Development of a Vertical Axis Type Marine Turbine Model With Variable-Pitch Blades and Its Basic Performance

This paper describes performance of a vertical axis type marine turbine with variable-pitch blades for marine current power utilization. A cyclic mechanism is applied to pitch control of turbine blades. In this paper, the experimental model is developed, which type is variable pitch control one. At the first, conditions of marine currents around Japanese islands is explained, the necessarily of development of marine turbines in low to middle current velocity range is shown. Effectiveness of pitch control of a vertical axis turbine is described from results of CFD calculations. In the calculations, as the basic model, which pitch angles are fixed, that of a past experimental study is applied. From these investigations, the vertical axis type water turbine with variable-pitch blades for model experiment in a channel is developed. Detail of the model developed is introduced. The model experiment is explained. In the experiment, performance of the self-starting and the number of rotations of the turbine is measured. From the results, effectiveness of the pitch control is shown. However, the characteristics are different between past quasi-statistical investigation with the single stream theory and the experimental results. From the experiments, it is confirmed that the turbine of the variable-pitch types can start by itself in very low velocity range in which conventional vertical axis turbines cannot start and also rotate even if the inertia moment is acted.