scholarly journals THE EFFECT OF NUMBER OF BLADES EXPERIMENTALLY ON THE HORIZONTAL WIND TURBINE SPEED

2021 ◽  
Vol 25 (Special) ◽  
pp. 2-1-2-8
Author(s):  
Aiya N. Hussein ◽  
◽  
Basim A. Sadkhan ◽  
Keyword(s):  
Wind Turbine ◽  
Wind Velocity ◽  
Rotational Speed ◽  
Rotor Blades ◽  
Horizontal Wind ◽  
Speed Ratio ◽  
High Wind ◽  
Tip Speed Ratio ◽  
Turbine Speed ◽  
Turbine Design

The aim of this research is to find the effect of the number of blades on the wind turbine speed and to find which number of blades is suitable for low wind areas and high wind areas. In wind turbine design; the number of blades, tip speed ratio, and the rotational speed of the rotor are the most important factors. At first, the tip speed ratio and the number of blades must be selected. The power of a wind turbine generator depends on the rotational speed of the rotor. The increase in wind velocity leads to an increase in the rotor speed. At wind velocity 2.36m/s, the rotational speed of 6 blades, 4 blades and 3 blades was 288, 54, and 34 rpm respectively. And, at wind velocity 13.85m/s, the rotational speed of 6 blades, 4 blades, and 3 blades are 1856, 2220, and 2103 rpm respectively. So, when the number of blades decreases, the rotational speed will increase at high wind velocity. But, at low wind velocity, the rotational speed is more effective when the number of blades increases. So, 6 rotor blades were found as suitable for low wind velocity areas as in Iraq.

scholarly journals Attempt to quantify the impact of seasonal air density variation on operating tip-speed ratio of small wind turbines

2021 ◽  
Vol 2090 (1) ◽  
pp. 012144
Author(s):  
Hiroki Suzuki ◽  
Yutaka Hasegawa ◽  
O.D. Afolabi Oluwasola ◽  
Shinsuke Mochizuki
Keyword(s):  
Wind Turbine ◽  
Wind Velocity ◽  
Governing Equation ◽  
Rotational Speed ◽  
Speed Ratio ◽  
Tip Speed Ratio ◽  
Air Density ◽  
Small Wind Turbines ◽  
The Impact ◽  
Aerodynamic Torque

Abstract This study presents the impact of seasonal variation in air density on the operating tip-speed ratio of small wind turbines. The air density, which varies depending on the temperature, atmospheric pressure, and relative humidity, has an annual amplitude of about 5% in Tokyo, Japan. This study quantified this impact using the rotational speed equation of motion in a small wind turbine informed by previous work. This governing equation has been simplified by expanding the aerodynamic torque coefficient profile for a wind turbine rotor to the tip-speed ratio. Furthermore, this governing equation is simplified by using nondimensional forms of the air density, inflow wind velocity, and rotational speed with their characteristic values. In this study, the generator’s load is set to be constant based on a previous analysis of a small wind turbine. By considering the equilibrium between the aerodynamic torque and the load torque of the governing equation at the optimum tip-speed ratio, the impact of the variation in the air density on the operating tip-speed ratio was expressed using a simple mathematical form. As shown in this derived form, the operating tip-speed ratio was found to be less sensitive to a variation in air density than that in inflow wind velocity.

Study on Performance and Flow Condition of a Cross-Flow Wind Turbine With a Symmetrical Casing

2011 ◽  
Vol 133 (5) ◽  
Author(s):  
Junichiro Fukutomi ◽  
Toru Shigemitsu ◽  
Hiroki Daito
Keyword(s):  
Wind Turbine ◽  
Rotational Speed ◽  
Flow Condition ◽  
Cross Flow ◽  
Low Noise ◽  
Maximum Power ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Tip Speed Ratio ◽  
The Cross

