Numerical analysis of the compromise between power output and fish-friendliness in a vortex power plant

Müller, Stephanie; Cleynen, Olivier; Hoerner, Stefan; Lichtenberg, Nils; Thévenin, Dominique

doi:10.1080/24705357.2018.1521709

Cited by 20 publications

(16 citation statements)

References 24 publications

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“…4), which is required by the higher density of water. Fish impact probability models take into account the rotational speed of the rotor (Turnpenny et al 2000;Deng et al 2007or Müller et al 2018; a common finding is that the impact risk rises along with the rotor frequency. The pressure drop, which is the other main cause of fish injury during turbine passage (Stephenson et al 2010), is negligible in hydrokinetic turbines.…”

Section: Introductionmentioning

confidence: 99%

Darrieus vertical-axis water turbines: deformation and force measurements on bioinspired highly flexible blade profiles

et al. 2020

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The characteristics of the fluid-structure interaction on the flexible blades of a horizontal-axis water turbine are studied; this bioinspired technology features mechanical simplicity, performance and lifetime improvement, and low fish impact risk, all characteristics of a truly sustainable renewable energy exploitation. A surface-tracking method synchronized with force measurements was applied on a surrogate model of single-bladed, vertical-axis water turbine in a water channel. This allows for the characterization of the structural deformations and their link to the hydrodynamic forces, over a large range of turbine designs and operating points. It is shown that the phase angles of the maxima in blade deformation coincide with those of the load maxima on a rigid blade in identical flow conditions. The influence of the turbine's tip/speed ratio on the blade deformation and blade load is investigated. With the chosen blade design, hydrofoil deformation is found to be maximum in the operating points where the performance improvement is maximized (k o = 0.3). With lower values of reduced frequency (corresponding to lower rotation speed), fluid-induced forces dominate the fluid-structure interaction. Conversely, at higher frequencies, structural inertia dominates the interaction, and blade deformation is again reduced. Results suggest that the optimal blade rigidity may depend on the operating point; nevertheless the potential of the flexible-blade design is demonstrated through clear linking of fluid-induced forces and blade deformation in the complex flow conditions of the Darrieus water turbine.

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Section: Introductionmentioning

confidence: 99%

Darrieus vertical-axis water turbines: deformation and force measurements on bioinspired highly flexible blade profiles

et al. 2020

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“…In fact, even small-scale facilities obstruct fish migration. This issue is of recent research interest, bringing the need for theoretical performance considerations [34,6] as well as assessment of fish passability [2,3,30]. Hydrokinetic turbines directly convert the kinetic energy of the flow and allow for a move away from dams and towards operation in very low-head flow conditions.…”

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confidence: 99%

“…The flexibility improved self-starting capabilities, raised the efficiency, and shifted the BEP to lower values of λ. One last advantage is the in-crease in fish-friendliness of the device associated with lower rotational speeds [30].…”

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confidence: 99%

Characteristics of the fluid–structure interaction within Darrieus water turbines with highly flexible blades

Hoerner

Abbaszadeh

Maı̂tre³

et al. 2019

Journal of Fluids and Structures

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acteristics of the fluid-structure interaction within Darrieus water turbines with highly flexible blades.Vertical-axis water turbines (VAWT), the target of the present study, provide a higher area-based power density when used in arrays, and are a promising alternative to horizontal-axis hydro-kinetic turbines (HAWT). Nevertheless, they operate under highly dynamic conditions near or even beyond dynamic stall at their best-efficiency-point. The abrupt loss of lift and strong increase of drag associated with hydrofoil stall can produce cyclic loads and possible damage of turbomachines due to material fatigue.The effect of flexible structures in a highly dynamic flow regime including separation and stall is here studied systematically in an experimental setup which permits observations of all regimes ranging from quasi-static state up to the occurrence of deep dynamic stall and beyond. The process is studied using a surrogate model consisting of an oscillating NACA0018 hydrofoil in a closed water channel, following a motion law comparable to the real angle of incidence of a Darrieus turbine blade along its rotation. The investigated parameters are the oscillation frequency and tip speed ratio, for one rigid as well as for three flexible hydrofoils of different stiffnesses. The coupling process is therefore investigated for multiple machine designs and working points. Lift and drag measurements have been carried out in a systematic manner.Results show that at tip speed ratios for which highly dynamic flow regimes occur, flexible blades provide not only higher thrust, but also reduced normal forces and reduced peak-to-peak cyclic normal force variations. This reduction of stress loads would translate into significantly increased turbine lifetime. This supports the need for further investigations in order to identify optimal blade flexibility and check further turbine designs.

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“…Due to their large dimensions, free surface operation and low rotational speed (<100 rpm), they intrinsically exhibit a good environmental behavior in relation to fish passage. FFTs used in the very low head context are, for example, water wheels (Quaranta and Wolter, 2021), the Vortex turbine (Müller et al, 2018), the Archimedes screw (Brackley, 2016;Piper et al, 2018), hydrokinetic turbines (Hammar et al, 2013), and the Very Low Head (VLH) turbine (Bozhinova et al, 2013). Further improvements in the latest decade seek to accommodate a larger biodiversity of fish present in migratory corridors, while at the same time enhancing the hydraulic FIGURE 1 | Injury and mortality probability versus the dimensionless time T* for water wheels (Quaranta and Wolter, 2021).…”

Section: Environmentally Enhanced Turbines: Fft Typementioning

confidence: 99%

Environmentally Enhanced Turbines for Hydropower Plants: Current Technology and Future Perspective

et al. 2021

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Environmentally enhanced turbines (EETs) have gained attention in the past two decades in order to reduce environmental impacts of hydropower plants on fish communities and on water quality. In this mini-review the main EETs are discussed, focusing on the Alden and Minimum Gap Runner turbines to reduce fish injury and on self-aerating and self/free-lubricant turbines to improve water quality. The review shows that EETs can be efficiently adopted instead of traditional turbines: EETs are cost-effective, efficient in terms of energy generation and have shown to reduce environmental impacts. Scientific gaps are also highlighted and case studies reported to better support refurbishment and new projects.

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Numerical analysis of the compromise between power output and fish-friendliness in a vortex power plant

Cited by 20 publications

References 24 publications

Darrieus vertical-axis water turbines: deformation and force measurements on bioinspired highly flexible blade profiles

Darrieus vertical-axis water turbines: deformation and force measurements on bioinspired highly flexible blade profiles

Characteristics of the fluid–structure interaction within Darrieus water turbines with highly flexible blades

Environmentally Enhanced Turbines for Hydropower Plants: Current Technology and Future Perspective

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