Leading-edge serrations for performance improvement on a vertical-axis wind turbine at low tip-speed-ratios

Wang, Zhenyu; Zhuang, Mei

doi:10.1016/j.apenergy.2017.09.034

Cited by 161 publications

(46 citation statements)

References 33 publications

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“…According to previous static wind tunnel measurements of different tubercle configurations 66 , the validation test for the optimum combination of and for NACA0021 was performed by Du et al 5 on an H-Darrieus wind turbine at Reynolds number of . It was demonstrated experimentally by Du et al 5 that this bioinspired blade could significantly increase the turbine self-starting capability at the expense of slightly lower peak power output, which was consistent with the numerical studies performed by Wang and Zhuang 67 and Wang et al 68 . These blades are very promising candidates for the future application in the low wind environment.…”

Section: Blade Profilesupporting

confidence: 78%

A review of H-Darrieus wind turbine aerodynamic research

Ingram

Dominy

2019

Proceedings of the Institution of Mechanical Engineers, Part C:

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The H-Darrieus vertical axis turbine is one of the most promising wind energy converters for locations where there are rapid variations of wind direction, such as in the built environment. The most challenging considerations when employing one of these usually small machines are to ensure that they self-start and to maintain and improve their efficiency. However, due to the turbine's rotation about a vertical axis, the aerodynamics of the turbine are more complex than a comparable horizontal axis wind turbine and our knowledge and understanding of these turbines falls remains far from complete. This paper provides a detailed review of past and current studies of the H-Darrieus turbine from the perspective of design parameters including turbine solidity, blade profile, pitch angle, etc. and particular focus is put on the crucial challenge to design a turbine that will self-start. Moreover, this paper summarizes the main research approaches for studying the turbine in order to identify successes and promising areas for future study.

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Section: Blade Profilesupporting

confidence: 78%

A review of H-Darrieus wind turbine aerodynamic research

Ingram

Dominy

2019

Proceedings of the Institution of Mechanical Engineers, Part C:

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“…Compared to the Savonius VAWT, this lift-based turbine attains its peak performance efficiency at relatively higher TSRs [21]. Attempts to boost this turbine's performance are numerous, for instance, Wang and Zhuang [22] adopted sinusoidal leading-edge serrations on a straight-bladed vertical-axis wind turbine (SB-VAWT) with different geometrical features, to avert the detrimental consequences of dynamic stall. After successfully conducting thorough 3D numerical simulations, it was shown that the power coefficient values increased especially at low-and mid-TSR values for serrations of wave amplitude and wavelength at 2.5% and 33% the chord length (c), respectively.…”

Section: Of 21mentioning

confidence: 99%

A Dynamic Rotor Vertical-Axis Wind Turbine with a Blade Transitioning Capability

2019

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This work presents an optimized design of a dynamic rotor vertical-axis wind turbine (DR VAWT) which maximizes the operational tip-speed ratio (TSR) range and the average power coefficient (Cp) value while maintaining a low cut-in wind velocity. The DR VAWT is capable of mimicking a Savonius rotor during the start-up phase and transitioning into a Darrieus one with increasing rotor radius at higher TSRs. The design exploits the fact that with increasing rotor radius, the TSR value increases, where the peak power coefficient is attained. A 2.5D improved delayed detached eddy simulation (IDDES) approach was adopted in order to optimize the dynamic rotor design, where results showed that the generated blades’ trajectories can be readily replicated by simple mechanisms in reality. A thorough sensitivity analysis was conducted on the generated optimized blades’ trajectories, where results showed that they were insensitive to values of the Reynolds number. The performance of the DR VAWT turbine with its blades following different trajectories was contrasted with the optimized turbine, where the influence of the blade pitch angle was highlighted. Moreover, a cross comparison between the performance of the proposed design and that of the hybrid Savonius–Darrieus one found in the literature was carefully made. Finally, the effect of airfoil thickness on the performance of the optimized DR VAWT was thoroughly analyzed.

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“…Meanwhile, the impact of a wider variety of operational parameters ( λ , Reynolds number, and turbulence intensity) on the turbine performance was investigated by Rezaeiha et al showing that turbine performance and wake are highly Re dependent up to Re = 4.2 × 10 5 and increasing λ increased the velocity deficit, wake expansion, and streamwise asymmetry in the wake. Wang et al showed that blade leading edge serrations could improve turbine performance and their optimized turbine showed an 18.3% increase of power output. Zanforlin and Deluca examined the effect of blade aspect ratio and Reynolds number on turbine power output.…”

Section: Introductionmentioning

confidence: 99%

Experimental study of the effects of turbine solidity, blade profile, pitch angle, surface roughness, and aspect ratio on the H‐Darrieus wind turbine self‐starting and overall performance

Ingram

Dominy

2019

Energy Science & Engineering

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New and comprehensive time‐accurate, experimental data from an H‐Darrieus wind turbine are presented to further develop our understanding of the performance of these turbines with a particular focus on self‐starting. The impact of turbine solidity, blade profile, surface roughness, pitch angle, and aspect ratio on the turbine's performance is investigated, parameters that are thought to be critical for small‐scale VAWT operation, particularly when operating in the built environment. It is demonstrated clearly that high turbine solidity (σ≥0.81) is beneficial for turbine self‐starting and that the selection of a thick, symmetrical aerofoil set at a low, negative pitch angle (β≥-2∘) is better than a cambered foil. Increased blade surface roughness is also shown to improve a turbine's self‐starting capability at low tip speed ratios and with high turbine solidity and the associated flow physics are discussed. Finally, it was confirmed that blade span has a significant impact on turbine starting. This paper contributes to the understanding of the turbine characteristics during the starting period and provides clear guidance and validation cases for future design and research in order to promote and justify the wider application of this wind turbine configuration.

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Leading-edge serrations for performance improvement on a vertical-axis wind turbine at low tip-speed-ratios

Cited by 161 publications

References 33 publications

A review of H-Darrieus wind turbine aerodynamic research

A review of H-Darrieus wind turbine aerodynamic research

A Dynamic Rotor Vertical-Axis Wind Turbine with a Blade Transitioning Capability

Experimental study of the effects of turbine solidity, blade profile, pitch angle, surface roughness, and aspect ratio on the H‐Darrieus wind turbine self‐starting and overall performance

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