Fuel injection system for a combustion chamber of a turbomachine
View Patent ↗A fuel injection system for an annular combustion chamber of a turbomachine including a support device for supporting and centering a fuel injector head; and a bowl arranged downstream from the support device and including at its downstream end an annular collar that extends radially outwards and that is cooled by air impacting against its upstream radial surface is disclosed. The upstream radial surface includes a device which disturbs the flow of cooling air and increases the heat exchange area between the air and the collar.
1. A fuel injection system for an annular combustion chamber of a turbomachine, the system comprising:
a support device which supports and centers a fuel injector head;
a bowl arranged downstream from the support device and including at its downstream end an annular collar that extends radially outwards; and
a substantially L-shaped annular deflector extending around the bowl and having an upstream cylindrical wall and a downstream radial wall extending upstream from said annular collar, said annular collar being cooled by air which passes radially inside said upstream cylindrical wall of said substantially L-shaped annular deflector and which impacts against an upstream radial surface of said annular collar,
wherein the collar includes a structure that is formed to project from or to be recessed into its upstream radial surface and that are designed to disturb the flow of cooling air and to increase the heat exchange area between said air and the collar.
2. A system according to claim 1 , wherein the structure comprises at least one annular row of pegs or studs projecting from the upstream radial surface of the collar, the pegs of the at least one row being regularly distributed around an axis of the collar.
3. A system according to claim 2 , wherein at least one peg comprises a first peripheral surface that is concave, plane, or with a reentrant angle, and a second peripheral surface that is convex or with a salient angle, the second peripheral surface being diametrically opposite to the first peripheral surface, which first peripheral surface is oriented radially inwards relative to the axis of the collar.
4. A system according to claim 3 , wherein each peg has a crescent-shaped section and presents a radially inner peripheral face that is concave and a radially outer peripheral face that is convex.
5. A system according to claim 2 , wherein the structure comprises two or three annular rows of pegs, which rows are disposed one around another.
6. A system according to claim 5 , wherein the pegs of one row are in a staggered configuration relative to the pegs of another row.
7. A system according to claim 5 , wherein the rows have the same number of pegs.
8. A system according to claim 5 , wherein the pegs of one row have at least one of a diameter or a height or axial dimension that are identical or different from at least one of the diameter or height of the pegs of at least one other row.
9. A system according to claim 8 , wherein the diameter of the pegs of an outer row is determined so that gap between the pegs of said outer row is less than or equal to a gap between the pegs of at least one inner row.
10. A system according to claim 8 , wherein the height or axial dimension of the pegs of an outer row is greater than or equal to the height of the pegs of at least one inner row.
11. An annular combustion chamber for a turbomachine, including fuel injection systems according to claim 1 .
12. A turbomachine including fuel injection systems according to claim 1 .
13. A system according to claim 1 , wherein an upstream surface of the radial wall of the substantially L-shaped annular deflector faces a chamber end wall of the combustion chamber, and a downstream surface of the radial wall of the substantially L-shaped annular deflector faces the structure formed on the upstream radial surface of the collar.