U.S. patent application number 12/514800 was filed with the patent office on 2010-06-24 for vane assembly configured for turning a flow in a gas turbine engine, a stator component comprising the vane assembly, a gas turbine and an aircraft jet engine.
Invention is credited to Stephane Baralon.
Application Number | 20100158684 12/514800 |
Document ID | / |
Family ID | 39401912 |
Filed Date | 2010-06-24 |
United States Patent
Application |
20100158684 |
Kind Code |
A1 |
Baralon; Stephane |
June 24, 2010 |
VANE ASSEMBLY CONFIGURED FOR TURNING A FLOW IN A GAS TURBINE
ENGINE, A STATOR COMPONENT COMPRISING THE VANE ASSEMBLY, A GAS
TURBINE AND AN AIRCRAFT JET ENGINE
Abstract
A vane assembly configured for turning a flow in a gas turbine
engine includes a stationary main guide vane and an additional
guide vane, wherein a leading edge of the additional guide vane is
positioned upstream of a leading edge of the main guide vane and
wherein the additional guide vane extends a distance along the main
guide vane towards a trailing edge of the main guide vane forming a
passageway between the additional guide vane and the main guide
vane.
Inventors: |
Baralon; Stephane; (Derby,
GB) |
Correspondence
Address: |
WRB-IP LLP
1217 KING STREET
ALEXANDRIA
VA
22314
US
|
Family ID: |
39401912 |
Appl. No.: |
12/514800 |
Filed: |
November 14, 2006 |
PCT Filed: |
November 14, 2006 |
PCT NO: |
PCT/SE2006/001292 |
371 Date: |
December 1, 2009 |
Current U.S.
Class: |
415/208.1 |
Current CPC
Class: |
F01D 9/065 20130101;
F01D 5/146 20130101; Y02T 50/60 20130101; Y02T 50/673 20130101;
F01D 9/041 20130101 |
Class at
Publication: |
415/208.1 |
International
Class: |
F01D 9/02 20060101
F01D009/02 |
Claims
1. Vane assembly (206) configured for turning a flow in a gas
turbine engine (100) comprising a stationary main guide vane (208)
and an additional guide vane (210), wherein a leading edge (318) of
the additional guide vane (210) is positioned upstream of a leading
edge (310) of the main guide vane (208) and wherein the additional
guide vane (210) extends a distance along the main guide vane (208)
towards a trailing edge (312) of the main guide vane (208) forming
a passageway (322) between the additional guide vane (210) and the
main guide vane (208).
2. Vane assembly according to claim 1, wherein the additional guide
vane (210) is positioned relative to the main guide vane (208) so
that the passageway (322) becomes more narrow in a downstream
direction.
3. Vane assembly according to claim 1 or 2, wherein the additional
guide vane (210) is positioned relative to the main guide vane
(208) so that the passageway (322) continuously narrows down from
an upstream opening (324) of the passageway to a downstream opening
(326).
4. Vane assembly according to any preceding claim, wherein the
additional guide vane (210) is positioned relative to the main
guide vane (208) so that the passageway (322) is shaped as a
nozzle.
5. Vane assembly according to any preceding claim, wherein the
additional guide vane (210) has an at least partly curved
shape.
6. Vane assembly according to claim 5, wherein a first, upstream
portion of a suction side of the additional guide vane (210)
extending from a leading edge of the additional guide vane (210) is
substantially straight and that a second, downstream portion of the
suction side of the additional guide vane (210) is curved.
7. Vane assembly according to claim 6, wherein the first, upstream
portion of the suction side of the additional guide vane (210)
extends over at least 50% of the chord of the additional guide
vane.
8. Vane assembly according to claim 6, wherein the first, upstream
portion of the suction side of the additional guide vane (210)
extends over about 70% of the chord of the additional guide
vane.
9. Vane assembly according to any of claims 5-8, wherein a concave
part of the additional guide vane (210) defines one side of the
passageway.
10. Vane assembly according to any preceding claim, wherein the
main guide vane (208) has an at least partly curved shape.
11. Vane assembly according to any preceding claim, wherein a
concave part of the additional guide vane (210) is arranged along a
convex part of the main guide vane (208), wherein the passageway is
defined therebetween.
12. Vane assembly according to any preceding claim, wherein a
leading edge of the additional guide vane (210) has an elliptic
cross sectional shape.
