Study of direct force measurement and characteristics on blades of Savonius rotor at static state

摘要

Experiments were conducted to measure and to clarify quantitative variations of fluid force on three kinds of setting blade configuration on a Savonius rotor at the static state in the steady uniform flow. In the experiments, by splitting both the end-disks of the blades into two half parts, the two blades were independent on each other and the one blade attached to both the half end-disks was only connected to the axis rod of the rotor, and the other blade connecting to the other half end-disks was free from the axis rod. Hence, the drag and lift forces acting on the former blade were directly measured in a short time at every phase angle and every overlap ratio of the two blades using the force balance meter. The experiment for the rotor of the diameter 160mm and the height 160mm was conducted in the steady wind flow of the Reynolds number, about 0.64×10~5 which based on the rotor diameter and the upstream velocity. From the experiment, value of the drag coefficient of the one blade in two blades with the overlap ratio of zero was taken from about -0.3 to 1.6, and the lift coefficient of it from about -1.0 to 1.4 in a cycle. The minus value of drag only appears in the setting of one blade in two blades, however the minus value does not exist in the distribution of tangential force on every overlap. And it was shown that the force distributions on the one blade in a cycle were very different in the first and second half cycle and interfered by the other blade, and strongly dependent on the overlap ratio between the blades.