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Showing papers on "Savonius wind turbine published in 2014"


Journal ArticleDOI
TL;DR: In this article, the authors evaluate how the conventional Savonius wind turbine performs when it rotates by the momentum of water current at low velocity from 0.3 m/s to 0.9m/s in an open water channel.

133 citations


Journal ArticleDOI
TL;DR: In this paper, the Savonius wind turbine bears unique features in both aspects of rotor structure and torque production, and a review of the relevant studies can be found in Section 2.1.
Abstract: The Savonius wind turbine bears unique features in both aspects of rotor structure and torque production. Continual improvement of the Savonius wind turbine motivates the authors of this review to gather, classify and discuss the quintessential parts of the relevant studies. Unambiguous priority is granted to the turbulent flow surrounding the Savonius wind rotor. Flow patterns near the Savonius wind rotor are represented with distributions of static pressure near conventional and spiral Savonius wind rotors. Assorted geometric shapes of Savonius wind rotors are demonstrated to illuminate a panorama of the development of the Savonius wind rotor, as well as to highlight the connection between rotor-based solid boundary and flow structures near Savonius wind rotor blades. Limitations of existing analytical methods used to predict the performance of the Savonius wind rotor are interpreted. Advantages of both numerical and experimental techniques in acquiring aerodynamics forces, shaft torque and internal stress distribution for the Savonius wind rotor blade are enumerated, and the difficulties incurred by curved blades and the rotation of the rotor are analyzed as well. Optimal values of tip-speed ratio corresponding to maximum power coefficient or maximum torque coefficient are different for various geometric shapes of Savonius wind rotors, which sheds new light upon the relationship between flow characteristics and performance parameters associated with the Savonius wind rotor.

47 citations


Journal ArticleDOI
TL;DR: In this paper, the vortex shedding phenomenon of a wind turbine rotor is modeled as a discrete bound vortices and the wake is generated in a time stepping calculation as an emission of free Vortices, and a code is developed which predicts the wake structure to be in good agreement with the experimental visualizations.

19 citations


Proceedings ArticleDOI
01 Dec 2014
TL;DR: In this paper, the authors compare aerodynamic characteristics of two and three bladed Savonius rotor with different overlap ratios by numerical analysis and find that rotor with less blade number produces higher torque.
Abstract: The aim of this paper is to compare aerodynamic characteristics of two and three bladed Savonius rotor with different overlap ratios by numerical analysis. The models with 0%, 20%, and 30% overlap having the same blade diameter and height are used for the comparison. To ensure the simulation model was correct the results obtained from the CFD were compared with experimental results. The established simulation model was used to find the static torque coefficients and power coefficients to analyze the aerodynamic performance of the taken geometries. From the analysis it was found that rotor with less blade number produces higher torque. It was also found that the rotors with no overlap produces negative torque and the introduction of overlaps in the rotor eliminates the negative torque. Another finding from the analysis is the increase in Reynolds number increases the static torque in the rotor.

12 citations


Journal ArticleDOI
22 Aug 2014
TL;DR: In this article, the performance of the Bach-type Savonius wind turbine with a constant cross-section is examined by means of quasi 2D and 3D flow predictions obtained from ANSYS CFX.
Abstract: The performance of the Bach-type Savonius wind turbine with a constant cross-section is examined by means of quasi 2D and 3D flow predictions obtained from ANSYS CFX. Simulations were performed in a way allowing for a comparison with the wind tunnel data presented by Kamoji et al. The comparison with the experiment has revealed that 2D solutions give much higher deviation from the reference data than the 3D ones, which guarantees a good solution quality. It can be stated that even simplified (lack of laminar-turbulence transition modelling and a coarser mesh) 3D simulations can yield more accurate results than complex 2D solutions for turbines with a low aspect ratio. The paper also presents a systematic analysis of the most characteristic flow structures which are identified in the rotor.

11 citations


Book ChapterDOI
01 Jan 2014
TL;DR: In this paper, the authors present the finite element modeling (FEM) by using the CFD based Ansys 14.0 software of a multiblade small Savonius wind turbine and the theoretical modelling of it; the purpose of the modeling consists in finding out the wind turbines behavior depending on its blades number.
Abstract: Vertical wind turbines are used in areas with non-stable wind directions or with turbulent air flows due to the reason that for a vertical wind turbine the wind direction is not an input design data—the functioning of the vertical wind turbine is not influenced by the wind direction. Built environments are characterized by turbulent air flows and small open spaces; due to that, according to the wind turbines applications, small Savonius wind turbines are used in these areas. The paper presents the finite element modeling (FEM) by using the CFD based Ansys 14.0 software of a multiblade small Savonius wind turbine and the theoretical modelling of it; the purpose of the modeling consists in finding out the wind turbines behavior depending on its blades number.

