Type Vertical Axis Wind Turbine Research Articles

Enhancing Savonius Rotor Performance With Zigzag Surface Investigated at Drag Force, Pressure, and Flow Visualization Analysis

Savonius, a type of vertical-axis wind turbine, is a small-scale energy conversion device suitable for low wind speeds, such as those characteristic of Indonesian wind speeds, yet has low efficiency. Savonius is a drag-type turbine. Drag force on the surface is affected by roughness or wavyness. The purpose of this study is to analyze the impact of applying wavy (zigzag) variations to the concave surface of Savonius blades on their performance. This was achieved by the use of 3D computational fluid dynamics simulation at TSR 0.6 with a velocity inlet of 5 m/s. The model was semicircular, zigzag on the concave surface on semicircular with t = 0.75, t = 0.25, and t = 1 mm. The result of this study's CD maximum is 1,817 at the zigzag model with t = 1 and CD avrg =1.24. The average drag coefficient increased by 14 percent compared to the conventional semicircular rotor. The maximum Cp value is also found at t = 1 mm, which is 0.315. The power coefficient increased by 29 percent compared to the conventional semicircular rotor. The total pressure on the blade shows the highest model with t = 1 mm at the same angle of attack (α = 30). Zigzag on the concave surface affects blade pressure, which improves the performance of the Savonius rotor.

Simulation Study of the Effect of Wind Speed and Material Type on the Mechanical Properties of Vertical Axis Wind Turbine Blades

Wind energy is a clean and fast-growing renewable energy source that can be harnessed using wind turbines. In a Vertical Axis Wind Turbine (VAWT), turbine blades are a crucial factor, and their fiasco leads to wind turbine failure. However, references to VAWT blade structural analysis are very limited. Therefore, the study was carried out to determine the material with the lowest degree of deformation without structural failure. The finding could be used as a recommendation in the material selection of Savonius type vertical axis wind turbine blades. The study used materials such as aluminum, stainless steel, and fiberglass. The analysis was carried out by simulating using ANSYS software. Computational Fluid Dynamics (CFD) was used for determining the loading by providing speed variations at 3 m/s, 4 m/s, 5 m/s, and 6 m/s. The Finite Element Analysis (FEA) method was applied to analyze the structure, which shows the results of total deformation, equivalent stress, and safety factor. The total deformation results from the aluminum blades showed values of 109.55 mm, 190.73 mm, 299.25 mm, and 425.39 mm. The safety factor values of 4.4049, 2.5166, 1.5647, and 1.1348 revealed that it was also technically safe. Aluminum material can be recommended to be used in the manufacture of Savonius type vertical axis wind turbine blades because of its low price, lightweight, corrosion resistance, and sufficient durability, as revealed from the results of total deformation and safety factor values.

SIMULASI BILAH TURBIN ANGIN SUMBU VERTIKAL (VAWT) TIPE ROTOR HELICAL UNTUK PEMBANGKIT LISTRIK TENAGA ANGIN DI TEPI PANTAI BUKIT DAN JALAN

The energy crisis is caused by rapid technological developments throughout the world resulting in increased use of fossil energy and global warming, so it is necessary to develop renewable energy technologies to maintain energy stability in the world. One of the renewable energy potentials is wind energy with a Helical rotor type vertical axis wind turbine using NACA 0021 as the blades, the research method used is the numerical method with the result that the wind speed on the parangtritis beach is 4.74 m/s and the air density is 1.2 Kg/m^3 with the power generated using 4 rotor blades of 59.2 Watt/h. then on the paragliding hill, an air speed of 4.55 m/s and an air density of 1.16 Kg/m^3 is obtained, and on the western Yogyakarta ringroad which has an airspeed of 3.885 m/s and an air density of 1.17 Kg/m^3, it produces an electric power of 31.9 Watt/h. The power results generated between the simulation and manual calculations are not much different, so the power accuracy between the two is quite good.

Perancangan Turbin Angin Vertikal Modifikasi Darrieus Menggunakan Geometri Airfoil Naca 2414

The National Energy General Plan policy is one of the government's focuses on controlling the use of renewable energy in line with the development of the need for energy use for the community, especially in the electricity sector. Electrical energy is energy that is very important for human needs, where every human being is very dependent on electricity for their daily needs. Currently, there is a crisis of fossil resources, so renewable energy can be developed. One renewable energy that is easy to develop is a wind turbine by utilizing the energy of the wind that blows. Indonesia has started to pay attention to increasing the efficiency of electricity generation, especially wind power. The type of turbine planned is the Darrieus type vertical axis wind turbine (VAWT) using a modified NACA Airfoil 2414 geometry with variations in wind speed. At a speed of 7,61 m/s from the test results obtained the power produced by the turbine is 20,78 watts with a voltage of 11,61 Volts and an electric current of 1,79 Amperes and at 354 rpm generator rotation. from the results obtained, the higher the wind speed, the higher the rotation produced by the turbine.

