Modeling of the flow in a Darrieus water turbine: Wall grid refinement analysis and comparison with experiments

Maı̂tre, Thierry; Amet, Ervin; Pellone, Christian

doi:10.1016/j.renene.2012.09.030

Cited by 140 publications

(129 citation statements)

References 11 publications

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“…This prediction accuracy is much higher than previous vertical axis turbine CFD predictions, which exhibit maximum Cp errors of more than 45% [12,14,[29][30][31], possibly due to the inclusion of the full turbine geometry in the present study. The use of 3D models also allows for the direct simulation of Cp without the need for empirical correction for 2D models as previous used [8,10,16].…”

Section: Validation Of Numerical Simulations With Experimental Fluid contrasting

confidence: 53%

Three-dimensional numerical simulations of straight-bladed vertical axis tidal turbines investigating power output, torque ripple and mounting forces

et al. 2015

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Three straight-bladed vertical axis turbine designs were simulated using ThreeDimensional (3D) transient Computational Fluid Dynamics (CFD) models, using a commercial Unsteady Reynolds Averaged Navier-Stokes (URANS). The turbine designs differed in support strut section, blade-strut joint design and strut location to evaluate their effect on power output, torque fluctuation levels and mounting forces. Simulations of power output were performed and validated against Experimental Fluid Dynamics (EFD), with results capturing the impacts of geometrical changes on turbine power output. Strut section and blade-strut joint design were determined to significantly influence total power output between the three turbine designs, with strut location having a smaller but still significant effect. Maximum torque fluctuations were found to occur around the rotation speed corresponding to maximum power output and fluctuation levels increased with overall turbine efficiency. Turbine mounting forces were also simulated and successfully validated against EFD results. Mounting forces aligned with the inflow increased with rotational rates, but plateaued due to reductions in shaft drag caused by rotation and blockage effects. Mounting forces perpendicular to the inflow were found to be 75% less than forces aligned with the inflow. High loading force fluctuations were found, with maximum values 40% greater than average forces.

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Section: Validation Of Numerical Simulations With Experimental Fluid contrasting

confidence: 53%

Three-dimensional numerical simulations of straight-bladed vertical axis tidal turbines investigating power output, torque ripple and mounting forces

et al. 2015

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“…As already mentioned in previous sections, a prism layer was built around the blades surface to ensure a smooth transition in size and skewness of the elements. The values of y + in the computations are kept below 1 as required by the selected turbulence model, which also guarantees an adequate resolution of the boundary layer development around the blades [16]. This fact, together with the employed second order schemes in the spatial and temporal discretization, gives confidence about the obtained numerical results.…”

Section: Resultsmentioning

confidence: 88%

“…Maître et al [16] performed detailed two dimensional simulations of the three blades model CFWT LEGI available in their laboratory. The influence of the grid refinement close to the blade surface on the mean power extracted is discussed and analyzed.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study of the Effect of Winglets on the Performance of a Straight Blade Darrieus Water Turbine

2018

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This study deals with the three-dimensional unsteady numerical simulation of the flow around a cross-flow vertical-axis water turbine (CFWT) of the Darrieus type. The influence of turbine design on its hydrodynamic characteristics and performance is investigated by means of a time-accurate Reynolds Averaged Navier Stokes (RANS) commercial solver. The flow unsteadiness is described using a transient rotor-stator model in connection with a sliding interface. A classical Darrieus straight blade turbine, based on the NACA0025 airfoil, has been modified adding winglets (symmetric and asymmetric designs) to the blades' tips with the objective of reducing the strength of the detached trailing vortices. The turbulent features of the flow have been modelled by using different turbulence models (k-ε Renormalization Group, standard Shear Stress Transport, transition Shear Stress Transport and Reynolds Stress Model). As a result, the predicted hydrodynamic performance of the turbine including winglets increases, independently of the employed turbulence model, being the improvement higher when a symmetric winglet design is considered. Moreover, visualization of skin friction lines pattern and their connection with vorticity isosurfaces, illustrating the flow detachment in the three blade configurations, has been carried out. Finally, a short discussion about the intermittency behavior along a turbine revolution is presented.

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“…Some studies for enhancing the performance of vertical axis tidal current turbine have been conducted previously by analytical, experimental and numerical methods [3][4][5][6][7][8][9]. Numerical method can be done by simulation using Computational Fluid Dynamics software [5][6][7]10].…”

Section: Introductionmentioning

confidence: 99%

“…Numerical method can be done by simulation using Computational Fluid Dynamics software [5][6][7]10]. One of the most familiar software is ANSYS-Fluent code.…”

Section: Introductionmentioning

confidence: 99%

The influence of time step setting on the CFD simulation result of vertical axis tidal current turbine

Satrio¹,

Utama²,

Mukhtasor³

2018

J. MECH. ENG. SCI.

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This paper investigates the influence of time step setting on the CFD simulation result of vertical axis tidal current turbine. Two main features of time step setting have been studied. The first feature concerns with time step size setting that representing the detailed calculation on each degree in one turbine rotation. The second feature deals with number of time step setting that representing how many turbine rotations need for achieving steadiness results. In this study, two-dimensional (2D) analysis of Computational Fluid Dynamics (CFD) simulation using ANSYS-Fluent code with Sliding Mesh technique is used to solve the incompressible Unsteady ReynoldsAveraged Navier-Stokes equations. The finite volume discretization method with second-order scheme and the SIMPLE algorithm are used for all transport equations. The steadiness calculation result is achieved at six turbine rotations and the rest has no significant effect.

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Modeling of the flow in a Darrieus water turbine: Wall grid refinement analysis and comparison with experiments

Cited by 140 publications

References 11 publications

Three-dimensional numerical simulations of straight-bladed vertical axis tidal turbines investigating power output, torque ripple and mounting forces

Three-dimensional numerical simulations of straight-bladed vertical axis tidal turbines investigating power output, torque ripple and mounting forces

Numerical Study of the Effect of Winglets on the Performance of a Straight Blade Darrieus Water Turbine

The influence of time step setting on the CFD simulation result of vertical axis tidal current turbine

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