A design and performance prediction method for small horizontal axis wind turbines and its application

A Direct Approach of Design Optimization for Small Horizontal Axis Wind Turbine Blades

This paper aims to do blade design of a small horizontal axis wind turbine and perform wind tunnel test to conform its efficiency. In this research Bladecalculator, Pro/E and ANSYS/CFX are used to find the relationship between the blade rotating speed with torque. The analytical results of wind turbine completely match with that of test data. Comparison with data of generator, new design blade gets more power. The power of new design blades is about ten times as the original blades.

In recent years, the energy production by wind turbines has been increasing, because its production is environmentally friendly; therefore, the technology developed for the production of energy through wind turbines brings great challenges in the investigation. The use of wind energy worldwide has overgrown in recent years to reduce greenhouse gas emissions. Wind power is free, but the installation and maintenance of wind turbines still remain costly. Wind vitality is the second biggest wellspring of sustainable power source after hydropower. However, it has not yet accomplished full matrix equality with fossil vitality sources. In this work experimental design of small HAWT for home electricity has been designed and analysed in the laboratory at the Libyan Academy for Postgraduate Studies, Al-Bayda-Libya. Experimental work was used in this paper to evaluate the wind energy data in Al-Bayda, East of Libya. The field tests and measurements proved that the present turbine is efficient and has long life-time and needs minimum maintenance. Wind turbines convert wind energy into electricity. The efficiency of this conversion is measured by comparing the incoming winds speed and the output power. From the experimental work it was found that the present turbine is efficient, easy to construct and assembly, has long life-time and needs minimum maintenance, suitable for different sites such as urban, suburban, rural, and sea coast and the output power of the turbine covers the consumption of many electric devices.

Accurate modeling of wind speed distributions is a crucial step in the design and sizing of small wind turbines. However, most current studies rely solely on the two-parameter Weibull distribution, without rigorous statistical analysis or comparison with other methods. This study presents a statistical analysis for the sizing of a small horizontal-axis wind turbine in northern Morocco. The proposed framework integrates hub-height optimization, probabilistic wind distribution modeling, and turbine parameter computation within a unified and robust methodology. The site hourly wind speed data, obtained from PVGIS, were extrapolated to an optimal hub height of 29 m using a power-law formulation combined with a cost-energy optimization approach. Then multiple distribution models were evaluated, which are the Weibull, Champernowne distribution, and kernel density estimation (KDE). Their performance was assessed using both conventional pointwise error metrics (RMSE and MAE) and distributional divergence measures, namely, Jensen‒Shannon divergence (JSD) and the Wasserstein distance (WD). Although the least-squares Weibull model produced the lowest pointwise errors (RMSE = 0.0136, MAE = 0.0103), it exhibited some distributional misspecification (JSD = 0.0132, WD = 0.0307) concentrated in the upper tail. Finally, based on a piecewise power-curve integration, the resulting turbine design parameters correspond to a swept area of 37.82 m², a blade length of 3.47 m, and a rated power of 8.28 kW to meet an annual energy demand of 33159 kWh. The results demonstrate that distributional metrics reveal modeling biases in the Weibull approach that remain undetected by traditional pointwise evaluation methods, with important implications for accurate energy yield prediction and turbine sizing reliability.

A small wind turbine blade was designed and optimized in this research paper. The blade plays an important role, because it is the most important part of the energy absorption system. Consequently, the blade has to be designed carefully to enable to absorb energy with its greatest efficiency. The main objective of this paper is to optimized blade number and selection of tip speed ratio corresponding to the solidity. The power performance of small horizontal axis wind turbines was simulated in detail using blade element momentum methods (BEM). In this paper for wind blade design various factors such as tip loss, hub loss, drag coefficient, and wake were considered. The design process includes the selection of the wind turbine type and the determination of the blade airfoil, twist angle distribution along the radius, and chord length distribution along the radius. A parametric study that will determine if the optimized values of blade twist angle and chord length create the most efficient blade geometry. The 3-bladed, 5-bladed and 7-bladed rotor achieved maximum values of Cp 0.46, 0.5 and 0.48 at the tip speed ratio 7, 5 and 4 respectively. It was observed that using BEM theory, maximum Cp varied with strongly solidity and weakly with the blade number. The studies showed that the power coefficient increases upto blade number B = 5, while the blade number if increased above 5 then the power coefficient decreases at operating pitch angle equal to 3°. Highest Cp would have solidity between 4% to 6% for number of blade 3 and design point tip speed ratio of about "7". Highest Cp would have solidity ranging from 5% to 10% for number of blade 5 and 7 and design point tip speed ratio of about 5 and 4 respectively.

Concerns over environmental impact and high infrastructure cost heavily influence the uptake of wind turbine technology. Recently researchers have started to look into wind turbines, which are much smaller in size and capacity. Small wind turbines have less environmental impact and low infrastructure cost. These small turbines have limited power generation capacity, requiring multiple turbines to be connected together to produce useful power. In order to capture power from multiple wind turbines, researchers have proposed numerous topologies in the literature. However, these traditional topologies were designed for high-power wind turbines and cannot be used to connect very small wind turbines since a significant amount of the generated power would be lost in driving the complex electronic circuits used in traditional topologies. In this paper, we present a multiple input non-isolated DC-DC converter design that collects the output power from series-connected very small wind turbines. The proposed system was implemented in our smart energy laboratory and experimental results were gathered, showing a significant improvement over existing converters.

