Analysis of the Design Parameters Related to a Fixed-Pitch Straight-Bladed Vertical Axis Wind Turbine

2008 ◽  
Vol 32 (5) ◽  
pp. 491-507 ◽  
Author(s):  
Mazharul Islam ◽  
Amir Fartaj ◽  
Rupp Carriveau

The fixed-pitch straight-bladed vertical axis wind turbine (SB-VAWT) is one of the simplest types of wind turbine. One of the main challenges of wide spread application of the smaller-capacity SB-VAWT is to design and develop it in a cost-effective manner. The overall cost of the SB-VAWT will mainly depend on judicious choice of multiple design parameters. An attempt has been made in this paper to identify and critically analyze the main design parameters related to smaller-capacity fixed-pitch SB-VAWT. It has been demonstrated in this paper that proper selections of these parameters are vital for a cost-effective smaller-capacity SB-VAWT which can be considered as a candidate for urban and off-grid rural applications.

2021 ◽  
pp. 0309524X2110039
Author(s):  
Amgad Dessoky ◽  
Thorsten Lutz ◽  
Ewald Krämer

The present paper investigates the aerodynamic and aeroacoustic characteristics of the H-rotor Darrieus vertical axis wind turbine (VAWT) combined with very promising energy conversion and steering technology; a fixed guide-vanes. The main scope of the current work is to enhance the aerodynamic performance and assess the noise production accomplished with such enhancement. The studies are carried out in two phases; the first phase is a parametric 2D CFD simulation employing the unsteady Reynolds-averaged Navier-Stokes (URANS) approach to optimize the design parameters of the guide-vanes. The second phase is a 3D CFD simulation of the full turbine using a higher-order numerical scheme and a hybrid RANS/LES (DDES) method. The guide-vanes show a superior power augmentation, about 42% increase in the power coefficient at λ = 2.75, with a slightly noisy operation and completely change the signal directivity. A remarkable difference in power coefficient is observed between 2D and 3D models at the high-speed ratios stems from the 3D effect. As a result, a 3D simulation of the capped Darrieus turbine is carried out, and then a noise assessment of such configuration is assessed. The results show a 20% increase in power coefficient by using the cap, without significant change in the noise signal.


2021 ◽  
Author(s):  
Moshe Zilberman ◽  
Abdelaziz Abu Sbaih ◽  
Ibrahim Hadad

Abstract Wind energy has become an important resource for the growing demand for clean energy. In 2020 wind energy provided more than 6% of the global electricity demand. It is expected to reach 7% at the end of 2021. The installation growth rate of small wind turbines, though, is relatively slow. The reasons we are interested in the small vertical axis wind turbines are their low noise, environmentally friendly, low installation cost, and capable of being rooftop-mounted. The main goal of the present study is an optimization process towards achieving the optimal cost-effective vertical wind turbine. Thirty wind turbine models were tested under the same conditions in an Azrieli 30 × 30 × 90 cm low-speed wind tunnel at 107,000 Reynolds number. The different types of models were obtained by parametric variations of five basic models, maintaining the same aspect ratio but varying the number of bucket phases, the orientation angles, and the gaps between the vanes. The best performing turbine model was made of one phase with two vanes of non-symmetric bipolynomial profiles that exhibited 0.2 power coefficient, relative to 0.16 and 0.13 that were obtained for symmetrical polynomial and the original Savonius type turbines, respectively. Free rotation, static forces and moments, and dynamic moments and power were measured for the sake of comparison and explanation for the variations in performances of different types of turbines. CFD calculations were used to understand the forces and moment behaviors of the optimized turbine.


