VARIABLE-PITCH NOZZLE FOR A RADIAL FLOW TURBINE, IN PARTICULAR FOR A TURBINE OF AN AUXILIARY POWER SOURCE

摘要

The aim of the invention is to modify the reduced flow intake of a radial flow turbine in accordance with the needs of the thermodynamic cycle, and to provide a seal in the area of maximum load of the blades of the nozzle. For this purpose, the invention proposes that the blades have a specific positioning. According to a preferred embodiment, the nozzle of the radial flow turbine of a turbine engine (7), which rotates about a central axis (X'X), comprises a first annular grille (G1) having fixed-pitch blades (2a) and a second annular grille (G2) having the same number of variable-pitch blades (2b). The blades (2a, 2b) have pressure (Fi) and suction (Fe) sides. Each variable-pitch blade (2b) is secured to cups (24a, 24b) and is capable of being rotated by a control means (40) about a geometric axis (R'R) connecting the centres (2A, 2B) of the cups (24a, 24b). Each variable-pitch blade (2b) is mounted so as to be spaced apart from the axis (R'R) of the cups (24a, 24b) such that said axis of rotation (R'R) is positioned opposite the suction side (Fe) of the blade (2b) and substantially closer to the trailing edge (Bf) than to the leading edge (Ba) of said blade (2b).