A dual-objective optimization study was carried out to illuminate how the tip speed ratio of a small wind turbine affects the aerodynamic noise as well as the blade geometry. A 0.75 kW three-bladed small horizontal axis wind turbine was selected as the case study. Two important goals were considered in the study: maximization of the output power and the minimization of the aerodynamic noise. The former was calculated by the well-known blade-element momentum theory while a validated semi-empirical model was adopted for the computation of the latter. A combination of these goals defined the objective function and the weighted-sum approach was employed to find the optimal values for the design variables of the optimization including the distributions of the chord and the twist angle along the blade together with the tip speed ratio. The extracted power was calculated at the rated wind speed of 10 m/s while the noise was computed at lower wind speeds of 5 and 7.5 m/s. The genetic algorithm technique was adopted for the muti-objective optimization. The results revealed the importance of the blade tip region in producing the emitted aerodynamic noise. Specifically, an increase in the chord and twist values near the tip results in the reduction in the emitted noise. Results also show that a good compromise between the two goals is achievable such that a noticeable reduction in the emitted aerodynamic noise is attainable in exchange for a very small drop in the power coefficient. The optimization results also indicated that the noise could be adequately reduced at the smaller value of the tip speed ratio without a large reduction in output power which is due to the decrease in the rotational speed of the turbine.

Review of aerodynamic developments on small horizontal axis wind turbine blade

This report presents the study of fluid-structure interaction (FSI) of a 5kW horizontal axis wind turbines (HAWT). The motivation of the current investigation is to address the FSI problem of HAWT in the whole flow field analysis with hybrid turbulence model method which is used to find out the flow and structure characteristics of wind turbine in operation under different tip speed ratio (TSR). The target of current work is to obtain detailed information of flow field and structure response simultaneously using the finite element analysis (FEA) method as well as providing new reliable and accurate approach which could be quickly and economically employed in wind turbine FSI problem analysis. In this report, a detailed and comprehensive literature review related to FSI problem of wind turbine has been presented and includes aerodynamic, wind turbine theory, computational fluid dynamic, fluid structure interaction and aeroelastic stability. A 5kW wind turbine is designed according to blade element momentum (BEM) method and a 3D wind turbine modeling is generated in SolidWorks. The 3D wind turbine modeling is imported into FEA software by coupling with the structure domain and the fluid domain to achieve FSI analysis and different TSR are applied to the computational fluid dynamics (CFD) analysis to gain the wind turbine operation information under different scenarios. The simulation results are investigated to reveal the influence of the FSI phenomenon on wind turbine performance. Analysis of wind turbine aeroelastic stability is conducted to prevent blade from experiencing flutter problem. A multiple objective optimization method for wind turbine design including aerodynamic and structure has been developed to improve wind turbine performance. The flow field analysis results showed that the strength of vortex at the tip and root of the blade increases as wind speed increases when wind turbine is under operating conditions. With wind speed of 10m⁄s, most of the flow over the lower surface remains attached and the wind turbine blade was running under design condition. As the wind speed increases, flow separation emerges. When the wind speed increasing to 16m⁄s, the wind turbine blade works under deep stall condition. The wind turbine power coefficient drops continuously from 0.46 to 0.22, as wind speed increased from 10m⁄s to 20m⁄s. The comparison of wind turbine power and torque coefficient under different CFD configuration shows the advantage of whole flow field analysis with hybrid turbulence model. The structural analysis results demonstrated that most of the pressure force acts at a region around the 1⁄4 chord from the leading edge of the blade under operating condition and the displacement of blade tip in flap direction is bigger than those in the other directions. Modal analysis results deduced that flap is the main type of vibration in first and second modes. The difference of natural frequency between single blade and blade rotor becomes larger as vibration order increases. The dynamic performances of wind turbine blade and rotor are totally different and show the whole flow field method is better than the one third domain method. The wind turbine aeroelastic analysis results illustrate that the bending frequency and torsion frequency are around 23.94Hz and 38.46Hz respectively under TSR=4 and both move towards 30Hz under TSR=1.7. When TSR is smaller than 1.7 the wind turbine will experience flutter due to the overlapping of bending and torsion frequencies. The multiple objectives optimization method takes the aerodynamic performance and blade loading into account to gain better design parameter. The comparison between initial and optimal design shows that optimized method could provide higher electrical energy around 1073kW•h per annum under rated wind speed. The optimized wind turbine critical flutter wind speed will increase from initial design speed of 35m/s to 38m/s under optimization design.

