Experimental and numerical investigations of actuator disks for wind turbines

Ranjbar, Mohammad Hassan; Kia, Hadi Zanganeh; Nasrazadani, Seyyed Abolfazl; Gharali, Kobra; Nathwani, Jatin

doi:10.1002/ese3.670

Cited by 6 publications

(11 citation statements)

References 19 publications

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“…Experimental and numerical investigations on bare wind turbines have shown that their maximum power coefficient is in the range of Betz-limit [45,46]. In order to investigate the effects of the duct on the performance of wind turbines, two simulations of a VAWT with and without the duct were done.…”

Section: Ducted Wind Turbine: Numerical Approachmentioning

confidence: 99%

Power Enhancement of a Vertical Axis Wind Turbine Equipped with an Improved Duct

et al. 2021

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Efforts to increase the power output of wind turbines include Diffuser Augmented Wind Turbines (DAWT) or a shroud for the rotor of a wind turbine. The selected duct has three main components: a nozzle, a diffuser, and a flange. The combined effect of these components results in enriched upstream velocity for the rotor installed in the throat of the duct. To obtain the maximum velocity in the throat of the duct, the optimum angles of the three parts have been analyzed. A code was developed to allow all the numerical steps including changing the geometries, generating the meshes, and setting up the numerical solver simultaneously. Finally, the optimum geometry of the duct has been established that allows a doubling of the flow velocity. The flow characteristics inside the duct have also been analyzed in detail. An H-Darrieus Vertical Axis Wind Turbine (VAWT) has been simulated inside the optimized duct. The results show that the power coefficient of the DAWT can be enhanced up to 2.9 times. Deep dynamic stall phenomena are captured perfectly. The duct advances the leading-edge vortex generation and delays the vortex separation.

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Section: Ducted Wind Turbine: Numerical Approachmentioning

confidence: 99%

Power Enhancement of a Vertical Axis Wind Turbine Equipped with an Improved Duct

et al. 2021

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“…It can capture the wind turbine's wake features while making the setup simple and convenient. The design of these PDs is adapted from the model of Ranjbar et al 21 All PDs have the same diameter of 0.196 m and a uniform thickness of 2.8 mm. They are made of Plexiglass and were manufactured using laser cut with an accuracy of ±0.1 mm.…”

Section: Methodsmentioning

confidence: 99%

“…The first layer thickness of the grid and the growth rate along walls 21 are selected to be 0.1 and 1.8 mm, respectively.…”

Section: Numerical Approachmentioning

confidence: 99%

“…Aubrun et al 20 compared a small wind turbine with PDs of different porosities with satisfactory results. Ranjbar et al 21 experimentally and numerically modeled wind turbines with different PDs. They studied the relationship between several wind turbine specifications such as power performance, thrust coefficient, and induction factor with the solidity of disks.…”

Section: Introductionmentioning

confidence: 99%

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Power augmentation of ducted wind turbines for urban structures: Experimental, numerical, and economic approaches

Ranjbar

Mashouf

Gharali

et al. 2022

Energy Science & Engineering

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Recent development in using wind turbines for urban areas results in inserting turbines inside buildings. As buildings' walls may act as a duct for the turbine, this study focuses on a ducted wind turbine with a fixed duct geometry. A method is organized for achieving the improved generated power and the wind speed augmentation with fixed geometry of duct regardless of the type of the turbine, which is the aim of building designers. Using a porous disc (PD) instead of a wind turbine rotor makes the study cost and time effective. PDs within a duct help estimate any given duct's maximum available power extraction capability. In addition, experimental and numerical tests examine the effect of PDs solidity on the performance of diffuser augmented wind turbines and the corresponding economic analysis. Both experimental and numerical results agree that the power coefficient highly depends on the solidities of the PD. The power coefficient of a ducted PD with a solidity of 0.3 is augmented by up to 30%. Nevertheless, in some cases, employing a duct can contribute to the power reduction if the solidity exceeds a critical value. A smoke visualization technique helps vortex study. Economic assessment of a ducted turbine for three scenarios belonging to Germany and Italy shows a 15.3% decline in cost per electricity production. The payback period decreases by 3.42 years, 7.68 months, and 6.36 months for Scenarios 1, 2, and 3.

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“…This is in contrast to results reported by Xiao et al, 41 which reported lower velocity deficit in the wake of a perforated disk with 75% blockage compared to the wake of a solid disk. Ranjbar et al 42 investigated the drag, induction factor, and the power coefficient estimated from the induction factor for porous disks of different solidities. Recently, Huang et al 43 introduced a new scaling parameter D Ã ¼ 4A=P, with A being the disk area and P the perimeter, to match the wake recovery of porous disks of different geometries: circular, square, and rectangular.…”

Section: Introductionmentioning

confidence: 99%

The far wake of porous disks and a model wind turbine: Similarities and differences assessed by hot-wire anemometry

Vinnes

Gambuzza

Ganapathisubramani

et al. 2022

Journal of Renewable and Sustainable Energy

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The wakes of two different porous disks have been evaluated experimentally. Such disks are commonly used as physical actuator disk analogs for wind turbines. One disk is made of a uniform wire mesh, while the other has a nonuniform design with radial spars connected by rings. The disks have the same solidity and produce approximately the same drag. The wakes have also been compared to the wake of a model wind turbine and a solid disk. In contrast to earlier studies, the far wake, up to 30 diameters downstream, is included in the comparison. In the near wake, the velocity deficit and turbulence intensity profiles of the disk wakes differ significantly. High levels of turbulence intensity in the wake of the nonuniform disk increase the transverse transport in the wake, which leads to faster spreading and lower velocity deficits in the far wake, compared to the uniform disk and the wind turbine. High velocity gradients in the wake of the uniform disk give rise to turbulence production farther downstream, maintaining higher turbulence levels in the far wake. In addition, coherent vortex shedding is only identified in the wake of the nonuniform disk. None of the disks were able to replicate the asymmetric features of the wind turbine wake. Nonetheless, the results highlight important flow physics that should be considered in the design process of a porous disk used as a wind turbine surrogate.

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Experimental and numerical investigations of actuator disks for wind turbines

Cited by 6 publications

References 19 publications

Power Enhancement of a Vertical Axis Wind Turbine Equipped with an Improved Duct

Power Enhancement of a Vertical Axis Wind Turbine Equipped with an Improved Duct

Power augmentation of ducted wind turbines for urban structures: Experimental, numerical, and economic approaches

The far wake of porous disks and a model wind turbine: Similarities and differences assessed by hot-wire anemometry

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