Aerodynamic analysis of a 2-stage elliptical-bladed Savonius wind rotor: Numerical simulation and experimental validation

ABSTRACT The Savonius rotor is a type of vertical-axis wind turbine that utilizes drag to generate power. Its design simplicity and ability to self-start at low wind speeds make it an attractive option for small-scale wind energy generation. Previous research has focused on optimizing the geometric configuration of a 1-stage, 2-bladed rotor with semicircular blade profiles to improve its performance and mitigate negative torque. However, limited research has been conducted on 2-stage, 2-bladed Savonius rotors with elliptical blade profiles. The present investigation aims to fill this research gap by evaluating the aerodynamic characteristics of a 2-stage, 2-bladed Savonius rotor with elliptical profiles. 3D unsteady simulations using the SST k-ω turbulence model in ANSYS Fluent are conducted to evaluate the performance coefficients over a range of tip speed ratios. The numerical results are validated through wind tunnel experiments. The results show that the CPmax (maximum power coefficient) for the 1-stage rotor is 0.19 and 0.12 for numerical and experimental analyses, respectively. For the 2-stage rotor, the CPmax is 0.21 and 0.17 for numerical and experimental analyses, respectively. These findings suggest that the 2-stage rotor with elliptical profiles has the potential to efficiently harness wind energy.

An overview of aerodynamic performance analysis of vertical axis wind turbines

In this paper, an attempt has been made to highlight major developments of vertical axis wind turbines (VAWTs) in the last few decades. The effects of various design parameters such as airfoil, number of blades, solidity, aspect ratio, blade helicity, and overlap ratio have been critically analyzed. Wind energy is the most promising renewable, cost-effective, efficient, and accessible source for both domestic and commercial applications. Horizontal axis wind turbines are highly developed and are being used for medium-to-large scale power projects. VAWT are considered viable options for urban and semi-urban areas. These turbines have several characteristics, such as omnidirectional, power generation in weak and unstable winds, esthetically sound, safety, and low noise. Darrieus turbines with a fixed blade-type have starting problems at low wind speeds. Savonius turbines have good starting capability; however, their power coefficients are lower than other types of VAWT. To overcome the shortcomings of conventional wind turbines, an innovative engineering solution was sought in the design of hybrid VAWT. The analysis revealed that hybrid wind turbines have addressed the deficiencies to an extent; however, the overall performance is still less than that of conventional wind turbines. Several recommendations have been made based on state-of-the-art information from the perspective of future studies and acceptability. It was concluded that vast opportunities for wind turbine applications are available in urban areas; however, further academic research is required on critical aspects such as self-starting at low wind speeds, efficiency, structural reliability, design improvement for aerodynamic performance, and wind resource assessment.

Plasma actuator effects on the flow physics of dynamic stall for a vertical axis wind turbine

Darrieus type vertical axis wind turbines have several advantages over other wind turbines for local electricity generation in urban environments. However, the main aerodynamic challenge is the negative impacts of the dynamic stall phenomenon on the turbine performance. This study numerically scrutinizes the effects of plasma actuators on the dynamic stall control and performance improvement of a Darrieus turbine. For this sake, unsteady Reynolds-averaged Navier–Stokes equations are solved using a pressure-based finite volume method. The Suzen–Hoang plasma actuator model is employed to calculate the body forces attributed to the plasma actuator. First, the dynamic stall characteristics of the turbine blade with no plasma actuator are explored. Then, three plasma actuator configurations (i.e., inboard, outboard, and double-sided) are considered. According to the results of the clean blade, the aerodynamic performance mainly depends on the reverse Karman vortex formation at the onset of the down-stroke motion and counterclockwise vortex formation on the blade suction side. The results of plasma configurations indicate that the inboard and double-sided actuators enhance the turbine power output by 10%, while the outboard actuator effects are negligible. Moreover, the plasma actuator is effective only in the down-stroke motion of the blade. Results also show that the inboard and double-sided plasma actuators eliminate the reverse Karman vortex and significantly reduce the counterclockwise vortex size, increasing the lift force and connection point moment. Consequently, the inboard and double-sided plasma actuators remove the negative torque generation in azimuth angles of 135° to 180°, primarily responsible for the output power enhancement.

