Computational Studies on the Flow Field of Various Shapes-Bladed Vertical Axis Savonius Turbine in Static Condition

2013 ◽  
Author(s):  
Jobaidur Khan ◽  
Mohammad Mohibbul Bashar ◽  
Mosfequr Rahman
Keyword(s):  
Turbine Blades ◽  
Static Condition ◽  
Vertical Axis ◽  
Efficient Design ◽  
Vertical Axis Wind Turbine ◽  
Ansys Fluent ◽  
Low Wind Speed ◽  
Computational Fluid Dynamics Cfd ◽  
Bladed Rotor ◽  
Near Future

Vertical Axis Wind Turbine (VAWT) is the least efficient conventional wind energy generator. But the inherent advantage of facing the wind direction and capability to operate in low wind speed and non-smooth wind flow regions are two main reasons to research on it and to find more efficient design. The simplest form of VAWT is known as Savonius turbine and difference of the drag force on its blades is the operating principal. The main objective of this study is to analyze the performance data (numerically obtained) Savonius turbine blades. This study is in preliminary stage; experiment will be performed in near future. A Computational Fluid Dynamics (CFD) analysis has been used. Effect of changing the inlet velocity and mesh dependency is observed in this study. These models are simulated with CFD software ANSYS/FLUENT. Comparing previous models it has been found that, airfoil shaped three bladed rotor produces better result than regular semi-circular wind turbines. Changing the airfoil shape may show more interesting result in future.

Computational Analysis of Airfoil Merging and its Effect on Performance of Lift Based Vertical Axis Wind Turbine

2016 ◽  
Author(s):  
Akshay Basavaraj
Keyword(s):  
Reynolds Number ◽  
Wind Turbine ◽  
Lift Coefficient ◽  
Turbine Blades ◽  
Vertical Axis ◽  
Aerodynamic Characteristics ◽  
Vertical Axis Wind Turbine ◽  
Low Wind Speed ◽  
Naca 0012 ◽  
Selection Of

In regions of low wind speed, overcoming the starting torque of a Vertical Axis Wind Turbine (VAWT) becomes a challenge aspect. In order to overcome this adversity, careful selection of airfoils for the turbine blades becomes a priority. This paper tries to address the issue utilizing an approach wherein by observing the effect of merging two airfoils. Two airfoils which are of varying camber and thickness are merged and their aerodynamic characteristics are evaluated using the software XFOIL 6.96. For a variation in angle of attack from 0 to 90°, aerodynamic analysis is done in order to observe the behavior of one quarter of the entire VAWT cycle. An objective function is developed so as to observe the maximum possible torque generated by these airfoils at Reynolds number varying from 15,000–120,000. Due to change in the value of CL observed at Low Reynolds Number using commercial CFD softwares, multiple objective functions are utilized to observe the behavior over a range of Reynolds number. An experimental co-relation between the cut-in velocity and the lift-coefficient of the airfoils is developed in order to predict the cut-in velocity of the interpolated airfoils. The airfoils used for this paper are NACA 0012, NACA 0018, FX 66 S196, Clark Y (smooth), PT 40, SD 7032, A 18, SD 7080, SG 6043 and SG 6040.

scholarly journals Aerodynamics and Modal Analysis for the Combined Vane type Vertical Axis Wind Turbine

2018 ◽  
Vol 7 (4.38) ◽  
pp. 1395 ◽  
Author(s):  
Kadhim H. Suffer ◽  
Yassr Y. Kahtan ◽  
Zuradzman M. Razlan
Keyword(s):  
Wind Turbine ◽  
Modal Analysis ◽  
Natural Frequencies ◽  
Turbine Blades ◽  
Vertical Axis ◽  
Turbine Rotor ◽  
Mode Shapes ◽  
Vertical Axis Wind Turbine ◽  
Ansys Fluent ◽  
Starting Torque