7 citations


01 Jan 2014
TL;DR: In this article, a small scale Savonius windmill was designed and simulated by using CAE techniques and the authors concluded that there is no research has been done to optimize aspect ratio of vertical axis wind turbine and had optimized aspect ratio by using CAD and CFD software to get maximum efficiency at particular aspect ratio with the same frontal area.
Abstract: A B S T R A C T We are going to design & simulate small scale Savonius windmill by using CAE techniques. After referring previous literatures, we conclude that there is no any research has been done to optimize aspect ratio of vertical axis savonius wind turbine. We had optimized aspect ratio by using CAD & CFD software to get maximum efficiency at particular aspect ratio with the same frontal area. Our concluding work is out of 1,2,3,4,5 aspect ratios of wind turbine that we had chosen, Maximum efficiency has been shown by Aspect Ratio 1.

5 citations


09 Dec 2014
TL;DR: In this paper, the influence of blade overlap, blade arc angle and the diameter of the hot air inlet hole on the torque and power coefficient of a Savonius wind turbine was investigated.
Abstract: When compared with other wind turbines, drag driven vertical axis Savonius wind turbine offers lower power coefficient due to its slow turning speed. However, they have many advantages over others, such as simplicity of manufacturing, ability to operate in any wind direction, and having a good starting torque at low wind speed. They are well suited to be integrated in urban environment as small scale power generating wind mills. Waste heats or naturally available heat sources such as geothermal and solar energy can be utilized to produce swirling flow when there is a source of angular momentum. Previous computational work suggests that the performance of Savonius turbine can be improved by providing a hot swirling flow inside the turbine chamber. The swirling flow can be induced by a design similar to that of split channels, which includes one or a few vertical slits, and is currently used to onset fire whirls in the laboratories. In the present experimental study, the influence of blade overlap, blade arc angle and the diameter of the hot air inlet hole on the torque and power coefficient have been investigated. The results indicate that the maximum power coefficient for a 258 mm diameter rotor occurs at 28 mm blade overlap, '195°' blade angle and 9 mm diameter of hot air inlet hole.

4 citations


Journal ArticleDOI
22 Aug 2014
TL;DR: In this paper, the authors present a preliminary analysis of the transient aerodynamic phenomena occurring in the innovative modification of classic Savonius wind turbine, and an attempt to explain the increased efficiency of the innovative design in comparison with the traditional solution is undertaken.
Abstract: This paper presents a preliminary three dimensional analysis of the transient aerodynamic phenomena occurring in the innovative modification of classic Savonius wind turbine. An attempt to explain the increased efficiency of the innovative design in comparison with the traditional solution is undertaken. Several vorticity measures such as enstrophy, absolute helicity and the integral of the velocity gradient tensor second invariant are proposed in order to evaluate and compare designs. Discussed criteria are related to the vortex structures and energy dissipation. These structures are generated by the rotor and may affect the efficiency. There are also different vorticity measure taking advantage of eigenvalues of the velocity gradient tensor.

4 citations


09 Dec 2014
TL;DR: In this paper, the influence of the installation of guide vane on the performance of Savonius wind turbine and the number of rotor blade which produces the most maximum performance was analyzed and the results indicated that rotor with three blades can give better performance than rotor with two and four blades.
Abstract: The objectives of research were to understand the influence of the installation of guide vane on the performance of Savonius wind turbine and to acknowledge the number of rotor blade which produces the most maximum performance. There are three variations for the number of rotor blade, which are 2, 3 and 4 blades on the range of wind speed are 4-7 m/s. Result of research indicated that rotor with three blades can give better performance than rotor with two and four blades. Rotor with guide vane has produced better performance in power coefficient rate for 0,3638 at wind speed 5 m/s, while rotor without guide vane can only provide power coefficient for 0,2595 at similar wind speed 5 m/s.