A cross-flow wind turbine has a high torque coefficient at a low tip speed ratio. Therefore, it is a good candidate for use as a self-starting turbine. Furthermore, it has low noise and excellent stability; therefore, it has attracted attention from the viewpoint of applications as a small wind turbine for an urban district. However, its maximum power coefficient is extremely low (10%) as compared to that of other small wind turbines. Prevailing winds in two directions often blow in urban and coastal regions. Therefore, in order to improve the performance and the flow condition of the cross-flow rotor, a casing suitable for this sort of prevailing wind conditions is designed in this research and the effect of the casing is investigated by experimental and numerical analysis. In the experiment, a wind tunnel with a square discharge is used and main flow velocity is set as 20 m/s. A torque meter, a rotational speed pickup, and a motor are assembled with the same axis as the test wind turbine and the tip speed ratio is changeable by a rotational speed controller. The casing is set around the cross-flow rotor and flow distribution at the rotor inlet and the outlet is measured by a one-hole pitot tube. The maximum power coefficient is obtained as Cpmax = 0.19 with the casing, however Cpmax = 0.098 without the casing. It is clear that the inlet and the outlet flow condition is improved by the casing. In the present paper, in order to improve the performance of a cross-flow wind turbine, a symmetrical casing suitable for prevailing winds in two directions is proposed. Then, the performance and the internal flow condition of the cross-flow wind turbine with the casing are clarified. Furthermore, the influence of the symmetrical casing on performance is discussed and the relation between the flow condition and performance is considered.

A Study of Electricity Generating from Small Multi-Blade Wind Turbine for a Household

2013 ◽  
Vol 291-294 ◽  
pp. 435-438
Author(s):  
Yuttachai Keawsuntia
Keyword(s):  
Wind Tunnel ◽  
Wind Turbine ◽  
Electric Power ◽  
Wind Velocity ◽  
Simulation Program ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Alternative Technology ◽  
Tip Speed Ratio ◽  
Program Show

A small multi-blade wind turbine is an alternative technology in order to electricity generating for use in a household because of the construction is cheap. From the study, the performance calculations by simulation program show that a number of blade at 12 blades is the optimum value for applying to this wind turbine that give maximum power coefficient of 0.29 at a tip speed ratio of 1.2. The results from the test run of wind rotor connected with generator in the wind tunnel at a wind velocity of 2 m/s, 3 m/s and 4 m/s, the system give the electric power of 2.5 W, 4.25 W and 4.49 W respectively.

scholarly journals Performance Augmenting of a Vertical Axis Wind Turbine using Adaptable Convergent Ducting System

2018 ◽  
Vol 14 (3) ◽  
pp. 141-148
Author(s):  
Abdullateef A. Jadallah ◽  
Sahar R. Farag ◽  
Jinan D. Hamdi
Keyword(s):  
Wind Turbine ◽  
Wind Velocity ◽  
Vertical Axis ◽  
Coefficient Of Performance ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Ansys Fluent ◽  
Tip Speed Ratio ◽  
Vertical Axis Wind Turbines ◽  
Inlet Angle

Developments are carried out to enhance the performance of vertical axis wind turbines (VAWT). This paper studies the performance of the ducted wind turbine with convergent duct (DAWT). Basically, the duct technique is utilized to provide the desired wind velocity facing the turbine. Methodology was developed to estimate the decisive performance parameter and to present the effect of the convergent duct with different inlet angles. The ducted wind turbine was analyzed and simulated using MATLAB software and numerically using ANSYS-Fluent 17.2. Result of both approaches were presented and showed good closeness for the two cases of covering angles 12  and 20 respectively. Results also showed that the convergent duct with an inlet angle 12   and 20  improved the coefficient of performance at a specified tip speed ratio by 25.8% and 33.33% respectively in the productivity of wind turbine.  

