Method for perforating a wall of a combustion chamber

1. A method for perforating a wall of a combustion chamber, said method comprising: before perforating at least one orifice in a first determined zone of said wall and at least one orifice in a second determined zone of said wall, calculating mechanical stresses applied on said wall when said combustion chamber is in operation, and after said calculating, perforating the at least one orifice in the first determined zone of said wall, said perforation being made using a tool with a cross-section dependent on the mechanical stresses calculated in said first determined zone,

wherein after said perforating, the perforation is reiterated in the second determined zone, said perforation in the second determined zone being made using a tool with a cross-section dependent on the mechanical stresses calculated in said second determined zone, and

wherein each orifice is perforated along a specific perforation axis passing through a same line circumferential to an axis of revolution of the combustion chamber, all of the perforation axes intersecting at a single point.

2. The method according to claim 1 , wherein each perforation axis forms an angle of between 20 and 70 degrees with a plane tangent to said wall.

3. The method according to claim 1 , the at least one orifice in the first determined zone is made by peripheral cutting.

4. The method according to claim 1 , wherein the at least one orifice in the first determined zone has an elliptical shaped outer end, said outer end with an elliptical section being located at the outer surface of the wall.

5. The method according to claim 1 , wherein the at least one orifice in the first determined zone has an outer end with a circular section, said outer section with a circular section being located at an outer surface of the wall.

6. The method according to claim 1 , wherein the tool used to make the perforation in the first determined zone or the second determined zone or both is:

a laser beam, or

a water jet.

7. The method according to claim 1 , wherein the orifice in said first determined zone is perforated with a first cross-section and the orifice in said second determined zone is perforated with a second cross-section, the first cross-section being different than the second cross-section.

8. The method according to claim 7 , further comprising perforating orifices in said wall with a third cross-section on the basis of the mechanical stresses calculated in said first determined zone, wherein said third cross-section is different from the first and second cross-sections.

9. The method according to claim 1 , wherein the mechanical stresses applied on said wall when said aircraft engine is in operation are calculated theoretically.

10. A wall of a combustion chamber perforated by a plurality of orifices with a similar orientation, said wall comprising:

first orifices of the plurality of orifices with an outer end with a circular cross-section,

second orifices of the plurality of orifices with an outer end with a first elliptical cross-section comprising a first major axis parallel to a determined axis,

third orifices of the plurality of orifices with an outer end with a second elliptical cross-section comprising a second major axis perpendicular to said determined axis,

wherein the cross-sections of the first, second and third orifices are based upon mechanical stresses applied on said wall when said combustion chamber is in operation, said mechanical stresses being determined before perforating the first, second and third orifices, and

wherein each orifice is perforated along a specific perforation axis passing through a same line circumferential to an axis of revolution of the combustion chamber, all of the perforation axes intersecting at a single point.

11. The method according to claim 7 , wherein the mechanical stresses applied on said wall when said aircraft engine is in operation are calculated theoretically.