Radial centrifugal turbomachine

A radial centrifugal turbomachine, comprising:

• a fixed casing;
• a rotor disc installed in the casing and rotatable in the casing around a respective rotation axis;
• a ring of rotor blades mounted on a front face of the rotor disc and coaxial with the rotation axis, in which the rotor blades project axially from the front face of the rotor disc;
• a ring of stator blades, radially inner and concentric with respect to the ring of rotor blades, in which the stator blades extend axially between the casing and the front face of the rotor disc, in which the stator blades delimit between them passage sections;
• wherein the casing has an axial inlet that is radially inner with respect to the ring of stator blades;
• an adjusting device operatively active at the axial inlet;
• in which the adjusting device comprises:
• an annular member delimiting at least one radially inner passage for the fluid, the annular member being located at the axial inlet, in which a front surface of the annular member and an abutment surface of the casing delimit between them a radial annular passage;
• at least one actuator connected to the annular member and configured to move axially and/or to rotate around the rotation axis, according to a predefined angle, the annular member so as to vary the radial annular passage and/or the passage sections;
• a transmission shaft coaxial with the rotation axis, integral with the annular member and operatively connected to the actuator.