Small-scale Horizontal Axis Wind Turbine Research Articles

Numerical investigation of sand erosion rate in a horizontal axis wind turbine

Renewable energy represents an important alternative solution for many energy problems nowadays and a tool for a healthier environment by reducing carbon footprints resulting from burning fossil fuels. However, more work needs to be done towards maximizing the energy produced from renewable energy methods and making sure that the infrastructure used stays in service for a longer duration. Sand erosion phenomena is responsible for the degradation of the wind turbine blades and hence the decrease in their performance and life. In the current research, a numerical study of both performance and sand erosion of a Small-Scale Horizontal Axis Wind Turbine (SS-HAWT) is carried out. This study introduces new sights of instantaneous and forecasted erosion rates within the blade of the wind turbines. Three-dimensional E216 airfoil blades of radius 0.5 m are established according to blade element momentum theory. Sand particles with different mass flow rates of 0.001, 0.002 and 0.003 kg/s and uniform diameters of 50, 100 and 200 μm have been selected as eroding particles under two different average air velocities of 8 m/s and 10 m/s. The results indicate that the performance of wind turbines is enhanced as the flow separation at the suction side is shifted to the trailing edge. Furthermore, the optimum tip speed ratio is about 5 at an air velocity of 8 m/s with a power coefficient of 0.432. In terms of erosion findings, V-shaped scars are reported near the leading edge of the blades. In addition, the instantaneous erosion rate grows exponentially with the tip speed ratio. Therefore, the yearly prediction of maximum erosion depth at the optimum operating conditions is obtained to be 5.7 mm/year in some spots of the turbine blades.

Effect of flanged diffuser divergence angle on wind turbine: A numerical investigation.

Power augmentation in a small-scale horizontal axis wind turbine, with its rotor encased in a flanged diffuser is explored. The power output of the wind turbine varies with changes in the diffuser design and the resulting back pressure. Reduction in this back pressure also results in early flow separation at the diffuser surface, which hinders turbine performance. The main aim of this study is to numerically investigate the local configuration of the wind turbine location inside the diffuser by varying diffuser angles and wind speeds. Therefore, shroud and flange were modeled and analyzed using the computational fluid dynamic (CFD) analyses and experiments were performed at two wind speeds 6 m/s and 8 m/s with and without the diffuser for model validation. The divergence angle of 4° was found to have no flow separation, thus maximizing flow rate. The proposed design shows wind speed improvement of up to 1.68 times compared to the baseline configuration. The corresponding optimum flange height was found to be 250 mm. However, increasing the divergence angle had a similar output. The dimensionless location of wind turbine was found to be between 0.45 and 0.5 for 2° and 4° divergence angle respectively. Furthermore, the maximum augmentation location varies with wind speed and diffuser's divergence angle as described by dimensionless location of wind turbine, thus presenting a noteworthy contribution to the horizontal axis wind turbine area with the flanged diffuser.

Single-objective optimization design of convergent-divergent ducts of ducted wind turbine using RSM and GA, to increase power coefficient of a small-scale horizontal axis wind turbine

Single-objective optimization design of convergent-divergent ducts of ducted wind turbine using RSM and GA, to increase power coefficient of a small-scale horizontal axis wind turbine

Development of a wind turbine for a hybrid solar-wind power system

Conventional energy supply has not been able to meet the energy needs of most developing nations. This calls for the need to invest in renewable energy systems which are not only sustainable but clean, abundant, and easily assessable. This research presents a study of wind variability by using wind data got from a weather station to design and fabricate a small-scale horizontal axis wind turbine (HAWT). This was done by using locally sourced materials for a Hybrid Solar-Wind power system for irrigation purposes, as a performance evaluation of the turbine. The materials used in the fabrication of the turbine include wood, polyvinyl chloride plastic, acrylic glass, Teflon, and steel all sourced locally. From the evaluation, the power capacity of the wind turbine was derived to be 40 W, 41 W and 43 W from the voltage and current output reading on the multi-meter from three average wind speed variations of 5 m/s, 10 m/s and 15 m/s measured from handheld digital anemometers respectively. A regression analysis of the relationship between the turbine's power capacity and the wind speed showed that the turbine operates best at low speed of 5 m/s, with an R2 value of 0.9602. The fabricated wind turbine was connected to a hybrid power system with the second energy source consisting of a 40 W solar tracking system to give a more stable power supply. The system was used for soil monitoring irrigation purposes. The design of the HAWT indicates a cheap, alternative and sustainable energy source that is more stable and suitable for smart solar panel irrigation system.

