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Patent 2335349 Summary

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(12) Patent: (11) CA 2335349
(54) English Title: FUEL INJECTOR FOR GAS TURBINE ENGINE
(54) French Title: INJECTEUR DE CARBURANT POUR MOTEUR A TURBINE A GAZ
Status: Expired
Bibliographic Data
(51) International Patent Classification (IPC):
  • F23R 3/28 (2006.01)
  • B05B 1/34 (2006.01)
  • F23D 11/10 (2006.01)
  • F23D 11/38 (2006.01)
  • F23D 11/40 (2006.01)
  • F23R 3/38 (2006.01)
(72) Inventors :
  • PROCIW, LEV A. (Canada)
  • SHAFIQUE, HARRIS (Canada)
  • SAMPATH, PARTHASARATHY (Canada)
(73) Owners :
  • PRATT & WHITNEY CANADA CORP./PRATT & WHITNEY CANADA CIE. (Canada)
(71) Applicants :
  • PRATT & WHITNEY CANADA CORP. (Canada)
(74) Agent: NORTON ROSE FULBRIGHT CANADA LLP/S.E.N.C.R.L., S.R.L.
(74) Associate agent:
(45) Issued: 2008-10-07
(86) PCT Filing Date: 1999-06-22
(87) Open to Public Inspection: 2000-01-06
Examination requested: 2003-11-12
Availability of licence: N/A
(25) Language of filing: English

Patent Cooperation Treaty (PCT): Yes
(86) PCT Filing Number: PCT/CA1999/000579
(87) International Publication Number: WO2000/000770
(85) National Entry: 2000-12-15

(30) Application Priority Data:
Application No. Country/Territory Date
2,241,674 Canada 1998-06-26

Abstracts

English Abstract




A fuel injector (60) for a combustor presented either as a simplex or duplex
pressurized fuel injector, wherein the fuel is introduced
into the injector to provide a swirl to the fuel in a first annular channel
(68) which communicates with a coaxial conical fuel swirl chamber
(70) and then the primary nozzle. In a duplex version, a secondary annular
swirl channel (76) is provided for spinning the fuel and
communicating downstream with a conical fuel swirl chamber (82) and eventually
an annular nozzle (84) whereby the fuel is atomized as it
exits the nozzle. An air swirler (66) is also provided with the fuel injector
(60), and the air swirler (66) includes air passages (90) arranged
in an annular array about the fuel injector tip (64). A second array of
auxiliary air passages (92) can be arranged spaced radially from the
first array (90) and also to provide an air swirl and to control the spray
cone of the fuel air mixture.


French Abstract

L'invention concerne un injecteur de carburant (60) pour dispositif combustor qui se présente sous la forme d'un injecteur de carburant pressurisé simplex ou à double débit. Le carburant est introduit à l'intérieur d'un injecteur pour y subir un tourbillonnement dans un premier canal annulaire (68) communiquant avec une chambre de tourbillonnement du carburant conique coaxiale (70) puis avec la tuyère primaire. Dans une version à double débit, un deuxième canal de tourbillonnement annulaire (76) met le carburant en rotation et communique en aval avec une chambre de tourbillonnement du carburant conique (82) et, finalement, avec une tuyère annulaire (84) si bien que le carburant est atomisé lorsqu'il quitte la tuyère. Un dispositif de turbulence (66) également équipé de l'injecteur de carburant (60) inclut des conduits d'air (90) disposés dans un réseau annulaire autour de la pointe de l'injecteur de carburant (64). Un deuxième réseau de conduits d'air auxiliaires (92) peut être disposé à une distance radiale du premier réseau (90) pour provoquer un tourbillonnement d'air et commander le cône de pulvérisation du mélange carburant-air.

Claims

Note: Claims are shown in the official language in which they were submitted.




-15-


CLAIMS:


1. A fuel injector for use in a combustor of a gas turbine engine, whereby
the combustor includes a combustor wall defining a combustion chamber
surrounded
by pressurized air, the injector comprising an injector tip adapted, when in
use, to
protrude through the combustor wall into the chamber, the injector tip having
an
injector body extending along an injector tip axis, a primary fuel nozzle
formed in the
injector tip concentrically of the injector tip axis and communicating with a
primary
fuel chamber formed as a cone upstream of the fuel nozzle and coaxial
therewith, at
least a first annular fuel channel defined in the injector body upstream of
the primary
fuel chamber concentric with the injector tip axis and communicating with the
primary fuel chamber, and flow passage means providing a flow of pressurized
fluid
to the first annular channel tangentially thereof in order to provide a swirl
to the fuel
flow in the first annular fuel channel, the primary fuel chamber, and thus to
the
primary fuel nozzle, thereby atomizing the fuel as it exists the primary fuel
nozzle.

2. The fuel injector as defined in claim 1, wherein an annular air swirl
member is provided mounted to the injector tip, the air swirl member including
an
annular array of first air passages communicating the pressurized air
surrounding the
combustor into the combustion chamber, the first air passages being concentric
with
the primary fuel nozzle and the tip axis whereby the first air passages are
arranged to
further atomize the fuel exiting from the primary fuel nozzle in order to
enhance the
atomization of the fuel exiting from the primary fuel nozzle and to provide a
cone-
shaped air and fuel spray within the combustion chamber.

