Parametric Study of Vertical Axis Wind Turbine Rotor Configurations Using CFD

2017 ◽  
Author(s):  
John Keithley Difuntorum ◽  
Louis Angelo M. Danao
Keyword(s):  
Leading Edge ◽  
Vertical Axis ◽  
Turbine Rotor ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Dynamics Modeling ◽  
Worst Case ◽  
Computational Fluid Dynamics Modeling ◽  
Baseline Case ◽  
Parametric Studies

Vertical axis wind turbines present several advantages over the horizontal axis machines that make them suitable to a variety of wind conditions. However due to the complexity of VAWT aerodynamics, available literature on VAWT performance in steady and turbulent wind conditions is limited. This paper aims to numerically predict the performance of a 5kW VAWT under steady wind conditions through computational fluid dynamics modeling by varying turbine configuration parameters. Two dimensional VAWT models using a cambered blade (1.5%) were created with open field boundary extents. Turbine configuration parameters studied include blade mounting position, blade fixing angle, and rotor solidity. Baseline case with peak Cp of 0.31 at tip speed ratio of 4 has the following parameters: mounting position at 0.5c, zero fixing angle, 3 blades (solidity = 0.3). Independent parametric studies were carried out and results show that a blade mounting position of 0.7c from the leading edge produces best performance with maximum Cp = 0.315 while worst case is a mounting position of 0.15c with peak Cp = 0.273. Fixing angle study reveals a toe-out setting of −1° producing the best performance with peak Cp of 0.315 and the worst setting at toe-in of 1.5° with peak Cp of 0.287. The solidity study resulted in a best case of 4 blades (solidity = 0.4) with peak Cp = 0.316 and worst case of 2 blades (solidity = 0.2) with peak Cp = 0.283.

Improving VAWT performance through parametric studies of rotor design configurations using computational fluid dynamics

2018 ◽  
Vol 233 (4) ◽  
pp. 489-509 ◽  
Author(s):  
John Keithley Difuntorum ◽  
Louis Angelo M Danao
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Leading Edge ◽  
Vertical Axis ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Dynamics Modeling ◽  
Worst Case ◽  
Baseline Case ◽  
Parametric Studies

Vertical axis wind turbines present several advantages over the horizontal axis machines that make them suitable to a variety of wind conditions. However, due to the complexity of vertical axis wind turbine (VAWT) aerodynamics, available literature on VAWT performance in steady and turbulent wind conditions is limited. This paper aims to numerically predict the performance of a 5 kW VAWT under steady wind conditions through computational fluid dynamics modeling by varying turbine configuration parameters. Two-dimensional VAWT models using a cambered blade (1.5%) were created with open field boundary extents. Turbine configuration parameters studied include blade mounting position, blade fixing angle, and rotor solidity. Baseline case with peak Cp of 0.31 at tip-speed ratio of 4 has the following parameters: mounting position at 0.5c, zero fixing angle, and three blades (solidity = 0.3). Independent parametric studies were carried out and results show that a blade mounting position of 0.7c from the leading edge produces the best performance with maximum Cp = 0.315 while the worst case is a mounting position of 0.15c with peak Cp = 0.273. Fixing angle study reveals a toe-out setting of −1° producing the best performance with peak Cp of 0.315 and the worst setting at toe-in of 1.5° with peak Cp of 0.287. The solidity study resulted in the best case of four blades (solidity = 0.4) with peak Cp = 0.316 and the worst case of two blades (solidity = 0.2) with peak Cp = 0.283.

Numerical Study of Vertical Axis Wind Turbine Rotor Configuration

2013 ◽  
Vol 859 ◽  
pp. 28-32
Author(s):  
Yi Mei ◽  
Jian Jun Qu ◽  
Xiao Ya Liu
Keyword(s):  
Wind Turbine ◽  
Urban Areas ◽  
Numerical Study ◽  
Vertical Axis ◽  
Turbine Rotor ◽  
Radius Ratio ◽  
Speed Ratio ◽  
Wind Condition ◽  
Vertical Axis Wind Turbine ◽  
Power Performance

This paper presents a numerical study of a vertical axis wind rotor configuration. Below constant wind condition 8m/s, rotor power performance was investigated over variable turbine configurations. Illustrated by the simulation, increasing rotor cord to radius ratio or blade numbers will enhance the generation of vortexes and flow separation on blades, leading to the significant degradation of turbine performance. It can be conclude form the numerical analysis, a vertical axis wind turbine with high height to radius ratio applied in urban areas experienced better performance when operating in optimal tip speed ratio, with rotor cord to radius ratio between 0.2 and 0.4 and blade number of 3 or 4.

Dynamic Stall: The Case of the Vertical Axis Wind Turbine

1986 ◽  
Vol 108 (2) ◽  
pp. 140-145 ◽  
Author(s):  
A. Laneville ◽  
P. Vittecoq
Keyword(s):  
Experimental Investigation ◽  
Reynolds Number ◽  
Leading Edge ◽  
Vertical Axis ◽  
Dynamic Stall ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Airfoil Surface ◽  
Helicopter Blade ◽  
Tip Speed Ratio

This paper presents the results of an experimental investigation on a driven Darrieus turbine rotating at different tip speed ratios. For a Reynolds number of 3.8 × 104, the results indicate the presence of dynamic stall at tip speed ratio less than 4, and that helicopter blade aerodynamics can be used in order to explain some aspects of the phenomenon. It was observed that in deep stall conditions, a vortex is formed at the leading edge; this vortex moves over the airfoil surface with 1/3 of the airfoil speed and then is shed at the trailing edge. After its shedding, the vortex can interact with the airfoil surface as the blade passes downstream.

