Annular combustion chamber for a turbine engine

1. An annular combustion chamber for a turbine engine, the chamber comprising:

two coaxial walls forming surfaces of revolution, of respectively an inner wall and an outer wall, the walls being connected together at upstream ends thereof by an annular chamber end wall including openings for mounting injection systems, each opening comprising at least one swirler for producing a rotating stream of air downstream from a fuel injector; and

a bowl mounted in each of the openings, each bowl including a substantially frustoconical wall downstream from the swirler and formed with an annular row of air injection orifices for producing a substantially frustoconical and rotating sheet of a mixture of air and of fuel,

wherein the outer wall includes an annular row of primary dilution orifices, and

wherein the orifices of the bowls are distributed and dimensioned such that at least some of the sheets of air/fuel mixture present, in a radial cross-section, at least one local circumferential enlargement relative to another part of the respective sheet, the enlargement circumferentially intersecting an adjacent air/fuel sheet upstream from the primary dilution orifices.

2. A chamber according to claim 1 , wherein the orifices of at least some bowls are regularly distributed around axes of the bowls, and some of the orifices of each of the bowls have a diameter smaller than other orifices of the bowls so that smaller-diameter orifices are formed over an angular sector of size and angular position that are predetermined to form the at least one local enlargement of the respective sheet of air/fuel.

3. A chamber according to claim 2 , wherein the orifices of the angular sector of each bowl have a diameter that is at least 40% smaller than the diameter of the other orifices of the bowl.

4. A chamber according to claim 1 , wherein at least some of the bowls have no orifices over an angular sector of size and angular position that are predetermined to form the at least one local enlargement of the sheet of air/fuel.

5. A chamber according to claim 2 , wherein some of the bowls include two diametrically opposite angular sectors with at least one of orifices of smaller diameter and/or with and no orifices.

6. A chamber according to claim 1 , further comprising a spark plug mounted in an orifice in the outer wall, and wherein the orifices in the bowl of the injection system situated closest to the spark plug are distributed and dimensioned such that the sheet of air/fuel mixture presents another local enlargement intersecting an axis of the spark plug between a radially inner end of the spark plug and a point of an outer periphery of the bowl.

7. A chamber according to claim 6 , wherein the bowl situated closest to the spark plug includes orifices of diameter smaller than the other orifices of the bowl, the orifices of smaller diameter being formed over an angular sector of dimension and angular position that are predetermined to form the local enlargement intersecting the axis of the spark plug.

8. A chamber according to claim 6 , wherein the bowl situated closest to the spark plug has no orifices over an angular sector of size and position that are predetermined to form the local enlargement intersecting the axis of the spark plug.

9. A chamber according to claim 2 , wherein the angular sector extends over about 20° to about 50°.

10. A turbine engine, an airplane turbojet, or a turboprop, comprising a combustion chamber according to claim 1 .