Enhancing Performance of Small Capacity Horizontal Axis Wind Turbine Using Grooved Linearized-Chord Blades

Abstract In the current article, E216 airfoil blades with linearized chord of a small-scale horizontal axis wind turbine are numerically investigated to enhance the performance of the turbine. The blade is modified by including grooves on its suction side. Three-dimensional Reynold’s averaged Navier–Stokes (RANS) simulations are performed with Shear Stress Transport k–ω as a turbulence model. The computed power-coefficient results are first validated with previous measurements by the present authors on a wind turbine of 1 m rotor diameter at two wind speeds of 6 and 8 m/s. Another validation with measurements from the literature is performed via comparison of the pressure-coefficient distribution along surfaces of E216 airfoil at an angle of attack of 6 deg. Based on the successful computation, six different rotor models are numerically investigated with different numbers and locations of grooves created along the blade length, from the hub to the tip region, on the blade suction side. The lift and drag coefficients are compared for the different simulated rotor models. Furthermore, the torque coefficient, thrust coefficient, and static torque coefficient are obtained for the simulated models. It is found that the best-simulated configuration is Model 1 having one groove at 80% blade-chord length from the leading edge, with a maximum power coefficient of 0.429 at a tip-speed ratio of 4.75. The aerodynamic performance of the blades is strongly affected by the groove on the suction surface. The results show that Model 1 blade reduces the generated mean-axial force and its vibration frequency on the rotor.

Mode interpretation of blade number effects on wake dynamics of small-scale horizontal axis wind turbine

The blade number of a wind turbine is a critical parameter that significantly affects its near-wake dynamics. In this study, we focused on the effect of the blade number on the wake of a small-scale horizontal-axis wind turbine (SHAWT) with a diameter of 0.18 m. An airfoil with a high lift coefficient was designed for a SHAWT model operating at a low Reynolds number. Large eddy simulation (LES) and optimal mode decomposition (OMD) were performed to identify the underlying coherence mode and to elucidate the wake dynamics. The LES results indicate that an increase in the blade number causes the double-peak velocity distribution to prematurely form a single peak shape. The effects of the blade number and tip speed ratio on the width and velocity deficit of the wake were also determined. The OMD results show that an increase in the number of blades results in the appearance of interharmonic modes with energies lower than that of the mean flow mode. Meanwhile, the increase in blade number causes early instability of the tip and hub/root vortices, leading to the break down and formation of patterns of streamwise vortices in the far wake. This leads to earlier wake recovery and influences the energy extraction and fatigue loads of the downstream turbines.

Design and Optimization of a Small-Scale Horizontal Axis Wind Turbine Blade for Energy Harvesting at Low Wind Profile Areas

