Counter-Rotating Type Hydroelectric Unit (Effects of Blade Numbers on On-Cam Operations)

To cope with warming global environments, authors have proposed the counter-rotating type hydroelectric unit, which is composed of tandem runners and the peculiar generator with double rotational armatures. The unit can be provided for various water circumstances at not only the onshore but also the offshore. This paper discusses effects of setting angle and the number of runner blades on turbine performances and then optimum blade setting angles giving the maximum output and/or the maximum efficiency, namely the on-cam operation, are presented at various discharges/heads.