BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be further described, by way of example, with reference to the accompanying drawings in which:
FIG. 1 shows a longitudinal section through a combustor,
FIG. 2 shows a perspective view of the inventive fuel injector,
FIG. 3 is a top view representation of two embodiments of the inventive fuel injector with axial injection installed in an axial swirler,
FIG. 4 is a side view representation of two embodiments of the inventive fuel injector with axial injection installed in an axial swirler,
FIG. 5 is a top view representation of two embodiments of the inventive fuel injector with radial injection installed in an axial swirler,
FIG. 6 is a side view representation of two embodiments of the inventive fuel injector with radial injection installed in an axial swirler,
FIG. 7 is a side view representation of an embodiment of the inventive fuel injector with radial injection installed in a radial swirler,
FIG. 8 shows a perspective view of the inventive fuel injector and swirler vanes arranged on a swirler base plate of a radial swirler,
FIG. 9 shows a swirler vane and a partial section of the fuel injector with a protruding key having a straight step,
FIG. 10 shows a swirler vane and a partial section of the fuel injector with a protruding stepped key,
FIG. 11 shows a swirler vane and a partial section of the fuel injector with a protruding key having an angled or curved step,
FIG. 12 shows a swirler vane and a partial section of the fuel injector with a protruding key having a varying step height,
FIG. 13 shows a swirler vane and a partial section of the fuel injector with a protruding key having a double-angled step,
FIG. 14 shows a swirler vane and a partial section of the fuel injector with a protruding-key having a double-angled step with a varying step height,
FIG. 15 shows a perspective view of straight cut-outs in the fuel injector,
FIG. 16 shows a top view of straight cut-outs in the fuel injector,
FIG. 17 shows a perspective view of triangular cuts in the fuel injector, and
FIG. 18 shows a top view of triangular cut-outs in the fuel injector.
In the drawings like references identify like or equivalent parts.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a longitudinal section through a combustor. The combustor comprises relative to a flow direction: a burner with swirler portion 2 and a burner-head portion 1 attached to the swirler portion 2, a transition piece referred to as combustion pre-chamber 3 and a main combustion chamber 4. The main combustion chamber 4 has a diameter being larger than the diameter of the pre-chamber 3. The main combustion chamber 4 is connected to the pre-chamber 3 via a dome portion 10 comprising a dome plate 11. In general, the transition piece 3 may be implemented as a one part continuation of the burner 1 towards the combustion chamber 4, as a one part continuation of the combustion chamber 4 towards the burner 1, or as a separate part between the burner 1 and the combustion chamber 4. The burner and the combustion chamber assembly show rotational symmetry about a longitudinally symmetry axis S.
A fuel conduit 5 is provided for leading fuel to the burner which is to be mixed with in-streaming air in the swirler 2. The fuel/air mixture 7 is then guided towards the primary combustion zone 9 where it is burnt to form hot, pressurised exhaust gases streaming in a direction 8 indicated by arrows to a turbine of the gas turbine engine (not shown).
With reference to FIG. 2 a fuel injector 12 comprises a ring 13. A fuel groove 14 is arranged in a face side 15 of the ring 13. Fuel injection openings 16,17 are arranged on the ring 13 as cut-back type 16 and/or machined-hole type 17 and connected to the fuel groove 14. A first outer notch 18 is arranged in the face side 15 of the ring 13. The first outer notch surrounds the fuel groove.
In an exemplary embodiment of the invention (FIGS. 3 and 4) two fuel injectors 12 of different size are fastened concentrically to an axial swirler. The fuel grooves 14 are covered by back plates 34 and the fuel injection openings 17 point in the direction of the symmetry axis of the fuel injectors 12. The instreaming air enters the swirler 19 between the two fuel injectors 12.
In another exemplary embodiment of the invention (FIGS. 5 and 6) two fuel injectors 12 are fastened concentrically to an axial swirler. The fuel grooves 14 are covered by back plates 34 and the fuel injection openings 17 are oriented in a radial direction. The fuel injection openings 16, 17 of the smaller fuel injector 12 point radially outwards and the fuel injection openings 16,17 of the larger fuel injector 12 point radially inwards.
