Alternative Blade Profile based on Savonius Concept for Effective Wind Energy Harvesting

2021 ◽  
pp. 1-32
Author(s):  
Parag K. Talukdar ◽  
Nur Alom ◽  
Umang H. Rathod ◽  
Vinayak Kulkarni
Keyword(s):  
Vertical Axis ◽  
Rotor Blades ◽  
Power Coefficient ◽  
Potential Candidate ◽  
Blade Profile ◽  
Ansys Fluent ◽  
Pressure Distributions ◽  
Bladed Rotor ◽  
Identical Test ◽  
Experimental Findings

Abstract The drag-based vertical-axis Savonius wind rotor is a potential candidate for harvesting renewable energy. It is very simple in design and can be deployed as an off-the-grid electricity system in remote locations having no access to electricity. The present work aims to develop a novel blade profile for the Savonius rotor in order to improve its performance. In that connection, an arc-elliptical-blade profile has been developed and rotor performance has been assessed through wind tunnel testing at three different Reynolds numbers (Re = 87039, 107348, and 131066). Further, its performance is compared to that of a conventional semicircular-bladed rotor under identical test conditions. The experiments revealed the maximum power coefficient (CPmax) of 0.11, 0.162, 0.213 at Re = 87039, 107348, and 131066, respectively for the arc-elliptical-bladed rotor. To complement the experimental findings and to examine the flow behaviour around the rotor blades, the computational fluid dynamics (CFD) simulations have also been performed using ANSYS FLUENT software. The local torque is found to be greater around the advancing arc-elliptical blade than around the advancing semicircular blade. It has been also noticed that the pressure distributions over concave sides are similar regardless of the blade shape.

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

2021 ◽  
Vol 11 (13) ◽  
pp. 6198
Author(s):  
Javier Blanco ◽  
Juan de Dios Rodriguez ◽  
Antonio Couce ◽  
Maria Isabel Lamas
Keyword(s):  
Numerical Model ◽  
Wind Tunnel ◽  
Wind Turbine ◽  
Experimental Model ◽  
Vertical Axis ◽  
Rotor Blades ◽  
Power Coefficient ◽  
Cfd Model ◽  
Blade Profile ◽  
Vertical Axis Wind Turbine

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.

Simulation on Performances of Vertical Axis Wind Turbine

2010 ◽  
Author(s):  
Chien-Chang Chen ◽  
Cheng-Hsiung Kuo
Keyword(s):  
Wind Turbine ◽  
Pitch Angle ◽  
Vertical Axis ◽  
Flow Structures ◽  
Vertical Axis Wind Turbine ◽  
Ansys Fluent ◽  
Moment Coefficient ◽  
Pressure Distributions ◽  
The Moment ◽  
Starting Torque

This study employs the commercialized computational fluid dynamics software (Ansys/Fluent), with the user’s defined technique, to simulate the unsteady flow structures around the small-size vertical axis wind turbines (VAWT) with three straight blades. This study addresses the effects of the collective variations of the pitch angle (within ± 10°) on the performance of the VAWT system. The results of the transient (acceleration) stage will be employed to evaluate the self-starting ability. While the vertical axis wind turbine (VAWT) reaches a steady rotating stage, the detailed flow structures, the vorticity fields, the pressure distributions around, and the forces on the airfoils at various azimuthal positions will be addressed. For the blades with a negative pitch angle (θ = −10°), has the peak value of the moment coefficient within one revolution is the largest which will provide the largest starting torque to drive the VAWT system more easily. However, in this case, the moment coefficients are negative within some part of the period. This cancels part of the positive moment within one revolution, thus the efficiency is reduced at this pitch angle. For the case with positive pitch angle (θ = 10°), the area under the moment coefficient curve is the smallest and the time elapse of large moment coefficient is relatively short. Thus the efficiency and the starting torque are the lowest among thee pitch angles.