Analysis on aerodynamic performance of mine horizontal axis wind turbine with air duct based on breeze power generation

The development of wireless sensor network based on breeze power generation is of great significance to promote the development of the intelligent mine. According to the underground environment of coalmine, a small horizontal axis wind turbine with mine air duct was designed. The aerodynamic performance of the wind turbine was analyzed by constructing the three‐dimensional solid model of the wind turbine. The results show that under the condition of underground low wind speed. Outer basin: the air flow entering the air duct is accelerated and rectified, and the speed increases near the impeller. The pressure value at the front end of the blade is the largest and the pressure value at the rear end of the blade is the smallest. A certain range of negative pressure zone is formed at the rear end of the impeller, which is conducive to the operation of the wind turbine. After passing through the impeller, the speed of the air flow decreases and is the lowest near the impeller rotating shaft. Inner basin: the air flow speed gradually increases along the radial direction of the impeller center. The pressure at the front end of the blade is greater than the atmospheric pressure, which is conducive to facilitating the operation of the wind turbine. When the wind speed reaches the rated wind speed of the wind turbine, the power, torque, and output power of the wind turbine increase, which can provide effective power generation. Compared with other airfoils, NACA5505 airfoil has higher lift drag ratio and thrust coefficient. Compared with the wind turbine without air duct, the wind turbine with air duct has higher wind energy conversion and output power under the condition of low Reynolds number, which verifies the feasibility of the wind turbine with air duct.

Small wind turbines are gaining popularity due to their ability to meet community or domestic needs in isolated areas with relatively easier installation and lower cost than large wind turbines. This study looks at optimizing airfoils for use in small horizontal axis wind turbines. The optimization looks to maximize the lift coefficient (Cl) while minimizing or fixing the drag coefficient (Cd). To satisfy these two objectives a multi–objective genetic algorithm is used. The airfoil is parameterized using a composite Bezier curve with two Bezier segments and 11 control points. Appropriate curvature conditions are implemented at the leading and trailing edge of the airfoil and geometric constraints are applied to maintain the maximum thickness between 8% to 14% of the chord for structural reasons. An existing genetic algorithm (GA) code is modified in C++ to generate suitable airfoils using the 13 control points and pass the coordinates to a solver for analysis. As a result four new airfoils are generated for application in low Reynolds number (Re) flow. The characteristics and suitability of the four airfoils are discussed while comparing them to the popular SG6043 airfoil.

The wind power industry has experienced fast and tremendous growth, globally, in recent years. Consequently, there is a growing interest in investigating aerodynamics and aeroacoustics characteristics of wind turbines and developing environmental standards aimed at decreasing noise levels in the design and manufacture of these machines. This study was carried out in the Carleton University Wind Induced Dynamic Laboratory (WInDLab) that was designed to evaluate and quantify noise levels emitted by a small horizontal axis wind turbine. This investigation provided the first-ever set of measurements carried out in the WInDLab following the successful installation of the wind turbine. The background acoustic data obtained for the wind tunnel showed that the wind tunnel is not quiet enough for measurements of the type undertaken. The wind tunnel would need to be silenced and acoustically treated to capture noise with low frequencies. Recommendations for further work have been provided.

Wind energy is a valuable renewable resource that holds great potential for generating electrical power through wind turbines. However, there is a lack of practical and cost-effective small-scale wind turbines designed specifically for household usage. This study aims to address this need by focusing on the design and performance analysis of a small-scale vertical Darrieus wind turbine tailored for household applications in Malaysia. The objective is to propose an optimized turbine design that maximizes energy conversion efficiency. Computational fluid dynamics (CFD) simulations using ANSYS Fluent software are conducted to evaluate the turbine's performance, with the power coefficient (Cp) calculated at various tip speed ratios (TSR). Two 3D designs with different blade configurations are developed using SolidWorks for the CFD simulations. The findings from this study contribute to the design optimization and performance evaluation of vertical Darrieus wind turbines, providing a sustainable and viable alternative for residential energy needs. This research addresses the pressing demand for clean and affordable energy solutions in Malaysia and supports the transition towards renewable sources.

This study employs a comprehensive combination of experimental and numerical methodologies to delve into the aeroacoustic attributes of a small horizontal axis wind turbine with optimized blades. The experimental investigation is conducted within a semi-anechoic chamber, where both original and optimized geometry models are meticulously positioned to measure the sound pressure levels across a range of rotational speeds and positions. In parallel, the numerical simulations employed the large eddy simulation, complemented by the Ffowcs Williams–Hawkings analogy, facilitating detailed examinations of both aerodynamic and acoustic aspects in the original and optimized modes. The findings reveal a subtle enhancement in aerodynamic performance with the optimized serrated blade configuration when compared to the original. Nevertheless, the reduction in noise levels within the frequency domain was remarkable, culminating in an impressive overall sound pressure reduction of about 10 dB. Furthermore, an intriguing observation emerged from noise measurement in acoustic room: the noise production experiences a marked escalation as the turbine rotational speed intensifies, particularly within the downstream domain. The lateral noise level is found to be lower compared to the axial direction and the reduced noise emission for the serrated optimized blade is more dispersed in the plane of rotation than the original blade, which was pointed out to be nearly uniform. The results provide valuable insights into the interplay of aerodynamics and aeroacoustics in the context of small wind turbines with optimized blades.