An Improved Model for the Performance Estimation of an H-Darrieus Wind Turbine in Skewed Flow

Bianchini, Alessandro; Ferrara, Giovanni; Ferrari, Lorenzo; Magnani, Sandro

doi:10.1260/0309-524x.36.6.667

Cited by 39 publications

(17 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The higher skewed angle experience by the CAWT at 100 mm height also contributed to the improved performance of the CAWT at that position ( Figure 14). At higher skewed angle the swept area of the turbine is increased due to the contribution of the downwind zon e which counterparts the decrease of the projected frontal area with an overall increase of the available surface area to intercept the wind as reported by Bianchini et al [35]. Furthermore, Skewed flow increases the performance of H-VAWT by modifying the region of interaction of the downwind blade passage with the upwind generated wake.…”

Section: Variation Of Height Above the Rooftopmentioning

confidence: 79%

“…Increasing the skewed angle will increase the area of the downwind blades passage which is operating outside the upwind generated wake thus experiencing an incoming flow with larger energy content [34]. While skewed angle is believed to improve the performance of wind turbine in urban buildings as reported by Mertens et al [33], Bianchini et al [35], and Ferreira et al [57]. ZanForlin and Letizia [56] reported that for the case of cowling system the wind turbine in a skewed flow can lead to power loss of 11.6%.…”

Section: Variation Of Height Above the Rooftopmentioning

confidence: 95%

“…Many studies have been reported on H-Darrieus wind turbine in skewed flow. Bianchini et al [35] developed an improved model for the performance prediction of H-Darrieus rotor under skewed flow. The model, which is based on momentum model, was properly modified to account for the variations induced by the new directions of the flow on the rotor.…”

Section: Building Integrated Wind Turbinesmentioning

confidence: 99%

See 2 more Smart Citations

Design and Testing of a Novel Building Integrated Cross Axis Wind Turbine

et al. 2017

View full text Add to dashboard Cite

Abstract:The prospect of harnessing wind energy in urban areas is not promising owing to low wind speeds and the turbulence caused by surrounding obstacles. However, these challenges can be overcome through an improved design of wind turbine that can operate efficiently in an urban environment. This paper presents a novel design of a building integrated cross axis wind turbine (CAWT) that can operate under dual wind direction, i.e., horizontal wind and vertical wind from the bottom of the turbine. The CAWT consists of six horizontal blades and three vertical blades for enhancing its self-starting behavior and overall performance. The study employed a mock-up building model with gable rooftop where both of the developed CAWT and the conventional straight-bladed vertical axis wind turbine (VAWT) are mounted and tested on the rooftop. The height of the CAWT and the VAWT above the rooftop was varied from 100 to 250 mm under the same experimental conditions. The results obtained from the experimental study showed that there is significant improvement in the coefficient of power (C p ) and self-starting behavior of the building integrated CAWT compared to the straight-bladed VAWT. At 100 mm height, the C p,max value of the CAWT increased by 266%, i.e., from 0.0345 to 0.1263, at tip speed ratio (TSR) (λ) of 1.1 and at wind speed of 4.5 m/s. Similar improvements in performance are also observed for all condition of CAWT heights above the rooftop where the CAWT outperformed the straight-bladed VAWT by 196%, 136% and 71% at TSR of 1.16, 1.08, and 1.12 for Y = 150, 200, and 250 mm, respectively. Moreover, the CAWT performs better at 10 • pitch angle of the horizontal blade compared to other pitch angles.

