Design and Evaluation of a Rooftop Wind Turbine Rotor With Untwisted Blades

2013 ◽  
Author(s):  
Sayem Zafar ◽  
Mohamed Gadalla
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Low Cost ◽  
Turbine Blades ◽  
Angle Of Attack ◽  
Turbine Rotor ◽  
Wind Turbine Blades ◽  
Wind Speeds ◽  
Small Wind Turbines ◽  
Wind Turbine Rotor

A small horizontal axis wind turbine rotor was designed and tested with aerodynamically efficient, economical and easy to manufacture blades. Basic blade aerodynamic analysis was conducted using commercially available software. The blade span was constrained such that the complete wind turbine can be rooftop mountable with the envisioned wind turbine height of around 8 m. The blade was designed without any taper or twist to comply with the low cost and ease of manufacturing requirements. The aerodynamic analysis suggested laminar flow airfoils to be the most efficient airfoils for such use. Using NACA 63-418 airfoil, a rectangular blade geometry was selected with chord length of 0.27[m] and span of 1.52[m]. Glass reinforced plastic was used as the blade material for low cost and favorable strength to weight ratio with a skin thickness of 1[mm]. Because of the resultant velocity changes with respect to the blade span, while the blade is rotating, an optimal installed angle of attack was to be determined. The installed angle of attack was required to produce the highest possible rotation under usual wind speeds while start at relatively low speed. Tests were conducted at multiple wind speeds with blades mounted on free rotating shaft. The turbine was tested for three different installed angles and rotational speeds were recorded. The result showed increase in rotational speed with the increase in blade angle away from the free-stream velocity direction while the start-up speeds were found to be within close range of each other. At the optimal angle was found to be 22° from the plane of rotation. The results seem very promising for a low cost small wind turbine with no twist and taper in the blade. The tests established that non-twisted wind turbine blades, when used for rooftop small wind turbines, can generate useable electrical power for domestic consumption. It also established that, for small wind turbines, non-twisted, non-tapered blades provide an economical yet productive alternative to the existing complex wind turbine blades.

scholarly journals Comparing the Effect of Rotor Tilt Angle on Performance of Floating Offshore and Fixed Tower Wind Turbines

2019 ◽  
Vol 12 (5) ◽  
pp. 84
Author(s):  
Wongsakorn Wisatesajja ◽  
Wirachai Roynarin ◽  
Decha Intholo
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Tilt Angle ◽  
Turbine Blades ◽  
Angle Of Attack ◽  
Offshore Wind ◽  
Floating Platform ◽  
Optimal Position ◽  
Wind Speeds ◽  
Floating Offshore Wind Turbines

The development of Floating Offshore Wind Turbines (FOWTs) aims to improve the potential performance of the wind turbine. However, a problem arises due to the angle of tilt from the wind flow and the floating platform, which leads to a vertical misalignment of the turbine axis, thereby reducing the available blade area and lowering the capacity to capture energy. To address this problem, this paper seeks to compare the influence of the rotor tilt angle on wind turbine performance between fixed tower wind turbines and FOWTs. The models used in the experiments have R1235 airfoil blades of diameter 84 cm. The experiment was analyzed using a wind tunnel and mathematical modelling techniques. Measurements were obtained using an angle meter, anemometer and tachometer. Testing involved wind speeds ranging from 2 m/s to 5.5 m/s, and the rotational speeds of the two turbine designs were compared. The study found that the rotational speeds of the FOWTs were lower than those of the fixed tower turbines. Moreover, at tilt angles from 3.5° – 6.1° there was a loss in performance which varied between 22% and 32% at different wind speeds. The tilt angle had a significant effect upon FOWTs due to the angle of attack was continuously changing, thus altering the optimal position of the turbine blades. This changing angle of attack caused the effective area of the rotor blade to change, leading to a reduction in power output at suboptimal angles. The study finally makes recommendations for future studies.

