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EP 0 841 520 B1 |
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EUROPEAN PATENT SPECIFICATION |
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Mention of the grant of the patent: |
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12.03.2003 Bulletin 2003/11 |
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Date of filing: 17.10.1997 |
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International Patent Classification (IPC)7: F23R 3/10 |
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Gas turbine engine combustor
Gasturbinenbrennkammer
Chambre de combustion pour une turbine à gaz
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Designated Contracting States: |
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DE FR GB |
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Priority: |
07.11.1996 GB 9623195
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Date of publication of application: |
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13.05.1998 Bulletin 1998/20 |
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Proprietor: ROLLS-ROYCE plc |
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London, SW1E 6AT (GB) |
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Inventor: |
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- Allen, John Guy
Chipping Sodbury,
Bristol BS17 6NS (GB)
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Representative: Chapman, Helga Claire |
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Rolls-Royce plc
Patents Department
Moor Lane
P.O. Box 31 Derby DE24 8BJ Derby DE24 8BJ (GB) |
(56) |
References cited: :
DE-A- 4 427 222 US-A- 4 914 918
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DE-A- 19 508 111 US-A- 4 934 145
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Note: Within nine months from the publication of the mention of the grant of the European
patent, any person may give notice to the European Patent Office of opposition to
the European patent
granted. Notice of opposition shall be filed in a written reasoned statement. It shall
not be deemed to
have been filed until the opposition fee has been paid. (Art. 99(1) European Patent
Convention).
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[0001] This invention relates to a gas turbine engine combustor and is particularly concerned
with the thermal protection of the combustor wall or bulkhead by heatshields and specifically
the miniflare associated therewith.
[0002] Modern gas turbine annular combustors are usually provided with a combustor which
is of generally annular configuration. Usually a wall or bulkhead is provided at the
upstream end of the combustor which is suitably apertured to receive a number of fuel
burners. The fuel burners are equally spaced around the combustor and direct fuel
into the combustor to support combustion therein. The combustor bulkhead is therefore
usually close to the high temperature combustion process taking place within the combustor
making it vulnerable to heat damage.
[0003] One way of protecting the bulkhead from the direct effects of the combustion process
is to position heat shields on its vulnerable parts. Typically each heat shield is
associated with a corresponding fuel burner and extends both radially towards the
radially inner and outer extents of the bulkhead and circumferentially to abut adjacent
heat shields. Each heat shield is spaced apart from the bulkhead so that a narrow
space is defined between them. Cooling air is directed into this space in order to
provide cooling of the heat shield and so maintain the heat shield and the bulkhead
at acceptably low temperatures.
[0004] More recently cylinders comprising end flanges, commonly known as miniflares, have
been used to direct a film of cooling air across the heatshield thus protecting it
from hot combustion gases.
US4,914,918 discloses one such prior art miniflare, however, although this miniflare provide a film of cooling air for the heat shield their own cooling is
insufficient to prevent overheating, in particular towards its outer edge. Additionally
the cooling film produced often ceases to be effective at the outer regions of the
heatshield. It is an aim of the present invention, therefore, to provide an improved
device for cooling a heatshield which attempts to alleviate the aforementioned problems.
[0005] According to the present invention there is provided a combustor for a gas turbine
engine in which a fuel nozzle is located in the upstream end thereof and is positioned
within a hollow, annular cylinder, said cylinder comprising at its downstream end
an annular flange extending from said cylinder in a generally radial direction and
said flange comprising a plurality of apertures extending therethrough.
[0006] Advantageously cooling air is directed through 'the apertures in the annular flange
thus increasing the outer edge of the cylinder and also provides an effective cooling
air film across an adjacent heatshield.
[0007] The present invention will now be described, by way of example, with reference to
the accompanying drawings in which:
Figure 1 is a schematic diagram of a ducted fan gas turbine engine having an annular
combustor.
Figure 2 is a partially sectioned side view of a combustor in accordance with the
present invention.
Figure 3 is view of a cylinder and flange in accordance with the present invention.
Figure 4 is a cross sectional view of a portion of the cylinder and flange (apertures
not shown) of figure 3.
[0008] With reference to figure 1 there is shown a three shafted ducted fan gas turbine
engine of generally conventional configuration. It will be understood however that
the present invention may be usefully employed in other engine configurations.
[0009] The engine of figure 1 comprises in axial flow series a low pressure spool consisting
of a fan 2 driven by a low pressure turbine 4 via a first shaft 6, an intermediate
pressure turbine 10 through a second shaft 12 and a high pressure compressor 14 driven
by a high pressure turbine 16 via a third shaft 18, an annular combustor 20 and a
propulsive nozzle 21.
[0010] The annular combustor 20 is shown in more detail in Figure 2. The combustor chamber
inner casing 22 comprises radially spaced inner and outer walls 24, 26 respectively,
interconnected at their upstream ends by means of an annular bulkhead 28. The walls
24 and 26 extend upstream of the bulkhead to form a domed combustor head 30. The bulkhead
divides the combustor into an upstream cooling air chamber 32 and a downstream combustion
region and a downstream combustion region 34.
