Aerodynamic Design and Optimization of a Small Scale Wind Turbine

2014 ◽  
Author(s):  
G. Kröger ◽  
U. Siller ◽  
J. Dabrowski
Keyword(s):  
Wind Turbine ◽  
Power Output ◽  
Rotor Blade ◽  
Residential Buildings ◽  
Speed Ratio ◽  
Small Scale ◽  
Substantial Part ◽  
Optimized Design ◽  
Horizontal Axis Wind Turbine ◽  
Wind Speeds

Small scale wind turbines can meet a substantial part of the electricity demand of residential buildings and facilities in isolated areas. It is a curious fact, however, that for many of these systems the actual power output has been dramatically overestimated. This can be partially explained by the very high rated wind speeds at which the design power output applies. The current work depicts the pathway to an aerodynamically optimized design of a small scale horizontal axis wind turbine in the 1kW class, optimized for wind speeds between 3.5 m/s and 5.5 m/s, a typical range of the energetic average of urban wind speeds. The aerodynamic stability of the blade has been a particular focus leading to a nearly constant efficiency over a range of wind speeds. The rotating speed of the system is adjusted to the optimal tip speed ratio at wind speeds up to maximum power via active control of the aerodynamic torque of the rotor blades. This is realized by adapting the generator torque to the current wind speed guaranteeing optimal efficiency and power output. The rotor blade optimization has been conducted unconventionally, in a turbomachinery-inspired 3D-blade design optimization campaign, using high-fidelity compressible CFD. This approach is described in detail, focussing on geometry parametrization and the numerical model with reasonable boundary conditions. Finally, the aerodynamic performance of the rotor blade is assessed at different wind speeds and pitching angles.

scholarly journals Canard optimization for enhancing the performance of small horizontal axis wind turbine at low wind speeds

2020 ◽  
Vol 37 ◽  
pp. 63-71
Author(s):  
Yui-Chuin Shiah ◽  
Chia Hsiang Chang ◽  
Yu-Jen Chen ◽  
Ankam Vinod Kumar Reddy
Keyword(s):  
Wind Turbine ◽  
Urban Areas ◽  
Horizontal Axis ◽  
Power Coefficient ◽  
Peak Performance ◽  
Small Scale ◽  
Horizontal Axis Wind Turbine ◽  
Wind Speeds ◽  
Optimum Parameters ◽  
Low Wind Speeds

ABSTRACT Generally, the environmental wind speeds in urban areas are relatively low due to clustered buildings. At low wind speeds, an aerodynamic stall occurs near the blade roots of a horizontal axis wind turbine (HAWT), leading to decay of the power coefficient. The research targets to design canards with optimal parameters for a small-scale HAWT system operated at variable rotational speeds. The design was to enhance the performance by delaying the aerodynamic stall near blade roots of the HAWT to be operated at low wind speeds. For the optimal design of canards, flow fields of the sample blades with and without canards were both simulated and compared with the experimental data. With the verification of our simulations, Taguchi analyses were performed to seek the optimum parameters of canards. This study revealed that the peak performance of the optimized canard system operated at 540 rpm might be improved by ∼35%.

scholarly journals Investigation of the Solidity Ratio in a Horizontal Wind Turbine

2021 ◽  
Vol 1 (2) ◽  
Author(s):  
Süleyman Tekşin ◽  
Mert Kurt
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Horizontal Wind ◽  
Speed Ratio ◽  
Horizontal Axis Wind Turbine ◽  
Generator System ◽  
Wind Speeds ◽  
Solidity Ratio ◽  
Different Diameters ◽  
Work Done

A wind turbine-generator system; Parameters such as wind speed, turbine blade diameter, number of blades, turbine height, tip speed ratio and solidity ratio are affected. In this study, horizontal axis wind turbine with diameter of 130 cm and blade solidity ratio values of 7%, 8,6% and 9,8% were constructed and the tests were made according to different blade speed ratios. The required blades were obtained from PVC pipes of different diameters. The experimental study was actualized in Erciyes University Mechanical Engineering, Engines Laboratory. For each profile, blade rotational speeds and wind speeds at various distances have been studied. It has been determined that the wind speed is reduced by the distance difference and accordingly the number of blade speed is decreased visibly. In the wing profiles with different blade solidity ratios resulting from the work done, the wing structure with the solidity ratio of 8.6% gave the best performance. CL and CD coefficients of the profiled specimens were analyzed by FLUENTTM, a program of computational fluid dynamics. One of the factors that should be taken into consideration in the production of wind turbines is the blade solidity ratio.

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.

Computational Analysis of an Optimized Curved-Bladed Small-Scale Horizontal Axis Wind Turbine

2020 ◽  
Vol 143 (6) ◽  
Author(s):  
Ali M. Abdelsalam ◽  
W. A. El-Askary ◽  
M. A. Kotb ◽  
I. M. Sakr
Keyword(s):  
Wind Turbine ◽  
Flow Behavior ◽  
Horizontal Axis ◽  
Power Coefficient ◽  
Peak Performance ◽  
Small Scale ◽  
Horizontal Axis Wind Turbine ◽  
Axial Thrust ◽  
Wind Speeds ◽  
Linear Profiles

Abstract This article aims to study numerically the effect of curvature of linear blade profile on the performance of small-scale horizontal axis wind turbine (SSHAWT). Rotors with two curvature types, f forward angles 5 deg, 10 deg, 15 deg, 20 deg, 30 deg, and 45 deg and backward angles −5 deg, −10 deg, and −15 deg, are investigated. Furthermore, three curvature positions of r/R = 0.8, 0.9, and 0.95 are studied. The numerical simulations are performed on rotors of radius 0.5 m at different wind speeds. The results are compared with straight rotor of linear profiles of chord and twist, which is considered as base rotor. It is found that the rotor with forward curvature of 5 deg and r/R = 0.9 has the highest power coefficient compared with the other rotors. At the peak performance, the proposed rotor reduces the axial thrust by about 12.5% compared with the base rotor. The flow behavior represented by the streamlines contours is also discussed. In such case, the separation approximately disappeared for the tip speed ratios of 5 and 6, which is responsible for the performance peak.

