scholarly journals Electric Circuit Model for the Aerodynamic Performance Analysis of a Three-Blade Darrieus-Type Vertical Axis Wind Turbine: The Tchakoua Model

Energies ◽  
2016 ◽  
Vol 9 (10) ◽  
pp. 820 ◽  
Author(s):  
Pierre Tchakoua ◽  
René Wamkeue ◽  
Mohand Ouhrouche ◽  
Ernesto Benini ◽  
Gabriel Ekemb
Keyword(s):  
Wind Turbine ◽  
Unsteady Aerodynamics ◽  
Electric Circuit ◽  
Vertical Axis ◽  
Aerodynamic Performance ◽  
Circuit Model ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Electrical Analogy ◽  
Electric Circuit Model

The complex and unsteady aerodynamics of vertical axis wind turbines (VAWTs) pose significant challenges for simulation tools. Recently, significant research efforts have focused on the development of new methods for analysing and optimising the aerodynamic performance of VAWTs. This paper presents an electric circuit model for Darrieus-type vertical axis wind turbine (DT-VAWT) rotors. The novel Tchakoua model is based on the mechanical description given by the Paraschivoiu double-multiple streamtube model using a mechanical‑electrical analogy. Model simulations were conducted using MATLAB for a three-bladed rotor architecture, characterized by a NACA0012 profile, an average Reynolds number of 40,000 for the blade and a tip speed ratio of 5. The results obtained show strong agreement with findings from both aerodynamic and computational fluid dynamics (CFD) models in the literature.

Prediction of Aerodynamic Noise Radiated From a Vertical-Axis Wind Turbine

2003 ◽  
Author(s):  
Akiyoshi Iida ◽  
Akisato Mizuno ◽  
Kyoji Kamemoto
Keyword(s):  
Flow Field ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Sound Source ◽  
Vertical Axis ◽  
Aerodynamic Performance ◽  
Low Noise ◽  
Aerodynamic Noise ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine

Unsteady flow field and flow induced noise of vertical axis wind turbine are numerically investigated. The flow field is numerically calculated by the vortex method with core-spreading model. This simulation obtains aerodynamic performance and aerodynamic forces. Aerodynamic noise is also simulated by using Ffowcs Williams-Hawkings equation with compact body and low-Mach number assumptions. Tip speed of rotor blades are not so high, then the contribution of the moving sound source is smaller than that of the dipole sound source. Since the maximum power coefficient of VAWT can be obtained at lower tip-speed ratio compared to the conventional, horizontal axis wind turbines, the aerodynamic noise from vertical axis wind turbine is smaller than that of the conventional wind turbines at the same aerodynamic performance. This result indicates that the vertical axis wind turbines are useful to develop low-noise wind turbines.

Dimple Shape Effect on the Aerodynamic Performance of H-Rotor Darrieus Vertical Axis Wind Turbine

2021 ◽  
Author(s):  
Kabita Naik ◽  
Niranjan Sahoo
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Turbulence Models ◽  
Vertical Axis ◽  
Aerodynamic Performance ◽  
Low Noise ◽  
Speed Ratio ◽  
Shape Effect ◽  
Vertical Axis Wind Turbine ◽  
Ansys Fluent

Abstract Nowadays, the vertical axis wind turbines (VAWTs) have gained significant attention among the small wind turbine (WT) due to their omnidirectional ability, low costs, low noise, and robustness, mainly for urban and off-shore applications. The H-rotor Darrieus is one of the class of VAWT that is mostly suitable for low-speed wind and low tip speed ratio (TSR) conditions. These VAWTs have relatively lesser performance than horizontal axis wind turbines (HAWTs). Therefore, to improve the performance of the H-rotor Darrieus VAWT, a dimple/cavity of different shapes is created into the surface of the blade airfoil as a power augmentation technique. The current study presents several two-dimensional numerical simulations on the H-rotor Darrieus VAWT in the turbulent flow. The performance of the VAWT has been examined through ANSYS Fluent solver with different turbulence models, and it is found that the Shear stress transport (SST) k–ω turbulence model shows better results. The study primarily focuses on the effect of the dimple location, diameter and shape to enhance the aerodynamic performance of the H-rotor Darrieus VAWT. It is found that the rotor performance is increased by about 13% with a quadral/rectangular dimple in comparison to without dimple. Further, with the inclusion of a dimple on the rotor blade airfoil, its performance is not only enhanced but also able to maintain it for a broad range of TSR. Thus, the present study suggests the implication of a dimple/cavity to be very promising in improving H-rotor Darrieus VAWT.

