COMBUSTOR AND GAS TURBINE
20170292705 · 2017-10-12
Inventors
Cpc classification
F23R3/12
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F05D2240/35
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F05D2220/32
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F23R3/16
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F23R3/286
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
International classification
F23R3/12
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F23R3/16
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F23R3/28
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
Abstract
A combustor according to the present invention is provided with: a pilot burner (15) disposed along an axis (P); a plurality of premixing burners (16), each of which has a premixing swirler cylinder (19) and a premixing nozzle (20) disposed inside the premixing swirler cylinder (19) and that are disposed about the axis (P) in the circumferential direction so as to surround the periphery of the pilot burner (15); a substrate (23) through which the pilot burner (15) and the premixing swirler cylinders (19) are individually inserted so as to be supported therein; and stagnation eliminating blocks (27) that are provided so as to fill spaces between the premixing swirler cylinders (19) on a surface of the substrate (23) on the downstream side, wherein air film supplying ports (38) that form air films A on surfaces of the stagnation eliminating blocks (27) are formed in the stagnation eliminating blocks (27).
Claims
1. A combustor, comprising: a pilot burner disposed along an axis; a plurality of premixing burners, each of which has a premixing swirler cylinder and a premixing nozzle disposed inside the premixing swirler cylinder and that are disposed about the axis in the circumferential direction so as to surround the periphery of the pilot burner; a substrate, through which the pilot burner and the premixing swirler cylinders are individually inserted so as to be supported therein; and stagnation eliminating blocks provided so as to fill spaces between the premixing swirler cylinders on a surface of the substrate on the downstream side; air film supplying ports that form air films on surfaces of the stagnation eliminating blocks are formed in the stagnation eliminating blocks.
2. The combustor according to claim 1, wherein the air film supplying ports eject substrate air from the air film supplying ports by communicating with an air inlet provided on the substrate.
3. The combustor according to claim 1, wherein the air film supplying ports are connected to air inlets provided on a surface on the outside in the radial direction of the stagnation eliminating blocks.
4. The combustor according to claim 2 comprising a plurality of the air film supplying ports, wherein the air film supplying ports are each provided in the space including the end part on the outside in the radial direction of the downstream side end part of the stagnation eliminating blocks, and in the space containing the end part on the inside in the radial direction.
5. The combustor according to claim 4, wherein the stagnation eliminating blocks are formed so the circumferential direction dimension decreases from the upstream side to the downstream side, and the plurality of the air film supplying ports are provided on a surface on one side in the circumferential direction of the stagnation eliminating blocks, and on a surface on the other side in the circumferential direction of the stagnation eliminating blocks.
6. A gas turbine, comprising: a combustor according to claim 1; a compressor for supplying compressed air to the combustor; and a turbine, to which combustion gas generated by the combustor is supplied.
Description
BRIEF DESCRIPTION OF DRAWINGS
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DESCRIPTION OF EMBODIMENTS
First Embodiment
[0038] A first embodiment of the present invention will be described below with reference to the drawings.
[0039] As illustrated in
[0040] The compressor 2 and the turbine 4 are provided with a rotor 5, which is connected so they rotate as one body; and a stator 6 for surrounding the outer peripheral side of the rotor 5. The rotor 5 has a rotating shaft 7 and a plurality of circular blade groups 8 that is fixed with an open interval between them in the direction of the axis O. Each circular blade group 8 is configured to have a plurality of blades fixed with intervals open between them in the circumferential direction on the outer periphery of the rotating shaft 7.
[0041] The stators 6 are each provided with a casing 9 and a plurality of circular vane groups 10 fixed with an interval open between them in the direction of the axis O within a chamber 11 sectioned off by the casing 9. Each circular vane group 10 has a plurality of vanes fixed with an interval open between them in the circumferential direction of the axis O, on the inner surface of the casing 9. The circular vane groups 10 are each disposed so as to alternate with a plurality of circular blade groups 8 in the direction of the axis O.
[0042] Further, the combustor 3 is provided in the interior of the casing 9 (the chamber 11). The combustor 3 has a pilot burner 15 disposed along an axis P; a plurality of premixing burners 16 that are disposed along the circumferential direction of the pilot burner 15; a substrate 23 through which the pilot burner 15 and the premixing burner 16 are inserted; and stagnation eliminating blocks 27 provided as one body on the substrate 23.