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.

scholarly journals Design of an active pitch control for small horizontal-axis wind turbine

2021 ◽  
Vol 19 ◽  
pp. 195-198
Author(s):  
J. Vilà ◽  
◽  
N. Luo ◽  
L. Pacheco ◽  
T. Pujol ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Power Output ◽  
Low Cost ◽  
Small Scale ◽  
End User ◽  
Power Capacity ◽  
Horizontal Axis Wind Turbine ◽  
Pitch Control ◽  
Small Wind Turbines

The installed power capacity from small wind turbines would rise in case of having higher efficiency values. The performance of these devices is very sensitive to wind conditions, especially to wind gusts and turbulence. Performance extracted from small-scale wind turbine datasheets show large variations of power output between turbulent and non-turbulent sites and often the installation in intermittent wind sites is discouraged. The use of blades with fixed positions is a clear drawback of small wind turbines. Here, we propose a design of a smart active pitch control to increase the energy generation of micro-wind turbines (< 5 kWp). The design consists of a simple mechanism that allows the rotation of the blades controlled by a low cost peripheral interface controller. The possibility to orientate the blades so as to maximise the power output at all wind conditions will increase the performance of this small wind turbines. The design is robust and economical, which will increase its potential adoptability rate by the end-user.

Study of Aerodynamic Performance and Power Output for Residential-Scale Wind Turbines

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Alaa S. Hasan ◽  
Mohammed Abousabae ◽  
Abdel Rahman Salem ◽  
Ryoichi S. Amano
Keyword(s):  
Wind Turbines ◽  
Power Output ◽  
Leading Edge ◽  
Boundary Layer Transition ◽  
Speed Ratio ◽  
Computational Domain ◽  
Horizontal Axis Wind Turbine ◽  
Layer Transition ◽  
Baseline Design ◽  
Wind Speeds

Abstract This study presents the rotor blade airfoil analysis of residential-scale wind turbines. On this track, four new airfoils (GOE 447, GOE 446, NACA 6412, and NACA 64(3)-618) characterized by their high lift-to-drag ratios (161.3, 148.7, 142.7, and 136.3, respectively). These new airfoils are used to generate an entire 7 m long blades for three-bladed rotor horizontal axis wind turbine models tested numerically at low, medium, and rated wind speeds of 7.5, 10, and 12.5 m/s, respectively, with a design tip speed ratio of 7. The criterion to judge each model’s performance is power output. Thus, the blades of the model that produce the highest power are selected to undergo a tip modification (winglet) and leading-edge modification (tubercles), seeking power improvement. It is found that the GOE 447 airfoil outperformed the other three airfoils at all tested wind speeds. Thus, it is opted for adding winglets and tubercles. At 12.5 m/s, winglet design produced 5% more power, while tubercles produced 5.5% more power than the GOE 447 baseline design. Furthermore, the computational domain is divided into two regions: rotating (the disc that encloses the rotor) and stationary (the rest of the flow domain). Meanwhile, the numerical model is validated against the experimental velocity measurements. Since Reynolds-averaged Navier–Stokes with k–ω shear stress transport turbulence model can capture the laminar-to-turbulent boundary layer transition, it is used in the 18 simulations of the current work. However, large eddy simulation (LES) can deal successfully with the various scale eddies resulting from the rotor blades and its interactions with the surrounding flow. Thus, the LES was used in the six simulations done at the rated wind speed. LES power output calculation is 7.9% to 11.9% higher than the RANS power output calculation.

Wake Patterns in a Dual-Rotor Wind Turbine

2020 ◽  
Author(s):  
K. Asfar ◽  
A. Mahasneh
Keyword(s):  
Wind Turbine ◽  
Numerical Study ◽  
Mechanical Energy ◽  
Orientation Angle ◽  
Rotor Blades ◽  
Scale Model ◽  
Small Scale ◽  
Complex Flow ◽  
Horizontal Axis Wind Turbine ◽  
Wind Speeds

Abstract A recently patented novel idea of an adjustable dual-rotor horizontal-axis wind turbine is investigated [1]. The idea behind this proposed design is to continue to extract more mechanical energy from the wind stream which has already passed through the front rotor by having a second identical rotor on the other side of the main shaft of the wind turbine. The complex flow in the dual-rotor is studied using computational fluid dynamics. The optimum performance of this unit is when the wake from each blade in the first rotor passes through the spacing between each two rear rotor blades while the undisturbed part of the wind stream is intercepted by the rear rotor blades. The strength and pattern of the wakes are determined for low and high wind speeds. The numerical study verified the feasibility of the proposed idea. The optimum orientation angle at which no interception of the front rotor wake by any of the rear rotor blades is found to be 60°. The axial spacing between the front and rear rotors is also investigated. A small scale model was built and tested in a subsonic wind tunnel. The comparison showed that the dual-rotor wind turbine produced nearly 100% more power than the single-rotor wind turbine.

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.

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