COMBUSTION CHAMBER IN A TURBOMACHINE

Abstract

A turbomachine combustion chamber has primary and dilution air inlet orifices formed by die stamping to have edges that project into the inside of the combustion chamber, and stress relaxation and/or reduction means in the edges or in the vicinity of the edges of said orifices, said means comprising, for each orifice, one, two, or three slots formed in the edge or around a fraction of the edge of said orifice.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be better understood and other characteristics, details, and advantages of the present invention appear more clearly on reading the following description made by way of non-limiting example with reference to the accompanying drawings, in which:

FIG. 1 is a diagrammatic half-view in axial section of a combustion chamber of a turbomachine;

FIG. 2 is a fragmentary diagrammatic view in perspective of the walls of the chamber;

FIG. 3 is a diagrammatic view on a larger scale of a portion of the combustion chamber wall in an embodiment of the invention;

FIGS. 4 to 6 are views corresponding to FIG. 3 and on a larger scale, showing variants of the invention; and

FIGS. 7 and 8 are views corresponding to FIG. 3 and showing other embodiments of the invention.

Claims

1. A combustion chamber for a turbomachine such as an aircraft turbojet or turbofan, the chamber comprising coaxial circularly-symmetrical walls extending one inside the other and connected together at their upstream ends by an annular chamber end wall, the inner and outer walls including primary air inlet orifices and dilution air inlet orifices formed by die stamping and having edges projecting into the inside of the chamber, the chamber including stress relaxation or reduction means in the edges or in the vicinity of the edges of at least some of said orifices, said stress relaxation or reduction means comprising, for each orifice, one, two, or three slots formed in the edge or around a portion of the edge of said orifice, each slot being connected at at least one of its ends to a crack propagation stop orifice.

2. A chamber according to claim 1, wherein the slots extend from the edges of the orifices to crack propagation stop orifices.

3. A chamber according to claim 2, wherein the slots formed in the edge of an orifice are symmetrical about a plane containing the axis of said orifice and the axis of the chamber.

4. A chamber according to claim 2, wherein the slots formed in the edge of an orifice are regularly distributed around the axis of the orifice.

5. A chamber according to claim 2, wherein the slots are rectilinear or curved in shape.

6. A chamber according to claim 1, wherein the slots are formed around a portion of the edges of the orifices and have a crack propagation stop orifice at each end.

7. A chamber according to claim 6, wherein a portion of each slot is of undulating shape and presents triple curvature.

8. A chamber according to claim 6, wherein a portion of each slot is formed by a circular arc centered on the axis of an orifice.

9. A chamber according to claim 8, wherein the end portions of the slot formed around the edge of an orifice are directed outwards away from the axis of said orifice.

10. A chamber according to claim 1, wherein the slots and the stop orifices extend substantially parallel to microperforations formed in the chamber for cooling purposes.

11. A chamber according to claim 1, wherein the stop orifices are of a diameter lying in the range about 1 mm to about 2 mm.

12. A chamber according to claim 1, wherein the slots are of width less than about 1 mm.

13. A chamber according to claim 1, wherein the slots and/or the stop orifices are formed by laser cutting.

14. A chamber according to claim 1, wherein at least some of the air inlet orifices are oval in shape with a long axis situated in a plane parallel or perpendicular to the axis of the chamber.

15. A chamber according to claim 14, wherein the long sides of the orifices are situated in the zones most subject to cracking.

16. A turbomachine, such as an aircraft turbojet or turboprop, the turbomachine including a combustion chamber according to claim 1.