U.S. patent application number 14/470286 was filed with the patent office on 2014-12-11 for afterburner and aircraft engine.
This patent application is currently assigned to IHI Corporation. The applicant listed for this patent is IHI Corporation. Invention is credited to Jun Hosoi, Katsuyoshi Takahashi, Shinji TANAKA.
Application Number | 20140360197 14/470286 |
Document ID | / |
Family ID | 49082835 |
Filed Date | 2014-12-11 |
United States Patent
Application |
20140360197 |
Kind Code |
A1 |
TANAKA; Shinji ; et
al. |
December 11, 2014 |
AFTERBURNER AND AIRCRAFT ENGINE
Abstract
An aircraft engine includes an afterburner which has a flame
stabilizer. The flame stabilizer maintains a flame generated from a
mixed gas of a combustion gas and air. The flame stabilizer
includes multiple gutters each configured to generate a flame
stabilization area for the flame on its downstream side. Each
gutter is formed from: a curved apex section having a stagnation
point; and flat plate-shaped side surface sections integrally
formed on the respective two sides of the apex section. Each gutter
has a V-shaped cross-sectional shape which is opened to the
downstream side. At least one through-hole is formed only in each
side surface section of each gutter.
Inventors: |
TANAKA; Shinji; (Tokyo,
JP) ; Takahashi; Katsuyoshi; (Tokyo, JP) ;
Hosoi; Jun; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
IHI Corporation |
Koto-Ku |
|
JP |
|
|
Assignee: |
IHI Corporation
Koto-ku
JP
|
Family ID: |
49082835 |
Appl. No.: |
14/470286 |
Filed: |
August 27, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/JP2013/055665 |
Mar 1, 2013 |
|
|
|
14470286 |
|
|
|
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Current U.S.
Class: |
60/765 |
Current CPC
Class: |
F02K 3/11 20130101; F23R
3/20 20130101 |
Class at
Publication: |
60/765 |
International
Class: |
F23R 3/20 20060101
F23R003/20 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 2, 2012 |
JP |
2012-046319 |
Claims
1. An afterburner configured to increase thrust of an aircraft
engine by burning a mixed gas of a combustion gas discharged from a
core passage of the aircraft engine and air discharged from a fan
passage of the aircraft engine again while supplying fuel to the
mixed gas, the afterburner comprising: an outer duct provided to an
outlet portion of an engine case of the aircraft engine; a
cylindrical liner provided inside the outer duct, and configured to
allow the mixed gas to flow through the liner; a fuel injector
configured to inject the fuel into the liner; an igniter configured
to ignite the mixed gas including the fuel inside the liner; and a
flame stabilizer disposed in a rear of the fuel injector inside the
liner, including a plurality of gutters arranged radially and each
configured to form a flame stabilization area on a downstream side
of the gutter, and configured to hold a flame, wherein each gutter
is formed from a curved apex section and flat plate-shaped side
surface sections integrally formed on two sides of the apex
section, and has a V-shaped cross- sectional shape which is opened
to a downstream side of the gutter, and at least one through-hole
is formed only in each side surface section of the gutter.
2. The afterburner according to claim 1, wherein a deceleration
space for mixing and concurrently decelerating the mixed gas
introduced through the at least one through-hole is defined inside
the gutter.
3. An aircraft engine configured to produce thrust by exhausting a
mixed gas of a combustion gas and air in a rearward direction,
comprising the afterburner according to claim 1.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation application of
International Application No. PCT/JP2013/055665, filed on Mar. 1,
2013, which claims priority to Japanese Patent Application No.
2012-046319, filed on Mar. 2, 2012, the entire contents of which
are incorporated by references herein.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to: an afterburner configured
to increase thrust of an aircraft engine by burning a mixed gas of
a combustion gas (a high-temperature gas) discharged from a core
passage of the aircraft engine and air (low-temperature air)
discharged from a fan passage of the aircraft engine again while
supplying fuel to the mixed gas; and the like.
[0004] 2. Description of the Related Art
[0005] Various research and development programs on afterburners
have been conducted in recent years to meet demands for aircraft
engines with higher thrust. A configuration and the like of a
general afterburner are as follows.