A Comparative Aerodynamic Analysis of NACA and NREL Aerofoils for Darrieus Turbines Using CFD

The selection of the aerofoil plays a crucial role in achieving optimum power output, especially for the inherently low-efficient turbines, such as the Darrieus wind turbine. For this purpose, different aerofoils belonging to NACA and NREL families have been investigated in terms of the aerodynamic performance, comparatively. Although NREL aerofoils are mainly utilised for the Horizontal Axis Wind Turbines, in the present study, their effect on the Darrieus type Vertical Axis Wind Turbine has been examined. In this point of view, the influence of the various aerofoils and their thickness on the turbine performance in different operating ranges have been evaluated using Computational Fluid Dynamics (CFD). Furthermore, by considering the low and high tip speed ratios, the instantaneous blade torque coefficient, and the contours of the pressure coefficient for the selected aerofoils have been analysed to provide further understanding. The research findings show that the conventional aerofoils, such as NACA0015 and NACA0021, illustrate better power output at optimum and high tip speed ratios, while the NREL aerofoils, such as S814 and S825, are able to increase the torque generation at the relatively low tip speed ratio regions. Even though this situation makes the NREL aerofoil more desirable to design a self-starting Darrieus turbine, NREL aerofoils lost their advantages due to the higher efficiency loss at the higher tip speed ratios. In addition to this, the thicker aerofoils, such as NACA0021 and S814, yield more power output at the low tip speed ratio compared to their counterpart profiles as a result of the high pressure difference achieved between their suction and pressure sides.

Aerodynamic study of a Savonius type vertical axis wind turbine for different axial positions between the blades

In this work we present a numerical study on the aerodynamic behavior of a vertical axis wind turbine of the Savonius type for different axial positions between the blades (overlap rates a/D). The study focuses on predicting the effect of the axial position of the blades to the torque coefficient and also to determine the dynamic field of the flow around the wind turbine for three cases overlap rates (a/D=0, a/D=0.16 and a/D=0.32). The study of the numerical simulation is carried out using a CFD calculation code with use of the finite volume method for the discretization of the differential equations. The equations governing the flow are solved by the SIMPLE algorithm using the K-epsilon model as the closure model.

Blade Dimension Optimization and Performance Analysis of the 2-D Ugrinsky Wind Turbine

With the increasing focus on renewable energy, there is a need to improve the efficiency of vertical-axis wind turbines (VAWTs). The Ugrinsky wind turbine is a type of VAWT, but there are few studies on this turbine. Previous studies have shown that the maximum power coefficient of the Ugrinsky wind turbine reaches 0.170, which is 54.5% higher than that of the Savonius type (0.110), and this turbine maintains a high power coefficient over a wide range of tip speed ratios (TSR). In this study, the dimensions of the two semicircles of the Ugrinsky wind turbine were further optimized to obtain a higher power coefficient. An analysis of the effect of the blade dimensions on the performance was conducted. The flow around the turbine was simulated using the regularized lattice Boltzmann method. The geometry of the turbine was simulated using the virtual flux method for the Cartesian grid. The optimization was conducted in terms of the output power coefficient and the average value of the power coefficient for neighboring TSR to consider the fluctuation of the TSR. This study demonstrates that a closer vortex distance favored the growth of the vortex and improved the power coefficient.

Performance research of VAWT with expandable blades based on savonius turbines

In order to improve the wind energy utilization of vertical axis wind turbine (VAWT), this paper presents a new structure of VAWT with expandable blades. The blades of the new turbine are symmetrical airfoil NACA0012 instead of curved blades. The blades of the new structure VAWT have open and folded state. While the blades rotate to the windward side, the blades are open and similar to the curved blades of the S-type turbine. While the blades rotate to the leeward side, the blades are folded and similar to the airfoil of the H-type turbine. In this paper, multistream tube theory was used to analyze the movement of the new type VAWT in the flow field, solve the wind speed influencing factors of the model, establish the theoretical formula of wind energy utilization (CP value) of the new type VAWT. And performance of the wind turbine was simulated and calculated by Matlab. Cp value and self-starting performance of the new type VAWT has greatly improved compared with Savonius type wind turbine. The blade of the new type VAWT is constant section in the vertical direction which can be produced by the costless form of straight blade production. The new type VAWT is not only suitable for medium and large wind farm, but also can be well applied in the areas with relatively poor wind energy resources.

