blade. Additionally, the employment of linearization technique further reduced the sectional chord ci and twist distribution θTi of the idealized blade by 17.9% and 14% respectively, thus achieving a viable blade bounded by the limits of economic and manufacturing constraints. Finally, the study also reveals that the iteratively reducing blade geometry has an influential effect on the solidity of the blade that in turn affects the performance of the wind turbine.


2014 ◽  
Vol 4 (2) ◽  
Author(s):  
I Kade Wiratama ◽  
Made Mara ◽  
L. Edsona Furqan Prina

The willingness of electrical energy is one energy system has a very important role in the economic development of a country's survival. As one energy source (wind) can be converted into electrical energy with the use of a horizontal axis wind turbine. Wind Energy Conversion Systems (WECS) that we know are two wind turbines in general, ie the horizontal axis wind turbine and vertical axis wind turbine is one type of renewable energy use wind as an energy generator. The purpose of this study was to determine the effect of the number of blade and the radius chord of rotation (n), Torque (T), Turbine Power (P), Power Coefficient (CP) and Tip Speed Ratio (λ) generated by the horizontal axis wind turbine with form linear taper. The results show that by at the maximum radius of the chord R3 the number blade 4 is at rotation = 302.700 rpm, Pturbine = 7.765 watt, Torque = 0.245 Nm, λ = 3.168 and Cp = 0.403 or 40.3%.


2014 ◽  
Vol 1079-1080 ◽  
pp. 543-546 ◽  
Author(s):  
Zhi Kui Wang ◽  
Yi Bao Chen ◽  
Gwo Chung Tsai

The wind turbines have gained a wide range of applications in Renewable Energy Sources (RES) by virtue of its dominant advantages, and it has achieved almost the state-of-the-art from the engineering point of view. Nevertheless, the starting behavior which plays a prominent role in wind power generation has achieved few studies up to this moment. We conducted this analysis of a micro horizontal axis wind turbine (MHAWT) on its starting behavior to give insight into its start-up torque as well as its start-up speed on an assumption that it is rigid body, and some relative simplification on its structure are adopted meanwhile. The wind turbine's power coefficient CP, tip-speed-ratio l along with torque coefficient CT were taken into consideration and discussed to a large extent in order to having a relative clear cognition of its operational characteristics.


Symmetry ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 18 ◽  
Author(s):  
Hani Muhsen ◽  
Wael Al-Kouz ◽  
Waqar Khan

This work aims at designing and optimizing the performance of a small Horizontal-Axis-Wind-Turbine to obtain a power coefficient (CP) higher than 40% at a low wind speed of 5 m/s. Two symmetric in shape airfoils were used to get the final optimized airfoil. The main objective is to optimize the blade parameters that influence the design of the blade since the small turbines are prone to show low performance due to the low Reynolds number as a result of the small size of the rotor and the low wind speed. Therefore, the optimization process will select different airfoils and extract their performance at the design conditions to find the best sections which form the optimal design of the blade. The sections of the blade in the final version mainly consist of two different sections belong to S1210 and S1223 airfoils. The optimization process goes further by investigating the performance of the final design, and it employs the blade element momentum theory to enhance the design. Finally, the rotor-design was obtained, which consists of three blades with a diameter of 4 m, a hub of 20 cm radius, a tip-speed ratio of 6.5 and can obtain about 650 W with a Power coefficient of 0.445 at a wind-speed of 5.5 m/s, reaching a power of 1.18 kW and a power coefficient of 0.40 at a wind-speed of 7 m/s.


Author(s):  
N. Asmuin ◽  
◽  
Basuno B. ◽  
M.F. Yaakub ◽  
N.A. Nor Salim ◽  
...  

The present work uses the method of Blade Element Momentum Theory as suggested by Hansen. The method applied to three blade models adopted from Rahgozar S. with the airfoil data used the data provided by Wood D. The wind turbine performance described in term of the thrust coefficient C_T, torque coefficient C_Q and the power coefficient C_p . These three coefficient can be deduced from the Momentum theory or from the Blade element Theory(BET). The present work found the performance coefficient derived from the Momentum theory tent to over estimate. It is suggested to used the BET formulation in presenting these three coefficients. In overall the Blade Element Momentum Theory follows the step by step as described by Hansen work well for these three blade models. However a little adjustment on the blade data is needed. To the case of two bladed horizontal axis wind


2014 ◽  
Vol 1070-1072 ◽  
pp. 1869-1873
Author(s):  
Hai Bo Jiang ◽  
Yun Peng Zhao ◽  
Zhong Qing Cheng

The lift coefficient of any wind turbine must have highest limit. In this paper, an analytical expression of lift coefficient associated with tip-speed ratio and lift-drag ratio of airfoil of wind turbine with ideal chord has been deduced by integrating along the blade wingspan using the blade element - momentum theory, which can be used for pre-estimating lift coefficient of actual wind turbine in design. Further, considering ideal fluid environment ( the drag coefficient is close to 0 ), an expression of the highest performance of lift only associated with tip-speed ratio has been deduced too, which is the highest boundary of lift coefficient of any actual wind turbine with same tip-speed ratio. The results show that for the wind turbine in steady state, there is a theoretical limit of the lift coefficient, 0.57795, which is the highest boundary that any actual wind turbine can not be crossed; if the tip-speed ratio is greater than 6 and lift-drag ratio less than 200, the lift coefficient is unlikely to exceed 0.2.


2016 ◽  
Vol 33 (3) ◽  
pp. 341-349
Author(s):  
C.-J. Bai ◽  
Y.-C. Shiah

AbstractThis paper proposes a correction method to improve the accuracy of traditional blade element momentum theory (BEMT) in predicting the mechanical power and power coefficient of horizontal-axis wind turbine (HAWT) blade. In this paper, the traditional BEMT incorporated with the Viterna-Corrigan (VC) stall/stall-delay model is proposed to improve the accuracy of power-curve prediction, by which its applicability is thus enhanced. For verification of the proposed method, three distinct types of geometries of HAWT blades subjected to different operations are studied with outcomes compared with experimental data. Two different wind turbines developed by National Renewable Energy Laboratory (NREL) were tested at constant rotational speeds in a full-scale wind tunnel to acquire performance data. As a comparative platform, another wind turbine designed by BEMT for this study was also experimented in identical environment but at variable rotational speeds. As expected, the results clearly indicate that the power-curve prediction is effectively improved by the proposed method especially in the stall region when compared with experimental data. Indeed, this study shows that the improved BEMT is an ideal means to accurately predict the power-curve used for designing an optimal HAWT rotor.


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