2018 ◽  
Vol 10 (9) ◽  
pp. 168781401879954
Author(s):  
Soo-Yong Cho ◽  
Sang-Kyu Choi ◽  
Jin-Gyun Kim ◽  
Chong-Hyun Cho

In order to augment the performance of vertical axis wind turbines, wind power towers have been used because they increase the frontal area. Typically, the wind power tower is installed as a circular column around a vertical axis wind turbine because the vertical axis wind turbine should be operated in an omnidirectional wind. As a result, the performance of the vertical axis wind turbine depends on the design parameters of the wind power tower. An experimental study was conducted in a wind tunnel to investigate the optimal design parameters of the wind power tower. Three different sizes of guide walls were applied to test with various wind power tower design parameters. The tested vertical axis wind turbine consisted of three blades of the NACA0018 profile and its solidity was 0.5. In order to simulate the operation in omnidirectional winds, the wind power tower was fabricated to be rotated. The performance of the vertical axis wind turbine was severely varied depending on the azimuthal location of the wind power tower. Comparison of the performance of the vertical axis wind turbine was performed based on the power coefficient obtained by averaging for the one periodic azimuth angle. The optimal design parameters were estimated using the results obtained under equal experimental conditions. When the non-dimensional inner gap was 0.3, the performance of the vertical axis wind turbine was better than any other gaps.


Author(s):  
Carlos Xisto ◽  
José Páscoa ◽  
Michele Trancossi

In the paper, four key design parameters with a strong influence on the performance of a small-scale high solidity variable pitch VAWT (Vertical Axis Wind Turbine), operating at low tip-speed-ratio (TSR) are addressed. To this aim a numerical approach, based on a finite-volume discretization of two-dimensional Unsteady RANS equations on a multiple sliding mesh, is proposed and validated against experimental data. The self-pitch VAWT design is based on a straight blade Darrieus wind turbine with blades that are allowed to pitch around a feathering axis, which is also parallel to the axis of rotation. The pitch angle amplitude and periodic variation are dynamically controlled by a four-bar-linkage system. We only consider the efficiency at low and intermediate TSR, therefore the pitch amplitude is chosen to be a sinusoidal function with a considerable amplitude. The results of this parametric analysis will contribute to define the guidelines for building a full size prototype of a small scale turbine of increased efficiency.


2014 ◽  
Vol 487 ◽  
pp. 429-434 ◽  
Author(s):  
Qiao Mei Li ◽  
Yang Cao ◽  
Guo Qing Wu ◽  
Xing Hua Chen ◽  
Yan Hua Cao

The spindle of a 10 kw vertical axis wind turbine is designed in this paper, and the relevant geometric parameters is given, and build the geometry of the finite element model. Calculation of the spindle under wind load and dead weight , and analyse the spindle Von Mess stress, deformation nephogram, and give the former six order vibration mode of the spindle. Through the analysis, Then the design parameters of the spindle are optimized. and the optimized structure of spindle has been got. optimized spindle is in lower quality, more satisfy the requirement of wind turbine running under high load at the same time .


2021 ◽  
pp. 1-14
Author(s):  
Owaisur Rahman Shah ◽  
Azfar Jamal ◽  
Talha Irfan Khan ◽  
Usama Waleed Qazi

Abstract The research work depicts the study of the comparison of a 1kW Fixed Pitch Vertical Axis Wind Turbine (VAWT) and a Variable Pitch VAWT via analytical, numerical and experimental results. Being an emerging technology, wind turbine is becoming a source of attraction for the researchers. The VAWT in comparison to the Horizontal Axis Wind Turbine (HAWT), has shown numerous benefits. The fundamental purpose of this work is to maximize the output power and output torque of the wind turbine. For achieving an improved output, a novel and unique mechanism, termed as pitching mechanism, is employed that follows the variable pitch concept. The mathematical modelling was done for the straight blade variable pitch VAWT as well as for the fixed rotor. The four bar mechanism was developed, to execute the variable pitch mechanism, and implemented in the form of the CAD model. A scaled down 3D Model of the rotor was manufactured using 3D printing technique. The aerodynamic forces such as lift and drag were measured upon the rotor as per the testing on the rotor in the wind tunnel. CFD simulations were run for the fixed pitch as well as the variable pitch rotor. The transient analysis was performed for the azimuthal angle ranging from 0 to 360 degrees and for a pitch angle varying from +25 to-25 degrees in ANSYS software. The comparative study was undertaken, keeping in view the analytical, simulation and experimental results. A worthy agreement was observed between analytical, software and experimental results and a promising increase in power and torque was observed due the introduction of the variable pitch mechanism. The power produced by the variable pitch design showed a significant increase in the power production as compared to the fixed pitch design. The numerical and experimental values of cp for the variable pitch design were quite comparable.