Development of Magatama Type Vertical Axis Wind Turbine Blade by Genetic Algorithm

Development of Magatama Type Vertical Axis Wind Turbine Blade by Genetic Algorithm

Study of performance of h-rotor darrieus wind turbines

Vertical Axis Wind Turbines (VAWTs) are mostly manufactured keeping in mind the site and conditions that the wind turbine would face. There is a need to know which type of VAWT would be optimal in the conditions present at the installation site. The major factors involved are blade profile, wind velocity and blade pitch angle. This study is undertaken to study these factors and their effects on influencing the efficiency of the VAWT. A model has been made of a Darrieus VAWT with H-rotor design and is analyzed using CFD. An Iso-surface mesh is made on the model with a cylindrical air-filled domain and a κ-ε turbulence model is applied to study the effects of the wind-and-turbine blade interaction. The domain inlet indicates wind velocity; outlet is set to zero atmospheric gauge pressure and the pressure distribution across the turbine blade wall is measured. The top bottom walls of the domain are not part of the interaction. The study shows that the NACA0012 blade profile fares better than the other profiles across the range of wind velocities. However, it is less efficient with an increase in blade pitch angle for the same value of velocity. NACA0015 blade profile gives good performance when it has a zero pitch angle for intermediate and high wind velocities.

Analysis of the Performance of The Four-Blade Darrieus Wind Turbine at the Jamik Bukit Asam Mosque Complex Tanjung Enim South Sumatra

Several types of renewable energy have been developed, such as solar energy, biomass, hydro energy, geothermal, and wind energy. Wind energy is an up-and-coming alternative and renewable energy. Wind energy is more environmentally friendly than available energy sources and has more accessible operational and maintenance costs. Indonesia has a relatively small natural wind energy potential because the wind speed in Indonesia is on average 3-6 m/s due to its location. Geographically, it is located in the equatorial area, especially the Muara Enim area, South Sumatra. This study aims to design a prototype the four-blade darrieus type vertical axis wind turbine (VAWT) needed for the utilization of wind energy which is used for Coffee Shop electricity needs at the Jamik Bukit Asam Tanjung Enim Mosque complex, South Sumatra, with the conclusion that the wind turbine, wind turbine rotation, the magnitude of the output voltage and The current generated significantly affects the wind speed in the area.

Studi Eksperimen Pengaruh Jumlah Sudu Terhadap Kinerja Wind Turbine Crossflow

<p>Wind is an alternative energy that is environmentally friendly and sustainable. Therefore, we need a type of wind turbine that can receive wind from all directions. The crossflow type vertical axis wind turbine has a high torque coefficient at a low tip speed ratio. The purpose of this study was to determine the effect of the number of blades on the performance of the vertical axis crossflow wind turbine. The experimental test was carried out by varying the number of blades. The configuration is analyzed using the experimental wind tunnel test scheme which has been modified in the section test section. The results showed that the number of blades 16 has a power coefficient ( ) = 0.23 tip speed ratio (TSR) = 0.42 at a wind speed of 4 m / s.</p><p><strong><br /></strong></p>

Numerical Investigation on the Effects of Varying the Arc length of a Windshield on the Performance of a Highway Installed Banki Wind Turbine

Two-dimensional computational fluid dynamics (CFD) simulations are employed to investigate the effects of adding a circular-arc-shaped windshield on the performance of a Banki type vertical axis wind turbine (VAWT), particularly to the application where the VAWT is harnessing wind energy in highway caused by the passing vehicles. Unsteady Reynolds-Averaged Navier-Stokes (URANS) is the computational approach used to calculate the turbulent flow within the domain. Two sets of simulation cases based on two different vehicles (i.e., car and a bus) are performed with varying arc-length of the windshield. The results show that the windshield provides an increase in the energy captured by the VAWT by up to 16.14% compared to no windshield case when the car model is used. In contrast, windshield in all the simulation cases using a bus model gives a negative effect to VAWT performance where the worst case yields −64.77%.

