Abstract
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 low-solidity rotors with wide flow passage in order to accomplish high performance and stable operation. These hydro turbines would be used in agricultural water channel. Performance of contra-rotating small hydro turbine is investigated when flow rate is changing because flow rate may be changing in the field. The test small hydro turbine has high tracking performance while flow rate changing and the performance of it is clarified by the experimental results
