Injection system for a combustion chamber of a turbine engine, comprising an annular wall having a convergent inner cross-section

An air and fuel injection system for an annular turbine engine combustion chamber dome comprising:

• a central fuel injector including a nose which sprays a flow of fuel;
• a peripheral annular fuel injector arranged around said central fuel injector;
• an inner annular air inlet channel in which the central fuel injector is disposed, air which is inlet into the inner annular air inlet channel forming a mix with fuel originating from the nose of the central fuel injector;
• an outer annular air inlet channel which generates a swirl movement of air which is inlet into the outer annular air inlet channel to enable enrichment of the mix with air and stabilization of a pilot combustion zone by generating an upstream recirculation zone close to the nose of the central fuel injector and a downstream recirculation zone downstream from the pilot combustion zone, the outer annular air inlet channel being disposed radially outward of the inner annular air inlet channel relative to a central axis of the injection system;
• and
• an intermediate annular wall extending around the central fuel injector and having a convergent inner profile that is convergent towards the central axis of the injection system such that the fuel flow sprayed by the nose of the central fuel injector and the air flow output from the inner annular air inlet channel are approximately perpendicular, the intermediate annular wall separating the inner annular air inlet channel and the outer annular air inlet channel,
• wherein the inner annular air inlet channel is free of a swirler to generate a swirl movement,
• wherein the intermediate annular wall includes a first upstream portion extending approximately along the central axis of the injection system and a second downstream portion convergent towards the central axis of the injection system, the nose of the central fuel injector being disposed downstream of the first upstream portion of the intermediate annular wall, and
• wherein the outer annular air inlet channel is delimited by the intermediate annular wall and an outer annular wall, the outer annular wall including an inner convergent divergent profile, and a downstream end of the outer annular wall being downstream of the second downstream portion of the intermediate annular wall and downstream of the nose of the central fuel injector.