Effects of Design Parameters on Aerodynamic Performance of New Profile Small Wind Turbine Blades

2015 ◽  
Author(s):  
Mahasidha Birajdar ◽  
Sandip Kale ◽  
S. N. Sapali
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Turbine Blade ◽  
Rotational Speed ◽  
Aerodynamic Performance ◽  
Design Parameters ◽  
Speed Ratio ◽  
Tip Speed Ratio ◽  
Small Wind Turbine ◽  
Thrust And Torque

Wind is a one of the clean resources of energy and has the ability to contribute a considerable share in growing world energy consumption. The small wind turbine plays a vital role in fulfillment of energy needs preferably for household purpose. In order to unleash the budding of applicability of small wind turbine, it is necessary to improve its performance. The performance of a small wind turbine can be distinguished by the manners in which power, thrust and torque vary with the wind speed. The wind power indicates the amount of energy captured by the wind turbine rotor. It is convenient to express the performance of small wind turbine by means of non-dimensional performance curves, therefore in this paper the most graphs are drawn to power, thrust and torque coefficients as a function of the tip speed ratio. This paper presents the effect of design parameters such as the tip speed ratio, angle of attack, wind speed, solidity, number of blades, etc. on the aerodynamic performance of small wind turbine and proposes the optimum values of these parameters for the newly designed blade. The new designed blade consists of two new airfoils and named as IND 15045 and IND 09848. This new profile blade is designed for a wind turbine of 1 kW rated power. The blade is divided into ten sections. The designed length of blade is 1.5 m and it is made using IND 15045 airfoils at three root sections and IND 09848 airfoils for remaining seven sections. Q-Blade is used for the numerical simulation of wind turbine airfoils and blade. It is integrated tool of XFOIL and blade element momentum theory of wind turbine blade design. Also the effect of constant rotational speed operation, effect of stall regulation effect of rotational speed change and the effect of solidity on the performance of wind turbine is discussed. This paper delivers a broad view of perception for design of small wind turbine and parameter selection for the new wind turbine blade. Also in this paper the effect of different losses viz. tip losses, drag losses, stall losses and hub losses on the small wind turbine are discussed. The efficiency of the small wind turbine varies significantly with wind speed, but it would be designed such a way that maximized efficiencies are achieved at the wind speed where the maximum energy is available.

A Suitable Load Control Method for Constant Tip Speed Ratio Operation of Stand-Alone Wind Turbine-Generator Systems

2008 ◽  
Vol 32 (2) ◽  
pp. 143-161 ◽  
Author(s):  
Tetsuya Wakui ◽  
Ryohei Yokoyama
Keyword(s):  
Measurement Error ◽  
Wind Speed ◽  
Wind Turbine ◽  
Rotational Speed ◽  
Control Method ◽  
Vertical Axis ◽  
Load Control ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Tip Speed Ratio

A suitable load control method for constant tip speed ratio operation of a stand-alone system using a vertical axis wind turbine with self-starting capability is discussed. The system with a straight-wing-type turbine is mainly operated at a constant tip speed ratio. Two types of load control methods are considered: Method-1, where the load torque is controlled in proportion to the square of the rotational speed, and Method-2, which adopts feedback control of the rotational speed in response to the measured wind speed. In this second report on a suitable load control method, the influence of the measurement error of the inflow wind speed is particularly focused on. The computational results obtained using the dynamic simulation model show that Method-1, which is not affected by the measurement error and has a fine smoothing effect of the output fluctuation, is the more suitable load control method.

scholarly journals Performance assessment and optimization of a helical Savonius wind turbine by modifying the Bach’s section

2021 ◽  
Vol 3 (8) ◽  
Author(s):  
M. Niyat Zadeh ◽  
M. Pourfallah ◽  
S. Safari Sabet ◽  
M. Gholinia ◽  
S. Mouloodi ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Performance Assessment ◽  
Turbulent Flows ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Tip Speed Ratio ◽  
Basic Model ◽  
Turbine Performance ◽  
Primary Model ◽  
Savonius Wind Turbine

