We have developed a breast shot water wheel in collaboration with Nagasaki University and West Japan Fluid Engineering Laboratory.

This research and development was carried out for comparison with a breast shot water wheel (Photo 1), which had been installed in the Niimi Takao Agricultural Aqueduct since March of last year and was engaged in the electricity sales business. The efficiency of the water turbine in Niimi City was found to be about 30% in the ETV demonstration project of the Ministry of the Environment, but it was confirmed by the model experiment that the efficiency was about 30%, which is the same as the actual machine.

▲Niimi City Takao ELIS Power Station (Photo 1)

In addition, in the water turbine in Niimi City, there was a stagnation of water under the headrace, which was expected to hinder efficiency, so we also conducted a model experiment to verify it.
Experimental results show that efficiency tends to be better when there is no stagnation than when there is no stagnation. (Fig. 1)

▲Efficiency of Niimi turbine (Fig. 1)

The newly developed breast shot water wheel is characterized by the adoption of a unique blade shape called the pitch flap blade. (Fig. 2)

▲The newly developed breast shot water wheel (Fig. 2)

It was confirmed by model experiments that the newly developed pitch flap turbine has a maximum output efficiency of about 40% even when there is stagnation. (Fig. 3)
　
▲Efficiency of pitch flap turbines (Fig. 3)

Note Yorito Miyake