Three-dimensional computational fluid dynamic analysis of a large-scale vertical axis wind turbine

2021 ◽  
pp. 0309524X2110379
Author(s):  
Brian Hand
Keyword(s):  
Wind Turbine ◽  
Large Scale ◽  
Three Dimensional ◽  
Vertical Axis ◽  
Offshore Wind ◽  
Speed Ratio ◽  
Offshore Wind Turbine ◽  
Vertical Axis Wind Turbine ◽  
Computational Fluid Dynamics Analysis ◽  
Torque Coefficient

The vertical axis wind turbine (VAWT) configuration has many advantages for an offshore wind turbine Installation. In this paper, the three dimensional (3D) computational fluid dynamics analysis of a large-scale 5 MW VAWT is conducted. At the optimum tip-speed ratio (TSR), the VAWT maximum inline force was 75% larger than the maximum lateral force. It was found the dynamic stall effects cause the VAWT flow field to become increasingly asymmetrical at the mid-span plane, when the TSR is reduced. The attachment of end plates to the blade tips, resulted in a performance improvement during the upwind phase with the average blade torque coefficient in this range being increased by 4.71%. Conversely, during the blade downwind phase a reduction in performance was found due to the increase in drag from the end plates and the average blade torque coefficient in this phase was reduced by 23.1%.

A comprehensive analysis of aerodynamic flow around H-Darrieus rotor with camber-bladed profile

2018 ◽  
Vol 43 (5) ◽  
pp. 459-475 ◽  
Author(s):  
Khaled Souaissa ◽  
Moncef Ghiss ◽  
Mouldi Chrigui ◽  
Hatem Bentaher ◽  
Aref Maalej
Keyword(s):  
Wind Turbine ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Vertical Axis ◽  
Speed Ratio ◽  
Blade Profile ◽  
Vertical Axis Wind Turbine ◽  
Tip Speed Ratio ◽  
Torque Coefficient ◽  
Darrieus Rotor

Improving the H-Darrieus rotor is often followed by the investigation of the influence of the turbine’s parameter design, notably, the aspect ratio, the solidity ( σ), the tip speed ratio, and the airfoil profile shape. In this work, we are interested in both the aerodynamic flows around a straight cambered blade profile and the rotor turbine wake separation of a Darrieus vertical axis wind turbine. The aim of this study is to better understand the evolution of the instantaneous torque and the generated-separated blade vortex during full rotation. Indeed, a three-dimensional computational fluid dynamics model of a vertical axis wind turbine with a straight cambered blade profile NACA4312 operating over a large range of tip speed ratio is considered. The flows are governed by Reynolds-averaged Navier–Stokes equations and the turbulence is modeled with shear stress transport formulations k- ω. This research revealed a high correlation between the evolution of the torque coefficient and the generated-separated blades vortex. In particular, a good correlation between the maximum tip vortices size and the torque coefficient peak is demonstrated.

scholarly journals Three-Dimensional CFD Simulation and Experimental Assessment of the Performance of a H-Shape Vertical-Axis Wind Turbine at Design and Off-Design Conditions

2019 ◽  
Vol 4 (3) ◽  
pp. 30 ◽  
Author(s):  
Nicoletta Franchina ◽  
Otman Kouaissah ◽  
Giacomo Persico ◽  
Marco Savini
Keyword(s):  
Wind Turbine ◽  
Large Scale ◽  
Computational Cost ◽  
Three Dimensional ◽  
Vertical Axis ◽  
Operating Conditions ◽  
Speed Ratio ◽  
Small Scale ◽  
Vertical Axis Wind Turbine ◽  
Numerical Predictions

The paper presents the results of a computational study on the aerodynamics and the performance of a small-scale Vertical-Axis Wind Turbine (VAWT) for distributed micro-generation. The complexity of VAWT aerodynamics, which are inherently unsteady and three-dimensional, makes high-fidelity flow models extremely demanding in terms of computational cost, limiting the analysis to mainly 2D or 2.5D Computational Fluid-Dynamics (CFD) approaches. This paper discusses how a proper setting of the computational model opens the way for carrying out fully 3D unsteady CFD simulations of a VAWT. Key aspects of the flow model and of the numerical solution are discussed, in view of limiting the computational cost while maintaining the reliability of the predictions. A set of operating conditions is considered, in terms of tip-speed-ratio (TSR), covering both peak efficiency condition as well as off-design operation. The fidelity of the numerical predictions is assessed via a systematic comparison with the experimental benchmark data available for this turbine, consisting of both performance and wake measurements carried out in the large-scale wind tunnel of the Politecnico di Milano. The analysis of the flow field on the equatorial plane allows highlighting its time-dependent evolution, with the aim of identifying both the periodic flow structures and the onset of dynamic stall. The full three-dimensional character of the computations allows investigating the aerodynamics of the struts and the evolution of the trailing vorticity at the tip of the blades, eventually resulting in periodic large-scale vortices.