[0043] The combustor 3 is provided with a combustion cylinder 12, which has a substantially cylindrical shape having in its interior a combustion area for combusting fuel and combustion air, and a swirler support cylinder 13, which has a substantially cylindrical shape and is accommodated in the inner peripheral side of the combustion cylinder 12. The combustion cylinder 12 is provided with a large diameter part 12A having a diameter dimension larger than that of the swirler support cylinder 13, and a small diameter part 12B having a diameter dimension smaller than the large diameter part 12A. A substantially circular ridge part 12C is provided between the large diameter part 12A and the small diameter part 12B, formed so that the dimension in the radial direction decreases sharply. This ridge part 12C and the end part of the swirler support cylinder 13 oppose each other in the direction of the axis P. That is, the inner diameter dimension of the combustion cylinder 12 at the small diameter part 12B is set to be smaller than the diameter dimension of the swirler support cylinder 13.
[0044] The combustion cylinder 12 and the swirler support cylinder 13 are disposed together along the same axis P. The swirler support cylinder 13 is fixed by a fixing member 14 to the combustion cylinder 12. The fixing member 14 is provided, for example, on the outer peripheral side of the swirler support cylinder 13 with an interval open in the circumferential direction. Further, a constant gap is formed between the inner peripheral surface of the combustion cylinder 12 and the outer peripheral surface of the swirler support cylinder 13; this acts as an air channel through which the compressed air A flows.
[0045] The pilot burner 15 and the premixing burner 16 are provided on the inner peripheral side of the swirler support cylinder 13. The pilot burner 15 is disposed so as to extend along the axis P. A plurality of the premixing burner 16 is disposed along the circumferential direction, so as to surround the periphery of the pilot burner 15. In the combustor 3 according to the present embodiment, eight premixing burners 16 are arranged along the circumferential direction of the combustor 3 with intervals open between them, surrounding the pilot burner 15. In the following description, the side on which the pilot burner 15 and the premixing burners 16 are positioned is called the upstream side, and the side positioned on the opposite side of the upstream side along the axis P direction is called the downstream side.
[0046] The pilot burner 15 has a pilot nozzle 17, which is not illustrated, in its interior. Further, a pilot cone 18 is provided on the outer periphery of the pilot nozzle 17. A tapered cone portion 18C, which is formed so the radial direction dimension progressively expands from the upstream side to the downstream side, is provided on the downstream side end part of the pilot cone 18. The downstream side end part of the tapered cone portion 18C is open toward the interior of the combustion cylinder 12. In the pilot burner 15 configured in this manner, fuel is supplied to the pilot nozzle 17 from the exterior. This fuel is ejected from the pilot nozzle 17.
[0047] Further, each premixing burner 16 has a premixing swirler cylinder 19, which has a substantially cylindrical shape; and a premixing nozzle 20 disposed in the premixing swirler cylinder 19.
[0048] The premixing swirler cylinder 19 and the premixing nozzle 20 are concentrically disposed. The premixing swirler 19 is formed so that the shape of the cross section changes gradually from the upstream side to the downstream side. As illustrated by the dashed line in
[0049] The pilot burner 15 is provided with a pilot swirler 20P, which is provided surrounding the periphery of the pilot nozzle 17. The pilot swirler 20P has a plurality of swirler vanes (not illustrated). The plurality of swirler vanes are each disposed forming a constant angle θ with the axis P. By this, a rotational component is imparted to the compressed air A passing through the pilot swirler 20P, leading to rotational flow.
[0050] In the same manner, the premixing burner 16 has a premixing swirler 20M provided on the upstream side of the premixing nozzle 20. The premixing swirler 20M is provided with a plurality of swirler vanes, and imparts a rotational component to the compressed air A passing through the inside of the premixing swirler cylinder 19.
[0051] Further, each swirler vane of the premixing swirler 20M is provided with a plurality of fuel ejection holes 22. A combustion gas G, composed of fuel supplied from the exterior and air mixed together, is ejected from these fuel ejection holes toward the downstream side.
[0052] The pilot burner 15 and the premixing burners 16 are both supported by the substrate 23. As illustrated in
[0053] Further, as illustrated in
[0054] A plurality of stagnation eliminating blocks 27 are provided as one body on a surface on the downstream side of the substrate 23. These stagnation eliminating blocks 27 are disposed so as to fill a space between the plurality of premixing swirler cylinders 19 arranged along the circumferential direction with an interval open between them. Specifically, the stagnation eliminating blocks 27 are disposed in the space between each short side part 19A of neighboring premixing swirler cylinders 19.