scholarly journals Aerodynamic Characteristics of Asymmetric Airfoils Blade Small Vertical Axis Wind Turbines

2014 ◽  
Vol 8 (1) ◽  
pp. 750-753
Author(s):  
Li-Hua Zhao ◽  
Ming Liu
Keyword(s):  
Wind Turbine ◽  
Vertical Axis ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Sliding Mesh ◽  
Moment Coefficient ◽  
Mesh Model ◽  
Fluent Software

In this paper, using sliding mesh model, the numerical simulation of small vertical axis wind turbine aerodynamic performance was studied with FLUENT software. Got change rule of four same thickness and different camber‘s NACA series asymmetrical airfoil moment coefficient of the wind turbine and wind power machine with the tip speed ratio. Wind turbine benchmark blade around the flow field was studied. Research shows that within a certain range, small vertical axis wind turbine aerodynamic performance be promoted if the airfoil relative thickness increases. In the case of large attack angle, the wind turbine blade is easy to be separated. It provides a theoretical reference for optimal design of a small vertical axis wind turbine.

Numerical Research on the Characteristics of Lift-Drag Type Vertical Axis Wind Turbine

2012 ◽  
Vol 189 ◽  
pp. 448-452
Author(s):  
Yan Jun Chen ◽  
Guo Qing Wu ◽  
Yang Cao ◽  
Dian Gui Huang ◽  
Qin Wang ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Vertical Axis ◽  
Chord Length ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Tip Speed Ratio ◽  
Middle Range ◽  
Parabolic Form ◽  
Cfd Method

Numerical studies are conducted to research the performance of a kind of lift-drag type vertical axis wind turbine (VAWT) affected by solidity with the CFD method. Moving mesh technique is used to construct the model. The Spalart-Allmaras one equation turbulent model and the implicit coupled algorithm based on pressure are selected to solve the transient equations. In this research, how the tip speed ratio and the solidity of blade affect the power coefficient (Cp) of the small H-VAWT is analyzed. The results indicate that Cp curves exhibit approximate parabolic form with its maximum in the middle range of tip speed ratio. The two-blade wind turbine has the lowest Cp while the three-blade one is more powerful and the four-blade one brings the highest power. With the certain number of blades, there is a best chord length, and too long or too short chord length may reduce the Cp.

scholarly journals Effect of Pitch Parameters on Aerodynamic Forces of a Straight-Bladed Vertical Axis Wind Turbine with Inclined Pitch Axes

2021 ◽  
Vol 11 (3) ◽  
pp. 1033
Author(s):  
Jia Guo ◽  
Timing Qu ◽  
Liping Lei
Keyword(s):  
Wind Turbine ◽  
Vertical Axis ◽  
Speed Ratio ◽  
Incline Angle ◽  
Asymmetric Distribution ◽  
Vertical Axis Wind Turbine ◽  
Power Performance ◽  
Aerodynamic Forces ◽  
Ansys Fluent ◽  
Pitch Regulation