Wind turbine blades perform the most important function in the wind energy conversion process. It plays the most vital role of absorbing the kinetic energy of the wind, and converting it to mechanical energy before it is transformed into electrical energy by generators. In this work, National Advisory Committee for Aeronautics (NACA) 4412 and SG6043 airfoils were selected to design a small horizontal axis variable speed wind turbine blade for harvesting efficient energy from low wind speed areas. Due to the low wind profile of the targeted area, a blade of one-meter radius was considered in this study. To attain the set objectives of fast starting time and generate more torque and power at low wind speeds, optimization was carryout by varying Reynolds numbers (Re) on tip speed ratios (TSR) values of 4, 5, and 6. The blade element momentum (BEM) method was developed in MATLAB programming code to iteratively find the best twist and chord distributions along the one-meter blade length for each Re and tip speed ratio (TSR) value. To further enhance the blade performance, the twist and chord distributions were transferred to Q-blade software, where simulations of the power coefficients (Cp) were performed and further optimized by varying the angles of attack. The highest power coefficients values of 0.42, 0.43, and 0.44 were recorded with NACA 4412 rotor blades, and 0.43, 0.44, and 0.45 with SG6043 rotor blades. At the Re of 3.0 × 105, the blades were able to harvest maximum power of 144.73 watts (W), 159.69 W, and 201.04 W with the NACA 4412 and 213.15 W, 226.44 W, 245.09 W with the SG6043 at the TSR of 4, 5, and 6 respectively. The lowest cut-in speed of 1.80 m/s and 1.70 m/s were achieved with NACA 4412 and SG6043 airfoils at TSR 4. At a low wind speed of 4 m/s, the blades were able to harness an efficient power of 79.3. W and 80.10 W with both rotor blades at the TSR 4 and 6 accordingly.

The impact of trailing edge flap on the aerodynamic performance of small-scale horizontal axis wind turbine

Despite the significant progress in the wind energy field, there is always space for new blade profiles to improve the efficiency and the energy extracted of HAWTs. To improve the performance of small-scale HAWTs, a new blade profile design using a fixed trailing-edge flap was investigated using blade element momentum (BEM) approach and validated using computational fluid dynamics (CFD) approach. The aim of this study is to obtain a new blade profile which has higher lift-to-drag coefficient for wind turbine by integrating a trailing-edge flap into a reference blade design. To determine the optimal blade profile, the annual yield based on the Weibull distribution is used. The full three-dimensional CFD analyses were performed on the new blade profile only. The BEM results show that at the design tip speed ratio of 7, the power coefficient of the new blade profile is 8.3% higher than the reference design. According to the new blade profile, the CFD method over-predicts the power coefficient compared with the BEM method. According to wind speed distribution in Turkey, the annual yield of the wind turbine with the reference blade profile and the new blade profile was found as 6378 kWh/year and 6944 kWh/year, respectively.

Parametric Analysis Using CFD to Study the Impact of Geometric and Numerical Modeling on the Performance of a Small Scale Horizontal Axis Wind Turbine

The reliance on Computational Fluid Dynamics (CFD) simulations has drastically increased over time to evaluate the aerodynamic performance of small-scale wind turbines. With the rapid variability in customer demand, industrial requirements, economic constraints, and time limitations associated with the design and development of small-scale wind turbines, the trade-off between computational resources and the simulation’s numerical accuracy may vary significantly. In the context of wind turbine design and analysis, high fidelity simulation under full geometric and numerical complexity is more accurate but pose significant demands from a computational standpoint. There is a need to understand and quantify performance deterioration of high fidelity simulations under reduced geometric or numerical approximation on a single small scale turbine model. In the present work, the flow past a small-scale Horizontal Axis Wind Turbine (HAWT) was simulated under various geometric and numerical configurations. The geometric complexity was varied based on stationary and rotating turbine conditions. In the stationary case, simple 2D airfoil, 2.5D blade, 3D blade sections are evaluated, while rotational effects are introduced for the configuration 3D blade, rotor only, and the full-scale wind turbine with and without the inclusion of a nacelle and tower. In terms of numerical complexity, the Single Reference Frame (SRF), Multiple Reference Frames (MRF), and the Sliding Meshing Interface (SMI) is analyzed over Tip Speed Ratios (TSR) of 3, 6, 10. The quantification of aerodynamic coefficients of the blade (Cl, Cd) and turbine (Cp, Ct) was conducted along with the discussion on wake patterns in comparison with experimental data.