[0006] An aircraft engine includes: an engine case; an outer duct
provided to an outlet portion (rear portion) of the engine case;
and a liner, a fuel injector and an igniter provided inside the
outer duct. The liner is shaped like a cylinder, and allows a mixed
gas to flow through the liner. The fuel injector injects fuel
inside the liner. The igniter is provided in the rear (on the
downstream side) of the fuel injector inside the outer duct. The
igniter ignites the mixed gas, inclusive of the fuel, inside the
liner. The aircraft engine further includes a flame stabilizer
(flame holder). The flame stabilizer is provided in the rear of the
fuel injector inside the liner, and holds the flame. The flame
stabilizer includes multiple gutters which are arranged radially.
Each gutter forms a flame stabilization area on its downstream side
(immediately downstream side).
[0007] While the aircraft engine is in operation, the fuel injector
continues injecting the fuel inside the liner, and the igniter
continues igniting the mixed gas inclusive of the fuel. For this
reason, the flame is formed on the downstream side (in the rear) of
the flame stabilizer inside the liner, and the mixed gas is burned
again with the fuel. Thereby, more thermal energy can be injected
into the combustion gas inside the liner, and the thrust of the
aircraft engine can be accordingly increased.
[0008] It should be noted that conventional techniques related to
the present invention are disclosed in Japanese Patent Application
Laid-Open Publication Nos. H 09-112345, H09-119346, and H06-137213
as well as JING-TANG YANG et al., Combustion and Flame,
99,288-294(1994).
SUMMARY OF THE INVENTION
[0009] As described above, the flame stabilization area is formed
on a downstream side of each gutter. The flow inside the flame
stabilization area has a relatively low velocity. In contrast, a
flow passing between each neighboring two gutters has a high
velocity because the flow area is narrowed. For this reason, as
shown in FIG. 7, the high-velocity flow passing between the two
neighboring gutters and the low-velocity flow inside the flame
stabilization area are mixed together on the immediately downstream
side of the flame stabilizer. The mixture of the two flows causes a
large pressure loss. The pressure loss lowers a rate of increase in
thrust of the aircraft engine, and makes it difficult to enhance
the engine performance of the aircraft engine to a high level.
Incidentally, in FIG. 7, reference sign "F" indicates a frontward
direction (upstream direction), reference sign "R" indicates a
rearward direction (downstream direction), and reference sign "C"
indicates a circumferential direction.
[0010] An object of the present invention is to provide an
afterburner and the like which can solve the foregoing problem.
[0011] A first aspect of the present invention provides an
afterburner configured to increase thrust of an aircraft engine by
burning a mixed gas of a combustion gas discharged from a core
passage of the aircraft engine and air discharged from a fan
passage of the aircraft engine again while supplying fuel to the
mixed gas. The afterburner includes: an outer duct provided to an
outlet portion (rear portion) of an engine case of the aircraft
engine; a cylindrical liner provided inside the outer duct,
configured to allow the mixed gas to flow through the liner; a fuel
injector configured to inject the fuel into the liner; an igniter
configured to ignite the mixed gas including the fuel inside the
liner; and a flame stabilizer (flame holder) disposed in the rear
(on the downstream side) of the fuel injector inside the liner,
including a plurality of gutters arranged radially and each
configured to form a flame stabilization area on a downstream side
(immediately downstream side) of the gutter, and configured to hold
a flame. Here, each gutter is formed from a curved apex section and
flat plate-shaped side surface sections integrally formed on two
sides of the apex section, and the gutter has a V-shaped
cross-sectional shape which is opened to a downstream side of the
gutter. Moreover, at least one through-hole is formed only in each
side surface section of the gutter.
[0012] It should be noted that in the scope of claims and the
specification of the application concerned, the term "provided"
means that a state of being provided indirectly through another
member as well as a state of being provided directly. Similarly,
the term "arranged" means a state of being arranged through another
member as well as a state of being arranged directly. Furthermore,
the term "downstream side" means a downstream side in view of a
flowing direction of a main stream.
[0013] A second aspect of the present invention provides an
aircraft engine configured to produce thrust by exhausting a mixed
gas of a combustion gas and air in a rearward direction, which
includes the afterburner of the first aspect.
[0014] The present invention can sufficiently reduce the pressure
loss on the downstream side of the flame stabilizer. Thereby, the
present invention can increase the rate of increase in thrust of
the aircraft engine, and can enhance the engine performance of the
aircraft engine to a high level.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a cross-sectional view of a gutter of an
embodiment of the present invention taken along the I-I line of
FIG. 2.