Proposal of a Nature-Inspired Shape for a Vertical Axis Wind Turbine and Comparison of Its Performance with a Semicircular Blade Profile

In order to improve the efficiency of the Savonius type vertical axis wind turbine, the present work analyzes an improvement based on an innovative rotor geometry. The rotor blades are inspired on an organic shape mathematically analyzed, the Fibonacci’s spiral, presented in many nature systems as well as in art. This rotor was analyzed in a wind tunnel and through a CFD model. The power coefficients at different tip speed ratios (TSR) were characterized and compared for the Savonius turbine and two versions using the Fibonacci’s spiral. One of the proposed geometries improves the performance of the Savonius type. Particularly, the optimal configuration lead to an improvement in maximum power coefficient of 14.5% in the numerical model respect to a conventional Savonius turbine and 17.6% in the experimental model.

Improving the Value of the Power Coefficient for Three Straight-Blades Darrieus Wind Turbine

In this study, an experimental test was carried out using a subsonic wind tunnel to study the improvement of the power coefficient of the three straight-blade Darrieus vertical axis wind turbine. A three-blade vane type vertical axis wind turbine with three movable vanes in each of the blades was fitted in the middle of the three straight-blade Darrieus (0012 Airfoil) vertical axis wind turbine, and they are installed on the same rotor shaft. For this purpose, two vertical axis wind turbine, the first one has three straight-blades Darrieus of type 0012 Airfoil and the second also has three straight-blade Darrieus but of type 0012 Airfoil with a three-blade vane type vertical axis wind turbine with three movable vanes were manufactured. Both turbines were tested using a subsonic wind tunnel at different wind speeds ranging from (4-28) m/s. The consequences showed that in the second turbine test, a power coefficient of Cp=0.39 was obtained, which is greater than the power coefficient of the first turbine (Cp =0.184) after the turbines were tested in a wind tunnel under identical conditions at a wind speed of 6 m/s. Therefore, the second wind turbine produces greater electrical power than the first wind turbine.

The effect of spacing between inner blades on the performance of the Savonius wind turbine

Savonius wind turbine is an interesting type of vertical axis wind turbines (VAWTs) which has a low cost of manufacturing, however, this turbine has a relatively low power output compared to the other types of VAWTs. Further study is required to enhance its performance to match the high demand of the power generation in small-scale applications. The main objective of the current study is to enhance the power output coefficient (Cp) of the conventional Savonius rotor by adding two-inner blades to the geometry. The performance assessment was performed for five different angles of inner blades (100°, 120°, 140°, 160°, and 180°). Moreover, the effect of spacing between inner blades was numerically examined for three values of spacing i.e. 0.02, 0.01, and 0.005 m. The current two-dimensional simulation was performed utilizing the Ansys Fluent solver. The simulation results affirmed that the maximum enhancement to be 32.9% compared to the conventional rotor at TSR equal to 0.7 when the spacing between inner blades is 0.005 m with an inner blades angle of 100°. Moreover, results demonstrated that the Ct max is 0.435 at TSR = 0.4 for the rotor with 160° inner blades and a spacing of 0.005 m.

Savonius wind turbines: A review of recent advances in design and performance enhancements

The energy crisis due to a rapid globalization and adverse effects of global warming has led to an increased need for the non-conventional sources of energy. In the recent times, significant research activities are carried out in the renewable energy field, mostly in solar and wind power generation. Wind turbines are categorised into vertical axis wind turbines (VAWT) and horizontal axis wind turbines (HAWT). Savonius rotor (S-type) is a type of VAWT and its function depends on the drag force. It has many advantages of easy installation, simplicity in design, good self-starting capability, low speeds operation and independency of direction of wind. Although, the negative torque produced on the returning blade leads to its low efficiency. Researchers have conducted several investigations to improve the functioning of Savonius rotor for satisfying large-scale energy demands. The parameters affecting the performance, such as, overlap ratio, aspect ratio, tip speed ratio and blade shapes, are improved by undergoing various designs. Several augmentation techniques, such as, end plates, shielding obstacle, guide box tunnel, deflecting plate, curtain plate, quarter blades and nozzles, have been used to enhance the performance of S-type VAWT. With the installation of these augmentation devices, the negative torque acting on the blades was reduced and the starting ability of the rotor was improved. These devices in turn help in increasing the power output as well as the torque coefficient of various rotor configurations. It has been reported in the literature that the coefficient of power of the conventional Savonius rotor lies in the span of 0.12 to 0.18. By using different methods for optimizing its design or installing the augmentation devices, the coefficient of performance can be improved to a value of 0.52. In this article various performance influencing parameters and the power augmentation techniques used for S-type VAWT have been studied and reported studies on these techniques have been reviewed. The article concludes with proposed directions for future research.