Wind shear effect on aerodynamic performance and energy production of horizontal axis wind turbines with developing blade element momentum theory

Abstract The small-scale horizontal-axis wind turbines (SHAWTs) have emerged as the promising alternative energy resource for the off-grid electrical power generation. These turbines primarily operate at low Reynolds number, low wind speed, and low tip speed ratio conditions. Under such circumstances, the airfoil selection and blade design of a SHAWT becomes a challenging task. The present work puts forward the necessary steps starting from the aerofoil selection to the blade design and analysis by means of blade element momentum theory (BEMT) for the development of four model rotors composed of E216, SG6043, NACA63415, and NACA0012 airfoils. This analysis shows the superior performance of the model rotor with E216 airfoil in comparison to other three models. However, the subsequent wind tunnel study with the E216 model, a marginal drop in its performance due to mechanical losses has been observed.

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Wake Expansion and the Finite Blade Functions for Horizontal-Axis Wind Turbines

Energies ◽

10.3390/en14227653 ◽

2021 ◽

Vol 14 (22) ◽

pp. 7653

Author(s):

David Wood

Keyword(s):

Radial Velocity ◽

Wind Turbines ◽

Loss Factor ◽

Axial Direction ◽

Horizontal Axis ◽

Speed Ratio ◽

Tip Speed Ratio ◽

Constant Pitch ◽

Horizontal Axis Wind Turbines ◽

Blade Element

This paper considers the effect of wake expansion on the finite blade functions in blade element/momentum theory for horizontal-axis wind turbines. For any velocity component, the function is the ratio of the streamtube average to that at the blade elements. In most cases, the functions are set by the trailing vorticity only and Prandtl’s tip loss factor can be a reasonable approximation to the axial and circumferential functions at sufficiently high tip speed ratio. Nevertheless, important cases like coned or swept rotors or shrouded turbines involve more complex blade functions than provided by the tip loss factor or its recent modifications. Even in the presence of significant wake expansion, the functions derived from the exact solution for the flow due to constant pitch and radius helical vortices provide accurate estimates for the axial and circumferential blade functions. Modifying the vortex pitch in response to the expansion improves the accuracy of the latter. The modified functions are more accurate than the tip loss factor for the test cases at high tip speed ratio that are studied here. The radial velocity is important for expanding flow as it has the magnitude of the induced axial velocity near the edge of the rotor. It is shown that the resulting angle of the flow to the axial direction is small even with significant expansion, as long is the tip speed ratio is high. This means that blade element theory does not have account for the effective blade sweep due to the radial velocity. Further, the circumferential variation of the radial velocity is lower than of the other components.

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Aerodynamic performance enhancement of horizontal axis wind turbines by dimples on blades: Numerical investigation

Energy ◽

10.1016/j.energy.2020.117056 ◽

2020 ◽

Vol 195 ◽

pp. 117056 ◽

Cited By ~ 5

Author(s):

Hamed Sedighi ◽

Pooria Akbarzadeh ◽

Ali Salavatipour

Keyword(s):

Numerical Investigation ◽

Wind Turbines ◽

Performance Enhancement ◽

Aerodynamic Performance ◽

Horizontal Axis ◽

Horizontal Axis Wind Turbines

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Design of Horizontal-Axis Wind Turbines with Six Blades by the Blade Element Momentum Method

The proceedings of the JSME annual meeting ◽

10.1299/jsmemecjo.2003.2.0_97 ◽

2003 ◽

Vol 2003.2 (0) ◽

pp. 97-98

Author(s):

Yutaka HARA ◽

Tsutomu HAYASHI ◽

Masatoshi KAJIWARA ◽

Toshimasa MATSUOKA

Keyword(s):

Wind Turbines ◽

Horizontal Axis ◽

Horizontal Axis Wind Turbines ◽

Blade Element

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Investigating blade performance of small horizontal axis wind turbine based on blade element momentum theory

2013 1st International Conference & Exhibition on the Applications of Information Technology to Renewable Energy Processes and Systems ◽

10.1109/it-dreps.2013.6588158 ◽

2013 ◽

Cited By ~ 2

Author(s):

Franklyn Kanyako ◽

Isam Janajreh

Keyword(s):

Wind Turbine ◽

Horizontal Axis ◽

Horizontal Axis Wind Turbine ◽

Blade Element Momentum Theory ◽

Momentum Theory ◽

Blade Element

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Analysis on Aerodynamic Performance of Horizontal Axis Wind Turbine Based on Nonlinear Wake Model

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.448-453.1716 ◽

2013 ◽

Vol 448-453 ◽

pp. 1716-1720

Author(s):

Rui Yang ◽

Jiu Xin Wang ◽

Sheng Long Zhang

Keyword(s):

Wind Turbine ◽

Wind Turbines ◽

Optimization Design ◽

Aerodynamic Performance ◽

Horizontal Axis ◽

Wake Vortex ◽

Horizontal Axis Wind Turbine ◽

Horizontal Axis Wind Turbines ◽

Wake Model ◽

Induced Velocity

A computational method based on nonlinear wake model was established for horizontal axis wind turbines aerodynamic performance prediction. This method makes use of finite difference method to solve the integral differential equation of the model, the induced velocity of wake vortex can be calculated from equations and compared with the induced velocity of wake vortex in linear model. The comparison between the calculated results of wind turbine under axis flow condition, including tip vortex geometry and aerodynamic performance, and available experimental data shows that this method is suitable for wind turbine aerodynamic performance analysis. Finally, a series of numerical calculations were made to investigate the change of wake geometry and aerodynamic performance of the wind turbine when yawing and pitch angle increasing, which provide foundations for aerodynamic optimization design of horizontal axis wind turbines.

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