scholarly journals Effect of solidity on the dynamic behaviour of the Darrieus turbine with leading-edge protuberance

2021 ◽  
Vol 850 (1) ◽  
pp. 012038
Author(s):  
U Lokesh ◽  
N Kirthika ◽  
K Madhu Madhan ◽  
C B Maheswaran ◽  
S Ramaswami ◽  
...  
Keyword(s):  
Wind Energy ◽  
Wind Turbine ◽  
Dynamic Behaviour ◽  
Leading Edge ◽  
Vertical Axis ◽  
Speed Ratio ◽  
Experimental Measurements ◽  
Vertical Axis Wind Turbine ◽  
Tip Speed Ratio ◽  
Vortex Induced Vibrations

Abstract The dynamic behaviour of the straight–type Darrieus turbine with leading-edge protuberance (LEP) was analysed under various solidity ratios at several tip speed ratios through experiments. The Darrieus turbine is a type of Vertical Axis Wind Turbine (VAWT) which uses wind energy to generate electricity. This type of turbine was subjected to vortex-induced and buffeting types of vibrations. These vibrations were more sensitive to the number of blades and tip speed ratios. Based on the experimental measurements, the results revealed that, at a low tip speed ratio, the four-bladed turbine exhibits lesser vortex-induced vibrations than those of the three and five-bladed turbines. However, at a high tip speed ratio, the three-bladed configuration operates well against the vortex-induced vibrations. In the case of buffeting, a three-bladed turbine diminishes the dynamic oscillations at both low and high tip speed ratios, whereas the four and five-bladed turbines induce dynamic oscillations at slightly higher amplitudes. However, the amplitude of buffeting is smaller than those of vortex-induced vibrations.

scholarly journals Unsteady Computational Study of Novel Biologically Inspired Offshore Vertical Axis Wind Turbine at Different Tip Speed Ratios: A Two-Dimensional Study

2019 ◽  
Vol 16 (2) ◽  
pp. 6753-6772
Author(s):  
S. N. Ashwindran ◽  
Azizuddin Abd Aziz ◽  
A. N. Oumer
Keyword(s):  
Wind Turbine ◽  
Computational Study ◽  
Leading Edge ◽  
Vertical Axis ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Biologically Inspired ◽  
Freestream Velocity ◽  
Fine Mesh ◽  
Moment Coefficient

The aim of this paper presents an unsteady numerical investigation of a novel biologically inspired vertical axis wind turbine. The simulation was conducted in 2D using the sliding mesh technique with non-conformal mesh spatial discretisation via FLUENT. Grid sensitivity study on mesh density and turbulent transport model indicated that fine mesh and medium converged well with trivial difference. SST and k-ω model presented stable behaviour and indicated good agreement. SST were chosen for the rest of the simulation. The proposed wind turbine was simulated at five different moderate tip speed ratios under the influence of freestream velocity U∞=8m/s. The highest moment coefficient is generated at tip speed ratio λ=1.3, which is Cm=0.1886 with a stable positive moment coefficient after 480°. The proposed turbine responded well at λ=1.3 and λ=1.7 with power coefficient result of Cp=0.245 and Cp=0.262 respectively. The effect of wake and voracity on the turbine at subjected tip speed ratios is studied. Wake regions induced by the leading edge of the aerofoil impacted the performance of the following blade. Furthermore, due to the less wake effect trailed by the leading edge at λ=1.3, it generates higher moment than λ=1.7. Since the proposed blade has a fixed 4° angle of attack, it was sensible for the turbine to experience such wake and vorticity effect.

scholarly journals Numerical Investigation on the Effects of Airfoil Leading Edge Radius on the Aerodynamic Performance of H-Rotor Darrieus Vertical Axis Wind Turbine

Energies ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3794
Author(s):  
Chenguang Song ◽  
Guoqing Wu ◽  
Weinan Zhu ◽  
Xudong Zhang ◽  
Jicong Zhao
Keyword(s):  
Wind Turbine ◽  
Leading Edge ◽  
Vertical Axis ◽  
Aerodynamic Characteristics ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Edge Radius ◽  
Flow Field Characteristics ◽  
Naca 0015

This paper numerically investigates the effects of airfoil leading edge radius on the aerodynamic characteristics of H-rotor Darrieus vertical axis wind turbine (VAWT). 10 modified airfoils are generated by changing the leading edge radius of the base NACA 0015 airfoil from 1%c to 9%c, respectively. A 2D unsteady Computational Fluid Dynamics (CFD) model is established and validated with the previously published experimental data. The power, torque, and flow field characteristics of the rotors are analyzed. The results indicate that the maximum and minimum power coefficient at the optimum tip speed ratio (TSR) are obtained for the LE-5%c and LE-1%c model, respectively. The best aerodynamic characteristics are determined by the LE-5%c model below the optimum TSR and the LE-3%c model beyond the optimum TSR. The torque characteristics and pressure distribution for the single blades with different airfoil leading edge radius show an obvious difference in the upwind region and a very small difference in the downwind region. Moreover, the airfoil leading edge radius influences the strength, region, and diffusion rate of the vortices, being the main reason for the observed differences in instantaneous torque coefficient and power coefficient. The vortices of the LE-1%c model are stronger, larger, and diffuse slower than those of the LE-2%c and LE-5%c model at the optimum TSR.

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.

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