Simulation Study on the Performance of Vertical Axis Wind Turbine

2013 ◽  
Vol 465-466 ◽  
pp. 270-274 ◽  
Author(s):  
N. Afzanizam Samiran ◽  
A.A. Wahab ◽  
Mohd Sofian ◽  
N. Rosly
Keyword(s):  
Output Power ◽  
Flow Characteristic ◽  
Cfd Simulation ◽  
Vertical Axis ◽  
Power Coefficient ◽  
Navier Stokes ◽  
Vertical Axis Wind Turbine ◽  
Ansys Fluent ◽  
Savonius Rotor ◽  
Torque Coefficient

The present study considered the design improvement of Savonius rotor, in order to increase the efficiency of output power. An investigation was conducted to study the effect of geometrical configuration on the performance of the rotor in terms of coefficient of torque, coefficient of power and power output. Modification of conventional geometry has been designed by combining the effect of number of blades and shielding method. CFD simulation was conducted to analyze the flow characteristic and calculate the torque coefficient of all the rotor configurations. The continuity and Reynolds Averaged Navier-Stokes (RANS) equations and realizable k-ε epsilon turbulence model are numerically solved by commercial software Ansys-Fluent 14.0. The results obtained by transient and steady method for the conventional two bladed Savonius rotor are in agreement with those obtained experimentally by other authors and this indicates that the methods can be successfully applied for such analysis. The modified 3 and 4 bladed rotors with hybrid shielding method gave the highest maximum power coefficient which 0.37 at TSR 0.5 and output power exceed 4 watts with rotor dimensions of 0.2m width and 0.2m height. This blade configuration also is the best configuration by several percentages compared to the other model from the previous study

scholarly journals Numerical efficiency evaluation of a vertical axis turbine equipped with 4 digits and 5 digits NACA airfoils

2019 ◽  
Vol 85 ◽  
pp. 03001
Author(s):  
Florina Costea ◽  
Ion Malael
Keyword(s):  
Wind Turbine ◽  
Vertical Axis ◽  
Scientific Paper ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Renewable Energy Resources ◽  
Ansys Fluent ◽  
Sst Turbulence Model ◽  
Fluent Software ◽  
Shape Influence

In the current age of global energy crisis, a run for the use of renewable energy resources as the wind energy has gained a significant attention. The main objective of this study is the comparison between two wind turbine configurations. These two turbines have the same geometric parameters but one with a 4 digits NACA0018 blades and the other with 5 digits NACA63-415 blades. In this scientific paper, a numerical evaluation of the airfoil shape influence on the VAWT efficiency is done. For this study the CFD methods with Ansys Fluent software, are used. All the simulations are for unsteady flow at 1e06 Reynolds number value with SST turbulence model. At the design point the wind velocity is 12 m/s and for the wind turbine geometric features, the diameter is 3.25m and the height 4.87m. The power coefficient variation through tip speed ratio will be represented for each wind turbine configurations. To estimate the recirculation zone effects on the efficiency, the vorticity magnitude contours are presented for different positions of the blades. The results will indicate the feasibility of optimization of future wind turbine more complex airfoils.

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.

Numerical Simulations of Spherical Vertical-Axis Wind Rotor

2013 ◽  
Vol 291-294 ◽  
pp. 456-460
Author(s):  
Yong Yu Huang ◽  
Qiu Yun Mo ◽  
Xu Zhang ◽  
Zu Peng Zhou
Keyword(s):  
Numerical Simulation ◽  
Aspect Ratio ◽  
Flow Simulation ◽  
Vertical Axis ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Projected Area ◽  
Simulation Code ◽  
Ansys Fluent ◽  
Identical Number

In this paper, the effects of the shape of three types of the blade on power coefficient of Savonius rotors are studied by simulating the model using numerical simulation under the same conditions. For this purpose, three spherical rotors with different configurations but identical number of stages and blades, aspect ratio and overlap keeping the identical projected area of each rotor are constructed. The geometries of blade of the three rotors are a plane, a semi-circle and a quarter of sphere. The building data are calculated on the basis of the nominal wind velocity V= 10m/s and the speed ratio λ= 0.3 with an industrial flow simulation code (ANSYS-Fluent). The result shows that the rotor with semicircular blades has a higher value of power coefficient in comparison with other rotors.

scholarly journals Recent Development in the Design of Wind Deflectors for Vertical Axis Wind Turbine: A Review