[0016] FIG. 2 is a magnified view of a part indicated with an arrow
II in FIG. 5.
[0017] FIG. 3 is a magnified perspective view of a part indicated
with an arrow III in FIG. 5.
[0018] FIGS. 4A, 4B and 4C are partial side views of gutter
portions in an afterburner of the embodiment of the present
invention, respectively.
[0019] FIG. 5 is a schematic sectional side view of an aircraft
engine of the embodiment of the present invention.
[0020] FIG. 6 is a diagram showing a relationship between a
predetermined mass flow rate while the aircraft engine is in
operation and a pressure coefficient on the downstream side of a
flame stabilizer.
[0021] FIG. 7 is a plan development of a vicinity of multiple
gutters in a general afterburner.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0022] The present invention has been made with a result of an
analysis using the below-described three-dimensional steady
viscosity CFD (Computational Fluid Dynamics) taken into
consideration.
[0023] This analysis used an assumed gutter having a V-shaped
cross-sectional shape which was opened to a downstream side of the
gutter and including multiple through-holes formed only in its two
side surface sections. The analysis found a relationship between a
ratio Qb/Qa of mass flow rates of mixed gases (a predetermined
ratio of mass flow rates in an aircraft engine in operation) and a
pressure coefficient on the downstream side of the flame
stabilizer. In this respect, Qa denotes amass flow rate of a mixed
gas flowing toward the gutter in the aircraft engine in operation,
and Qb denotes a mass flow rate of a mixed gas introduced into the
gutter through the multiple through-holes in the gutter. FIG. 6
shows the result of the analysis. As shown in the graph, it was
learned that as the ratio Qb/Qa of the mass flow rates became
larger (became equal to 0.10 or more, preferably), the pressure
loss on the downstream side of the flame stabilizer could be
reduced sufficiently. In this graph, one scale mark on the vertical
axis represents 0.1. FIG. 6 shows that a smaller value of the
pressure coefficient on the vertical axis means a smaller pressure
loss on the downstream side of the flame stabilizer. In short, it
was learned from this analysis that when the gutter had the
above-mentioned shape, the pressure loss on the downstream side of
the flame stabilizer could be reduced sufficiently.
[0024] A preceding study (see NPL 1), meanwhile, has already showed
clearly that when multiple through-holes are formed not only in the
two side surface sections of the gutter but also in an apex section
of the gutter, a high-velocity mixed gas flows into the gutter and
the flame stabilization performance (combustion stabilization
performance) of the flame stabilizer accordingly deteriorates to a
large extent.
[0025] Next, referring to FIGS. 1 to 5, descriptions will be
provided for an embodiment of the present invention. It should be
noted that reference sign "F" indicates a forward direction
(upstream direction) and reference sign "R" indicates a rearward
direction (downstream direction.)
[0026] As shown in FIG. 5, an aircraft engine (hereinafter simply
referred to as an engine) 1 of the embodiment is an apparatus
configured to produce thrust (engine thrust) by discharging a mixed
gas of a combustion gas (a high-temperature gas) and air
(low-temperature air) in the rearward direction. The engine 1
includes: a cylindrical engine case 3; and a core passage (a main
passage) 5 and a fan passage (a bypass passage) 7 formed in the
inside of the engine case 3 by partitioning the inside thereof. The
core passage 5 is formed in an annular shape (in a hollowed
cylindrical shape), and allows the combustion gas to flow through
the core passage 5 in the rearward direction. The fan passage 7 is
placed outside the core passage 5, and is formed in an annular
shape (a hollowed cylindrical shape). The fan passage 7 allows the
air (the low-temperature air) to flow through the fan passage 7 in
the rearward direction.
[0027] The engine 1 includes: a fan 9 disposed in a front portion
of the inside of the engine case 3; and an inlet cone 11 disposed
in a center portion on the front side of the fan 9. The fan 9 takes
air into the core passage 5 and the fan passage 7. The inlet cone
11 guides the air in the rearward direction. The engine 1 further
includes: a compressor 13 disposed in the rear of the fan 9; and a
combustor 15 disposed in the rear of the compressor 13. The
compressor 13 compresses the air which has been taken into the core
passage 5. The combustor 15 generates the combustion gas by
combusting the air including fuel.
