Abstract

The purpose of this dissertation is the experimental calculation of the efficiency of a small wind turbine’s rotor and the comparison of experimental results with the computational analyses. The experimental tests were performed at the wind tunnel of the Laboratory of Aerodynamics of the National Technical University of Athens.

First, a general reference to the different types of wind turbines and a brief description of the way they work is conducted, focusing mainly on the basic theoretical tools for their study, which are later used for the small wind turbine’s power curve calculation.

Moreover, specificities of small wind turbines like the one examined here are detected and briefly analyzed. More attention is given to the specificities concerning the aerodynamic features of the blades and specifically to the phenomena that rise when an airfoil operates at low Reynolds number airflows.

Next, the procedure that has been followed for the computational estimation of the CP-λ curves is described. The results of this procedure are presented, explained and compared to experimental data acquired from a similar project for the same rotor.

At the end, the methodology applied for the installation of the experimental equipment and the measurement’s recording procedure is traced step-by-step. The experimental power curves are compared finally not only with the computational results, but also with the other experimental results of the corresponding rotors.

Keywords: small wind turbines, rotor efficiency, BEM theory, small wind turbines specificities, Low Reynolds airfoils’ aerodynamics, power curve computational calculation, XFOIL, RAFT, wind tunnel testing

Author: Alexandros Rontogiannis

Responsible PhD: Kostas Latoufis / latoufis@power.ece.ntua.gr

Supervising Professor: Vasilis Riziotis / vasilis@fluid.mech.ntua.gr

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