A water turbine or pump having a rotor (1) and a stator (2). The leading edges (13) and the trailing edges (14) at least of the rotor blades (6) form a bend (15) projecting in opposite relationship to the flow direction (12). That causes a flow force resulting in a self-cleaning effect being applied to impurities which are deposited at the leading edges (13). However the adjustment design providing for adjustability of the rotor blades remains substantially unchanged.
A Francis turbine with an improved shape of blades, which can reduce cavitations generated on the surface of the blades or reduce the secondary flow around the blades, is provided. A Francis turbine comprises a rotating shaft, a crown, a plurality of blades, and a band. The crown can rotate with the rotating shaft. The blades are circumferentially arranged on the crown, each of which including an inner end as a trailing edge. The band is coaxially coupled with the crown by the blades. The rotating shaft, the crown, the blades, and the band as a whole rotate toward a turbine direction during a turbine operation. A projected profile of the trailing edge on a perpendicular plane, which is perpendicular to a center axis of the rotating shaft, is curved toward a direction opposite to the turbine direction at least in the crown side.