[0055] The detailed configuration of the stagnation eliminating blocks 27 according to the present invention will be described with reference to
[0056] The surface on the side of the substrate 23 on the block base part 28 (the upstream side) forms a block substrate surface 31 by being formed in a substantially rectangular shape extending along the radial direction of the combustor 3. The side part on both sides of the circumferential direction of the block substrate surface 31 is formed curved so as to correspond to the shape of the short side parts 19A of the premixing swirler cylinder 19. In other words, both sides on the circumferential direction of the block substrate surface 31 are formed so they are recessed toward the inside along the circumferential direction. Meanwhile, both sides in the radial direction of the block substrate surface 31 are formed curving in an arc shape along the circumferential direction. That is, both sides in the radial direction are formed curving so they protrude toward the outside in the radial direction from the inside in the radial direction.
[0057] The stagnation eliminating blocks 27 extend toward the downstream side from the block substrate surface 31 formed as described above. Specifically, as illustrated in
[0058] A block outer peripheral surface 32, which forms the surface of the outside in the radial direction of the stagnation eliminating blocks 27, extends toward the downstream side along a direction substantially orthogonal to the block substrate surface 31. Further, the block outer periphery surface 32 protrudes in an arc shape toward the outside in the radial direction, along the inner periphery shape of the combustor 3.
[0059] The block inner periphery surface 33, which forms the surface on the inside in the radial direction of the stagnation eliminating blocks 27, extend slightly slanted toward the outside in the radial direction, where the block substrate surface 31 is the reference. More specifically, the block inner periphery surface 33 is slanted and extends so it gradually curves from the inside to the outside in the radial direction. Further, the block inner periphery surface 33 is recessed in an arc shape toward the outside in the radial direction, along the inner periphery shape of the combustor 3.
[0060] Additionally, the center part of the stagnation eliminating blocks 27 when viewed from the radial direction is analogous to each of the block outer periphery surface 32 and the block inner periphery surface 33, and form an isosceles triangle shape which has a smaller area than the block outer periphery surface 32 and the block inner periphery surface 33.
[0061] Further, the cross sectional area of the stagnation eliminating blocks 27 when viewed from the radial direction is formed so that it continuously decreases from the block outer periphery surface 32 toward the central part.
[0062] Meanwhile, the cross sectional area of the stagnation eliminating blocks 27 when viewed from the radial direction is formed so that it continuously increases from the central part toward the block inner periphery surface 33. In other words, the stagnation eliminating blocks 27 compose a substantially triangular pillar shape, where a neck is formed in the central part in the radial direction (the height direction). Further, a part of the inside in the radial direction on the downstream side of the stagnation eliminating blocks 27 protrudes toward the downstream side, forming the inside protruding part 29. In a similar manner, a part of the outside in the radial direction on the downstream side protrudes toward the downstream side, forming the outside protruding part 30. The outside protruding part 30 is set so the dimension in the axial direction is large compared to the inside protruding part 29.
[0063] As such, the end edge of the downstream side of the stagnation eliminating block 27 is composed of an outside curved part 34 extending from the tip of the outside protruding part 30 toward the upstream side while curving toward the inside in the radial direction; an inside curved part 35 extending from the tip of the inside protruding part 29 toward the upstream side while curving toward the outside in the radial direction; and a straight part 36, which connects the outside curved part 34 and the inside curved part 35 in a straight line.
[0064] Further, a pair of surfaces forming the one side and the other side in the circumferential direction of the stagnation eliminating blocks 27 are each the block side surfaces 37. On this pair of block side surfaces 37 is formed an air film supplying port 38 for flowing an air film. In the stagnation eliminating blocks 27 according to the present embodiment, as illustrated in
[0065] The block substrate surface 31 is provided with the air inlet 26, which is connected to the air film supplying port 38. As illustrated in
[0066] The air inlets 26 and the air film supplying ports 38 are connected in a straight line when viewed from the radial direction. Further, the air inlets 26 and the substrate slit parts 25 are connected to each other. By this, the substrate slit part 25 and the air film supplying ports 38 compose an air film channel 39 by being connected via the air inlet 26.
[0067] Note that the angle θ formed by the direction in which the air film channel 39 extends and the block side surfaces 37 can be determined appropriately according to the design. That is, by adjusting the angle θ formed by the air film channel 39 and the block side surfaces 37, the tracking properties of the air film relating to the block side surfaces 37 can be freely controlled. For example, when the angle θ is adjusted so as to form an acute angle, the air film can be made to flow in the vicinity of the block side surfaces 37. The optimal direction for the air film channel 39 to extend is determined by considering the flow of such an air film and various conditions such as structural strength of the stagnation eliminating blocks 27.