[0028] The engine 1 includes: a high-pressure turbine 17 disposed
in the rear of the combustor 15; and a low-pressure turbine 19
disposed in the rear of the high-pressure turbine 17. The
high-pressure turbine 17 is driven by expansion of the combustion
gas from the combustor 15. In conjunction with this, the
high-pressure turbine 17 drives the compressor 13. The low-pressure
turbine 19 is driven by expansion of the combustion gas. In
conjunction with this, the low-pressure turbine 19 drives the fan
9. Furthermore, a tail cone 21 is disposed in the rear of the
low-pressure turbine 19. The tail cone 21 guides the combustion gas
in the rearward direction.
[0029] The engine 1 includes an afterburner 23 disposed in the rear
of the engine case 3. The afterburner 23 increases the thrust (the
engine thrust) of the engine 1 by: burning again the mixed gas of
the combustion gas discharged from the core passage 5 and the air
(the low-temperature air) discharged from the fan passage 7 while
supplying fuel to the mixed gas. An exhaust nozzle 25 configured to
exhaust the mixed gas which has been burned again by the
afterburner 23 is disposed in the rear of the afterburner 23.
[0030] Next, descriptions will be provided for a concrete
configuration of the afterburner 23 of the embodiment.
[0031] As shown in FIGS. 2 and 5, the afterburner 23 includes: an
outer duct 27 disposed in the rear (in the outlet portion) of the
engine case 3; and a cylindrical liner 29 disposed inside the outer
duct 27. The outer duct 27 is connected to the exhaust nozzle 25.
Furthermore, the liner 29 allows the mixed gas to flow through the
liner 29 in the rearward direction. In addition, a mixer 31 is
disposed in the rear of the engine case 3. The mixer 31 is placed
inside the liner 29, and mixes the combustion gas discharged from
the core passage 5 and the air discharged from the fan passage 7.
Incidentally, the mixer 31 may have the same configuration as does
a publicly-known mixer shown in Japanese Patent Application
Laid-Open Publication No. H06-137213 as described above.
[0032] The afterburner 23 includes multiple spray bars 33 which are
examples of a fuel injector, and the spray bars 33 are provided to
the outer duct 27. The spray bars 33 are disposed at intervals in
the circumferential direction of the outer duct 27. The tip
end-side portion of each spray bar 33 is placed inside the liner
29. Each spray bar 33 injects the fuel into the liner 29. The
afterburner 23 further includes an ignition device (an igniter) 35
provided to the outer duct 27 in the rear of the spray bars 33. The
igniter 35 ignites (lights off) the mixed gas including the fuel
inside the liner 29.
[0033] As shown in FIGS. 2 and 3, the afterburner 23 includes a
flame stabilizer (a flame holder) 37. The flame stabilizer 37 is
disposed in the rear (on the downstream side) of the spray bars 33
inside the liner 29, and holds the flame. In addition, the flame
stabilizer 37 includes multiple gutters 39 arranged radially. Each
gutter 39 generates a flame stabilization area FA on the downstream
side (immediately on the downstream side) of the gutter 39.
Incidentally, the tip end-side portion (whose illustration is
omitted) of the igniter 35 is placed in the flame stabilization
area FA.
[0034] As shown in FIGS. 1 and 4A, each gutter 39 is formed from: a
curved apex section 39a including a stagnation point P; and flat
plate-shaped side surface sections 39b integrally formed on the two
sides of the apex section 39a. Each gutter 39 has a V-shaped
cross-sectional shape which is opened to the downstream side.
Furthermore, multiple circular through-holes 41 are formed only in
the two side surface sections 39b of each gutter 39. It should be
noted that the shape of each through-hole 41 is not limited to the
circular one. In other words, as shown in FIGS. 4B and 4C, each
through-hole 41 may be shaped like an ellipse, or like a slit
(slot). Otherwise, instead of the multiple through-holes 41, a
single slit (slot)-shaped through-hole (whose illustration is
omitted) may be formed.
