Annular wall of a combustion chamber with optimised cooling
An annular turbine engine combustion chamber wall including air admission orifices to create zones of steep temperature gradient, and cooling orifices to enable the air flowing on the cold side to penetrate to the hot side in order to form a film of cooling air along the annular wall, the annular wall being further includes, in the zones of steep temperature gradient, multi-perforation holes having respective bends of an angle α greater than 90°, the angle α being measured between an inlet axis Ae and an outlet axis As of the multi-perforation hole, the outlet axis of the multi-perforation hole being inclined at an angle θ 3 relative to the normal N to the annular wall through which the multi-perforation holes with bends are formed, in a “gyration” direction that is at most perpendicular to the axial flow direction D of the combustion gas.
1. An annular turbine engine combustion chamber wall comprising, between a cold side and a hot side:
a plurality of air admission orifices distributed along at least one circumferential row to enable an air flowing on said cold side to penetrate to said hot side; and
a plurality of cooling orifices to enable the air flowing on said cold side to penetrate to said hot side in order to form a film of cooling air along said annular wall, said cooling orifices being distributed in a plurality of circumferential rows that are axially spaced apart from one another, and axes of each of said cooling orifices being inclined in an axial flow direction of a combustion gas at an angle of inclination θ 1 relative to a normal to said annular turbine engine combustion chamber wall; and
in zones around a circumference of each of said plurality of air admission orifices, multi-perforation holes having respective bends of an angle α equal or greater than 90 ° , said angle α being measured between an inlet axis and an outlet axis of each of said multi-perforation hole, each said outlet axis of said multi-perforation holes being inclined at an angle θ 3 relative to said normal to said annular turbine engine combustion chamber wall through which said multi-perforation holes with bends of an angle β lying in a range of 50° to 90° to said axial flow direction of the combustion gas wherein the multi-perforation holes and the cooling orifices alternate around at least a portion of a circumference of said plurality of air admission orifices.
2. The annular turbine engine combustion chamber wall according to claim 1 , wherein said angle α lies in a range of 90° to 170°.
3. The annular turbine engine combustion chamber wall according to claim 1 , wherein said multi-perforation holes present a diameter that is identical to a diameter of said cooling orifices, and said angle θ 3 is identical to said angle of inclination θ 1 of said cooling orifices.
4. The annular turbine engine combustion chamber wall according to claim 3 , wherein said inlet axis of each of said multi-perforation holes is inclined at an angle θ 4 relative to said normal to said annular turbine engine combustion chamber wall in the axial flow direction of the combustion gas, said angle θ 4 being identical to said angle of inclination θ 1 of said cooling orifices.
5. The annular turbine engine combustion chamber wall according to claim 3 , wherein each of said multi-perforation holes presents a varying profile section so as to optimize cooling locally.
6. The annular turbine engine combustion chamber wall according to claim 1 , wherein said multi-perforation holes split into two after a bend portion so as to form two air outlets opening out into the hot side.
7. The annular turbine engine combustion chamber wall according to claim 1 , wherein an air outlet opening out into the hot side of each of said multi-perforation holes presents a varying diameter in a shape of a cone.
8. The annular turbine engine combustion chamber wall according to claim 1 , wherein said plurality of air admission orifices are primary holes enabling the air flowing on said cold side to penetrate to said hot side in order to create an air/fuel mixture.
9. The annular turbine engine combustion chamber wall according to claim 8 , wherein said plurality of air admission orifices are dilution holes enabling the air flowing on said cold side to penetrate to said hot side in order to dilute the air/fuel mixture.
10. A turbine engine combustion chamber having at least one annular wall according to claim 1 .
11. A turbine engine including a combustion chamber having at least one annular wall according to claim 1 .