Design and analysis of small-scale horizontal axis wind turbine using PVC material

The project aims to develop a low-cost horizontal axis wind turbine that will reduce energy costs and reduce reliance on non-renewable resources for power generation. There are many types of commercially available wind turbine designs are present currently but they require sophisticated manufacturing using composite materials that makes it very complex hence they are very costly. Our aim is to suggest a suitable alternate to this that can cater the needs of small-scale wind turbine design having a simple and cost-effective design. For this, PVC was chosen as a material because it is readily available, inexpensive, and lightweight, allowing it to deliver more power. Our main focus was to study the feasibility of this design and have a comparison with the current industrial 3D blade designs. CFD analysis on the proposed design was conducted including parametric studies on PVC, as well as structural and modal analysis for blades with appropriate power coefficients and it is compared with the industrial 3D wind turbine blades. The analysis is carried out in such a way that the pressure distribution obtained from the CFD analysis is imported into structural analysis and used as a load boundary condition. The total deformation and equivalent stress on the blade are calculated for a design which was giving the highest efficiency from the parametric studies.

Experimental and numerical investigation of the effect of blade number on the aerodynamic performance of a small-scale horizontal axis wind turbine

This study presents experimental and numerical investigation for the effect of number of blade (solidity) on the power and thrust coefficients of a small-scale horizontal-axis wind turbine HAWT. An experimental set- up was installed on wind turbine rotors with different number of blades, i.e. three, five and six, and at different tip speed ratios, in the closed-circuit open-test section wind tunnel. The obtained results from CFD simulations were performed to compare numerical data with experimental measurements. In addition, there is a lack of information presented for the effect of rotor blade number on the flow field for HAWT like vertical axis wind turbine VAWT. Therefore, the current study extends to study the effect of solidity on the flow field using numerical calculation. The numerical simulation was performed using a steady-RANS method. The SST k-ω turbulence model was used to represent turbulence characteristics. It is found that decreasing the number of blades (which makes the turbine less sensitive to the change in tip speed ratio) the wind turbine with 3 blade configuration has the maximum power coefficient in respect to 5 and 6 blade turbines, higher by around 2 and 4 percent respectively.

Canard optimization for enhancing the performance of small horizontal axis wind turbine at 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%.

Experimental study on small scale horizontal axis wind turbine of analytically-optimized blade with linearized chord twist angle profile

Blade linearization is used to simplify the blade design and reduce the blade manufacturing cost of Small-Scale Horizontal Axis Wind Turbine (SSHAWT). Compared to analytical studies, experimental investigations on the blade linearization of SSHAWT are rare. The present work aims to introduce a simple and efficient design of SSHAWT, and verify its performance experimentally. Two designs of rotor models are proposed and their performance is analyzed. The first one is a classical rotor with non-linear chord and twist distributions and the second one is a new linearized rotor design. Analytical optimizations of the linearized blades are employed through three tuning steps using Blade Element Momentum (BEM) theory. The highest coefficient of correlation with the classical rotor among the linearized rotor is found to be 0.969. The two rotor models, selected based on the optimization results are then fabricated, tested, and compared. The comparison made between the two designs is verified experimentally, at different wind speeds of 5, 6, 8, and 10 m/s. Further, measurements are performed at blade pitching of −3, 0, and 3°. It was found that, the proposed new linear design of the rotor blades has efficient performance, with maximum power coefficient Cpmax=0.426 at tip-speed ratio 5.1 and wind speed 10 m/s. The performance in terms of power coefficient approaches that achieved by non-linear blades. Moreover, there is significant reduction in the blade size volume of the new design by 26% which consequently reduces the blade weight. The results obtained in the present work show higher starting ability and extended operating range of the linearized model at lower wind speed compared with the classical model.

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

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.

Investigation of an Innovative Rotor Modification for a Small-Scale Horizontal Axis Wind Turbine

This paper presents the results of the computational fluid dynamics (CFD) simulation of the airflow for a 300 W horizontal axis wind turbine, using additional structural elements which modify the original shape of the rotor in the form of multi-shaped bowls which change the airflow distribution. A three-dimensional CAD model of the tested wind turbine was presented, with three variants subjected to simulation: a basic wind turbine without the element that modifies the airflow distribution, a turbine with a plano-convex bowl, and a turbine with a centrally convex bowl, with the hyperbolic disappearance of convexity as the radius of the rotor increases. The momentary value of wind speed, recorded at measuring points located in the plane of wind turbine blades, demonstrated an increase when compared to the base model by 35% for the wind turbine with the plano-convex bowl, for the wind speed of 5 m/s, and 31.3% and 49% for the higher approaching wind speed, for the plano-convex bowl and centrally convex bowl, respectively. The centrally convex bowl seems to be more appropriate for higher approaching wind speeds. An increase in wind turbine efficiency, described by the power coefficient, for solutions with aerodynamic bowls was observed.