Basalt Carbon Hybrid Composite for Wind Turbine Rotor Blades: A Short Review

2014 ◽  
Vol 970 ◽  
pp. 67-73 ◽  
Author(s):  
Ali Nawaz Mengal ◽  
Saravanan Karuppanan ◽  
Azmi Abdul Wahab
Keyword(s):  
Composite Material ◽  
Carbon Fiber ◽  
Wind Turbine ◽  
Hybrid Composite ◽  
Turbine Blades ◽  
Basalt Fiber ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Wind Turbine Blades ◽  
Wind Turbine Rotor

Wind turbine blades are the major structural element and highest cost component in the wind power system. Modern wind turbine blade sizes are increasing, and the driving motivation behind this is to increase the efficiency and energy output per unit rotor area, and to reduce the cost per kilowatt hour. However due to the increase in size the material selection for wind turbine has become critical and complex. To achieve the desired materials to improve the design of wind turbine blades several factors such as high fatigue strength, less weight, less cost and potential of recycling must be focused. Basalt fiber is a relative newcomer to fiber reinforced polymers and structural composites. Basalt fiber with their excellent mechanical properties represents an interesting alternative composite material for modern wind turbine blades. Some manufacturers claim that basalt fiber has similar or better properties than S-2 glass fiber and its cheaper than carbon fiber. Basalt fiber together with carbon fiber are the most advanced and interesting area of hybrid technologies. This paper reviews extra ordinary properties of basalt fiber over other fiber reinforced composites and highlight how the basalt special properties together with carbon fiber will reduce the weight and cost of wind turbine blades while improving their performance. This paper also demonstrates why the basalt carbon hybrid composite material will be an ideal alternative for the wind turbine rotor blades.

scholarly journals Pengaruh Jumlah Bilah dan Sudut Pasang terhadap Daya Turbin Angin Poros Vertikal Tipe H-Darrieus Termodifikasi sebagai Energi Alternatif Pembangkit Tenaga Listrik Skala Rumah Tangga

2019 ◽  
Vol 12 (2) ◽  
pp. 92
Author(s):  
Susilo Susilo ◽  
Bambang Widodo ◽  
Eva Magdalena Silalahi ◽  
Atmadi Priyono
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Output Power ◽  
Wind Turbines ◽  
Output Voltage ◽  
Turbine Rotor ◽  
Wind Speeds ◽  
Blade Shape ◽  
Low Wind Speeds ◽  
Wind Turbine Rotor

Bentuk sudu taper linier merupakan bentuk sudu yang paling optimal untuk kecepatan angin yang rendah. Jumlah sudu yang baik untuk kecepatan angin rendah berkisar antara 3-7 buah sudu, namun desain sudu dengan menggunakan airfoil dan profil pada sudut pasang sudu yang bagaimana memberikan daya keluaran dan tegangan keluaran yang optimal. Turbin angin didesain dengan 2 bilah dan 4 bilah dengan sudut pasang yang bisa diatur untuk mendapatkan perbedaan daya optimal masing-masing desain. Pengujian dilakukan di 3 area berbeda untuk mendapatkan gambaran geografis kondisi angin yang berbeda khususnya masalah kecepatan angin di ksiaran 2 m/s - 7 m/s. Pengujian dilakukan dengan luas penampang turbin angin (A) sebesar 3m2 Hasil penelitian menunjukkan bahwa nilai terbaik diperoleh pada kecepatan angin maksimal 4 m/s dan jumlah blade 4  sedangkan untuk nilai terkecil diperoleh pada kecepatan angin 3 m/s dan jumlah blade 2 yaitu. Untuk nilai TSR maksimal pada kecepatan maksimal 4 m/s terjadi pada jumlah blade 4, sedangkan untuk nilai terendah pada kecepatan angin 3 m/s dihasilkan pada jumlah blade 2. Melalui pengukuran berbasis teknologi smart monitoring system, dari penelitian diperoleh semakin tinggi kecepatan angin maka tegangan keluaran semakin tinggi. Semakin tinggi tegangan keluaran, semakin tinggi daya keluaran pada generator. Sudut pasang ? dan jumlah sudu mempengaruhi kecepatan putaran rotor turbin angin. Kecepatan putaran rotor turbin angin berelasi dengan tegangan keluaran generator. pada sudut pasang ? dan jumlah sudu 4, diperoleh daya keluaran yang sebesar 150 watt namun pada kecepatan angin 7 m/s daya turbin yang dihasilkan mencapai 600 watt. Dengan kondisi ini cukup memenuhi untuk alternatif cadangan listrik skala rumah tangga khusunya di pedesaan dan daerah terpencil (rural area). The linear taper blade shape is the most optimal blade shape for low wind speeds. The number of blades that are good for low wind speeds ranges from 3-7 blades, but the blade design uses an airfoil and profile on the blade mounting angle which is how to provide optimal output power and output voltage. Wind turbines are designed with 2 blades and 4 blades with adjustable tide angles to get the difference in the optimal power of each design. Tests were carried out in 3 different areas to obtain a geographical description of different wind conditions, especially the problem of wind speed in the range of 2 m / s - 7 m / s. Tests carried out with a cross section area of  wind turbines (A) of 3m2 The results showed that the best value was obtained at a maximum wind speed of 4 m / s and number 4 blade while the smallest value was obtained at wind speeds of 3 m / s and number 2 blades namely. For the maximum TSR value at a maximum speed of 4 m / s occurs in the number of 4 blades, while for the lowest value at 3 m / s wind speed is produced on the number of blades 2. From the research, the higher the wind speed, the higher the output voltage. The higher the output voltage, the higher the output power at the generator. The ? tide angle and number of blades affect the speed of the wind turbine rotor rotation. The rotational speed of the wind turbine rotor is related to the generator output voltage. at the tide angle ? and number of blades 4, the output power of 150 watts is obtained but with wind speed 7 m/s turbine power 600 watt achieved. With this condition, it is sufficient for alternative household electricity reserves, especially in rural and remote areas (rural areas).