13. Vane assembly according to any preceding claim, wherein the
main guide vane (208) is configured to turn an incoming flow.
14. Vane assembly according to any preceding claim, wherein the
additional guide vane (210) is configured to turn an incoming
flow.
15. Vane assembly according to any preceding claim, wherein the
main guide vane (208) has the shape of an airfoil in cross
section.
16. Vane assembly according to any preceding claim, wherein the
additional guide vane (210) has the shape of an airfoil in cross
section.
17. Vane assembly according to claim 15 and 16, wherein a pressure
side of the additional guide vane (210) faces a suction side of the
main guide vane (208), wherein the passageway is defined
therebetween.
18. Vane assembly according to any preceding claim, wherein a
trailing edge of the additional guide vane (210) is arranged
upstream of the trailing edge of the main guide vane (208).
19. Vane assembly according to any preceding claim, wherein a
trailing edge of the additional guide vane (210) is arranged
upstream of a point halfway of the chord of the main guide vane
(208).
20. Vane assembly according to any preceding claim, wherein the
additional guide vane (210) has a substantially smaller thickness
to chord ratio than the main guide vane (208).
21. Vane assembly according to any preceding claim, wherein the
main guide vane (208) is structurally bearing.
22. Vane assembly according to any preceding claim, wherein the
main guide vane (208) is adapted for housing service
components.
23. Vane assembly according to any preceding claim, wherein the
additional guide vane (210) is stationary.
24. Stator component comprising a plurality of said vane assemblies
according to any preceding claim, wherein the main guide vanes
(208) are circumferentially spaced.
25. A gas turbine engine comprising a stator component according to
claim 24.
26. An aircraft jet engine comprising a stator component according
to claim 24.
Description
BACKGROUND AND SUMMARY
[0001] The present invention relates to a vane assembly configured
for turning a flow in a gas turbine engine. The invention is also
related to a stator component comprising the vane assembly.
[0002] The gas turbine engine is especially intended for an
aircraft jet engine. Jet engine is meant to include various types
of engines, which admit air at relatively low velocity, heat it by
combustion and shoot it out at a much higher velocity. Accommodated
within the term jet engine are, for example, turbojet engines and
turbo-fan engines.
[0003] In the aircraft jet engine, stationary guide vane assemblies
are used to turn the flow from one angle to another. The stationary
guide vane assembly may be applied in a stator component of a
turbo-fan engine at a fan outlet, in a Turbine Exhaust Case (TEC)
and even in an InterMediate Case (IMC).
[0004] The flow turning results in flow diffusion, i.e. pressure
increase which puts serious limits on the amount of flow turning
allowed for a given number of guide vanes. The number of guide
vanes vs. the amount of flow turning often is governed by the so
called solidity parameter "s", i.e. the ratio between the vane
chord "c" or length and the distance between two neighbouring vanes
also called pitch "p", "s=c/p".
[0005] Turning the flow from 45 degrees to 0 degrees (axial
direction) requires for instance a solidity of about 1.45.
Depending on the flow Mach number and the radius of the component,
this may result in more than 100 vanes. The design constraints are
made even more challenging when thick structurally bearing vanes
with engine servicing have to be used.
[0006] Typical Fan OGV configurations, which turn the flow by about
40-50 degrees, with structural loads but no servicing through may
result in 58 vanes in the bypass duct. Typical TEC have about 14
vanes to turn the flow by about 30 degrees. TEC are however much
thicker and have a max thickness to chord ratio of about 14%.
[0007] To achieve a larger amount of turning while keeping thick
vanes, solutions have been presented based on high-lift devices
which are comprised of a main vane and an additional vane just
downstream to help the flow at turning further. These
configurations are very much similar to high-lift wings on
aircraft. However, the solutions proposed so far are often
expensive and require a very long axial length to cope with the
large thickness vs. flow turning. In aircraft engines, additional
problems arise with thick and long vanes because of the upstream
influence of the vane pressure field. Forcing of the upstream
component becomes a major issue, especially in the engine core TEC
and IMC. Other solutions opt for separation of mechanical and
servicing functionality and aerodynamic functionality leading to
the two rows solution with vanes followed by symmetrical
struts.
[0008] It is desirable to achieve a vane assembly, which creates
conditions for a large amount of flow turning while minimizing the
upstream influence of the vane pressure field. Further, the axial
extension of the vane assembly should be kept to a minimum.
