Aerodynamic optimization of the blades of diffuser-augmented wind turbines

Vaz, Jerson Rogério Pinheiro; Wood, David

doi:10.1016/j.enconman.2016.06.015

Cited by 80 publications

(27 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Therefore, models that include factors such as emissions reduction, minimization of imported energy, and even social acceptance are proposed in many studies, such as Novosel et al [2] and Kumu et al [3]. Lately research, has been focused on wind turbine blade improvements to optimize rotor dynamic behavior (Jaume et al [4] and Vaz et al [5]). …”

Section: Introductionmentioning

confidence: 99%

Microtab Design and Implementation on a 5 MW Wind Turbine

et al. 2017

View full text Add to dashboard Cite

Microtabs (MT) consist of a small tab placed on the airfoil surface close to the trailing edge and perpendicular to the surface. A study to find the optimal position to improve airfoil aerodynamic performance is presented. Therefore, a parametric study of a MT mounted on the pressure surface of an airfoil has been carried out. The aim of the current study is to find the optimal MT size and location to increase airfoil aerodynamic performance and to investigate its influence on the power output of a 5 MW wind turbine. Firstly, a computational study of a MT mounted on the pressure surface of the airfoil DU91W(2)250 has been carried out and the best case has been found according to the largest lift-to-drag ratio. This airfoil has been selected because it is typically used on wind turbine, such as the 5 MW reference wind turbine of the National Renewable Energy Laboratory (NREL). Second, Blade Element Momentum (BEM) based computations have been performed to investigate the effect of the MT on the wind turbine power output with different wind speed realizations. The results show that, due to the implementation of MTs, a considerable increase in the turbine average power is achieved.

show abstract

Section: Introductionmentioning

confidence: 99%

Microtab Design and Implementation on a 5 MW Wind Turbine

et al. 2017

View full text Add to dashboard Cite

show abstract

“…However, the application of diffusers and existing models at the time made the use of this equipment economically unviable. Most work available in the literature has examined a parameter named speedup factor, or simply speed ratio Vaz & Wood, 2016;Rio Vaz et al, 2014). This ratio, in the presence of the turbine, is defined by the ratio between the effective velocity along the turbine and the incident speed.…”

Section: Diffuser-augmented Wind Turbinesmentioning

confidence: 99%

“…Nowadays, the diffuser technology has still been source of research worldwide. For example, Vaz & Wood (2016) reported that the addition of an exit diffuser to a horizontal-axis wind turbine is one of the few ways in which power output may be increased. In their work, a new approach to the aerodynamic optimization of a wind turbine with a diffuser was proposed, which was based on an extension of the well-known Blade Element Theory (BET) and a simple model for diffuser efficiency.…”

Section: Diffuser-augmented Wind Turbinesmentioning

confidence: 99%

Experimental Study of Three Different Airfoils Applied to Diffuser-Augmented Wind Turbines

Vaz

Maia²,

Menezes³

et al. 2018

JUEE

View full text Add to dashboard Cite

Over the years the electricity generation based on alternative energy systems applied to remote regions has been increased in Brazil, mainly due to the lack of conventional electric grid structure, specially in places as the Amazon. In this scenario, it is wellknown that the wind power technology attracts great attention because the wind potential available in the country coast is really representative, leading this sort of technology to an important position into the local energy matrix. However, it is necessary to search new technology developments in order to get efficient turbines applied to isolated regions, where usually low wind speeds are found. The small wind systems using diffuser appear as a relevant alternative, which can be adapted to the characteristics of low wind speed conditions. Hence, in this work, an experimental study on diffusers using three different airfoils (SELIG 1223, EPPLER 423 and NACA 4412) was performed. The goal was to evaluate the influence of the diffuser velocity ratio on the classical theory (axial moment theory with diffuser), in order to show the increasing efficiency typically noticed in studies on Diffuser-Augmented Wind Turbines (DAWTs). In this regard, it was concluded that the wind speed increases under diffuser effect even whether the geometric model is composed by two straight parallel airfoils. Consequently, a DAWT might be adapted to low wind speeds usually found in northern Brazil.

show abstract

“…In practical terms, these facts may bring two great problems to hydrokinetic systems operating close to the free surface. The first one relies on the concern that the turbine efficiency is dependent of the flow velocity in the far wake, as recently demonstrated by Vaz and Wood 2016, in which they pointed out the complexity in to determine the far wake velocity when the flow is restricted. In their case, the restriction was due to the use of a diffuser around wind turbines.…”

Section: Wake Characteristics Of the Hydrokinetic Turbinementioning

confidence: 99%

Numerical Study of Wake Characteristics in a Horizontal-Axis Hydrokinetic Turbine

Silva

Oliveira

Brasil

et al. 2016

An. Acad. Bras. Ciênc.

Self Cite

View full text Add to dashboard Cite

Over the years most studies on wake characteristics have been devoted to wind turbines, while few works are related to hydrokinetic turbines. Among studies applied to rivers, depth and width are important parameters for a suitable design. In this work, a numerical study of the wake in a horizontal-axis hydrokinetic turbine is performed, where the main objective is an investigation on the wake structure, which can be a constraining factor in rivers. The present paper uses the Reynolds Averaged Navier Stokes (RANS) flow simulation technique, in which the Shear-Stress Transport (SST) turbulent model is considered, in order to simulate a free hydrokinetic runner in a typical river flow. The NREL-PHASE VI wind turbine was used to validate the numerical approach. Simulations for a 3-bladed axial hydrokinetic turbine with 10 m diameter were carried out, depicting the expanded helical behavior of the wake. The axial velocity, in this case, is fully recovered at 12 diameters downstream in the wake. The results are compared with others available in the literature and also a study of the turbulence kinetic energy and mean axial velocity is presented so as to assess the influence of proximity of river surface from rotor in the wake geometry. Hence, even for a single turbine facility it is still necessary to consider the propagation of the wake over the spatial domain.

show abstract

Aerodynamic optimization of the blades of diffuser-augmented wind turbines

Cited by 80 publications

References 23 publications

Microtab Design and Implementation on a 5 MW Wind Turbine

Microtab Design and Implementation on a 5 MW Wind Turbine

Experimental Study of Three Different Airfoils Applied to Diffuser-Augmented Wind Turbines

Numerical Study of Wake Characteristics in a Horizontal-Axis Hydrokinetic Turbine

Contact Info

Product

Resources

About