Author(s):  
Teresa Parra-Santos ◽  
Diego J. Palomar Trullen ◽  
Armando Gallegos ◽  
Cristobal N. Uzarraga ◽  
Maria Regidor-Sanchez ◽  
...  

The performance of a Vertical Axis Wind Turbine (VAWT) is numerically analyzed. Influence of fixed pitch angle is studied to get tendencies on the characteristic curves. The set up corresponds with an H-Darrieus with three straight NACA airfoils attached to a vertical shaft. Two-dimensional, transient, Navier Stokes equations are solved with a Third-Order Muscl scheme using SIMPLE to couple pressure and velocity. At least three revolutions must be simulated to get the periodic behaviour. Transition SST turbulence model has been chosen based on literature. Pitch angles of −6° and −10° have been analyzed with Tip Speed Ratios ranging from 0.7 and 1.6. The pitch angle of −10° improves the performance of the wind turbine. Instantaneous and averaged power coefficients as well as detailed flow field around the airfoils are shown.


The consumption of electricity in urban as well as rural is increasing every day and became an essential commodity for household and industrial purposes. Unfortunately the availability of electrical energy in India is not sufficient to the required demand and it is essential to discover and generate energy from non-conventional sources with cheap cost. On the same time it is necessary to reduce the consumption of conventional sources and to save fuel. Among all the renewable resources, wind is one of the best resources available all the time at free of cost. Especially vertical axis wind turbines (VAWT) are self-starting, omni directional. They require no yaw mechanism to continuously orient towards the wind direction and provide a more reliable energy conversion technology, as compared to horizontal axis wind turbine. Particularly savonius vertical axis wind turbines (SVAWT) are suitable and practically possible at low or uncertain wind speed regimes. They can be fitted on rooftops and also suitable for the urban areas where electricity is not available properly. This project deals with the fabrication and performance evaluation of savonius vertical axis wind turbine using two blade rotor. The amount of power developed by the wind turbine is calculated under theoretical and practical conditions and aerodynamics coefficients are also estimated. And various design parameters of savonious rotor are identified and determined.


Author(s):  
Jesse J. French ◽  
Corey P. Ressler ◽  
John J. Weigelt

Previous work at the institution has successfully shown that a novel VAWT design can be employed to provide electrical power to remote rural villages in a cost effective manner. The VAWT’s design can effectively utilize the non-laminar, low level winds and survive the increased turbulence present at remote and non-optimal installation locations. Previous efforts have improved the overall aerodynamic characteristics of the turbine and scaled these designs from a 100W to a 1kW scaled turbine. In order to remain a viable and affordable solution for use worldwide by truly rural users, these turbines need to have low manufacturing cost and low maintenance costs. This paper presents the work done by the authors to analyze the main cost contributors, manufacturing methods, techniques, and tooling used to improve productivity in the manufacturing process. Design improvements and construction materials were analyzed to reduce overall weight which leads to cost reduction and overall improvements in manufacturability. The specific improvements explored by the authors include redesigning the arms of the turbine to improve aerodynamic efficiency of the turbine, reducing construction materials to minimum allowable values, and designing manufacturing tooling which will allow for rapid production of large quantities of the turbine. Results are presented from over 4000 hours of in-situ testing of the turbine showing that the manufacturing improvements reduced construction time to 25% of the original design and reduced weight by 25% while maintaining full functionality and high-wind survivability.


Sign in / Sign up

Export Citation Format

Share Document