Assessment of the Performance of Various Airfoil Sections on Power Generation From a Wind Turbine Using the Blade Element Momentum Theory

2013 ◽  
Author(s):  
Xiaomin Chen ◽  
Ramesh Agarwal
Keyword(s):  
Wind Turbine ◽  
Phase Ii ◽  
Turbine Rotor ◽  
Phase Iii ◽  
Speed Ratio ◽  
Stream Velocity ◽  
Horizontal Axis Wind Turbine ◽  
Airfoil Section ◽  
Flat Back ◽  
Blade Element

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 λ (blade tip speed/wind free stream velocity) and the lift to drag ratio (CL/CD) of the airfoil sections of the blade. The airfoil sections used in HAWT are generally thick airfoils such as the S, DU, FX, Flat-back and NACA 6-series of airfoils. These airfoils vary in (CL/CD) for a given B and λ, and therefore the power generated by HAWT for different blade airfoil sections will vary. The goal of this paper is to evaluate the effect of different airfoil sections on HAWT performance using the Blade Element Momentum (BEM) theory. In this study, we employ DU 91-W2-250, FX 66-S196-V1, NACA 64421, and Flat-back series of airfoils (FB-3500-0050, FB-3500-0875, and FB-3500-1750) and compare their performance with S809 airfoil used in NREL Phase II and III wind turbines; the lift and drag coefficient data for these airfoils sections are available. The output power of the turbine is calculated using these airfoil section blades for a given B and λ and is compared with the original NREL Phase II and Phase III turbines using S809 airfoil section. It is shown that by a suitable choice of airfoil section of HAWT blade, the power generated by the turbine can be significantly increased. Parametric studies are also conducted by varying the turbine rotor diameter.

Inclusion of a Simple Dynamic Inflow Model in the Blade Element Momentum Theory for Wind Turbine Application

2014 ◽  
Author(s):  
Xiaomin Chen ◽  
Ramesh Agarwal
Keyword(s):  
Steady State ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Turbine Blades ◽  
Operating Conditions ◽  
Phase Iii ◽  
Speed Ratio ◽  
Horizontal Axis Wind Turbine ◽  
Bem Theory ◽  
Blade Element

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.

scholarly journals Determination of the Angle of Attack on a Research Wind Turbine Rotor Blade Using Surface Pressure Measurements

2020 ◽  
Author(s):  
Rodrigo Soto-Valle ◽  
Sirko Bartholomay ◽  
Joerg Alber ◽  
Marinos Manolesos ◽  
Christian Navid Nayeri ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Rotor Blade ◽  
Angle Of Attack ◽  
Leading Edge ◽  
Turbine Rotor ◽  
Speed Ratio ◽  
Horizontal Axis Wind Turbine ◽  
Turbine Rotor Blade ◽  
Wide Range ◽  
Wind Turbine Rotor

Abstract. In this paper, a method to determine the angle of attack on a wind turbine rotor blade using a chordwise pressure distribution measurement was applied. The approach uses a reduced number of pressure taps data located close to the blade leading edge. The results were compared with three 3-hole probes located at different radial positions and analytical calculations. The experimental approaches are based on the 2-D flow assumption; the pressure tap method is an application of the thin airfoil theory and the 3-hole probe method uses external probe measurements and applies geometrical and induction corrections. The experiments were conducted in the wind tunnel at the Hermann Föttinger Institut of the Technische Unversität Berlin. The research turbine is a three-bladed upwind horizontal axis wind turbine model with a rotor diameter of 3 m. The measurements were carried out at rated condition with a tip speed ratio of 4.35 and different yaw and pitch angles were tested in order to compare both methods over a wide range of conditions. Results show that the pressure taps method is suitable with a similar angle of attack results as the 3-hole probes for the aligned case. When a yaw misalignment was introduced the method captures the same trend and feature of the analytical estimations. Nevertheless, it is not able to capture the tower influence. Regarding the influence of pitching the blades, a linear relationship between the angle of attack and pitch angle was found.

Lift Limit of Horizontal Axis Wind Turbine

2014 ◽  
Vol 1070-1072 ◽  
pp. 1869-1873
Author(s):  
Hai Bo Jiang ◽  
Yun Peng Zhao ◽  
Zhong Qing Cheng
Keyword(s):  
Wind Turbine ◽  
Lift Coefficient ◽  
Speed Ratio ◽  
Theoretical Limit ◽  
Horizontal Axis Wind Turbine ◽  
Tip Speed Ratio ◽  
Momentum Theory ◽  
Fluid Environment ◽  
Drag Ratio ◽  
Blade Element

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.

scholarly journals Determination of the angle of attack on a research wind turbine rotor blade using surface pressure measurements

2020 ◽  
Vol 5 (4) ◽  
pp. 1771-1792
Author(s):  
Rodrigo Soto-Valle ◽  
Sirko Bartholomay ◽  
Jörg Alber ◽  
Marinos Manolesos ◽  
Christian Navid Nayeri ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Rotor Blade ◽  
Angle Of Attack ◽  
Turbine Rotor ◽  
Speed Ratio ◽  
Horizontal Axis Wind Turbine ◽  
Turbine Rotor Blade ◽  
Wide Range ◽  
Wind Turbine Rotor

