Wind tunnel testing at the NTUA
A closed loop wind tunnel is located at the Mechanical Engineering building, which allows for rotors of up to 1.2m diameter to be tested in wind speeds of up to 13m/s. With the use of a 900W DC motor, a DC bi-directional drive and a tachogenerator, the rotors can be driven at different and constant revolutions per minute (RPM) and specifically up to 1000 RPM. A rotary torque transducer with a DAC card is used for measuring the mechanical power in terms of torque and RPM at the shaft of the rotor. The rotors can be driven at different wind speeds and different tip speed ratios in order to describe the behavior of the rotor blades. A 1.2m diameter HP turbine rotor has been tested in the wind tunnel and driven at different RPM for a specific wind speed. This provides information on the cp vs tsr curve for different wind speeds from 3m/s up to 10m/s.