The present global energy economy suggests the use of renewable sources such as solar, wind, and biomass to produce the required power. The vertical axis wind turbine is one of wind power applications. Usually, when the vertical axis wind turbine blades are designed from the airfoil, the starting torque problem begins. The main objective of this research is to numerically simulate the combination of movable vanes of a flat plate with the airfoil in a single blade configuration to solve the starting torque problem. CFD analysis in ANSYS-FLUENT and structural analysis in ANSYS of combined blade vertical axis wind turbine rotor has been undertaken. The first simulation is carried out to investigations the aerodynamic characteristic of the turbine by using the finite volume method. While the second simulation is carried out with finite element method for the modal analysis to find the natural frequencies and the mode shape in order to avoid extreme vibration and turbine failure, the natural frequencies, and their corresponding mode shapes are studied and the results were presented with damping and without damping for four selected cases. The predicted results show that the static pressure drop across the blade increase in the active blade side because of the vanes are fully closed and decrease in the negative side because of the all the vanes are fully open. The combined blade helps to increase turbine rotation and so, thus, the power of the turbine increases. While the modal results show that until the 5th natural frequency the effect of damping can be neglected. The predicted results show agreement with those reported in the literature for VAWT with different blade designs.   

Stress Analysis of Various Shaped Blade of Savonius Wind Turbine

2014 ◽  
Author(s):  
Jobaidur R. Khan ◽  
Mosfequr Rahman
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Alternative Energy ◽  
Energy Requirement ◽  
Turbine Blades ◽  
Vertical Axis ◽  
Physical Models ◽  
Vertical Axis Wind Turbine ◽  
Low Wind Speed ◽  
The World

Amidst of high demand of energy, the world is seeking alternative energy sources. Wind alone can fulfill most of the energy requirement of the world by its efficient conversion into energy. On efficiency measurement, Horizontal Axis Wind Turbines (HAWT) is the popular to the researchers, but it works best in places where the wind is not disturbed and has high wind power. The inherent advantage of facing the wind direction, design simplicity, less expensive technology for construction, lower wind start-up speeds, easier maintenance, and relatively quietness are turning the focus to Vertical Axis Wind Turbine (VAWT). The low wind speed and non-smooth wind flow regions are attracted for these machines. Savonius turbine is the simplest form of VAWT and operation is based on the difference of the drag force on its blades. The main objective of this study is to analyze a perfect mixture of new and innovative designs of Savonius turbine blades, which can make VAWT more attractive, efficient, durable and sustainable. This is studied by using blade with different numbers in operating in different wind speed. A Computational Fluid Dynamics (CFD) analysis has been used. 2D CAD models of various VAWT geometries are created and tested with CFD software ANSYS/FLUENT with a similar flow-driven motion in a wind tunnel. These simulations provided the aero-dynamic characteristics like shear stress, velocity distribution and pressure distribution. Some physical models with desired properties needed to be fabricated and tested inside tunnel to find the effect of different shapes in real.

scholarly journals Preliminary Performance Tests and Simulation of a V-Shape Roof Guide Vane Mounted on an Eco-Roof System

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2846 ◽  
Author(s):  
Xiaohang Wang ◽  
Wentong Chong ◽  
Kokhoe Wong ◽  
Liphuat Saw ◽  
Sinchew Poh ◽  
...  
Keyword(s):  
Power Generation ◽  
Guide Vane ◽  
Vertical Axis ◽  
Power Coefficient ◽  
Vertical Axis Wind Turbine ◽  
Roof System ◽  
Low Wind Speed ◽  
Computational Fluid Dynamics Cfd ◽  
Power Generation System ◽  
Low Efficiency

The technical and economic features of a patented V-shape roof guide vane (VRGV) with a solar and wind power generation system mounted on an eco-roof system are presented in this paper. Moreover, this innovative VRGV was investigated on for the purpose of improving the performance of a vertical axis wind turbine (VAWT), which was installed on an eco-roof system to solve the low-efficiency power generation problem of the wind turbines under the condition of a low wind speed. This paper proposes a preliminary study for the performance of the VAWT with the VRGV on a building. This research used a mock-up building with a double slope roof, where a five straight-bladed VAWT was mounted and tested under two conditions, with and without the VRGV. From the comparative experiments, the self-starting performance and rotational speed of the VAWT mounted above a double slope roof with the VRGV have been significantly improved compared to the VAWT without the VRGV. Further, the power coefficient (Cp) of the VAWT can be augmented to about 71.2% increment due to the VRGV design. In addition, numerical simulations by computational fluid dynamics (CFD) were proposed to verify the augmented effect of the Cp of the VAWT under the influence of the VRGV in the experiment. Besides, economic estimation of the VRGV was conducted.