scholarly journals Comparative Fatigue Life Assessment of Wind Turbine Blades Operating with Different Regulation Schemes

2019 ◽  
Vol 9 (21) ◽  
pp. 4632 ◽  
Author(s):  
Brian Loza ◽  
Josué Pacheco-Chérrez ◽  
Diego Cárdenas ◽  
Luis I. Minchala ◽  
Oliver Probst
Keyword(s):  
Wind Turbine ◽  
Fatigue Damage ◽  
Wind Turbines ◽  
Turbine Blades ◽  
Cost Effective ◽  
Life Assessment ◽  
Wind Speeds ◽  
Small Wind Turbines ◽  
Pitch Regulation ◽  
Power Curves

A comparative evaluation of the fatigue damage occurring in the blades of small wind turbines, with different power regulation schemes, has been conducted for the first time. Three representative test cases were built, one based on stall regulation and two using pitch regulation. The power curves were tuned to be identical in all cases, in order to allow for a direct comparison of fatigue damage. A methodology combining a dynamic simulation of a wind turbine forced by stochastic wind speed time series, with the application of the IEC 61400-2 standard, was designed and applied for two levels of turbulence intensity. The effect of the wind regime was studied by considering Weibull-distributed wind speeds with a variety of parameter sets. Not unexpectedly, in typical wind regimes, stall regulation led to a generally higher fatigue damage than pitch regulation, for similar structural blade design, but the practical implications were smaller than thought previously. Given the need for cost-effective designs for small wind turbines, stall regulation may be a viable alternative for off-grid applications.

scholarly journals Review of Wind Turbine Icing Modelling Approaches

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 5207 ◽  
Author(s):  
Fahed Martini ◽  
Leidy Tatiana Contreras Montoya ◽  
Adrian Ilinca
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Farm ◽  
Low Cost ◽  
Turbine Blades ◽  
Experimental Tests ◽  
Ice Accretion ◽  
Wind Turbine Blades ◽  
Additional Section ◽  
Research Findings

