Turbine engine outer shroud

#The invention relates to the field of axial turbomachinery and more particularly aircraft turbojets. More specifically, the invention relates to the design of an outer shroud of a compressor provided with stator vanes with variable orientation. The invention also relates to an assembly kit and a turbomachine provided with such a shroud, as well as an assembly method.

#The document US 2016/0160675 describes an axial turbomachine with a particular arrangement of the trunnions of stator vanes with variable orientation in an external compressor shroud. The vane orientation actuation system is positioned downstream of each vane. A connecting rod, denoted 80, makes it possible to adjust the pivoting of the vanes. This connecting rod can be manipulated by a synchronization ring, so that all the vanes of a given stage are oriented synchronously. The synchronization ring is also called a handling ring, an actuation ring or a control ring.

#Such a ring can sometimes rest directly on the outer shroud.

#FIGS. 1A and 1B represent an axial turbomachine;

#FIG. 2 is a diagram of a turbomachine compressor according to the background art;

#FIGS. 3 and 4 respectively show a compressor according to the invention with a shroud and an enlarged part of the shroud;

#In the following description, the terms “internal” and “external” refer to a positioning relative to the axis of rotation of an axial turbomachine. The axial direction corresponds to the direction along the axis of rotation of the turbomachine. The radial direction is perpendicular to the axis of rotation. Upstream and downstream are in reference to the main flow direction of the flow in the turbomachine.

#FIG. 1A shows a simplified axial turbomachine. This is here a two-stream turbojet engine. The turbojet engine 2 comprises a first stage of compression, called a low-pressure compressor 4, a second stage of compression, called a high-pressure compressor 6, a combustion chamber 8 and one or more stages of turbines 10. In operation, the mechanical power from the turbine 10 transmitted via the central shaft to the rotor 12 sets in motion the two compressors 4 and 6. The latter comprise several rows of rotor vanes associated with rows of stator vanes. The rotation of the rotor around its axis of rotation 14 thus makes it possible to generate an air flow and to gradually compress the latter until the inlet of the combustion chamber 8.

#An inlet fan 16 is coupled to the rotor 12 via a gear 17, and generates an air flow which is divided into a primary flow 18 passing through the various aforementioned different stages of the turbomachine, and by a secondary flow 20 passing through an annular duct (partially shown) along the machine to then join the primary flow at the outlet of the turbine.