[0009] According to an aspect of the present invention, a vane
assembly is configured for turning a flow in a gas turbine engine
comprising a stationary main guide vane and an additional guide
vane, wherein a leading edge of the additional guide vane is
positioned upstream of a leading edge of the main guide vane and
wherein the additional guide vane extends a distance along the main
guide vane towards a trailing edge of the main guide vane forming a
passageway between the additional guide vane and the main guide
vane. The main guide vane is preferably configured to turn an
incoming flow and the additional guide vane is configured to assist
the main guide vane in turning the incoming flow.
[0010] In other words, the additional stationary guide vane is
arranged in the vicinity of the leading edge of the main guide vane
and the additional guide vane is aerodynamically coupled to the
main guide vane.
[0011] This design creates conditions for achieving a larger flow
turning with a smaller number of main guide vanes (struts). For
example, for a TEC, about 50% more flow turning may be achieved
with about 30% less main guide vanes.
[0012] Further, a less complicated manufacturing (for example
casting and forging) may be used compared to classical high lift
devices.
[0013] Further, for IMC, fan OGV and TEC, this type of vane
assembly may lead to more loading on upstream stages, a shorter
engine length, reduced engine weight and reduced part count.
[0014] According to one embodiment of the invention, the additional
guide vane is positioned relative to the main guide vane so that
the passageway becomes more narrow in a downstream direction.
Preferably, the additional guide vane is positioned relative to the
main guide vane so that the passageway continuously narrows down
from an upstream opening of the passageway to a downstream opening.
More preferably, the additional guide vane is positioned relative
to the main guide vane so that the passageway is shaped as a
nozzle. Such a design creates conditions for tone noise reduction,
the noise resulting from the vane interacting with upstream wakes,
through phase cancellation effect and cavity volume dampening.
[0015] According to a further embodiment of the invention, the
additional guide vane has an at least partly curved shape.
Preferably, a first, upstream portion of a suction side of the
additional guide vane extending from a leading edge of the
additional guide vane is substantially straight and that a second,
downstream portion of the suction side of the additional guide vane
is curved. More preferably, the first, upstream portion of the
suction side of the additional guide vane extends over at least 50%
of the chord of the additional guide vane. Such a design creates
conditions for reducing upstream pressure gradients.
[0016] According to a further embodiment of the invention, a
leading edge of the additional guide vane has an elliptic cross
sectional shape. In this way, upstream forcing may be reduced.
[0017] Further advantageous embodiments and advantages of the
invention will be apparent from the following description, drawings
and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The invention will be explained below, with reference to the
embodiment shown on the appended drawings, wherein
[0019] FIG. 1 is a schematic side view of the engine cut along a
plane in parallel with the rotational axis of the engine,
[0020] FIG. 2 is a perspective view of a stator component
comprising an inventive guide vane assembly, and
[0021] FIG. 3 shows the vane assembly of FIG. 2 in cross
section.
DETAILED DESCRIPTION
[0022] The invention will below be described for a high bypass
ratio aircraft engine 100, see FIG. 1. The engine 100 comprises an
outer housing 102, an inner housing 104 and an intermediate housing
106 which is concentric to the first two housings and divides the
gap between them into an inner primary gas channel 108 for the
compression of the propulsion gases and a secondary channel 110 in
which the engine bypass circulates. Thus, each of the gas channels
108,110 is annular in a cross section perpendicular to an axial
direction 112 of the engine 100.
[0023] The engine 100 comprises a fan 114 which receives ambient
air 115, a booster or low pressure compressor (LPC) 116 and a high
pressure compressor (HPC) 118 arranged in the primary gas channel
108, a combustor 120 which mixes fuel with the air pressurized by
the high pressure compressor 118 for generating combustion gases
which flow downstream through a high pressure turbine (HPT) 122 and
a low pressure turbine (LPT) 124 from which the combustion gases
are discharged from the engine.
[0024] A first or high pressure shaft joins the high pressure
turbine 122 to the high pressure compressor 118 to substantially
form a first or high pressure rotor. A second or low pressure shaft
joins the low pressure turbine 124 to the low pressure compressor
116 to substantially form a second or low pressure rotor. The high
pressure compressor 118, combustor 120 and high pressure turbine
122 are collectively referred to as a core engine. The second or
low pressure shaft is at least in part rotatably disposed
co-axially with and radially inwardly of the first or high pressure
rotor.
