Small hydropower generation is one of important alternative energy, and potential of small hydropower is great. Efficiency of small hydro turbines is lower than that of large one, and these small hydro turbine’s common problems are out of operation by foreign materials. Then, there are demands for small hydro turbines to keep high performance and wide flow passage. Therefore, we adopted contra-rotating rotors, which can be expected to achieve high performance and enable to use low-solidity rotors with wide flow passage, in order to accomplish high performance and stable operation. Final goal of this study is development of a small hydro turbine like electrical goods, which has high portability and makes an effective use of unused small hydro power energy source. In this research, experimental apparatus of the contra-rotating small hydro turbine with 60mm casing diameter was manufactured and performance of it was investigated by an experiment. Efficiency of the contra-rotating small hydro turbine was high in pico-hydro turbine and high efficiency could be kept in wide flow rate range. Internal flow condition, which was difficult to measure experimentally, was shown by the numerical flow analysis. Further, influence of spokes to support the rotor was clarified. Then, a relation between the performance and internal flow condition was considered by the experimental and numerical analysis results.
Silt Erosion in Hydro Turbines and Status of Small Hydropower in India - A Review