Drag and Lift Characteristics of a Novel Elliptical-Bladed Savonius Rotor With Vent Augmenters

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Nur Alom ◽  
Ujjwal K. Saha
Keyword(s):  
Identical Condition ◽  
Three Dimensional ◽  
Vertical Axis ◽  
Rotor Blades ◽  
Vertical Axis Wind Turbine ◽  
Ansys Fluent ◽  
Savonius Rotor ◽  
Bladed Rotor ◽  
Drag And Lift ◽  
Lift And Drag

Savonius rotor, a class of drag-driven vertical axis wind turbine, has been extensively investigated mainly to calculate the torque and power coefficients (CT and CP) by various investigators. Hitherto, studies related to lift and drag characteristics are very few and have mainly been restricted to a semicircular-bladed rotor. A deeper investigation into the drag and lift coefficients (CD and CL) can result in the better design of rotor blades leading to an increment in CT and CP. In view of this, in the present investigation, CD and CL of an elliptical-bladed rotor with vent augmenters have been studied numerically. Initially, two-dimensional (2D) unsteady simulations using an ansys fluent solver is carried out to estimate the instantaneous CD and CL. The shear stress transport (SST) k–ω turbulence model is selected to solve the Reynolds averaged Navier Stokes (RANS) equations. Finally, three-dimensional (3D) unsteady simulations are carried out for the vented elliptical-bladed rotor. The unsteady simulations are performed for the nonvented elliptical- and semicircular-bladed rotors at the identical condition in order to have a direct comparison. From the unsteady simulations, the average CD for the vented elliptical profile is found to be 1.45; whereas, the average CD for the nonvented elliptical and semicircular profiles is found to be 1.43 and 1.35, respectively.

scholarly journals Nonlinear Stress Analysis of Vertical-Axis Wind Turbine Blades

1975 ◽  
Vol 97 (4) ◽  
pp. 1234-1237 ◽  
Author(s):  
L. I. Weingarten ◽  
R. E. Nickell
Keyword(s):  
Wind Turbine ◽  
Turbine Blades ◽  
Vertical Axis ◽  
General Purpose ◽  
Analytical Models ◽  
Efficient Design ◽  
Vertical Axis Wind Turbine ◽  
Wind Turbine Blades ◽  
Nonlinear Stress ◽  
Blade Shape

A Darrieus-type vertical-axis wind turbine has been proposed as an alternate to conventional horizontal axis, propeller-type machines. An advantage is that the blades will be primarily in tension, thus making for a more efficient design. In connection with its vertical-axis wind turbine program, Sandia Laboratories has developed the “troposkien” (Greek for turning rope) shape for the blade design. The prototype blade shape is similar to that of the troposkien, but more easily manufactured. The effect on the stress distribution of this alternate blade shape is investigated. Analytical models of the blades were constructed using a general purpose, nonlinear, dynamic finite element structural code. This code accounts for the large deflection effects of the various blade shapes through incremental applications of angular velocity.

scholarly journals CFD ANALYSIS OF THE AIR FLOW AROUND THE BLADES OF THE VERTICAL AXIS WIND TURBINE

2017 ◽  
Vol 3 (1) ◽  
pp. 1-7
Author(s):  
Muhammed Musab Gavgali ◽  
Zbigniew Czyż ◽  
Jacek Czarnigowski
Keyword(s):  
Wind Turbine ◽  
Three Dimensional ◽  
Vertical Axis ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Cfd Analysis ◽  
Vertical Axis Wind Turbine ◽  
Ansys Fluent ◽  
Bladed Rotor ◽  
The Individual