[0011] Compressor delivery air from an upstream compressor (not shown, but situated to the
left of the drawing) enters the cooling air chamber 32 through a plurality of circumferentially
spaced inlet apertures 36 before entering the combustion chamber 34. Fuel is delivered
to the combustion chamber by means of a plurality of air spray type fuel supply nozzles
38. The nozzles are suspended from a combustion chamber outer casing structure 40
and extend into the combustor 20 through a corresponding array of circumferentially
spaced apertures 42 is provided in the bulkhead member 28, each to receiver the outlet
of an adjacent one of the nozzles.
[0012] A protective heatshield 44 is mounted on the downstream face of the bulkhead 28 to
provide thermal shielding from combustion temperatures. This heatshield has an annular
configuration made up of a plurality of abutting heatshield segments 46. The segments,
which are of substantially identical form, extend both radially towards the inner
and outer walls 24, 26 of the combustor and circumferentially towards adjacent segments
to define a fully annular shield. Some or all of the heatshield segments may be adapted
to receive a fuel nozzle. Those which receive a fuel nozzle comprise an aperture the
periphery of which is defined by an axially extending cylindrical flange 48 which
locates the heatshield in the corresponding aperture 42 in the bulkhead wall 28.
[0013] Each heatshield segment receives an airspray burner and a miniflare seal 49. The
miniflare seal 49 is in the form of an annular cylinder 50 and is provided with a
pair of axially spaced radial flanges 52 and 54 which slidably engage with the heatshield
flange extremities. The cylindrical miniflare 49 has an external diameter which is
less than the heatshield aperture. The miniflare radial flange 54 extends radially
from the downstream end of the cylinder. This flange 54 comprises a further axially
extending end flange portion 56. This axially extending flange portion comprises two
rows of holes 58, 60 axially spaced from one another. The upstream outer rim of this
end flange portion 56 is provided with castellations 62 at its outer edge.
[0014] In use air passes through
slots 64 defined in the heat shield flange 48 between the miniflare 49 and the heatshield 44 into a chamber. The air then discharges
through the two rows 58 and 60 of holes to,produce a cooling film across the heatshield
44 or head of the chamber. Also air passing through the holes will remove heat from
the edge of the miniflare 49. The provision of multi rows of holes 58, 60 in the miniflare
flange end portion 56 increases the cooling of the outer edge of the miniflare and
as such reduces its surface temperature and provides a more effective air film across
the heatshield 44 or combustor head face thus increasing the protection from hot combustion
gases.
1. A combustor (20) for a gas turbine engine in which a fuel nozzle (38) is located in
the upstream end thereof and is positioned within an annular cylinder (50) coaxial
with the fuel nozzle (38), the annular cylinder (50) comprising at its downstream
end an annular flange (54) extending from the annular cylinder (50) in a generally
radial direction, the annular flange (50) further comprises a flange portion (56), the flange portion
(56) defines a plurality of castellations (62) in the an upstream edge thereof, characterised in that said flange portion (56) extends axially and defines a plurality of cooling fluid
apertures (58) that radially extend therethrough.
2. A combustor (20) according to claim 1 characterised in that the annular cylinder (50) is of unitary construction.
3. A combustor (20) according to any one of claims 1-2 characterised in that the flange portion (56) extends axially in the upstream direction
4. A combustor (20) according to any one of the preceding claims characterised in that the apertures (58, 60) are provided in two axially spaced rows (58, 60) within the
flange portion (56).
5. A combustor (20) according to any one of the preceding claims characterised in that said annular cylinder (50) also comprises a second flange (52) positioned axially upstream from said flange (54) of claim 1.
6. A combustor (20) according to any one of the preceding claims characterised in that a heatshield (44) is provided within an aperture for receiving said fuel nozzle (38).
7. A combustor (20) according to claim 6 characterised in that said heatshield (44) aperture comprises an axially extending cylindrical flange (48)
which locates the heatshield (44) in a corresponding aperture in the bulkhead (28)
of the combustor (20).
8. A combustor (20) according to claim 7 characterised in that the heatshield flange (48) is provided with slots (64) to direct cooling fluid to
an annular region (66) between the heatshield flange (48) and the cylinder (50).
9. A combustor (20) according to any one of the preceding claims characterised in that said cooling air is directed radially by said cylinder (50) and associated flange
(54) as a film of air across the heatshield (44).
1. Brennkammer (20) für ein Gasturbinentriebwerk mit einer Brennstoffdüse (38) im stromaufwärtigen
Ende, die innerhalb eines Ringzylinders (50) koaxial zur Brennstoffdüse (38) liegt,
wobei der Ringzylinder (50) an seinem stromabwärtigen Ende einen Ringflansch (54)
aufweist, der sich von dem Ringzylinder (50) in einer allgemein radialen Richtung
erstreckt und der Ringflansch (54) weiter einen Flansch (56) aufweist, der mehrere
Verzahnungen (62) am stromaufwärtigen Rand aufweist, dadurch gekennzeichnet, daß der Flansch (56) sich axial erstreckt und mehrere Kühlfluidöffnungen (58) aufweist,
die sich in Radialrichtung durch den Flansch hindurch erstrecken.
