Injection system for a turbomachine combustion chamber, including air injection means improving the air-fuel mixture

摘要

An air and fuel injection system for the back of a turbomachine's annular combustion chamber, including a central injector and a peripheral annular fuel injector including at least one fuel injection aperture made in an annular wall and emerging in a peripheral annular channel separated from a central channel by the annular wall and having an annular space of admission of air. The system also includes multiple air ejection apertures made in the annular wall downstream from the fuel ejection aperture or apertures in reference to the flow of the air stream, for an additional injection of air into the channel.

主权项

1. An air and fuel injection system for the back end wall of a turbomachine's annular combustion chamber, comprising:
at least two coaxial fuel injecting devices, said two coaxial fuel injecting devices including a central injector and a peripheral annular injector, the central injector emerging in a first channel designed for admission of a first air stream and having an aft outlet opened in a downstream direction for ejecting said first air stream so that said first air stream will mix in said injection system with fuel from said central injector, the peripheral annular injector including at least one fuel ejection aperture made in a first annular wall and emerging in a peripheral annular channel separated from said first channel by said first annular wall, said first annular wall externally delimiting said aft outlet of the first channel, and said peripheral annular channel having an annular space of admission of a second air stream intended to be blended in said peripheral annular channel with fuel delivered by said peripheral injector; and multiple air ejection apertures traversing said first annular wall so as to open in said first channel and in said peripheral annular channel downstream from said at least one fuel ejection aperture in reference to the flow of the second air stream for an additional injection of air from said first channel into said peripheral annular channel, wherein said first channel includes an external annular channel and an internal channel, where said external annular channel is installed around a second a annular wall separating the external annular channel from said internal channel, and wherein said central injector emerges into said internal channel, and wherein said second annular wall has on its internal face a convergent-divergent profile intended for aspiration by a venturi effect of a film of fuel from said central injector, and the second annular wall has at its downstream end an annular lip intended for spraying said fuel film under the effect of a flow of a part of the first air stream admitted into the external annular channel.