The paper presents the results of calculations of flow around the vertical axis wind turbine. Three-dimensional calculations were performed using ANSYS Fluent. They were made at steady-state conditions for a wind speed of 3 m/s for 4 angular settings of the three-bladed rotor. The purpose of the calculations was to determine the values of the aerodynamic forces acting on the individual blades and to present the pressure contours on the surface of turbine rotor blades. The calculations were made for 4 rotor angular settings

scholarly journals Performance Enhancement of a Darrieus Vertical Axis Wind Turbine using Divergent Ducting System

2018 ◽  
Vol 25 (3) ◽  
pp. 58-66
Author(s):  
Abdullateef A. Jadallah ◽  
Sahar R. Farag ◽  
Jinan D. Hamdi
Keyword(s):  
Wind Turbine ◽  
Urban Areas ◽  
Performance Enhancement ◽  
Vertical Axis ◽  
Power Coefficient ◽  
Opening Angle ◽  
Vertical Axis Wind Turbine ◽  
Ansys Fluent ◽  
Low Wind Speed ◽  
Enhancement Method

Ducting system is an effective way to potentially augment the performance of wind turbine for applications in building architectures. This paper is aimed to study one of the possible enhancement method of the vertical axis wind turbine performance. It is characterized by adding divergent duct to facilitate imparting more flow rate. The divergent duct was designed and adapted with wind turbine. The system was modelled and simulated analytically and numerically. A computer program built in MATLAB 16 to simulate the performance of system. The performance and flow are also solved numerically using ANSYS-FLUENT 17.2. Two opening angles of the divergent -duct were employed to study the behavior of air flow through divergent duct and results were compared with base vertical axis wind turbine. The duct turbine with a straight wall type diffuser demonstrate power coefficient augmentation by 24.2% and 9.09% for opening angle 20 and 12 respectively. The optimum half opening angle was attained for the diffuser. The diffuser’s length of a half of the throat opening is recommended, and its angle of opening is 20. The diffuser was located in a stream-was direction that adequately aligned with the center of the vertical axis wind turbine. Results showed a reasonable influence on the performance of wind turbine. This technology may be used in gates and in urban areas with a relatively low wind speed regime.

Numerical Studies on the Effect of Cambered Airfoil Blades on Self-Starting of Vertical Axis Wind Turbine Part 1: NACA 0012 and NACA 4415

2015 ◽  
Vol 787 ◽  
pp. 250-254 ◽  
Author(s):  
T. Micha Premkumar ◽  
Sivamani Seralathan ◽  
T. Mohan ◽  
N.N.P. Saran Reddy
Keyword(s):  
Wind Turbine ◽  
Turbine Blades ◽  
Vertical Axis ◽  
Vertical Axis Wind Turbine ◽  
Wind Turbine Blades ◽  
Static Pressure Distribution ◽  
Numerical Studies ◽  
Airfoil Blades ◽  
Torque Values ◽  
Naca 0012

This is Part-1 of the two-part paper in considering the effect of cambered airfoil blades on self-starting of vertical axis wind turbine. Part 1 reports the numerical studies on self-starting of vertical axis wind turbine with comparative studies involving NACA 0012 and cambered airfoil NACA 4415. Part 2 of the paper deals with numerical studies of NACA 0018 and cambered air foil NACA 63415. Darrieus type VAWT is attracting many researchers attention for its inherent advantages and its diversified applications. However, a disadvantage is when the rotor is stationary, no net rotational forces arises, even at high-wind speed. The principal advantage of the vertical axis format is their ability to accept wind from any direction without yawing mechanism. However, self-starting capability is the major drawbacks. Moreover, literatures based on computational analysis involving the cambered airfoil are few only. The objective of this present study is to select the suitable airfoil blades on self-starting of VAWT at low-Reynolds number. The numerical studies are carried out to identify self-starting capability of the airfoil using CFD analysis by studying the flow field over the vertical axis wind turbine blades. The commercial CFD code, ANSYS CFX 13.0© was used for the present studies. Initially, the flow over NACA 0012 was simulated and analyzed for different angles of attacks and similarly carried out for NACA 4415. The contours of static pressure distribution and velocity as well as the force and torque were obtained. Even though the lift force for cambered airfoil NACA 4415 is higher, based on the torque values of the above blade profiles, asymmetrical airfoil NACA 0012 is found to be appropriate for self-starring of VAWT.

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