[0068] The gas turbine 1 provided with the combustor 3 configured in the aforementioned manner operates in the following manner.
[0069] First, fuel supplied by the pilot nozzle 17 of the combustor 3 is ignited by an igniter, which is not illustrated; this causes a pilot flame to be formed in the interior of the pilot burner 15. Next, the pilot flame ignites a premixed gas F supplied from the premixing nozzle 20, forming a premixing flame. This premixed flame is stabilized in the interior of the combustion cylinder 12, generating the high temperature combustion gas G. The combustion gas G generated in the combustion cylinder 12 flows toward and rotationally drives the following turbine 4.
[0070] Here, as illustrated in
[0071] By this, in the interior of the pilot burner 15, the pilot flame formed downstream of the pilot nozzle 17 is stabilized by the compressed air A being supplied thereto.
[0072] In the interior of the premixing burner 16, the compressed air A is mixed with the fuel ejected from the fuel ejection hole 22 provided on the premixing swirler 20M. This generates a premixed gas F of fuel and air. After being ejected toward the downstream side from the swirler support cylinder 13, the premixed gas F is ignited by the pilot flame described above, forming a premixing flame.
[0073] At this time, as described above, the compressed air A is flowing through the space sectioned off by the outer peripheral surface of the premixing swirler cylinder 19 and the outer peripheral surface of the pilot cone 18. After flowing toward the substrate 23 provided on the downstream side, the compressed air A flows toward the downstream side of the substrate 23 via the substrate slit parts 25 provided on the substrate 23. Of the compressed air A, the component which passes through the substrate slit parts 25 in this manner is called substrate air A.
[0074] The substrate air A which has flowed toward the downstream side from the substrate slit part 25 is ejected from the air film supplying port 38 via the air film channel 39 provided on the stagnation eliminating block 27. More specifically, as illustrated in
[0075] In this manner, the stagnation eliminating block 27 can be protected from radiant heat and the like from the flame of the combustor 3 by having an air film layer formed on the surface of the stagnation eliminating block 27. That is, the possibility of a burn occurring on the stagnation eliminating block 27 can be reduced.
[0076] On one hand, once burning occurs on a stagnation eliminating structure, because stagnation of the combustion gas G occurs immediately, there is a possibility of leading to dramatically reduced combustion efficiency, and leading to an increase in NOx generation from turbulence occurring in the combustion area. However, according to a configuration as described above, such a possibility can be reduced, improving the combustion efficiency of the combustor 3 and achieving a reduction in the concentration of NOx contained in the exhaust gas.
[0077] Further, with a configuration such as that described above, the substrate air A flowing through the upstream side of the substrate 23 can be directed to the air inlet 26 and ejected from the air film supplying port 38. That is, the substrate air A can be effectively used as an air film. In other words, instead of separately providing an air film supply source, an air film can be generated.
Second Embodiment
[0078] Next, a second embodiment of the present invention will be described below with reference to
[0079] The combustor 3 according to the present embodiment differs from the first embodiment with regard to the following points. That is, in the combustor 3 according to the present embodiment, two air film supplying ports 38 formed on the stagnation eliminating blocks 27 are formed as openings provided on a pair of block side surfaces 37 in the circumferential direction. In the present embodiment, both air film supplying ports 38 have a substantially circular opening shape.
[0080] These two air film supplying ports 38 are a first supplying port 42 provided in a space on the inside in the radial direction on the block side surface 37, and a second supply port 43 provided in a space on the outside in the radial direction. In more detail, as illustrated in
[0081] With a stagnation eliminating block 27 configured in the above manner, an air film is ejected from each air film supply port 38, composed of the first supplying port 42 and the second supplying port 43. This air film flows toward the downstream side along the block side surface 37 of the stagnation eliminating block 27, in the same manner as in the first embodiment described above. This forms an air film layer in each space inside and outside in the radial direction on the block side surface 37.
[0082] It is known that the possibility of stagnation occurring is particularly high in the space containing the end part on the outside in the radial direction on the downstream end part of the stagnation eliminating blocks 27, and in the space containing the end part on the inside in the radial direction. By this, the possibility of a burn occurring on the stagnation eliminating block 27 increases. However, according to a configuration as described above, an air film can be supplied in a focused manner because an air film supplying port 38 is provided for each space.