With reference to FIG. 7 a fuel injector 12 is attached to a swirler base plate 20. The swirler base plate 20 covers the fuel groove 14. Fuel injection openings 17 connect to the fuel groove 14 and inject fuel radially inwardly into swirler passages 22 where the fuel mixes with the instreaming compressor air 32.
With reference to FIG. 8 a swirler 19 comprises a swirler base plate 20, a plurality of swirler vanes 21 arranged on the swirler base plate 20 about a central axis S. A plurality of swirler passages 22 extends from a compressor air inlet opening 23 to a mixture outlet opening 24, said swirler passages 22 formed by first and second side faces 25, 26 of the swirler vanes 21 and the swirler base plate 20. A fuel injector 12 is attached to the swirler base plate 20. The fuel injector 12 has the shape of a ring 13 with an inner diameter equal to the outer diameter of a circle formed by outer faces 27 of the swirler vanes. The height of the fuel injector 12 is smaller than a swirler vane 21 height. A fuel groove 14 arranged in a face side 15 of the fuel injector 12 is facing the swirler base plate 20. A first outer notch 18 is arranged in the face side 15 of the fuel injector 12 facing the swirler base plate 20. A second outer notch 28, facing the first outer notch 18, is arranged in the swirler base plate 20. First and second outer notches 18, 28 act as counterparts to form a cavity that carries a sealing element 29 for providing a seal between the swirler base plate 20 and the fuel injector 12. The sealing element 29 may be a crushable C-seal.
FIG. 8 further shows a cross-section through an embodiment with two fuel injection openings 16 facing a swirler passage 22, whereby the cross-section projects through one of the openings 16. Some of the cut-away parts like a swirler vane 21 in the foreground and a tip of a neighbouring swirler vane 21 arranged behind are shown with dashed lines.
The swirler vane tips do not point to the central axis S but are turned to one side giving rise to different lengths of first and second side faces 25, 26 of swirler vanes 21—the first side face 25 is shorter than the second side face 26 as well as sharp and obtuse edges 30, 33 at the compressor air inlet opening 23. The height and/or cross-sectional area of the fuel injection opening 16 closest to a sharp edge 30 is the largest. Height and/or cross-sectional area of fuel injection openings 16 decrease relative to a distance to a sharp edge 30 of the compressor air inlet opening 23.
With reference to FIG. 9 keys 42 can be arranged on the fuel injector 12 extending into swirler passages 22. In a simple embodiment a key 42 is forming a straight step 31 parallel to the ring contour.
With reference to FIG. 10 keys 42 can be stepped.
With reference to FIG. 11 the protruding key 42 is angled or curved relative to the fuel injector ring 13 forming a winder-like tread 36.
With reference to FIG. 12 the tread 36 of the step 31 formed by the protruding key 42 is not parallel to the face side 15 of the fuel injector 12 but tilted or curved.
With reference to FIG. 13 the tread 36 of the step 31 formed by the protruding key 42 has an angle 43.
With reference to FIG. 14 the step 31 formed by the protruding key 42 has a maximum height at the step angle 43.
With reference to FIGS. 15, 16, 17, and 18 cut-outs with triangular cross-sections are arranged on the ring 13 of the fuel injector 12 turned away from the instreaming air 32. FIG. 16 shows a top view of FIG. 15 in the direction indicated by the arrow. The cut-outs in the FIGS. 15 and 16 are straight. The front faces are upright 37 or inclined 38 as well as the rear faces that are either upright 39 or inclined 40. Fuel openings 17 are arranged on the remaining triangular solid portions 41 between the cut-outs and on the rear faces 39, 40 of the cut-outs. The preferred rear face is an inclined rear face 40, shown in FIG. 15. The cut-outs shown in FIGS. 17 and 18 are triangular. FIG. 18 shows a top view of FIG. 17 in the direction indicated by the arrow. Again, the front faces are upright 37 or inclined 38.
Patent Application
20080041060
