Wind tunnel experiments of a pair of interacting vertical-axis wind turbines (original) (raw)
Related papers
Experimental characterisation of the wake behind paired vertical-axis wind turbines
Journal of Wind Engineering and Industrial Aerodynamics, 2020
Two vertical-axis wind turbines (VAWTs) benefit from a power increase when placed side by side in close proximity. To study the potential of paired VAWTs for integration in wind farms, wind tunnel wake measurements of lift-driven VAWTs are compared for isolated and three counter-rotating configurations. Because the wake of an isolated VAWT is deflected, the direction of rotation significantly influences the wake of paired VAWTs. The wake of counter-rotating VAWTs where the adjacent blades move downwind, exhibits a similar length, width and replenishment as the wake of an isolated VAWT. The wake of counter-rotating VAWTs with adjacent upwind moving blades, however, significantly differs from an isolated VAWT wake. While its wake length is similar to an isolated VAWT wake, its width and replenishment are not. Because of appealing wake characteristics, paired VAWTs exhibit unique advantages for wind farm applications, and especially for offshore floating wind farms.
Fluid dynamic mechanisms of enhanced power generation by closely spaced vertical axis wind turbines
Renewable Energy (2016)
We present a comprehensive set of two-dimensional (2D) unsteady Reynolds-averaged Navier-Stokes (URANS) simulations of flow around a pair of counter-rotating vertical-axis wind turbines (VAWTs). The simulations are performed for two possible configurations of the counter-rotating VAWT pair, with various gaps between the two turbines, tip-speed-ratios and wind directions, in order to identify key flow mechanisms contributing to the enhanced performance of a pair of turbines compared to an isolated turbine. One of the key mechanisms identified, for the case of two turbines arrayed side-by-side with respect to the incoming wind, is the change of lateral velocity in the upwind path of each turbine due to the presence of the neighbouring turbine, making the direction of local flow approaching the turbine blade more favourable to generate lift and torque. The results also show that the total power of a staggered pair of turbines cannot surpass that of a side-by-side pair of turbines. Some implications of the present results for the prediction of the performance of single and multiple rows (or a farm) of VAWTs are also discussed. The local flow mechanisms identified in the present study are expected to be of great importance when the size of the farm is relatively small.
Energy Procedia, 2014
To increase the competitiveness of offshore wind energy in the global energy market, it is necessary to identify optimal offshore wind turbine configurations to deliver the lowest cost of energy. For deep waters where floating wind turbines are the feasible support structure option, the vertical axis wind turbine concept might prove to be one of these optimal configurations. This paper carries out a preliminary investigation into the dynamics of a vertical axis wind turbine coupled with three generic floating support structures originally intended for horizontal axis wind turbines. The modifications to the original characteristics of the support structures were kept to a minimum to illustrate the use of floating horizontal axis wind turbine platforms for floating vertical axis wind turbines Issues regarding the adequacy of the mooring systems are outlined and an overview of platform responses in a number of varying met-ocean conditions is presented and discussed.
Wind Tunnel Experiments on Vertical-Axis Wind Turbines with Straight Blades
Renewable Energy and Power Quality Journal, 2014
This paper gives the experimental performances obtained in a wind tunnel for a flexible experimental model of vertical axis wind turbine (VAWT) with straight blades. The effects of blades arrangement in one or two stages, of setting angle and of blade numbers influences on the output performance were analysed. The results showed that the VAWT developed torque at low speeds is greater when the setting angle of blades is greater but the VAWT developed torque at higher speeds is greater when the setting angles of blades is less.
Determination of performance parameters of vertical axis wind turbines in wind tunnel
MATEC Web of Conferences, 2017
The paper deals with the determination of the performance parameters of a small vertical axis wind turbines (VAWT), which operate by the utilization of drag forces acting on the blades of the turbine. The performance was evaluated by investigating the electrical power output and torque moment of the wind machine. Measurements were performed on the full-scale model and the experimental data are assessed and compared to other types of wind turbines, with respect to its purpose.
Experimental results of a vertical axis wind turbine
ASME 2010 10th Biennial Conference on Engineering Systems Design and Analysis, ESDA2010, 2010
In the present paper the new wind tunnel located at the Fluid-dynamic Laboratory of the Department of Mechanical and Management Engineering (DIMeG) of the Polytechnic University of Bari will be shortly described and the first experimental measurements on a model of Vertical Axis Wind Turbine (VAWT) tested in the wind tunnel will be shown. The wind tunnel has been designed by the research group on wind energy of the Department. It is a subsonic, closed loop, wind tunnel with a transparent test section where small scale models can be analysed. The first experimental activity has been performed on a VAWT model, of the Giromill type with parallel blades. The turbine has been connected to an AC brushless servo, able to control either the braking torque or the rotational speed. Experimental results of the flow field in two horizontal planes have been set up using a two component hot wire probe.
2020
Floating vertical-axis wind turbines for offshore wind energy present a concept with novelty and potentials for reducing COE. Cost reduction for offshore wind power plants is an industrial challenge, and DeepWind is -as the analysis of the current design shows-believed to be a good candidate in achieving this. In the paper the current design status of the 5 MW DeepWind concept is presented. The intended siting for the turbine is off the Norwegian west coast at about 250 m of sea depth. Focus is set on the integrated design highlighting structural benefits of the light rotor, the hydrodynamic aspects of the floating hull, and new generator design embracing magnetic bearings. Two important design tools were developed which allow the industry to analyze various VAWT(vertical Axis Wind Turbine) variants for offshore applications: a main design tool "HAWC2" for aeroelastic design of VAWTs, and a generator design tool "NESSI". HAWC2 has been adopted for VAWT rotors by ...
Numerical modelling and optimization of vertical axis wind turbine pairs: A scale up approach
Renewable Energy
The performance augmentation of pairs of vertical axis wind turbines (VAWTs) is known to be dependent on incident wind direction, turbine spacing and direction of rotation. Yet, there is a lack of robust numerical models investigating the impact of these parameters. In this study two-dimensional CFD simulations of an isolated VAWT and of co-and counter-rotating pairs of VAWTs were performed with the aim to determine turbine layouts that can increase the power output of VAWT farms. More than 11,500 h of simulations were conducted at a turbine diameter Reynolds number of 1.35 $ 10 7. A mesh convergence study was conducted, investigating the influence of mesh size, domain size, azimuth increment, number of iterations per time step, and domain cell density. Results showed that mesh size, domain size, and azimuth increment proved to have the biggest impact on the converged results. For the configurations analysed, pairs of VAWTs exhibited a 15% increase in power output compared to operating in isolation, when the second rotor was spaced three turbine diameters downstream and at an angle of 60 to the wind direction. Furthermore, when three turbines were positioned in series, the power output was greater than a pair by an additional 3%.