francis wheel for turbine or hydraulic pump turbine, and process of reducing fluctuations in a flow

摘要

This wheel comprises a plurality of vanes (2) arranged on a crown (3) and is equipped with a tip-forming member (10) attached to a central region (32) of the crown or hub of the wheel (1), radially inside the vanes (2), the crown defining a wet surface (31) for guiding a flow (E) passing between the vanes. The tip-forming member (10) is provided with at least one opening (121) for diverting a fraction (E1) of the flow towards the internal volume (V10) of this member. This member comprises a frustoconical annular skirt (11) and at least one fin (15) arranged in its internal volume (V10) and able to modify the path of the flow fraction (E1) entering this volume through the opening (121). This fin (15) extends as far as the edge (112) of the skirt (11) which defines an outlet opening (14) of the member (10) for the flow fraction (E1).