Modeling of Energy and Exergy Efficiencies of a Wind Turbine Based on the Blade Element Momentum Theory Under Different Roughness Intensities

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Ali Khanjari ◽  
Ali Sarreshtehdari ◽  
Esmail Mahmoodi
Keyword(s):  
Wind Turbine ◽  
Environmental Parameters ◽  
Horizontal Axis Wind Turbine ◽  
Turbine Performance ◽  
Good Ability ◽  
Energy And Exergy ◽  
Negative Effect ◽  
Wind Tunnel Data ◽  
Bem Theory ◽  
Blade Element

In this study, the analysis of energy and exergy of a horizontal axis wind turbine based on blade element momentum (BEM) theory is presented. The computations are validated against wind tunnel data measured in the MEXICO wind turbine experiment. Blade roughness as one of the important environmental parameters is considered in the computations. Results show that the blade element momentum (BEM) theory has good ability to predict the energy and exergy efficiencies. The computation of energy and exergy exhibits that with the increasing the roughness from 0 mm to 0.5 mm, 2324 W of the output power is reduced. Roughness of 0.5 mm at the wind speed of 16 m/s reduced exergy and energy efficiencies 5.75% and 5.83%, respectively. It is also found that the roughness in the first four months of the operation has a more negative effect on the wind turbine performance.

scholarly journals Geometrical Design of a Rotor Blade for a Small Scale Horizontal Axis Wind Turbine

2019 ◽  
Vol 8 (3) ◽  
pp. 3390-3400
Keyword(s):  
Wind Turbine ◽  
Rotor Blade ◽  
Operating Conditions ◽  
Horizontal Axis ◽  
Small Scale ◽  
Horizontal Axis Wind Turbine ◽  
Geometrical Properties ◽  
Momentum Theory ◽  
Bem Theory ◽  
Blade Element

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.

HAWT Rotor Design and Performance Analysis

2009 ◽  
Author(s):  
Emrah Kulunk ◽  
Nadir Yilmaz
Keyword(s):  
Performance Analysis ◽  
Computer Program ◽  
Wind Turbine ◽  
Design Method ◽  
Aerodynamic Performance ◽  
Horizontal Axis Wind Turbine ◽  
Rotor Design ◽  
And Performance ◽  
Bem Theory ◽  
Blade Element

In this paper, a design method based on blade element momentum (BEM) theory is explained for horizontal-axis wind turbine (HAWT) blades. The method is used to optimize the chord and twist distributions of the blades. Applying this method a 100kW HAWT rotor is designed. Also a computer program is written to estimate the aerodynamic performance of the existing HAWT blades and used for the performance analysis of the designed 100kW HAWT rotor.

scholarly journals Horizontal Axis Wind Turbine Performance Analysis

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
N. Asmuin ◽  
◽  
Basuno B. ◽  
M.F. Yaakub ◽  
N.A. Nor Salim ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Horizontal Axis ◽  
Power Coefficient ◽  
Horizontal Axis Wind Turbine ◽  
Thrust Coefficient ◽  
Blade Element Momentum Theory ◽  
Blade Element Theory ◽  
Momentum Theory ◽  
Turbine Performance ◽  
Blade Element

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

Assessment of a Modified Blade Element Momentum Methodology for Diffuser Augmented Wind Turbines

2017 ◽  
Author(s):  
Stavros N. Leloudas ◽  
Georgios N. Lygidakis ◽  
Ioannis K. Nikolos
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Power Output ◽  
Horizontal Axis Wind Turbine ◽  
Correction Model ◽  
Short Period ◽  
Turbine Design ◽  
The Impact ◽  
Bem Theory ◽  
Blade Element

The Blade Element Momentum (BEM) theory is nowadays the cornerstone of the horizontal axis wind turbine design, as its application allows for the accurate aerodynamic simulation and power output prediction of wind turbine rotors in a remarkably short period of time. Therefore, efforts have been made for the extension of the classic BEM theory to the performance analysis of Diffuser Augmented Wind Turbines (DAWTs) as well. In this study, the development and assessment of such an in-house BEM code are presented. The proposed computational model is based on the modification of the momentum part of the classical BEM theory; thus, it is capable to account for the diffuser’s effect on the calculation of the axial and tangential induction factors, through the utilization of the velocity speed-up distribution over the rotor plane of the unloaded diffuser. Furthermore, a detailed Glauert’s correction model, which employs Buhl’s modification, specially tailored for the DAWT case is included, to deal with the high values of the axial induction factor. The accuracy of the model is assessed against numerical and experimental results available in the literature, while the impact of the Prandtl’s tip loss correction model on the rotor’s predicted power output is also examined.

Aerodynamic Design and Performance Analysis of HAWT Blades

2009 ◽  
Author(s):  
Emrah Kulunk ◽  
Nadir Yilmaz
Keyword(s):  
Performance Analysis ◽  
Computer Program ◽  
Wind Turbine ◽  
Design Method ◽  
Aerodynamic Performance ◽  
Aerodynamic Design ◽  
Horizontal Axis Wind Turbine ◽  
And Performance ◽  
Bem Theory ◽  
Blade Element

In this paper, a design method based on blade element momentum (BEM) theory is explained for horizontal-axis wind turbine (HAWT) blades. The method is used to optimize the chord and twist distributions of the blades. Applying this method a 100kW HAWT rotor is designed. Also a computer program is written to estimate the aerodynamic performance of the existing HAWT blades and used for the performance analysis of the designed 100kW HAWT rotor.

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.

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