scholarly journals On mooring line tension and fatigue prediction for offshore vertical axis wind turbines: A comparison of lumped mass and quasi-static approaches

2018 ◽  
Vol 42 (2) ◽  
pp. 97-107 ◽  
Author(s):  
D Cevasco ◽  
M Collu ◽  
CM Rizzo ◽  
M Hall
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Line Tension ◽  
Vertical Axis ◽  
Offshore Wind ◽  
Mooring Line ◽  
Offshore Wind Turbine ◽  
Vertical Axis Wind Turbine ◽  
Lumped Mass ◽  
Vertical Axis Wind Turbines

Despite several potential advantages, relatively few studies and design support tools have been developed for floating vertical axis wind turbines. Due to the substantial aerodynamics differences, the analyses of vertical axis wind turbine on floating structures cannot be easily extended from what have been already done for horizontal axis wind turbines. Therefore, the main aim of the present work is to compare the dynamic response of the floating offshore wind turbine system adopting two different mooring dynamics approaches. Two versions of the in-house aero-hydro-mooring coupled model of dynamics for floating vertical axis wind turbine (FloVAWT) have been used, employing a mooring quasi-static model, which solves the equations using an energetic approach, and a modified version of floating vertical axis wind turbine, which instead couples with the lumped mass mooring line model MoorDyn. The results, in terms of mooring line tension, fatigue and response in frequency have been obtained and analysed, based on a 5 MW Darrieus type rotor supported by the OC4-DeepCwind semisubmersible.

Application of Variable Blade Pitch Control on Improving the Performance of Vertical Axis Wind Turbine

2012 ◽  
Vol 229-231 ◽  
pp. 2339-2342
Author(s):  
J.C. Cheng ◽  
S.J Su ◽  
J.J Miau
Keyword(s):  
Wind Turbine ◽  
Vertical Axis ◽  
Aerodynamic Characteristics ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Energy Capture ◽  
Pitch Control ◽  
Tip Speed Ratio ◽  
Torque Coefficient ◽  
Variable Pitch Control

A three blades vertical axis wind turbine simulation is performed to study the unsteady aerodynamic characteristics with blade pitch control. Several fixed and variable blade pitch models under different tip speed ratio are adopted to improve performance of the wind turbine. Results show that an appropriate pitch control model can effectively decrease the range of negative torque regime to reduce the vibration of the wind turbine. Besides, the average torque coefficient as well as the energy capture efficiency can be also improved, especially for the lower tip speed ratio. The overall efficiency of the wind turbines in power generation will be enhanced. For the cases under the tip speed ratio between 1 and 3, the efficiency can be enhanced 243% and 486% for fixed and variable pitch control models respectively as comparing with non-pitch control cases.

Design and Aero-Elastic Simulation of a 5MW Floating Vertical Axis Wind Turbine

2012 ◽  
Author(s):  
Luca Vita ◽  
Uwe S. Paulsen ◽  
Helge A. Madsen ◽  
Per H. Nielsen ◽  
Petter A. Berthelsen ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Wind Waves ◽  
Vertical Axis ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
The European Union ◽  
Vertical Axis Wind Turbine ◽  
Floating Platform ◽  
Mooring Lines ◽  
Sea Bed