[0035] As shown in FIG. 1, a deceleration space (a deceleration
section, a mixing space) S for mixing and concurrently decelerating
mixed gases introduced through the multiple through holes 41 is
formed in each gutter 39. In addition, the multiple through-holes
41 are formed in each gutter 39 in a way that the ratio Qb/Qa of
the mass flow rates of the mixed gases is equal to 0.10 or more. As
discussed in the beginning, Qa denotes the mass flow rate of the
mixed gas flowing toward each gutter 39 while the engine 1 is in
operation, and Qb denotes the mass flow rate of the mixed gas
introduced into the inside (the deceleration space S) of each
gutter 39 through the multiple through-holes 41 in the gutter 39.
To put it concretely, in each gutter 39, the total opening area and
arrangement pattern of the multiple through-holes 41, the
orientation of the multiple through-holes 41 with respect to the
thickness direction of the side surface sections 39b, and the like
are set in a way that the ratio (Qb/Qa) of the mass flow rates is
equal to 0.10 or more. It should be noted that when the ratio
(Qb/Qa) of the mass flow rates exceeds 0.30, it is difficult to
sufficiently secure the flame stabilization performance (the
combustion stabilization performance) of the flame stabilizer
37.
[0036] As shown in FIG. 2, an annular liner cooling passage 43 is
formed between the inner surface of the outer duct 27 and the outer
surface of the liner 29. The liner cooling passage 43 allows part
of the air discharged from the fan passage 7 to flow through the
liner cooling passage 43 as cooling air.
[0037] Next, descriptions will be provided for the working and
effects of the embodiment.
[0038] Once the fan 9 and the compressor 13 are driven by an
operation of an appropriate starter apparatus (whose illustration
is omitted), the air can be taken by the fan 9 into the core
passage 5 and the fan passage 7, and the air taken into the core
passage 5 can be compressed by the compressor 13. Subsequently,
once the high-pressure combustion gas is generated by causing the
combustor 15 to combust the air including the fuel, the
high-pressure turbine 17 and the low-pressure turbine 19 are driven
by the expansion of the combustion gas. Thereby, the compressor 13
and the fan 9 can be driven in conjunction with the high-pressure
turbine 17 and the low-pressure turbine 19, respectively.
Thereafter, the engine 1 can be put into operation through a series
of operations (the driving of the fan 9, the driving of the
compressor 13, the combustion by the combustor 15, as well as the
driving of the high-pressure turbine 17 and the low-pressure
turbine 19). Subsequently, while the engine 1 is in operation, the
combustion gas discharged from the core passage 5 and the air
discharged from the fan passage 7 are mixed together by the mixer
31, and, as the mixed gas, are exhausted through the exhaust nozzle
25 in the rearward direction. Thereby, the thrust (the engine
thrust) of the engine 1 can be produced.
[0039] While the engine 1 is in operation, the fuel is injected
from the multiple spray bars 33 into the liner 29, and the mixed
gas including the fuel is ignited by the igniter 35. Thereby, the
flame is produced in the rear (on the downstream side) of the flame
stabilizer 37 inside the liner 29, and the mixed gas is burned
again with the fuel. By this, thermal energy can be injected into
the combustion gas inside the liner 29, and the thrust of the
engine 1 can be increased. On the other hand, while the engine 1 is
in operation, part of the air discharged from the fan passage 7
flows through the liner cooling passage 43 as the cooling air.
Thereby, the liner 29 can be cooled (in the normal operation of the
afterburner 23).
[0040] In this respect, each gutter 39 has the V-shaped
cross-sectional shape which is opened to the downstream side of the
gutter 39, and the multiple through-holes 41 are formed only in the
two side surface sections 39b of each gutter 39. Furthermore, in
each gutter 39, the total opening area of the multiple
through-holes 41 and the like are set in a way that the ratio Qb/Qa
of the mass flow rates is in the range of 0.10 to 0.30 inclusive.
For these reasons, as learned from the above-discussed result of
the analysis, the afterburner 23 of the embodiment is capable of
sufficiently reducing the pressure loss on the downstream side of
the flame stabilizer 37 while sufficiently securing the flame
stabilization performance of the flame stabilizer 37.
[0041] Accordingly, the present invention makes it possible to
improve the engine performance of the engine 1 to a high level by:
sufficiently securing the flame stability performance of the flame
stabilizer 37; and additionally improving a rate of increase in
thrust of the engine 1.
[0042] It should be noted that the present invention is not limited
to the foregoing descriptions which have been provided for the
embodiment, and can be carried out in various modes. Moreover, the
scope of rights covered by the present invention is not limited to
the embodiment.
* * * * *