[0025] The housings 102,104,106 are supported by structures 126
which connect the housings by radial arms. These arms are generally
known as struts. The struts must be sufficiently resistant to
provide this support and not to break or buckle in the event of a
fan blade coming loose and colliding with them. Further, the struts
are designed for transmission of loads in the engine.
[0026] Further, often the struts are hollow in order to house
service components such as means for the intake and outtake of oil
and/or air, for housing instruments, such as electrical and
metallic cables for transfer of information concerning measured
pressure and/or temperature, a drive shaft for a start engine etc.
The struts can also be used to conduct a coolant.
[0027] The compressor structure 126 connecting the intermediate
housing 106 and the inner housing 104 is conventionally referred to
as an Intermediate Case (IMC) or Intermediate Compressor Case
(ICC). The compressor structure 126 is designed for guiding the gas
flow from the low pressure compressor 116 radially inwards toward
to the high pressure compressor 118 inlet. The compressor structure
126 connecting the intermediate housing 106 and the inner housing
102 comprises a plurality of radial struts 208 see FIGS. 2 and 3,
at mutual distances in the circumferential direction of the
compressor structure. These struts 208 are structural parts,
designed for transmission of both axial and radial loads and at
least some are hollow in order to house service components.
[0028] FIG. 2 shows a perspective view of a stator component in the
form of the compressor structure 126. The compressor structure 126
comprises an inner ring 202, an outer ring 204 encompassing the
inner ring 202, and a plurality of vane assemblies 206 extending
radially between the inner ring 202 and the outer ring 204. The
vane assemblies 206 are circumferentially spaced and rigidly
connected to the rings 202,204. Each of the vane assemblies 206
comprises the strut 208 and an additional guide vane 210, see also
FIG. 3.
[0029] FIG. 3 shows one vane assembly 206 of FIG. 2 in an enlarged
cross section view. The vane assembly 206 comprises a stationary
main guide vane 208 (the strut) and the additional stationary guide
vane 210. The main guide vane 208 is structurally bearing. The main
guide vane 208 has a first sidewall 306 and a second sidewall 308
that are connected at a leading edge 310 and a trailing edge 312.
The main guide vane 208 is configured to turn an incoming flow. The
main guide vane 208 has an at least partly curved shape. The first
side wall 306 of the main guide vane 208 is convex and defines a
suction side. The second side wall 308 of the main guide vane 208
is concave and defines a pressure side.
[0030] The additional guide vane 210 has a first sidewall 314 and a
second sidewall 316 that are connected at a leading edge 318 and a
trailing edge 320. The additional guide vane 210 is configured to
turn an incoming flow. The additional guide vane 210 has an at
least partly curved shape. The first side wall 314 of the
additional guide vane 210 is convex and defines a suction side. The
second side wall 316 of the additional guide vane 210 is concave
and defines a pressure side.
[0031] The magnitude of the turning of the gas flow in the stator
component 126 depends on several parameters. In order to accomplish
a turning of the gas flow in the magnitude of 40-60.degree., the
main guide vane 208 has a cambered airfoil shape, see FIG. 3. In
other words, the main guide vanes are designed with a sufficient
curvature for a substantial turning of the gas flow. Hence, the
main vane 208 is not only structural, but also has an aerodynamic
function. More specifically, the direction of a mean camber line M
at the leading edge 310 is inclined with an angle in relation to
the direction of the mean camber line M at the trailing edge 312
corresponding to the desired turning angle. The direction of the
mean camber line M at the leading edge 310 of the cambered main
vane 208 is therefore inclined with at least 20.degree., suitably
at least 30.degree., especially at least 40.degree., and preferably
at least 50.degree. in relation to the direction of the mean camber
line M at the trailing edge 312.
[0032] The chord is defined as the distance between the leading
edge 310 and the trailing edge 312 of the main vane 208 along the
chord line C, see FIG. 3. The chord line C is defined as a straight
line connecting the leading edge 310 and the trailing edge 312.