3 citations


Patent
30 Jun 2014
TL;DR: In this article, the Savonius wind turbine is described as a wind turbine with a vertical axis and two circuits with automatic blade shift to the wind flow direction consisting of the foundation (1) within which is through the bearings (2) and mounted the tower (3), on whose top there is attached the deflector (42) and below it the precipitation shield (41), whereat to the tower there is fixed the gear (5) and above it through the bearing (12), and the lower circuit composed of the tube (15) welded to the bearing supports
Abstract: Invention herewith described refers to the wind turbine with a vertical axis and two circuits with automatic blade shift to the wind flow direction consisting of the foundation (1) within which is through the bearings (2) and (4) mounted the tower (3), on whose top there is attached the deflector (42) and below it the precipitation shield (41), whereat to the tower there is fixed the gear (5) and above it through the bearings (12) and (20) there is mounted the lower circuit composed of the tube (15) welded to the bearing supports (14) and (16), and to which are laterally welded the square tubes (11) and (19), between which along the rim there are mounted the so-called Savonius wind turbine blades (18) which are with the bottom side via the pins (17), (9), (7) and the levers (10) and (8) pivotally connected to the so-called planetary gears (6), which are through the pins (13) fastened to the square tubes (11) and keyed with the gear (5), while to the upper side of the square tubes (19) there is attached the housing (21) with the induction coils (22), and the upper circuit is through the bearings (26) and (39) also drawn over the tower (3) and is made of the pipe (29) welded to the bearing supports (27) or (38) on which are laterally welded the square tubes (25) or (30), between which along the rim there are mounted the so-called Savonius wind turbine blades (28) identical to the blades (18) in the lower circuit, but inversely oriented along the vertical with regard to the blades (18) and on the upper side via the pins (31), (32), (35) and the levers (33) and (34) the Savonius blades are hingedly connected to the so-called planetary gears (36) which are through the pins (37) fastened to the square tubes (30) and keyed with the gear (40), while to the underside of the square tubes (25) there is attached the housing (24) with the permanent magnets (23).

Journal ArticleDOI
TL;DR: In this paper, an S-shaped blade tip is proposed as a means of reducing the noise generated by small vertical (Savonius) wind turbines, which induces phase differences in the shedding vortices from the blades, and thus reduces the noise from the wind turbine.
Abstract: In this study, low noise designs for a Savonius wind turbine were numerically investigated. As was reported in our previous study, the harmonic components with a fundamental frequency higher than the BPF were identified as being dominant in the noise spectrum of a Savonius wind turbine, and these components were a result of vortex shedding. On a basis of this observation, an S-shaped blade tip is proposed as a means of reducing the noise generated by small vertical(Savonius) wind turbines. This blade induces phase differences in the shedding vortices from the blades, and thus reduces the noise from the wind turbine. The aerodynamic noise characteristics of the conventional and "S-shaped" Savonius turbines were investigated by using the Hybrid CAA method where the flow field around the turbine is computed using the CFD techniques and the radiated noise are predicted by applying acoustic analogy to the computed flow field data. The degree of noise reduction resulting from the proposed design and its reduction mechanism were confirmed by comparing the predicted noise spectrum of these turbines and the flow characteristics around them.


Proceedings ArticleDOI
22 May 2014
TL;DR: In this paper, a wind curtain arrangement, shell type, has been designed and placed around the rotor, aimed to prevent the negative torque that occurs on the convex blades surface of the Savonius wind rotor moving against the wind.
Abstract: In the present work the increasing of the energy production efficiency of a wind turbine Savonius type had been studied. In order to increase the aerodynamic performances of a Savonius rotor a wind curtain arrangement, shell type, has been designed and placed around the rotor, aimed to prevent the negative torque that occurs on the convex blades surface of the Savonius wind rotor moving against the wind, thereby causing the performance of the rotor to be low. The effect of a semi cylindrical shell shield on the power output of a vertical-axis-wind-turbine was investigated experimentally. The vertical axis wind turbine consist in a vertical axis with U-shaped blades (Savonius) placed into a semi-cylindrical chamber, closed for a 270 0 sector, in order to reduce the counter effect of the wind on the turbine blades moving against it. Screening the wind turbine geometry has the advantage of reducing the wind resistance that acts in the opposite direction of the rotation of the turbine. In addition, the air swirl form in the shield shell increase the turbine torque, therefore an increasing of the power at the output of the generator have been obtained. The shield Savonius wind turbine is presented in Fig.1.