Effect of blade skew, endplate and casing groove on the aerodynamic performance of Wells turbine for OWC: a review

Kumar, Amit; Das, Tapas K.; Samad, Abdus

doi:10.1088/1742-6596/2217/1/012070

Cited by 2 publications

(1 citation statement)

References 38 publications

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“…The introduction of blade sweep and skew reduced losses, delayed stalls, and minimized drag forces [17]. The experimental work [18] compares the aerodynamic performance of backward swept angle blades to unswept angle blades of different rotor solidities (0.64 and 0.32) at 0 • and 20 • pitch angles.…”

Section: Introductionmentioning

confidence: 99%

CFD Investigation of a Hybrid Wells Turbine with Passive Flow Control

Uddin

Atkinson

Opoku³

2023

Energies

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In the past decade, there has been renewed interest in wave energy harvesting utilizing oscillating water columns (OWC), one of the most well-studied wave energy harnessing technologies. In the OWC, pneumatic power from ocean waves is converted to mechanical energy by Wells turbines. It should be noted, however, that such turbines tend to perform poorly, have a limited operating range, and have low efficiency. In the present study, we incorporate a rectangular Gurney flap (GF) at the trailing edge (TE) of a Wells turbine consisting of hybrid airfoil (NACA 0015 and NACA 0025) blades with variable chord distribution along the span. This passive flow control mechanism was adopted to achieve increased power production by the Wells turbine. This study aimed to determine the aerodynamic performance of the variable chord turbine with GF compared to a turbine with a constant chord. By using ANSYS™ CFX, the three-dimensional, steady-state, incompressible Reynolds averaged Navier–Stokes (RANS) equations coupled with the k-ω SST turbulence model are solved. The performance was evaluated through the use of non-dimensional coefficients of torque, pressure drop, and efficiency. In addition, the numerical accuracy was achieved through a grid independence study. There was a good agreement between the computed results and the available experimental and numerical data. The GF increased the torque coefficient by 18.6% and 47.3% but with the expense of peak efficiency of 8.5% and 7.4% for the baseline and the hybrid turbine, respectively. Additionally, the hybrid turbine with GF delayed the onset of the stall by ~3° angle of attack (AOA).

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Section: Introductionmentioning

confidence: 99%

CFD Investigation of a Hybrid Wells Turbine with Passive Flow Control

Uddin

Atkinson

Opoku³

2023

Energies

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Cavitation Hydrodynamic Performance of 3-D Printed Highly Skewed Stainless Steel Tidal Turbine Rotors

et al. 2023

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Hydraulic turbines contribute to 60% of renewable energy in the world; however, they also entail some adverse effects on the aquatic ecology system. One such effect is their excessive noise and vibration. To minimize this effect, one of the most effective and feasible solutions is to modify the design of the turbine rotor blade by introducing a skew. In this study, two 0.3-meter tidal turbines with 0-degree (no-skewness) and positive 90-degree skewness made of stainless steel 316L were designed and printed using a 3-D printing powder bed fusion technique. These rotors were then tested at the Emerson Cavitation Tunnel (ECT) at Newcastle University, UK, and the variation in the skewness of the blades of the turbines as a function of the power coefficient on a given tip speed ratio (TSR) value was ascertained. Results showed that the highly skewed rotor had significantly lower drag and torque fluctuations, with a slight decrease in efficiency compared to the non-skewed one, which warrants further investigation on the effect of added skew to reduce vibration and noise. Numerical simulations were also performed for verification and validation of the experimental tests, using the H45 dynamometer at the ECT. A comprehensive software code for propellers and tidal turbines, ROTORYSICS, was used to examine the cavitation effect of the two rotors; a comparison was made for both, with and without cavitation. The results indicate that for a high immersion depth of tidal turbine rotors, cavitation rarely occurs, but for hydrokinetic turbines that are installed on dams in rivers and falls, cavitation could be a serious concern. It was concluded that the 0-degree skewed rotor is more hydrodynamically efficient than the 90-degree skewed rotor.

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Effect of blade skew, endplate and casing groove on the aerodynamic performance of Wells turbine for OWC: a review

Cited by 2 publications

References 38 publications

CFD Investigation of a Hybrid Wells Turbine with Passive Flow Control

CFD Investigation of a Hybrid Wells Turbine with Passive Flow Control

Cavitation Hydrodynamic Performance of 3-D Printed Highly Skewed Stainless Steel Tidal Turbine Rotors

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