Performance prediction of darrieus type vertical axis wind turbines using numerical simulations

Gömeç, Fazıl Selçuk
Flow over Darrieus type straight-bladed vertical axis wind turbines (VAWT) with NACA 0021 blade profile is simulated using ANSYS Fluent software. SST k- turbulence model is used for the two-dimensional, unsteady simulations. Wind speed is taken as 7 m/s and part of the problem domain including the rotating blades is modeled using the sliding mesh technique. Effects of boundary layer mesh parameters, time step and convergence tolerance on the solution accuracy are investigated with carefully designed runs. Performance of VAWTs with 2 and 3 blades, which are designed to have the same solidity ratio, are compared at different tip speed ratios. Instantaneous flow patterns of unsteady flow fields are analyzed by examining velocity and pressure contours. Start-up performance, which is known to be critical for Darrieus turbines, is investigated with special care and the effect of number of blades to this issue is studied.


Application of numerical shape optimization to the runner blades of a francis turbine
Yalılı, Mehmet; Aksel, Mehmet Haluk; Department of Mechanical Engineering (2015)
The multi-objective design of hydraulic turbines using computational fluid dynamics software has been an important subject in turbomachinery area recently. Researches focus especially on obtaining higher turbine efficiency by the improvement of runner shapes. Thus in the present study, a multi-objective shape optimization procedure was applied to improve the runner blade shapes of a small Francis turbine named as GAMM turbine which was selected from the literature. CFD computations as well as blade generati...
Design and analysis of a vertical axis water turbine for river applications using computational fluid dynamics
Demircan, Eren; Aksel, Mehmet Haluk; Pınarcıoğlu, Mehmet Melih; Department of Mechanical Engineering (2014)
The main purpose of this study is to design a Darrieus rotor type vertical axis water turbine using Computational Fluid Dynamics (CFD) in order to be used in river currents. The CFD modeling is based on two dimensional numerical solution of the rotor motion using commercial Unsteady Reynolds Averaged Navier-Stokes solvers, Ansys Fluent and CFX. To validate the two dimensional numerical solution, an experimental Darrieus rotor type water turbine from literature is studied and performance of several turbulenc...
Development of a high fidelity finite element model of a wind turbine blade via modal testing
Amer, Chadi; Şahin, Melin; Department of Aerospace Engineering (2015)
The design of an optimised horizontal axis 5-meter-long wind turbine rotor blade, is a research and development project, in order to fulfil the requirements of high efficiency torque-from-wind production. For this purpose, a research study is presented here, by investigating the structural characteristics of a composite wind turbine blade via finite element modelling and experimental modal analysis. At first, modal tests are performed by using various sensor-actuator pair combinations. After that the geomet...
Optimization of aeroelastic flapping motion of thin airfoils in a biplane configuration for maximum thrust
Kaya, Mustafa; Tuncer, İsmail Hakkı; Jones, Kevin D.; Platzer, Max F. (2007-01-01)
An aeroelastic flapping motion of thin airfoils in a biplane configuration is optimized for maximum thrust. Airfoils are attached to swing arms by an elastic joint, which is model led by a torsional spring. A spring-mass system is employed for the aeroelastic coupling. The stiffness coefficient and the mass moment of inertia of the airfoil are optimized for maximum thrust. A gradient based optimization method is employed in a parallel computing environment. Unsteady, low speed flows are computed in parallel...
Dynamic modelling and simulation of a wind turbine
Altuğ, Ayşe Hazal; Yavrucuk, İlkay; Department of Aerospace Engineering (2015)
In this thesis, a dynamic model for a horizontal axis wind turbine is developed for an upwind configuration using the MATLAB/Simulink environment. Blade Element Momentum Theory is used to model the rotor. It is assumed that the rotor blades are rigid and wind speed is uniform. Aerodynamic and gravitational forces are calculated as distributed loads. Verification of the model is done by using the LMS Samtech, Samcef for Wind Turbines software. Aerodynamic properties of the blades, sectional loads and moments...
Citation Formats
F. S. Gömeç, “Performance prediction of darrieus type vertical axis wind turbines using numerical simulations,” M.S. - Master of Science, Middle East Technical University, 2014.