Numerical investigation of Darrieus wind turbine with slotted airfoil blades

Mohamed, Omar S.; Ibrahim, Ahmed; Etman, Ahmed K.; Abdelfatah, Amr A.; El-Baz, Ahmed

doi:10.1016/j.ecmx.2019.100026

Cited by 44 publications

(25 citation statements)

References 33 publications

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“…Alternatively, Reynolds averaged Navier Stokes (RANS) models can be used, which allow for faster analysis, including in 2D. Within RANS there are several popular models for the analysis of VAWTs, the most common option being k-ω SST (MacPhee and Beyene 2016; Balduzzi et al 2016;Zanforlin 2018;Su et al 2020;Kothe et al 2020), followed by k-ε (Howell et al 2010;Castelli et al 2011;Lee and Lim 2015;Pan et al 2020;Mohamed et al 2020) and transition SST (Rezaeiha et al 2018(Rezaeiha et al , 2019bAsr et al 2016). Previous studies have also used other models including Spalart-Allmaras which has shown to be inadequate (Daróczy et al 2015;Danao et al 2012), k-k l -ω (Daróczy et al 2015;Arab et al 2017), and corrections of k-ω SST (Danao et al 2012) and transition SST (Almohammadi et al 2013) such as the low Reynolds number and curvature corrected versions.…”

Section: Simulationsmentioning

confidence: 99%

Validation and comparison of turbulence models for predicting wakes of vertical axis wind turbines

Barnes

Marshall-Cross

Hughes

2021

J. Ocean Eng. Mar. Energy

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Vertical axis wind turbine (VAWT) array design requires adequate modelling of the turbine wakes to model the flow throughout the array and, therefore, the power output of turbines in the array. This paper investigates how accurately different turbulence models using 2D computational fluid dynamics (CFD) simulations can estimate near and far wakes of VAWTs to determine an approach towards accurate modelling for array design. Three experiments from the literature are chosen as baselines for validation, with these experiments representing the near to far wake of the turbine. Five URANS turbulence models were chosen due to their common and potential usage for VAWT CFD: models k–ω SST, k–ω SST LRN, k–ω SSTI, transition SST, and k–kl–ω. In addition, the lifting line-free vortex wake (LLFWV) model was tested as an alternative to CFD for the far turbine wake where it was appropriate for use. The results for turbulent kinetic energy and vorticity were compared for the first experiment, whilst streamwise and cross-stream velocity were used for the other two experiments. It was found that none of the turbulence models tested or LLFVW produced adequate estimations within the methodology tested, however, transition SST produced the closest estimations. Further adjustments to the methodology are required to improve accuracy due to their large impact on results including use of 3D CFD, adjustment of surface roughness, and inlet flow characteristics.

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Section: Simulationsmentioning

confidence: 99%

Validation and comparison of turbulence models for predicting wakes of vertical axis wind turbines

Barnes

Marshall-Cross

Hughes

2021

J. Ocean Eng. Mar. Energy

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“…Mohamed O. S. et al studied the startup performance of a vertical axis offshore wind turbine with slotted airfoil blades and optimized the slotted position, inclination, and size. The results showed that at large angles of attack, the torque and power coefficient at low tip speed ratio could be improved by delayed eddy current separation [15].…”

Section: Introductionmentioning

confidence: 99%

Numerical Analysis and Parameter Optimization of J-Shaped Blade on Offshore Vertical Axis Wind Turbine

et al. 2021

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In this study, the performance of offshore wind turbines at low tip speed ratio (TSR) is studied using computational fluid dynamics (CFD), and the performance of offshore wind turbines at low tip speed ratio (TSR) is improved by revising the blade structure. First, the parameters of vertical axis offshore wind turbine are designed based on the compactness iteration, a CFD simulation model is established, and the turbulence model is selected through simulation analysis to verify the independence of grid and time step. Compared with previous experimental results, it is shown that the two-dimensional simulation only considers the plane turbulence effect, and the simulation turbulence effect performs more obviously at a high tip ratio, while the three-dimensional simulation turbulence effect has well-fitting performance at high tip ratio. Second, a J-shaped blade with optimized lower surface is proposed. The study showed that the optimized J-shaped blade significantly improved its upwind torque and wind energy capture rate. Finally, the performance of the optimized J-blade offshore wind turbine is analyzed.

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“…The increasing rate of energy consumption, depletion of fossil fuel reservoir, and environmental matters are great important factors contributing to motivating researchers to improve and optimize energy-generating devices. In this vein, aerodynamic optimization of components in such conventional machines as gas turbine (GT), [1][2][3][4] wind turbine (WT), [5][6][7][8] and current turbine [9][10][11] has an undeniable role. Typically, separation of a boundary layer (B.L.…”

Section: Introductionmentioning

confidence: 99%

“…elimination, required additional facilities limit their application. At the same time, no matter what type of the blade is, the application of passive methods such as using slot treatment, 6,18,31,32 partial flexibility material, 33 vortex generator (VG), 9,15,34 gurney flaps, 35,36 slats, 37 and leading-edge serrations 38 is wide from compressor blades to hydrofoils due to its simplicity and cost-effectiveness. In spite of wide application, using VGs and the slotted blade will not always result in desirable performance; in that, these methods are utterly sensitive to their associated design parameters and operating conditions.…”

Section: Introductionmentioning

confidence: 99%

Effect of optimal slot location on the performance of cascades of blades

Nia

Gharehghani

Zadeh

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part G:

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Overloaded blades and lower solidities are two main characteristics of modern gas engines to reach lower specific fuel consumption and weight to thrust ratio. Hence, flow optimization methods are employed to maximize the performance. Slot treatment on blades is considered as a potential method to stand against the boundary layer separation for this issue. In the present study, the different locations of passive flow control with the slot along the compressor blade chord are simulated at four angles of attack (α), ranging from 10.93° to 28.93°. The purpose of this study is to discover the underlying reason in obtaining the best slot location, regarding the blade turning angle and total loss coefficient, in every tested inflow angle. Based on the results, the slot jet shows its utmost performance in eliminating the trailing edge separation when it is located upstream of the separation lines in the mid-span. The best slot location is able to improve the turning angle and the total loss coefficient up to 16.41% and 16.47% at 26.93°, respectively. The synthetic slot jet confines the growth of corner vortices and increases the turning angle near end walls up to 4°. In addition, the slot treatment pushes the backflow region over the suction surface up to 10% of the span toward the side walls. The importance of choosing the slot location decreases with an increase in inflow angle. However, the effect of slot locations on the performance in low angles is still considerable. With the tested blade geometry, the slotted profile in locations between 0.5 and 0.8 of axial chord length indicates a promising blade performance either in low or high angles. The slot treatment weakens the flow upstream of its location which is in contradiction with previous investigations. Two separation bubbles near the leading edge in the baseline profile have a greater size of about 2% of the blade chord for the slotted case.

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Numerical investigation of Darrieus wind turbine with slotted airfoil blades

Cited by 44 publications

References 33 publications

Validation and comparison of turbulence models for predicting wakes of vertical axis wind turbines

Validation and comparison of turbulence models for predicting wakes of vertical axis wind turbines

Numerical Analysis and Parameter Optimization of J-Shaped Blade on Offshore Vertical Axis Wind Turbine

Effect of optimal slot location on the performance of cascades of blades

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