Pitch regulation plays a significant role in improving power performance and achieving output control in wind turbines. The present study focuses on a novel, pitch-regulated vertical axis wind turbine (VAWT) with inclined pitch axes. The effect of two pitch parameters (the fold angle and the incline angle) on the instantaneous aerodynamic forces and overall performance of a straight-bladed VAWT under a tip-speed ratio of 4 is investigated using an actuator line model, achieved in ANSYS Fluent software and validated by previous experimental results. The results demonstrate that the fold angle has an apparent influence on the angles of attack and forces of the blades, as well as the power output of the wind turbine. It is helpful to further study the dynamic pitch regulation and adaptable passive pitch regulation of VAWTs. Incline angles away from 90° lead to the asymmetric distribution of aerodynamic forces along the blade span, which results in an expected reduction of loads on the main shaft and the tower of VAWTs.

Design and performance evaluation of vertical axis wind turbine for wind energy harvesting at railway

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hashwini Lalchand Thadani ◽  
Fadia Dyni Zaaba ◽  
Muhammad Raimi Mohammad Shahrizal ◽  
Arjun Singh Jaj A. Jaspal Singh Jaj ◽  
Yun Ii Go
Keyword(s):  
Wind Speed ◽  
Energy Harvesting ◽  
Wind Energy ◽  
Wind Turbine ◽  
High Speed ◽  
Vertical Axis ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Modeling Tools ◽  
Content Type

PurposeThis paper aims to design an optimum vertical axis wind turbine (VAWT) and assess its techno-economic performance for wind energy harvesting at high-speed railway in Malaysia.Design/methodology/approachThis project adopted AutoCAD and ANSYS modeling tools to design and optimize the blade of the turbine. The site selected has a railway of 30 km with six stops. The vertical turbines are placed 1 m apart from each other considering the optimum tip speed ratio. The power produced and net present value had been analyzed to evaluate its techno-economic viability.FindingsComputational fluid dynamics (CFD) analysis of National Advisory Committee for Aeronautics (NACA) 0020 blade has been carried out. For a turbine with wind speed of 50 m/s and swept area of 8 m2, the power generated is 245 kW. For eight trains that operate for 19 h/day with an interval of 30 min in nonpeak hours and 15 min in peak hours, total energy generated is 66 MWh/day. The average cost saved by the train stations is RM 16.7 mil/year with battery charging capacity of 12 h/day.Originality/valueWind energy harvesting is not commonly used in Malaysia due to its low wind speed ranging from 1.5 to 4.5 m/s. Conventional wind turbine requires a minimum cut-in wind speed of 11 m/s to overcome the inertia and starts generating power. Hence, this paper proposes an optimum design of VAWT to harvest an unconventional untapped wind sources from railway. The research finding complements the alternate energy harvesting technologies which can serve as reference for countries which experienced similar geographic constraints.

scholarly journals Numerical Simulation of Aerodynamic Performance of Off-grid Small Vertical Axis Wind Turbine

2018 ◽  
Vol 53 ◽  
pp. 02004
Author(s):  
Qiuyun Mo ◽  
Jiabei Yin ◽  
Lin Chen ◽  
Weihao Liu ◽  
Li Jiang ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Turbine Blades ◽  
Vertical Axis ◽  
Aerodynamic Performance ◽  
Velocity Fields ◽  
Compact Model ◽  
Vertical Axis Wind Turbine ◽  
Wind Turbine Blades ◽  
Rotation Domain ◽  
Rng Turbulence Model

In this paper, a 2D off-grid small compact model of vertical axis wind turbine was established. The sliding grid technology, the RNG turbulence model and the Coupld algorithm was applied to simulate the unsteady value of the model's aerodynamic performance. Through the analysis on the flow field at difference moments, the rules about velocity fields, vortices distributions and the wind turbine's total torque were obtained. The results show that: the speed around wind turbine blades have obvious gradient, and the velocity distribution at different times show large differences in the computional domain. In the rotating domain vorticity is large. With away from the rotation domain, vorticity reduced quickly. In the process of rotating for vertical axis wind turbine, the wind turbine's total torque showed alternating positive and negative changes.

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