When operating in cold climates, wind turbines are vulnerable to ice accretion. The main impact of icing on wind turbines is the power losses due to geometric deformation of the iced airfoils of the blades. Significant energy losses during the wind farm lifetime must be estimated and mitigated. Finding solutions for icing calls on several areas of knowledge. Modelling and simulation as an alternative to experimental tests are primary techniques used to account for ice accretion because of their low cost and effectiveness. Several studies have been conducted to replicate ice growth on wind turbine blades using Computational Fluid Dynamics (CFD) during the last decade. While inflight icing research is well developed and well documented, wind turbine icing is still in development and has its peculiarities. This paper surveys and discusses the models, approaches and methods used in ice accretion modelling in view of their application in wind energy while summarizing the recent research findings in Surface Roughness modelling and Droplets Trajectory modelling. An An additional section discusses research on the modelling of electro-thermal icing protection systems. This paper aims to guide researchers in wind engineering to the appropriate approaches, references and tools needed to conduct reliable icing modelling for wind turbines.

Statistical extrapolation methods for estimating extreme loads on wind turbine blades under turbulent wind conditions and stochastic material properties

2020 ◽  
pp. 0309524X2093620
Author(s):  
Panagiotis N Schinas ◽  
Dimitris I Manolas ◽  
Vasilis A Riziotis ◽  
Theodore P Philippidis ◽  
Spyros G Voutsinas
Keyword(s):  
Wind Turbine ◽  
Material Properties ◽  
Ultimate Load ◽  
Turbine Blades ◽  
Turbine Rotor ◽  
Wind Turbine Blades ◽  
Extreme Loads ◽  
Certification Procedure ◽  
Peak Over Threshold ◽  
Wind Turbine Rotor

According to the IEC Standard 61400-1, designers of wind turbines are required to apply statistical extrapolation techniques to estimate the extreme (ultimate) load. In the present article, the certification procedure is assessed under the uncertainty of the material properties using a simulated load time series of the National Renewable Energy Laboratory 5MW reference wind turbine rotor. The uncertainty of the material properties is introduced in the elastic properties of the composite materials based on the OptiDAT composite material database. The assessment relies on the comparison of the estimated blade extreme loads and deflections, obtained for the reference and the stochastically varied material properties. It is found that the variability of the material properties does not affect the estimated ultimate moments (differences < 1.5%) but affects the maximum flapwise deflection (differences ~8%). It is concluded that the peak over threshold peak extraction technique and the three-parameter Weibull fitting functions outperform among those considered in the article.

Far-Field Noise Prediction of Wind Turbines at Different Receivers and Wind Speeds: A Computational Study

2015 ◽  
Author(s):  
Fardin Khalili ◽  
Pradip Majumdar ◽  
Mehdi Zeyghami
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Turbine Blades ◽  
Wind Farms ◽  
Acoustic Power ◽  
Far Field ◽  
Wind Turbine Blades ◽  
Wind Speeds ◽  
Field Noise ◽  
Field Sound

Far-field noise propagation from wind turbines propel development of wind farms to an issue for public acceptance. Airstream contains pressure fluctuations as a result of instability, giving a regular eddy pattern or an irregular turbulent motion which are responsible for the sound produced by wind turbine blades. Aeroacoustic noise emanated from a wind turbine is mainly generated by the interactions of tip and trailing edge of wind turbine blades with the mechanics in wake region such as inflow turbulence structures, boundary layer separation and vortex shedding. Hence, there is a strong necessity for an analytical investigation for noise reducing design and development of the technology in order to further expand wind farms. The objectives of this study are to analyze the far-field aeroacoustics of wind turbines with the purpose of predicting far-field sound pressure levels at different receivers and monitoring total acoustic power captured within wind turbine performance for various wind speeds. Blades are modeled based on NREL S825 airfoil since it has high maximum lift and low profile drag. With the purpose of predicting far-field noise, the Ffowcs Williams-Hawkings (FW-H) acoustics model is the preferred method in order to compute the far-field sound signal which is released from near-field flow. As the key attribute of the research, detached eddy simulation (DES) provides accurate results for the desired simulation since it is a hybrid modeling approach that combines features of Reynolds-averaged Navier-Stokes (RANS) simulation in boundary layers and irrotational flow regions, and large-eddy simulation (LES) in unsteady separation regions. In addition, SST K-Omega detached eddy turbulence model is used due to its good compromise between robustness, computational cost and accuracy. Aerodynamic and aeroacoustic analysis of a wind turbine is performed using a three-dimensional model and a commercial CFD Software, STAR-CCM+. In order to predict far-field sound pressure levels and acoustic powers on different locations, five point receivers are defined downstream of the wind turbine model. Receivers are placed one diameter, D, over the wind turbine rotor blades with 1D, 2D, 5D, 10D and 15D away from the wind turbine that represent receivers 1 to 5. Higher acoustic powers are delivered at closer receivers. It means that acoustic power fades out with larger distances. It is observed that there is a fractional variation of 61%, 17%, 6% and 3% as compared to the receiver 1 for receivers 2, 3, 4 and 5 respectively. Moreover, the results show that variation in total acoustic power is non-linear and higher acoustic powers will be captured for higher velocities. This comparison is done between wind speeds of 10m/s and 15m/s.