show abstract

Section: Variation Of Height Above the Rooftopmentioning

confidence: 79%

Section: Variation Of Height Above the Rooftopmentioning

confidence: 95%

Section: Building Integrated Wind Turbinesmentioning

confidence: 99%

See 1 more Smart Citation

Design and Testing of a Novel Building Integrated Cross Axis Wind Turbine

et al. 2017

View full text Add to dashboard Cite

show abstract

“…In particular, Vertical-Axis Wind Turbines (VAWTs), both drag [14][15][16] and lift-driven [17][18][19][20], are gaining popularity in the wind energy scenario, especially in medium and small-size installations, where they can work effectively even in presence of low-speed and unstructured flows with low noise emissions and high reliability. Among others, H-Darrieus rotors are increasingly appreciated in unconventional contexts as they are even assumed to increase their performance in case of an oncoming flow misaligned with respect to the axis of the rotor [17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Design guidelines for H-Darrieus wind turbines: Optimization of the annual energy yield

Bianchini

Ferrara

Ferrari

2015

Energy Conversion and Management

Self Cite

View full text Add to dashboard Cite

H-Darrieus wind turbines are gaining popularity in the wind energy market, particularly as they are thought to represent a suitable solution even in unconventional installation areas. To promote the diffusion of this technology, industrial manufacturers are continuously proposing new and appealing exterior solutions, coupled with tempting rated-power offers. The actual operating conditions of a rotor over a year can be, however, very different from the nominal one and strictly dependent on the features of the installation site. Based on these considerations, a turbine optimization oriented to maximize the annual energy yield, instead of the maximum power, is thought to represent a more interesting solution. With this goal in mind, 21,600 test cases of H-Darrieus rotors were compared on the basis of their energy-yield capabilities for different annual wind distributions in terms of average speed. The wind distributions were combined with the predicted performance maps of the rotors obtained with a specifically developed numerical code based on a Blade Element Momentum (BEM) approach. The influence on turbine performance of the cut-in speed was accounted for, as well as the limitations due to structural loads (i.e. maximum rotational speed and maximum wind velocity). The analysis, carried out in terms of dimensionless parameters, highlighted the aerodynamic configurations able to ensure the largest annual energy yield for each wind distribution and set of aerodynamic constraints

show abstract

“…To account for skewed flow effects on VAWT performance, the efforts of researchers have focused on the implementation of semi-empirical corrections in blade element momentum models [12,13]. To the authors' knowledge, there are no studies in the literature presenting a 3D CFD (Computational Fluid Dynamics) study on inclined VAWT performance.…”

Section: Introductionmentioning

confidence: 99%

3D URANS analysis of a vertical axis wind turbine in skewed flows

Orlandi

Collu

Zanforlin

et al. 2015

Journal of Wind Engineering and Industrial Aerodynamics

View full text Add to dashboard Cite

The article demonstrates the potential of an unsteady RANS 3D approach to predict the effects of skewed winds on the performance of an H-type vertical-axis wind turbine (VAWT). The approach is validated through a comparison between numerical and experimental results for a full-scale Darrieus turbine, demonstrating an improved prediction ability of 3D CFD with respect to both 2D CFD and semi-empirical models based on the double multiple stream tubes method. A 3D URANS approach is then adopted to investigate the power increase observed for a straight-bladed small-scale turbine in a wind tunnel when the rotational axis is inclined from 0 • to 15 • from the vertical. The main advantage of this approach is a more realistic description of complex three-dimensional flow characteristics, such as dynamic stall, and the opportunity to derive local blade flow conditions on any blade portion during upwind and downwind paths. Consequently, in addition to deriving the turbine overall performance in terms of power coefficient, a better insight into the temporal and spatial evolution of the physical mechanisms is obtained. Our principal finding is that the power gain in skewed flows is obtained during the downwind phase of the revolution as the end part of the blade is less disturbed by the wake generated during the upwind phase.

show abstract

An Improved Model for the Performance Estimation of an H-Darrieus Wind Turbine in Skewed Flow

Cited by 39 publications

References 17 publications

Design and Testing of a Novel Building Integrated Cross Axis Wind Turbine

Design and Testing of a Novel Building Integrated Cross Axis Wind Turbine

Design guidelines for H-Darrieus wind turbines: Optimization of the annual energy yield

3D URANS analysis of a vertical axis wind turbine in skewed flows

Contact Info

Product

Resources

About