Abstract
An experiment was conducted to study the effect of the located position or the setting angle of a sub-blade on performance of the rotor, which the inner edge of it was always attached on the convex surface of the main blade. The chord length ratios of the sub-blade to the main blade length 90mm were prepared as 0.667 or 0.833. The two ways of location of the sub-blade was selected as changing of the opening angle and sliding to keep a constant opening on the main blade. The rotor diameter was 160mm and the wind velocity was about 5.5 m/s in the experiment, so that the Reynolds number was about 5.87×10^4. From the experimental result, it is shown that the maximum output power coefficient of the rotor with the sub-blades was succeeding about 20 percent to the normal rotor. Furthermore, the adding coefficient of the sub-blade was empirically estimated by applying the momentum theory to the flow around it and agreed well to the experiment.