2. Brennkammer (20) nach Anspruch 1,
dadurch gekennzeichnet, daß der Ringzylinder (50) eine einheitliche Konstruktion aufweist.
3. Brennkammer (20) nach einem der Ansprüche 1 oder 2,
dadurch gekennzeichnet, daß der Flansch (56) sich axial stromauf erstreckt.
4. Brennkammer (20) nach einem der vorhergehenden Ansprüche,
dadurch gekennzeichnet, daß die Öffnungen (58, 60) in zwei axial im Abstand zueinander angeordneten Reihen (58,
60) innerhalb des Flansches (56) liegen.
5. Brennkammer (20) nach einem der vorhergehenden Ansprüche,
dadurch gekennzeichnet, daß der Ringzylinder (50) außerdem einen zweiten Flansch (52) aufweist, der axial stromauf
des Flansches (54) gemäß Fig. 1 angeordnet ist.
6. Brennkammer (20) nach einem der vorhergehenden Ansprüche,
dadurch gekennzeichnet, daß ein Hitzeschild (44) innerhalb einer Öffnung vorgesehen ist, um die Brennstoffdüse
(38) aufzunehmen.
7. Brennkammer (20) nach Anspruch 6,
dadurch gekennzeichnet, daß die Öffnung des Hitzeschildes (44) einen axial verlaufenden zylindrischen Flansch
(48) aufweist, der den Hitzeschild (44) in einer entsprechenden Öffnung im Brennerkopf
(28) der Brennkammer (20) festlegt.
8. Brennkammer (20) nach Anspruch 7,
dadurch gekennzeichnet, daß der Flansch (48) des Hitzeschildes mit Schlitzen (64) versehen ist, um Kühlluft auf
einen Ringbereich (66) zwischen dem Hitzeschildflansch (48) und dem Zylinder (50)
zu richten.
9. Brennkammer (20) nach einem der vorhergehenden Ansprüche,
dadurch gekennzeichnet, daß die Kühlluft durch den Zylinder (50) und den zugeordneten Flansch (54) radial als
Luftfilm über den Hitzeschild (44) gerichtet wird.
1. Chambre de combustion (20) pour un moteur à turbine à gaz dans lequel une buse de
combustible (38) est située dans l'extrémité amont de la chambre et est positionnée
à l'intérieur d'un cylindre annulaire (50) qui s'étend coaxialement à la buse de combustible
(38), le cylindre annulaire (50) comprenant au niveau de son extrémité aval une bride
annulaire (54) s'étendant à partir du cylindre annulaire (50) dans une direction généralement
radiale, la bride annulaire (50) comprenant en outre une partie de bride (56), la
partie de bride (56) définissant plusieurs crénelures (62) dans un bord amont de celle-ci,
caractérisé en ce que ladite partie de bride (56) s'étend axialement et définit plusieurs ouvertures de
refroidissement de fluide (58) qui s'étendent radialement à travers.
2. Chambre de combustion (20) selon la revendication 1, caractérisée en ce que le cylindre annulaire (50) est monobloc.
3. Chambre de combustion (20) selon l'une quelconque des revendications 1 et 2, caractérisée en ce que la partie de bride (56) s'étend axialement dans la direction amont.
4. Chambre de combustion (20) selon l'une quelconque des revendications précédentes,
caractérisée en ce que les ouvertures (58, 60) sont prévues en deux rangées espacées axialement (58, 60)
à l'intérieur de la partie de bride (56).
5. Chambre de combustion (20) selon l'une quelconque des revendications précédentes,
caractérisée en ce que ledit cylindre annulaire (50) comprend également une seconde bride (52) positionnée
axialement en amont de ladite bride (54) de la revendication 1.
6. Chambre de combustion (20) selon l'une quelconque des revendications précédentes,
caractérisée en ce qu'un écran thermique (44) est prévu à l'intérieur d'une ouverture pour recevoir ladite
buse de combustible (38).
7. Chambre de combustion (20) selon la revendication 6, caractérisée en ce que ladite ouverture à écran thermique (44) comprend une bride cylindrique (48) qui s'étend
axialement et qui positionne l'écran thermique (44) dans une ouverture correspondante
dans le cadre (28) de la chambre de combustion (20).
8. Chambre de combustion (20) selon la revendication 7, caractérisée en ce que la bride à écran thermique (48) est pourvue de fentes (64) pour diriger un fluide
de refroidissement vers une région annulaire (66) située entre la bride à écran thermique
(48) et le cylindre (50).
9. Chambre de combustion (20) selon l'une quelconque des revendications précédentes,
caractérisée en ce que ledit air de refroidissement est dirigé radialement par ledit cylindre (50) et la
bride associée (54) sous la forme d'un film d'air à travers l'écran thermique (44).