[0033] The thickness of the main vane 208 is defined as the maximum
distance between the two opposing strut surfaces 306,308 in a
direction perpendicular to a mean chamber line M. The mean camber
line M is defined as the locus of points halfway between the upper
and lower surfaces 306,308 of the main vane as measured
perpendicular to the mean camber line itself. The camber A is
defined as the maximum distance between the mean chamber line M and
the chord line C measured perpendicular to the chord line. The main
guide vane 208 has the shape of an airfoil in cross section. In
other words, the mean camber line M is curved.
[0034] Further, the maximum thickness to chord ratio is another
measure for the gas flow turning capacity of the struts. The
maximum thickness is preferably less than 20%, especially less than
15% and more specifically about 10% of the chord according to the
example shown in the drawings.
[0035] The leading edge 318 of the additional guide vane 210 is
positioned upstream of the leading edge 310 of the main guide vane
208. The additional guide vane 210 extends a distance along the
main guide vane 208 forming a passageway 322 between the additional
guide vane 210 and the main guide vane 208. Thus, the additional
guide vane 210 at least partly overlaps the main guide vane 208.
The additional guide vane 210 is positioned relative to the main
guide vane 208 so that the passageway 322 becomes more narrow in a
downstream direction.
[0036] More specifically, the additional guide vane 210 is
positioned relative to the main guide vane 208 so that the
passageway 322 continuously narrows down from an upstream opening
324 of the passageway to a downstream opening 326. Thus, the
leading edge 318 of the additional guide vane 210 is at a greater
distance from a periphery of the main guide vane 208 than a
trailing edge 320 of the additional guide vane 210 is from a
periphery of the main guide vane 208. More specifically, the
additional guide vane 210 is positioned relative to the main guide
vane 208 so that the passageway 322 is shaped as a nozzle.
[0037] The trailing edge 320 of the additional guide vane 210 is
arranged upstream of the trailing edge 312 of the main guide vane
208. More specifically, the trailing edge 326 of the additional
guide vane 210 is arranged upstream of a point halfway of the chord
of the main guide vane 208.
[0038] A pressure side of the additional guide vane 210 faces a
suction side of the main guide vane 208, wherein the passageway 322
is defined therebetween.
[0039] The additional guide vane 210 has the shape of an airfoil in
cross section. In other words, the mean camber line is curved.
[0040] Further, the additional guide vane 210 has a substantially
smaller thickness to chord ratio than the main guide vane 208.
[0041] The vane assembly 206 is designed for turning a swirling gas
flow. The swirling gas normally flows with an angle of
40-60.degree. relative to the axial direction 112 of the engine. In
this case the turning of the gas flow is in the combined
axial-tangential and axial-radial directions.
[0042] A first, upstream portion 328 of a suction side 314 of the
additional guide vane 210 extending from a leading edge 318 is
substantially straight and a second, downstream portion 330 of the
suction side 314 of the additional guide vane is curved. More
specifically, the first, upstream portion 328 of the suction side
of the additional guide vane extends over at least 50% of the chord
of the additional guide vane. Especially, the first, upstream
portion 328 of the suction side of the additional guide vane
extends over about 70% of the chord of the additional guide
vane.
[0043] A concave part of the additional guide vane 210 defines one
side of the passageway 322. More specifically, the concave part of
the additional guide vane 210 is arranged along a convex part of
the main guide vane 208, wherein the passageway 322 is defined
therebetween.
[0044] According to the shown embodiment, the vane assembly 206 is
adapted to turn an incoming flow with a flow angle of about -45
degrees to an outgoing flow with a flow angle of about -5 degrees.
It is expected that this type of vane assembly may turn a flow with
about 60 degrees.
[0045] Further, it is expected that a minimum solidity of about 0.6
may be achieved with this type of vane assembly.
[0046] The struts are often hollow in order to house service
components such as means for the intake and outtake of oil and/or
air, for housing instruments, such as electrical and metallic
cables for transfer of information concerning measured pressure
and/or temperature etc. The struts normally have a symmetric
airfoil shape in cross section in order to effect the gas flow as
little as possible. The servicing requirement usually governs the
number of struts required.
[0047] The invention is not in any way limited to the above
described embodiments, instead a number of alternatives and
modifications are possible without departing from the scope of the
following claims.
[0048] The main guide vane 208, described above has an at least
partly curved shape. Preferably, the mean camber line M is curved.
However, according to an alternative, the main guide vane may be
symmetrical in that its mean camber line may be straight.
* * * * *