This paper deals with the design of a 5MW floating offshore Vertical Axis Wind Turbine (VAWT). The design is based on a new offshore wind turbine concept (DeepWind concept), consisting of a Darrieus rotor mounted on a spar buoy support structure, which is anchored to the sea bed with mooring lines [1]. The design is carried out in an iterative process, involving the different sub-components and addressing several conflicting constraints. The present design does not aim to be the final optimum solution for this concept. Instead, the goal is to have a baseline model, based on the present technology, which can be improved in the future with new dedicated technological solutions. The rotor uses curved blades, which are designed in order to minimize the gravitational loads and to be produced by the pultrusion process. The floating platform is a slender cylindrical structure rotating along with the rotor, whose stability is achieved by adding ballast at the bottom. The platform is connected to the mooring lines with some rigid arms, which are necessary to absorb the torque transmitted by the rotor. The aero-elastic simulations are carried out with Hawc2, a numerical solver developed at Risø-DTU. The numerical simulations take into account the fully coupled aerodynamic and hydrodynamic loads on the structure, due to wind, waves and currents. The turbine is tested in operative conditions, at different sea states, selected according to the international offshore standards. The research is part of the European project DeepWind (2010–2014), which has been financed by the European Union (FP7-Future Emerging Technologies).

scholarly journals Numerical Analysis and Parameter Optimization of J-Shaped Blade on Offshore Vertical Axis Wind Turbine

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6426
Author(s):  
Lin Pan ◽  
Ze Zhu ◽  
Haodong Xiao ◽  
Leichong Wang
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Vertical Axis ◽  
Offshore Wind ◽  
Speed Ratio ◽  
Offshore Wind Turbine ◽  
Offshore Wind Turbines ◽  
Tip Speed Ratio ◽  
Turbulence Effect ◽  
Dimensional Simulation

In this study, the performance of offshore wind turbines at low tip speed ratio (TSR) is studied using computational fluid dynamics (CFD), and the performance of offshore wind turbines at low tip speed ratio (TSR) is improved by revising the blade structure. First, the parameters of vertical axis offshore wind turbine are designed based on the compactness iteration, a CFD simulation model is established, and the turbulence model is selected through simulation analysis to verify the independence of grid and time step. Compared with previous experimental results, it is shown that the two-dimensional simulation only considers the plane turbulence effect, and the simulation turbulence effect performs more obviously at a high tip ratio, while the three-dimensional simulation turbulence effect has well-fitting performance at high tip ratio. Second, a J-shaped blade with optimized lower surface is proposed. The study showed that the optimized J-shaped blade significantly improved its upwind torque and wind energy capture rate. Finally, the performance of the optimized J-blade offshore wind turbine is analyzed.

scholarly journals Studi Eksperimen Pengaruh Jumlah Sudu Terhadap Kinerja Wind Turbine Crossflow

2021 ◽  
Vol 16 (2) ◽  
pp. 218
Author(s):  
Fahrudin Fahrudin ◽  
Fitri Wahyuni ◽  
Dini Oktavitasari
Keyword(s):  
Wind Turbine ◽  
Alternative Energy ◽  
Wind Tunnel Test ◽  
Vertical Axis ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Test Scheme ◽  
Vertical Axis Wind Turbine ◽  
Tip Speed Ratio ◽  
Torque Coefficient

<p>Wind is an alternative energy that is environmentally friendly and sustainable. Therefore, we need a type of wind turbine that can receive wind from all directions. The crossflow type vertical axis wind turbine has a high torque coefficient at a low tip speed ratio. The purpose of this study was to determine the effect of the number of blades on the performance of the vertical axis crossflow wind turbine. The experimental test was carried out by varying the number of blades. The configuration is analyzed using the experimental wind tunnel test scheme which has been modified in the section test section. The results showed that the number of blades 16 has a power coefficient ( ) = 0.23 tip speed ratio (TSR) = 0.42 at a wind speed of 4 m / s.</p><p><strong><br /></strong></p>

Comparison of Experimental and Numerically Predicted Three-Dimensional Wake Behaviour of a Vertical Axis Wind Turbine

2017 ◽  
Author(s):  
Joseph Saverin ◽  
David Marten ◽  
David Holst ◽  
George Pechlivanoglou ◽  
Christian Oliver Paschereit ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Large Scale ◽  
Computational Cost ◽  
Three Dimensional ◽  
Vertical Axis ◽  
Tip Vortex ◽  
Vertical Axis Wind Turbine ◽  
Design And Optimization ◽  
Aerodynamic Model ◽  
Lift And Drag

