二重反転形小型ハイドロタービンのスペーサの有無がスラストに及ぼす影響

抄録

Small-scale hydropower is one of the important alternative energy and is expected because of its large amount of energy and high capacity factor. Pico hydropower generation less than 1 kW can be applied in many locations, such as agricultural pipelines and small rivers, and has a low environmental load. Since, pico hydropower generation has the problem of low efficiency, we adopt contra-rotating rotors that can be expected to achieve high performance. In previous research, performance characteristics for contra-rotating small hydroturbines were investigated by experiments and numerical analysis, and the possibility of higher performance was shown. As the next step, our research is on the verification stage in field experiments. First, we investigated the theoretical power from the head and flow rate of the field and designed a small hydroturbine having a 76mm rotor diameter which was suitable for the field. Next, we constructed an experimental apparatus and conducted field tests to investigate the power generation performance of the hydroturbine. In addition, there was concern that the bearings connecting the rotors and spacer would wear out due to long-term operation. Therefore, we evaluated the effects of the spacer presence on the thrust and performance of the hydroturbine by numerical analysis, and examined operation without spacers for long-term operation.