AXIAL FLOW WATER TURBINE RUNNER BLADE, AXIAL FLOW WATER TURBINE RUNNER AND AXIAL FLOW WATER TURBINE

摘要

PROBLEM TO BE SOLVED: To provide an axial flow water turbine runner blade in which the occurrence of cavitation can be suppressed and which can smoothly turn.SOLUTION: An axial flow water turbine runner blade 20 according to the embodiment includes a blade body 21 arranged at a runner hub 11 through a clearance 40 and having a blade positive pressure surface 22 and a blade negative pressure surface 23; a stem 24 which extends from an inside of the runner hub 11 up to the blade body 21 and supports the blade body 21; and a protrusion part 30 which is arranged at the runner hub 11 in the blade negative pressure surface 23 of the blade body 21 and projects from the blade negative pressure surface 23. The blade body 21 has an upstream side area 21a, a downstream side area 21b and a connecting area 21c which is arranged between the upstream side area 21a and the downstream side area 21b as seen from a direction of a rotating axis Y of the runner blade 20 and in which the blade body 21 and the stem 24 are connected . The protrusion part 30 extends in the blade negative pressure surface 23 of the blade body 21 from the upstream side area 21a of the blade body 21 to the connecting area 21c.