Evaluation of the influence of wind speed and angle of attack on the aerodynamic effect of wind turbine blades

2017 ◽  
Author(s):  
Salete Alves ◽  
Luiz Guilherme Vieira Meira de Souza ◽  
Edália Azevedo de Faria ◽  
Maria Thereza dos Santos Silva ◽  
Ranaildo Silva
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Turbine Blades ◽  
Angle Of Attack ◽  
Wind Turbine Blades ◽  
Aerodynamic Effect

scholarly journals Novel Application and Validation of a Method to Assess Visual Impacts of Rotating Wind Turbine Blades Within Woodland Areas

2021 ◽  
Vol 89 (1) ◽  
pp. 1-14
Author(s):  
U. Nopp-Mayr ◽  
F. Kunz ◽  
F. Suppan ◽  
E. Schöll ◽  
J. Coppes
Keyword(s):  
Environmental Impact ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Power Plants ◽  
Laser Scanning ◽  
Forest Canopy ◽  
Turbine Blades ◽  
Wind Turbine Blades ◽  
Environmental Impact Assessments ◽  
Independent Field

AbstractIncreasing numbers of wind power plants (WPP) are constructed across the globe to reduce the anthropogenic contribution to global warming. There are, however, concerns on the effects of WPP on human health as well as related effects on wildlife. To address potential effects of WPP in environmental impact assessments, existing models accounting for shadow flickering and noise are widely applied. However, a standardized, yet simple and widely applicable proxy for the visibility of rotating wind turbines in woodland areas was largely lacking up to date. We combined land cover information of forest canopy extracted from orthophotos and airborne laser scanning (LiDAR) data to represent the visibility of rotating wind turbines in five woodland study sites with a high spatial resolution. Performing an in-situ validation in five study areas across Europe which resulted in a unique sample of 1738 independent field observations, we show that our approach adequately predicts from where rotating wind turbine blades are visible within woodlands or not. We thus provide strong evidence, that our approach yields a valuable proxy of the visibility of moving rotor blades with high resolution which in turn can be applied in environmental impact assessments of WPP within woodlands worldwide.

scholarly journals Sustainable End-of-Life Management of Wind Turbine Blades: Overview of Current and Coming Solutions

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1124
Author(s):  
Leon Mishnaevsky Mishnaevsky
Keyword(s):  
Wind Turbine ◽  
End Of Life ◽  
Wind Turbines ◽  
Natural Fiber ◽  
Turbine Blades ◽  
Wind Turbine Blades ◽  
Maintenance And Repair ◽  
Life Management ◽  
Large Wind

Various scenarios of end-of-life management of wind turbine blades are reviewed. “Reactive” strategies, designed to deal with already available, ageing turbines, installed in the 2000s, are discussed, among them, maintenance and repair, reuse, refurbishment and recycling. The main results and challenges of “pro-active strategies”, designed to ensure recyclability of new generations of wind turbines, are discussed. Among the main directions, the wind turbine blades with thermoplastic and recyclable thermoset composite matrices, as well as wood, bamboo and natural fiber-based composites were reviewed. It is argued that repair and reuse of wind turbine blades, and extension of the blade life has currently a number of advantages over other approaches. While new recyclable materials have been tested in laboratories, or in some cases on small or medium blades, there are remaining technological challenges for their utilization in large wind turbine blades.

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