Modeling and Investigation Performance of Small-Scale PMSG based HAWT with FOC

This paper focused on modeling and simulation of small-scale horizontal axis wind turbine (HAWT) based on permanent magnetic synchronous generator (PMSG) with filed oriented control (FOC) circuit connected to 3-phase full bridge rectifier by MATLAB software. FOC system developed for generator side converter to regulate mechanical speed and electromagnetic torque at variable wind speed. Space vector pulse width modulation (SVPWM) had been implanted in FOC system to turn on six-IGBT switches and validate pure and steady-state of output voltage. Results showed optimum performance coefficient was 0.48 and tip speed ratio 8.1 at zero pitch angle, also when pitch angle increase by 5°coefficient performance decreased to 0.35. The simulated waveforms of the mechanical speed, and electromagnetic torque were contained two case, before and after applied FOC. With FOC, the results shown faster and smooth response to the faster change in wind speed.

Numerical Simulation of a Bionic Blade on Small-Scale Wind Turbine

This study presents the aerodynamic characteristics of a small-scale horizontal axis wind turbine (HAWT) with bionic blade contours. Taiwan incense cedar was chosen as imitations. On account of the contour of the winged disseminules and the ANSYS FLUENT 14, we designed the bionic blades to process the computations of aerodynamic characteristics of the bionic wind turbine blades. The aerodynamic characteristics and the wind/electricity power transform efficiency of the turbines were examined in a wind tunnel. The wind tunnel experimental outcomes showed that the wind/electricity transformation efficiency of the wind turbine setup could reach to 37%, and it is benefit environment and global energy management.

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

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.

Aerodynamic and structural analysis of a small-scale horizontal axis wind turbine using QBlade

In this paper the aerodynamic and structural analysis of a small-scale horizontal axis wind turbine using QBlade software will be presented. QBlade software will be used to validate the wind turbine design, according with the Blade Element Momentum theory. The influence of the tip and root losses on the power curve will be analysed. The pitch angle control curve will be obtained. The annual energy production will be analysed on the basis of Weibull parameters. The structural analysis in terms of modal and static structural will be presented for three different internal structures: solid blade, hollow blade without spar, and hollow blade with spar. It has been found that the natural frequencies obtained for lateral translations (flapwise and edgewise), chord rotation around the blade longitudinal axis and longitudinal translation are in a safety range from the harmonics of wind turbine rotational speed at the operating condition, thus avoiding the resonance.

Vibration characteristic responses due to transient mass loading on wind turbine blades

Wind turbine blades can experience mass collision events during operations, either due to bird strikes or with other flying objects. The rapid impact loadings due to these events can cause fatigue damage leading to subsequent blade loss or even wind turbine system failure. This paper addresses the effects of transient loadings resulting from a rapid mass reduction event from the rotating blade as well as an impacting mass onto the wind turbine blade, leading to transient vibration and unbalance within the turbine system. The novelty of the research is that it shows the coupling between the blade in-plane with tower transverse (Z-direction) vibrations, and blade out-of-plane with tower front (Y-direction) vibrations which have been identified through different experiments. Measurements from an experimental small-scale horizontal axis wind turbine test rig are reported, instrumented with contact and non-contact sensors and rotating and non-rotating sensors, to investigate the various transient impact loading events. Additionally, the drive shaft vibration for different conditions has been monitored by utilizing orthogonal laser measurement for detecting the main shaft displacements towards perpendicular axes. Subsequent orbit analysis is presented showing the analysis of different shaft orders during the rapid mass reduction and mass collision events. Complex orbit and filtering analysis of shaft orders during the transient mass impact loading events are used to demonstrate the sensitivity of the sensors for further fault detection.