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 5140
Author(s):  
Altaf Hussain Rajpar ◽  
Imran Ali ◽  
Ahmad E. Eladwi ◽  
Mohamed Bashir Ali Bashir
Keyword(s):  
Wind Turbines ◽  
Vertical Axis ◽  
Optimization Techniques ◽  
Rotor Blades ◽  
Power Coefficient ◽  
Potential Contribution ◽  
Vertical Axis Wind Turbine ◽  
Vertical Axis Wind Turbines ◽  
Horizontal Axis Wind Turbines ◽  
Network Costs

Developments in the design of wind turbines with augmentation are advancing around the globe with the goal of generating electricity close to the user in built-up areas. This is certain to help lessen the power generation load as well as distribution and transmission network costs by reducing the distance between the user and the power source. The main objectives driving the development and advancement of vertical-axis wind turbines are increasing the power coefficient and the torque coefficient by optimizing the upstream wind striking on the rotor blades. Unlike horizontal-axis wind turbines, vertical axis turbines generate not only positive torque but also negative torque during operation. The negative torque generated by the returning blade is a key issue for vertical-axis wind turbines (VAWTs) that is counterproductive. Installation of wind deflectors for flow augmentation helps to reduce the negative torque generated by the returning blades as well as enhance the positive torque by creating a diversion in the upstream wind towards the forwarding blade during operation. This paper reviews various designs, experiments, and CFD simulations of wind deflectors reported to date. Optimization techniques for VAWTs incorporating wind deflectors are discussed in detail. The main focus of the review was on the installation position and orientation of the deflectors and their potential contribution to increasing the power coefficient. Topics for future study are suggested in the conclusion section of the paper.

scholarly journals Design and numerical analysis of an efficient H-Darrieus vertical-axis hydrokinetic turbine

2019 ◽  
Vol 13 (4) ◽  
pp. 6036-6058
Author(s):  
Ramirez D. ◽  
Rubio-Clemente A. ◽  
E. Chica
Keyword(s):  
Rural Communities ◽  
Three Dimensional ◽  
Vertical Axis ◽  
Turbine Rotor ◽  
Power Coefficient ◽  
Stream Velocity ◽  
Ansys Fluent ◽  
Electrical Grid ◽  
2D Simulation ◽  
Hydrokinetic Turbine

Hydrokinetic turbines are one of the technological alternatives to generate and supply electricity for rural communities isolated from the national electrical grid with almost zero emission. The Darrieus turbine is one of the options that can be used as a hydrokinetic turbine due to its high power coefficient (Cp) and easy manufacture. In the present work, the design and hydrodynamic analysis of a Darrieus vertical-axis hydrokinetic turbine of 500 W was carried out. A free stream velocity of 1.5 m/s was used for the design of the blades. The diameter (D) and blade length (H) of the turbine were 1.5 m and 1.13 m, respectively. The blade profile used was NACA0025 with a chord length of 0.33 m and solidity () of 0.66. Two (2D) and three dimensional (3D) numerical analyses of the unsteady flow through the blades of the turbine were performed using ANSYS Fluent version 18.0, which is based on a Reynolds-Averaged Navier-Stokes (RANS) model. A transient 2D simulation was conducted for several tip speed ratios (TSR) using a k-ω Shear Stress Transport turbulence (SST) scheme. The optimal TSR was found to be around 1.75. Main hydrodynamic parameters, such as torque (T) and CP, were investigated. Additionally, 3 geometrical configurations of the turbine rotor were studied using a 3D numerical model in order to identify the best configuration with less Cp and T fluctuation. The maximum Cp average was 0.24 and the amplitude of Cp variation, near 0.24 for the turbine model with 3 blades of H equal to 1.13 m. On the other hand, for the turbine models with 6 and 9 blades of H equal to 0.565 m and 0.377 m, respectively, the maximum Cp averages were 0.51 and 0.55, respectively, and the amplitude of Cp variation, near 0.07 for the model with 6 blades and 0.17 for the model with 9 blades. This revealed that the hydrokinetic turbine with a geometrical configuration of 6 blades greatly improves the performance of the turbine due to this model has advantages compared to models with 3 and 9 blades, in terms of the reduction of their T curve fluctuation.

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