Abstract. In this paper, a method to determine the angle of attack on a wind turbine rotor blade using a chordwise pressure distribution measurement was applied. The approach used a reduced number of pressure tap data located close to the blade leading edge. The results were compared with the measurements from three external probes mounted on the blade at different radial positions and with analytical calculations. Both experimental approaches used in this study are based on the 2-D flow assumption; the pressure tap method is an application of the thin airfoil theory, while the probe method applies geometrical and induction corrections to the measurement data. The experiments were conducted in the wind tunnel at the Hermann Föttinger Institut of the Technische Universität Berlin. The research turbine is a three-bladed upwind horizontal axis wind turbine model with a rotor diameter of 3 m. The measurements were carried out at rated conditions with a tip speed ratio of 4.35, and different yaw and pitch angles were tested in order to compare the approaches over a wide range of conditions. Results show that the pressure tap method is suitable and provides a similar angle of attack to the external probe measurements as well as the analytical calculations. This is a significant step for the experimental determination of the local angle of attack, as it eliminates the need for external probes, which affect the flow over the blade and require additional calibration.

scholarly journals Structural Performance of 14m HAWT blade through CFD

2020 ◽  
Vol 9 (3) ◽  
pp. 1846-1955
Keyword(s):  
Wind Turbine ◽  
Structural Integrity ◽  
Operating Conditions ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Horizontal Axis Wind Turbine ◽  
Element Analysis ◽  
Process Verification ◽  
Efficient Extraction ◽  
Blade Element

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.

scholarly journals Performance Analysis of Small Horizontal Axis Wind Turbine with Airfoil NACA 4412

2021 ◽  
Vol 2 (1) ◽  
pp. 347-357
Author(s):  
Syam Widiyanto ◽  
Sasongko Pramonohadi ◽  
Mohammad Kholid Ridwan
Keyword(s):  
Wind Turbine ◽  
Turbine Rotor ◽  
Horizontal Axis ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Horizontal Axis Wind Turbine ◽  
Integral Boundary ◽  
Low Wind Speed ◽  
A Value ◽  
Optimal Power

The horizontal axis wind turbine (HAWT) design with low wind speed requires blade geometry selection. The analysis uses the potential flow panel method and the integral boundary layer formulation to analyze wind flow around the airfoil. The blade design with the blade element momentum (BEM) theory has an aerodynamic coefficient value along the blade. Power wind calculates to model the wind shear pressure at each blade. This research aims to determine the wind turbine rotor based on the performance, including the power coefficient, tip speed ratio, power, and rpm. The simulation uses an airfoil NACA 4412 which has optimal coefficient lift (Cl) = 1.92 at 190 pitch of angle, coefficient drag (Cd) = 0.0635 at 130 pitch angle and Cl / Cd = 155 at tilt angle = 40. Five models of 2.5 m diameter blades with different angles for each chord. The test results show that the change in the speed ratio affects the power coefficient so that the optimal power coefficient on NACA 4412 in experiment 5 is 0.56, and change in rotation per minute affects the output power so that the rotation per minute and the optimal power in experiment 4 with a value of 374 rpm and 553 W.

Modeling and Control of a Continuously Variable Planetary Transmission for a Small Wind Turbine Drivetrain

2013 ◽  
Author(s):  
Zhi Yang ◽  
Mahesh Krishnamurthy ◽  
Jose M. Garcia
Keyword(s):  
Wind Turbine ◽  
Turbine Rotor ◽  
Induction Generator ◽  
Speed Ratio ◽  
Horizontal Axis Wind Turbine ◽  
Modeling And Control ◽  
Small Wind Turbine ◽  
Wind Turbine System ◽  
Continuously Variable Transmissions ◽  
And Control

This paper presents the modeling and control of a Continuously Variable Planetary (CVP) transmission in a wind turbine system. The primary purpose of this paper is to evaluate its effectiveness for mechanically decoupling the variable speed turbine rotor from the grid tied induction generator. It is expected that a CVP controlled wind turbine can take advantage of the grid tied induction generator without the use of an inverter, while optimizing the blade speed aerodynamically. This system also expands its operating range making it possible to track the optimal tip speed ratio over a wider wind speed range, which allows higher power to be captured from the wind. System characteristics have been studied by simulating an 8kW horizontal axis wind turbine in a MatLab/Simulink® environment. Experimental results have been included to verify the model of the system. Analyses conducted show that the continuously variable transmissions are potential candidates for small wind turbine applications.

scholarly journals Insight into Rotational Effects on a Horizontal Axis Wind Turbine NREL Phase ii Using CFD simulation and inverse BEM

2017 ◽  
Vol 2 (1) ◽  
pp. 29
Author(s):  
Belamadi Riyadh
Keyword(s):  
Wind Turbine ◽  
Phase Ii ◽  
Cfd Simulation ◽  
Stokes Equations ◽  
Large Deviation ◽  
Aerodynamic Characteristics ◽  
Turbine Rotor ◽  
Horizontal Axis ◽  
Horizontal Axis Wind Turbine ◽  
Wind Turbine Rotor

The present work aims to study the aerodynamic characteristics of the NREL phase II rotor (generated only with S809 profile along the span for an untwisted case) that is a horizontal axis downwind wind turbine rotor and which is assumed to stand isolated in the space. The three-dimensional steady-incompressible flow Reynolds Averaged Navier-Stokes equations are solved by using the commercial CFD package ANSYS FLUENT and, the turbulence closure model k-ω with shear stress transport correction was adopted for all computations. The computations were done for wind speed of 7.2, 10.56, 12.85, 16.3, and 9.18 m.s-1. Results of pressure and torque for considered wind turbine rotor have been directly compared to the available experimental data. The comparisons show that CFD results along with the turbulence model can predict the span-wise loading of the wind turbine rotor with reasonable agreement. Secondly, A comparison of lift and drag coefficients was made between the results obtained using the inverse algorithm BEM based on the calculated pressure distributions and the experimental test data. The result show that the general trend is similar for all sections of the scale, however, large deviation exists between the 2-D and   3-D case.

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