AbstractIn this paper, we attempted to measure the effect of Bach’s section, which presents a high-power coefficient in the standard Savonius model, on the performance of the helical Savonius wind turbine, by observing the parameters affecting turbine performance. Assessment methods based on the tip speed ratio, torque variation, flow field characterizations, and the power coefficient are performed. The present issue was stimulated using the turbulence model SST (k- ω) at 6, 8, and 10 m/s wind flow velocities via COMSOL software. Numerical simulation was validated employing previous articles. Outputs demonstrate that Bach-primary and Bach-developed wind turbine models have less flow separation at the spoke-end than the simple helical Savonius model, ultimately improving wind turbines’ total performance and reducing spoke-dynamic loads. Compared with the basic model, the Bach-developed model shows an 18.3% performance improvement in the maximum power coefficient. Bach’s primary model also offers a 12.4% increase in power production than the initial model’s best performance. Furthermore, the results indicate that changing the geometric parameters of the Bach model at high velocities (in turbulent flows) does not significantly affect improving performance.

Numerical Research on the Characteristics of Lift-Drag Type Vertical Axis Wind Turbine

2012 ◽  
Vol 189 ◽  
pp. 448-452
Author(s):  
Yan Jun Chen ◽  
Guo Qing Wu ◽  
Yang Cao ◽  
Dian Gui Huang ◽  
Qin Wang ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Vertical Axis ◽  
Chord Length ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Tip Speed Ratio ◽  
Middle Range ◽  
Parabolic Form ◽  
Cfd Method

Numerical studies are conducted to research the performance of a kind of lift-drag type vertical axis wind turbine (VAWT) affected by solidity with the CFD method. Moving mesh technique is used to construct the model. The Spalart-Allmaras one equation turbulent model and the implicit coupled algorithm based on pressure are selected to solve the transient equations. In this research, how the tip speed ratio and the solidity of blade affect the power coefficient (Cp) of the small H-VAWT is analyzed. The results indicate that Cp curves exhibit approximate parabolic form with its maximum in the middle range of tip speed ratio. The two-blade wind turbine has the lowest Cp while the three-blade one is more powerful and the four-blade one brings the highest power. With the certain number of blades, there is a best chord length, and too long or too short chord length may reduce the Cp.

Experimental Study of Vertical Axis Wind Turbine with Wind Speed Self-Adapting

2012 ◽  
Vol 215-216 ◽  
pp. 1323-1326
Author(s):  
Ming Wei Xu ◽  
Jian Jun Qu ◽  
Han Zhang
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Wind Velocity ◽  
Vertical Axis ◽  
Maximum Power ◽  
The Self ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Opening And Closing

A small vertical axis wind turbine with wind speed self-adapting was designed. The diameter and height of the turbine were both 0.7m. It featured that the blades were composed of movable and fixed blades, and the opening and closing of the movable blades realized the wind speed self-adapting. Aerodynamic performance of this new kind turbine was tested in a simple wind tunnel. Then the self-starting and power coefficient of the turbine were studied. The turbine with load could reliably self-start and operate stably even when the wind velocity was only 3.6 m/s. When the wind velocity was 8 m/s and the load torque was 0.1Nm, the movable blades no longer opened and the wind turbine realized the conversion from drag mode to lift mode. With the increase of wind speed, the maximum power coefficient of the turbine also improves gradually. Under 8 m/s wind speed, the maximum power coefficient of the turbine reaches to 12.26%. The experimental results showed that the new turbine not only improved the self-starting ability of the lift-style turbine, but also had a higher power coefficient in low tip speed ratio.

scholarly journals Effects of tip speed ratio on the performance of an H-Darriues wind turbine with NACA 4415 air foil

2020 ◽  
Author(s):  
Yogie P. Sibagariang ◽  
Indro Pramono ◽  
Koki Kishinami ◽  
Himsar Ambarita
Keyword(s):  
Wind Turbine ◽  
Speed Ratio ◽  
Tip Speed Ratio
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