Nacelle and tower effect on a stand-alone wind turbine energy output—A discussion on field measurements of a small wind turbine

Guo, Tao; Guo, Xingduo; Gao, Zhiteng; Zheng, Xing; Gao, Xiaoxia; Li, Rennian; Wang, Tongguang; Li, Ye

doi:10.1016/j.apenergy.2021.117590

Cited by 31 publications

(11 citation statements)

References 44 publications

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“…In comparison to the effect of the nacelle, the effect of the tower can be ignored. The same conclusion has been also demonstrated for small-scale wind turbines (Guo et al 2021;Santoni et al 2017).…”

Section: Introductionsupporting

confidence: 78%

“…9, the fluid is subjected to excessive acceleration in the root area of the blades in the case of the turbine without the nacelle. Previous research has observed this phenomenon (Guo et al 2021;Zheng et al 2018).…”

Section: Axial Flow Behaviorsmentioning

confidence: 65%

“…Based on large eddy simulations, Zhu et al (2022) concluded that the nacelle and tower increase the instability of the tip vortices. Guo et al (2021) showed that the increase in vorticities and turbulent kinetic energy produced by a wind turbine in the presence of a nacelle is the primary cause of rotor output power fluctuations. These fluctuations lead to an increase in fatigue loads and thus reduce wind turbine life operation.…”

Section: Introductionmentioning

confidence: 99%

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Numerical Investigations on the Fluid Behavior in the Near Wake of an Experimental Wind Turbine Model in the Presence of the Nacelle

2023

JAFM

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Accurate predictions of the near wake of horizontal-axis wind turbines are critical in estimating and optimizing the energy production of wind farms. Consequently, accurate aerodynamic models of an isolated wind turbine are required. In this paper, the steady-state flow around an experimental horizontal-axis wind turbine (known as the MEXICO model) is investigated using full-geometry computational fluid dynamics (CFD) simulations. The simulations are performed using Reynolds-Averaged Navier-Stokes (RANS) equations in combination with the transitional k-kl-w turbulence model. The multiple reference frame (MRF) approach is used to allow the rotation of the blades. The impacts of the nacelle and blade rotation on the induction region and near wake are highlighted. Simulation cases under attached and detached flow conditions with and without the nacelle were compared to the detailed particle image velocimetry (PIV) measurements. The axial and radial flow behaviors at the induction region have been analyzed in detail. This study attempts to highlight the nacelle effects on the near wake flow and on numerical prediction accuracy under various conditions, as well as the possible reasons for these effects. According to simulation results, the rotation of blades dominates the near wake region, and including the nacelle geometry can improve both axial and radial flow prediction accuracy by up to 15% at high wind speeds. At low wind speeds, the nacelle effects can be ignored. The presence of the nacelle has also been shown to increase flow separation at the trailing edges of the blade airfoils, increasing both root and tip vorticities. Finally, small nacelle diameters are recommended to reduce flow separation on the blades and increase the average velocity downstream of the rotor, thereby optimizing wind farm output power.

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Section: Introductionsupporting

confidence: 78%

Section: Axial Flow Behaviorsmentioning

confidence: 65%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Numerical Investigations on the Fluid Behavior in the Near Wake of an Experimental Wind Turbine Model in the Presence of the Nacelle

2023

JAFM

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“…Researchers have also attempted to determine how the efficiency is impacted by various internal and external forces [26,27], and how the overall wind turbine performance is affected by ice, sand, and blade roughness. Other studies have examined the effect of the hub and tower in the context of the wake flow [28][29][30][31][32]. The authors determined that they needed to formulate means of streamlining the calculations of the interaction forces and momentum on the wind turbine components so as to reduce the simulation durations for all lateral studies.…”

Section: Rotormentioning

confidence: 99%

On the Investigation of the Effect of Tower and Hub Exclusion on the Numerical Results of a Horizontal Axis Wind Turbine

2022

IJM

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In order to construct a 3D rotor model, periodicity and Multiple Reference Frame (MRF) strategies were applied to address full Computational Fluid Dynamics (CFD) that incorporate the Reynolds-averaged Navier-Stokes (RANS) equations. A simulation model was run to examine the power of the wind turbines, both including and excluding the hub and tower. The purpose of this was to identify an approach that would decrease the computational time cost of wind turbine simulation. Firstly, a full-scale horizontal axis wind turbine simulation was carried out, and subsequently, comparisons were made with the results of the wind tunnel experiment utilizing the K-omega SST and Sparlat Allmaras viscosity models. The results were compared to determine the optimum model with the lowest simulation time and highest accuracy to the experimental results. Following this, the complete models' simulation was compared to the model excluding the hub and tower in order to check the disparity in the results of the two. Additionally, to ascertain the computational cost saving, the ratio of the two simulation times was established. The findings show that the two models produce results that correspond well to the experimental results, and that the power coefficient had a greater value for the complete model than the simple model. Furthermore, it was found that the power coefficient values of the full model have significantly higher levels of similarity to the experimental values. The Sparlat Allmaras and K-omega SST viscosity models returned error percentages of 0.52% and 12.6% respectively. For the partial model utilizing the same computer device, a 5.7% error rate was recorded, with a computational time saving of approximately 34%.

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“…Despite such a pronounced scale‐effect, SHAWT designers have not been dissuaded from building ever‐more efficient turbines, with the hope of overcoming the limitations imposed by transitional flows. A recent review lists over 70 studies dealing with the design issues aimed at improving SHAWT behaviour, 11 and further research published since shows that the interest on the sector prevails 12,22–24 …”

Section: Introductionmentioning

confidence: 99%

Impact of turbulence and blade surface degradation on the annual energy production of small‐scale wind turbines

Zarketa‐Astigarraga,

Penalba,

Martin‐Mayor

et al. 2023

Wind Energy

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Small‐scale horizontal axis wind‐turbines (SHAWTs) are acquiring relevance within the regulatory policies of the wind sector aiming at net‐zero emissions, while reducing visual and environmental impact by means of distributed grids. SHAWTs operate transitionally, at Reynolds numbers that fall between . Furthermore, environmental turbulence and roughness affect the energetic outcome of the turbines. In this study, the combined effect of turbulence and roughness is analysed via wind tunnel experiments upon a transitionally operating NACA0021 airfoil. The combined effects cause a negative synergy, inducing higher drops in lift and efficiency values than when considering the perturbing agents individually. Besides, such losses are Reynolds‐dependent, with higher numbers increasing the difference between clean and real configurations, reaching efficiency decrements above 60% in the worst‐case scenario.Thus, these experimental measurements are employed for obtaining the power curves and estimating the annual energy production (AEP) of a 7.8‐kW‐rated SHAWT design by means of a BEM code. The simulations show a worst‐case scenario in which the AEP reduces above 70% when compared to the baseline configuration, with such a loss getting attenuated when a pitch‐regulated control is assumed. These results highlight the relevance of performing tests that consider the joint effect of turbulence and roughness.

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Nacelle and tower effect on a stand-alone wind turbine energy output—A discussion on field measurements of a small wind turbine

Cited by 31 publications

References 44 publications

Numerical Investigations on the Fluid Behavior in the Near Wake of an Experimental Wind Turbine Model in the Presence of the Nacelle

Numerical Investigations on the Fluid Behavior in the Near Wake of an Experimental Wind Turbine Model in the Presence of the Nacelle

On the Investigation of the Effect of Tower and Hub Exclusion on the Numerical Results of a Horizontal Axis Wind Turbine

Impact of turbulence and blade surface degradation on the annual energy production of small‐scale wind turbines

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