The evolution of the wake of a wind turbine contributes significantly to its operation and performance, as well as to those of machines installed in the vicinity. The inherent unsteady and three-dimensional aerodynamics of Vertical Axis Wind Turbines (VAWT) have hitherto limited the research on wake evolution. In this paper the wakes of both a troposkien and a H-type VAWT rotor are investigated by comparing experiments and calculations. Experiments were carried out in the large-scale wind tunnel of the Politecnico di Milano, where unsteady velocity measurements in the wake were performed by means of hot wire anemometry. The geometry of the rotors was reconstructed in the open-source wind-turbine software QBlade, developed at the TU Berlin. The aerodynamic model makes use of a lifting line free-vortex wake (LLFVW) formulation, including an adapted Beddoes-Leishman unsteady aerodynamic model; airfoil polars are introduced to assign sectional lift and drag coefficients. A wake sensitivity analysis was carried out to maximize the reliability of wake predictions. The calculations are shown to reproduce several wake features observed in the experiments, including blade-tip vortex, dominant and submissive vortical structures, and periodic unsteadiness caused by sectional dynamic stall. The experimental assessment of the simulations illustrates that the LLFVW model is capable of predicting the unsteady wake development with very limited computational cost, thus making the model ideal for the design and optimization of VAWTs.

Motion Performances of a 5 MW VAWT Supported by Spar Floating Foundation With Heave Plates

2017 ◽  
Author(s):  
Liqin Liu ◽  
Ying Guo ◽  
Weichen Jin ◽  
Rui Yuan
Keyword(s):  
Wind Turbine ◽  
Large Scale ◽  
Vertical Axis ◽  
Offshore Wind ◽  
Vertical Axis Wind Turbine ◽  
Motion Equations ◽  
Offshore Wind Power ◽  
Floating Foundation ◽  
Motion Study ◽  
Truss Spar

The VAWT (vertical axis wind turbine) has advantages in the development of large-scale offshore wind power. This paper presents a motion study of a 5 MW floating VAWT composed of the Φ type Darrieus wind turbine and a truss spar floating foundation with heave plates. The surge, heave and pitch motion equations considering the effects of retardation function of the floating VAWT were established and solved numerically. Several load cases were carried out to analyze the motion performances of the floating VAWT. The results show that the wind forces have minimal influence on the heave motions of the floating VAWT, while they obviously increase its surge and pitch mean displacements. For LC3, the surge, heave and pitch frequencies of the floating VAWT are dominated by the wave frequencies, and the 2P (twice-per-revolution) response of pitch motions is not significant. For LC4, the 2P response of pitch motions of the floating VAWT are more significant than LC4.

scholarly journals Nonlinear Lifting Line Theory Applied to Vertical Axis Wind Turbines: Development of a Practical Design Tool

2017 ◽  
Vol 140 (2) ◽  
Author(s):  
David Marten ◽  
Georgios Pechlivanoglou ◽  
Christian Navid Nayeri ◽  
Christian Oliver Paschereit
Keyword(s):  
Wind Turbine ◽  
Large Scale ◽  
Unsteady Aerodynamics ◽  
Vertical Axis ◽  
Design Tool ◽  
Offshore Wind ◽  
Vertical Axis Wind Turbine ◽  
Floating Structure ◽  
Horizontal Axis Wind Turbine ◽  
Lifting Line

Recently, a new interest in vertical axis wind turbine (VAWT) technology is fueled by research on floating support structures for large-scale offshore wind energy application. For the application on floating structures at multimegawatt size, the VAWT concept may offer distinct advantages over the conventional horizontal axis wind turbine (HAWT) design. As an example, VAWT turbines are better suited for upscaling, and at multimegawatt size, the problem of periodic fatigue cycles reduces significantly due to a very low rotational speed. Additionally, the possibility to store the transmission and electricity generation system at the bottom, compared to the tower top as in a HAWT, can lead to a considerable reduction of material logistics costs. However, as most VAWT research stalled in the mid 1990s, no sophisticated and established tools to investigate this concept further exist today. Due to the complex interaction between unsteady aerodynamics and movement of the floating structure, fully coupled simulation tools modeling both aero and structural dynamics are needed. A nonlinear lifting line free vortex wake (LLFVW) code was recently integrated into the open source wind turbine simulation suite qblade. This paper describes some of the necessary adaptions of the algorithm, which differentiates it from the usual application in HAWT simulations. A focus is set on achieving a high robustness and computational efficiency. A short validation study compares LLFVW results with those of a two-dimensional (2D) unsteady Reynolds-averaged Navier–Stokes (URANS) simulation.

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