[0083] Specifically, the air film supplied from the first supplying port 42 forms an air film layer by flowing over the surface of the inside curved part 35 of the stagnation eliminating block 27. The air film supplied from the second supplying port 43 forms an air film layer by flowing over the surface of the outside curved part 34 of the stagnation eliminating block 27. This allows the possibility of a burn occurring on the inside curved part 35 and the outside curved part 34 to be reduced.
Third Embodiment
[0084] Next, a third embodiment of the present invention will be described with reference to
[0085] Further, as illustrated in
[0086] Further, in the interior of the stagnation eliminating block 27, the air film channel 39 is formed extending toward the inside along the radial direction from the air inlet 26. The air inlet 26 is connected to the air film supply port 38 provided on the block side surface 37 via the air film channel 39.
[0087] In more detail, the air film channel 39 according to the present embodiment has a main flow channel 39A extending along the radial direction, and two branch channels 39B, 39C formed extending toward the downstream side from halfway through the main channel 39A. The branch channel 39B is provided on the inside in the radial direction, and the branch channel 39C is provided on the outside in the radial direction.
[0088] With a configuration as described above, the air (chamber air A′) flowing through a space (chamber 11) on the outside of the combustion cylinder 12 can be taken into the interior of the combustion cylinder 12 by a chamber air inlet 44. The chamber air A′ is supplied from the compressor 2 as a part of the compressed air A, in the same manner as the substrate air A described above. While a small fuel component is contained in the substrate air A, a fuel component is not contained in the chamber air A′. Thus, the possibility of flashback occurring from the gas component being ignited can be reduced.
[0089] Further, with a configuration like that described above, the substrate air A is not used as an air film, and can be used as combustion air for the premixing flame in the swirler support cylinder 13. Thus, the combustion efficiency can be improved, and the combustion gas G generated by the combustor 3, that is, the exhaust gas of the gas turbine 1 can be kept in a cleaner state.
[0090] Embodiment of the present invention have been described above in detail with reference to the drawings, but the specific configurations are not limited to the embodiments, and design changes and the like that do not depart from the scope of the present invention are also included.
[0091] For example, in the third embodiment described above, an example is described wherein the air film supplying port 38 is formed as an opening on the block side surface 37, as illustrated in
[0092] Further, in the third embodiment, a configuration is described wherein two air inlets 26 are provided corresponding to each of the air film supplying ports 38 on the block side surface 37. However, the mode of the air inlet 26 is not limited to this, and for example, as illustrated in
INDUSTRIAL APPLICABILITY
[0093] According to the combustor and the gas turbine described above, the combustion efficiency can be improved, and the generation of NOx can be further mitigated.
REFERENCE SIGNS LIST
[0094] 1 Gas turbine [0095] 2 Compressor [0096] 3 Combustor [0097] 4 Turbine [0098] 5 Rotor [0099] 6 Stator [0100] 7 Rotating shaft [0101] 8 Circular blade group [0102] 9 Casing [0103] 10 Circular vane group [0104] 11 Combustor compressor cylinder [0105] 12 Combustion liner [0106] 13 Swirler assembly [0107] 12A Large diameter part [0108] 12B Small diameter part [0109] 12C Ridge part [0110] 14 Fixed member [0111] 15 Pilot burner [0112] 16 Premixing burner [0113] 17 Pilot nozzle [0114] 18 Pilot cone [0115] 18C Tapered cone portion [0116] 19 Main swirler [0117] 20 Main nozzle [0118] 19A Short side part [0119] 19B Long side part [0120] 20P Pilot swirler [0121] 20M swirler [0122] 22 Fuel ejection hole [0123] 23 Swirler base [0124] 24 Support opening [0125] 25 Substrate slit part [0126] 26 Air inlet [0127] 27 block [0128] 28 Block base part [0129] 29 Inside protruding part [0130] 30 Outside protruding part [0131] 31 Block substrate surface [0132] 32 Block outer periphery surface [0133] 33 Block inner periphery surface [0134] 34 Outside curved part [0135] 35 Inside curved part [0136] 36 Straight part [0137] 37 Block side surface [0138] 38 Air film supplying port [0139] 39 Air film channel [0140] 40 Angle [0141] 41 Substrate air [0142] 42 First supplying port [0143] 43 Second supplying port [0144] 44 Cylinder air inlet [0145] A Compressed air [0146] F Premixed gas [0147] G Combustion gas [0148] O Axis [0149] P Axis