Abstract: A hydraulic turbine includes a rotor with a runner, which is concentrically surrounded by a stator, whereby the runner comprises a plurality of runner blades arranged and distributed in a ring around a rotor axis, and each runner blade extends between a runner crown and a runner band; whereby the stator comprises a plurality of guide vanes arranged and distributed in a ring around the rotor axis, and each guide vane extends between an upper stator ring and a lower stator ring; and whereby a predetermined clearance is provided at least between the runner band and the lower stator ring. A substantial reduction of pressure pulsations in the vane-less gap between said runner blades of said runner is achieved by substantially increasing said predetermined clearance.

Abstract: A hydraulic turbine includes a rotor with a runner, which is concentrically surrounded by a stator, whereby the runner comprises a plurality of runner blades arranged and distributed in a ring around a rotor axis, and each runner blade extends between a runner crown and a runner band; whereby the stator comprises a plurality of guide vanes arranged and distributed in a ring around the rotor axis, and each guide vane extends between an upper stator ring and a lower stator ring; and whereby a predetermined clearance is provided at least between the runner band and the lower stator ring. A substantial reduction of pressure pulsations in the vane-less gap between said runner blades of said runner is achieved by substantially increasing said predetermined clearance.

Abstract: A hydraulic turbine includes a rotor with a runner, which is concentrically surrounded by a stator, whereby the runner comprises a plurality of runner blades arranged and distributed in a ring around a rotor axis, and each runner blade extends between a runner crown and a runner band; whereby the stator comprises a plurality of guide vanes arranged and distributed in a ring around the rotor axis, and each guide vane extends between an upper stator ring and a lower stator ring; and whereby a predetermined clearance is provided at least between the runner band and the lower stator ring. A substantial reduction of pressure pulsations in the vane-less gap between said runner blades of said runner is achieved by substantially increasing said predetermined clearance.

Abstract: This method can be used for refurbishing a facility for converting hydraulic energy into electrical or mechanical energy, and vice versa. The facility includes a Francis type pump-turbine. The pump-turbine includes a runner movable about an axis, a pre-distributor, including stay vanes defining between each pair of two adjacent stay vanes a first water passage channel and a distributor, including guide vanes arranged downstream of the stay vanes in the direction of water flow feeding the pump-turbine operating in turbine mode. The guide vanes define between each pair of two adjacent guide vanes a second water passage channel. This method includes steps of reducing the height, taken parallel to the axis of rotation of the runner, of the first water passage channels and reducing the height, taken parallel to the axis of rotation of the runner, of the second water passage channels.

Abstract: A hydraulic turbine includes a rotor with a runner, which is concentrically surrounded by a stator, whereby the runner comprises a plurality of runner blades arranged and distributed in a ring around a rotor axis, and each runner blade extends between a runner crown and a runner band; whereby the stator comprises a plurality of guide vanes arranged and distributed in a ring around the rotor axis, and each guide vane extends between an upper stator ring and a lower stator ring; and whereby a predetermined clearance is provided at least between the runner band and the lower stator ring. A substantial reduction of pressure pulsations in the vane-less gap between said runner blades of said runner is achieved by substantially increasing said predetermined clearance.

Abstract: The invention relates to a Francis runner (200) for a hydraulic machine, comprising: a wheel (1), which is rotationally symmetrical about an axis of rotation (Z) of the runner (200); a crown (12); and a plurality of inwardly curved vanes (21), each of which has a peripheral edge (212). The peripheral edge (212) of at least one of the vanes is curved, the concavity thereof facing toward the outside of the runner (200). The maximum value of the distance measured between any point on the peripheral edge (202) and a straight line passing through a first connection point between the peripheral edge (212) and the wheel (1), and through a second connection point between the peripheral edge (212) and the crown (12), is at an intermediate point on the peripheral edge (212). The radius (Rn) from the intermediate point (N) is strictly smaller than the radius (Ra) from the first connection point (A).

Abstract: This method can be used for refurbishing a facility for converting hydraulic energy into electrical or mechanical energy, and vice versa. The facility includes a Francis type pump-turbine. The pump-turbine includes a runner movable about an axis, a pre-distributor, including stay vanes defining between each pair of two adjacent stay vanes a first water passage channel and a distributor, including guide vanes arranged downstream of the stay vanes in the direction of water flow feeding the pump-turbine operating in turbine mode. The guide vanes define between each pair of two adjacent guide vanes a second water passage channel. This method includes steps of reducing the height, taken parallel to the axis of rotation of the runner, of the first water passage channels and reducing the height, taken parallel to the axis of rotation of the runner, of the second water passage channels.

Abstract: The invention relates to a wheel (R) of the Francis type that comprises a ring (1) with revolution symmetry about the rotation axis (Z) of the wheel (R), and curved blades (21, 22) connected to the ring (1) and each having an outer peripheral edge (212, 222) and an inner central edge (211, 221). The connection points (B21, B22) between the ring (1) and the inner central edges (211, 221) of the blades (21, 22) are located on a same circle (C20) centered on the axis (Z). The connection points (A21, A22) between the ring (1) and the outer peripheral edges (212, 222) of the blades (21, 22) are located on at least two distinct circles (C21, C22) (D21, D22) centered on the axis (Z).

Abstract: The invention relates to a Francis runner (200) for a hydraulic machine, comprising: a wheel (1), which is rotationally symmetrical about an axis of rotation (Z) of the runner (200); a crown (12); and a plurality of inwardly curved vanes (21), each of which has a peripheral edge (212). The peripheral edge (212) of at least one of the vanes is curved, the concavity thereof facing to ward the outside of the runner (200). The maximum value of the distance measured between any point on the peripheral edge (202) and a straight line passing through a first connection point between the peripheral edge (212) and the wheel (1), and through a second connection point between the peripheral edge (212) and the crown (12), is at an intermediate point on the peripheral edge (212). The radius (Rn) from the intermediate point (N) is strictly smaller than the radius (Ra) from the first connection point (A).

Abstract: The invention relates to a wheel (R) of the Francis type that comprises a ring (1) with revolution symmetry about the rotation axis (Z) of the wheel (R), and curved blades (21, 22) connected to the ring (1) and each having an outer peripheral edge (212, 222) and an inner central edge (211, 221). The connection points (B21, B22) between the ring (1) and the inner central edges (211, 221) of the blades (21, 22) are located on a same circle (C10) centred on the axis (Z). The connection points (A21, A22) between the ring (1) and the outer peripheral edges (212, 222) of the blades (21, 22) are located on at least two distinct circles (C21, C22) (D21, D22) centred on the axis (Z).