EnginSoft - Conference Abstracts

EnginSoft Users' Meeting 2008
Le Tecnologie CAE nell'Industria

Optimizing of a wind turbine rotor by CFD modeling

Congedo Paolo Maria - University of Salento, Dep. Engineering for Innovation, Research Center for Energy and Environment
De Giorgi Maria Grazia - University of Salento, Dep. Engineering for Innovation, Research Center for Energy and Environment

Abstract

The increasing awareness of the need for environmentally sustainable energy production has driven the promotion of wind energy conversion systems. Wind energy applications sometimes suffer from lack of field measurements support, mostly during the preliminary stages of their development, due to either incomplete availability or inadequacy of the existing measuring network. The problem intensifies in cases of complex terrain sites where accurate estimations of the energy production play a critical role in determining the viability of the investment. In the first part of the current paper the study of a wind farm in regions of particular complexity has been performed. The second part is concerning the optimization of the wind turbine rotor profile to improve performances. Energy output production losses are often due to turbulence and wake effect around turbines downstream, so it is good to design wind farm in order to space wind turbine about 5 and 9 rotor diameters be apart in the prevailing wind direction, and between 3 and 5 diameters apart in the direction perpendicular to the prevailing winds, in order to avoid too much turbulence around the turbines downstream. Spacing between turbines together land use and the cost of connecting wind turbines each other and to the electrical grid have a significant weight in the wind farm investment and realization costs. Hence, It would be a relevant gain to have turbine with smaller rotor diameter but which are able in producing the same energy output that largest rotor wind turbine produce. Different configurations for the wind turbine rotors can increase the power production for a given blade length, making them attractive on wind farm sites, especially with design restrictions on the rotor radius. This work in aimed to understand how the different rotor geometries influence the wake lengths and the turbulence behind wind turbine, in order to verify and quantify the gain in wind turbine spacing. In particular the present paper describes the numerical investigation of the aerodynamics around a wind turbine blade with and without a winglet using Computational Fluid Dynamics, CFD. The purpose of adding a winglet to a rotor blade design is to decrease the induced drag from the blade by changing the downwash distribution. Numerical investigation and Fluid Dynamics CFD simulation will be done in order to achieve the above described objectives, studying in particular blades turbines with and without winglets, and evaluate the thrust increment trend and induced vibration on turbine than thrust and vibration on traditional bladed turbine. Three blades turbines with different configurations will be design in CAD program which is able to create complex 3D models, assemblies, and 2D measured drawings, in order to have a coherent blade shape to be used in CFD simulation. Fluent CFD software will be used for simulating the fluid flow.