3. The fuel injector as defined in claim 2, wherein a set of second air
passages is arranged in an annular array in the air swirl member spaced
radially
outwardly from the first air passages and concentric with the injector tip
axis whereby
the second air passages are arranged to shape the spray of a mixture of
atomized fuel
and air and to add supplemental air to the mixture.



-16-


4. The fuel injector as defined in claim 1, wherein a plurality of slots
communicate the annular channel to the primary fuel chamber in a manner so as
to
enhance the swirl of the fuel flow passing from the first annular channel to
the
primary fuel chamber.

5. The fuel injector for a combustor as defined in claim 1, wherein the
fuel injector is mounted to a stem containing at least one fuel flow passage
extending
from a stem fuel inlet to a fuel delivery outlet, a first annular fuel flow
cavity
provided in the stem near the fuel stem inlet, an inlet conduit extending from
the fuel
stem inlet to the annular cavity and being angled to provide a tangential flow

direction to the fuel passing to the annular cavity, an outlet conduit
extending at an
acute angle from the first annular cavity to receive the fuel therefrom in
tangential
direction and deliver it to a linear fuel conduit extending axially of the
stem and
communicating with an injector inlet conduit at the fuel delivery outlet, the
injector
inlet conduit being angled to direct fuel flow to the first annular channel
tangentially
thereof.

6. The fuel injector as defined in claim 1, wherein a secondary fuel
delivery arrangement is provided which is concentric and radially outward of
the
primary fuel channel, the fuel delivery arrangement including a secondary
annular
conical fuel swirl chamber provided concentrically and outwardly of the
primary fuel
swirl chamber, a secondary fuel nozzle provided concentrically and outwardly
of the
primary fuel nozzle and the injector tip axis, and means for providing a flow
of
pressurized fuel to the secondary annular channel tangential thereof in order
to
provide a swirl to the fuel flow in the secondary annular fuel channel, the
secondary
annular fuel channel communicating with the secondary fuel swirl chamber so as
to
provide a swirl to the fuel whereby the secondary fuel will exit the secondary
fuel
nozzle in an atomized state.



-17-


7. The fuel injector as defined in claim 2, wherein the fuel injector body
sits within a concentric cylindrical extension of the air swirl member.

8. In a fuel injector for use in a combustor of a gas turbine engine,
wherein the fuel injector includes an injector tip having annular fuel flow
passages, a
stem containing at least one fuel flow passage extending from a stem fuel
inlet to a
stem fuel delivery outlet, a first annular fuel flow cavity provided in the
stem near the
fuel stem inlet, an inlet conduit extending from the fuel stem inlet to the
annular
cavity wherein the inlet conduit is angled to provide a tangential flow
direction to the
fuel passing through the conduit to the annular cavity, an outlet conduit
extending at
an acute angle from the first annular cavity to receive the fuel therefrom in
a
tangential direction, a first linear fuel conduit extending from the outlet
conduit and
extending axially of the stem and communicating with an injector inlet conduit
at the
fuel delivery outlet of the stem, the injector inlet conduit being angled to
direct the
fuel flow to a first annular passage in the injector in a tangential direction
to provide a
swirl to the fuel flow entering the annular passage in the injector tip.

9. In the injector as defined in claim 8, wherein the injector tip has a
secondary annular fuel flow passage and the stem comprises a second annular
fuel
flow channel concentric with the fuel flow cavity, a second inlet conduit
extends
from the fuel stem inlet to the second annular channel and being angled to
provide a
tangential flow direction to the secondary fuel into the second annular
channel, an
outlet conduit extending at an acute angle from the second annular channel to
receive
the secondary fuel therefrom in a tangential direction, a second linear fuel
conduit
parallel to the first linear fuel conduit and extending from the second outlet
conduit
and communicating with a second injector inlet conduit at the fuel delivery
outlet, the
second injector inlet conduit being angled to direct the fuel flow to the
secondary
annular passage in the injector tip in a tangential direction to provide a
swirl to the
secondary fuel flow entering the secondary annular passage in the injector
tip.


-18-
10. In the injector as define din claim 8, wherein certain of the conduits
include at least portions that have a cross-sectional diameter smaller than
adjacent
conduit portions in order to meter the fuel flow passing therethrough.

11. The fuel injector as defined in claim 4, wherein the slots are provided
with portions of reduced diameter in order to provide for the metering of the
fuel
flow between the various annular passages.

12. The fuel injector as defined in claim 4, wherein the slots extending
between the annular passages are angled to provide a tangential delivery of
the fuel
flow to downstream annular passages

13. In the injector as defined in claim 6, wherein certain of the conduits
include at least portions that have a cross-sectional diameter smaller than
adjacent
conduit portions in order to meter the fuel flow passing therethrough.

14. A method for atomizing fuel delivered by an injector to a gas turbine
combustor, including the steps of preswirling the fuel prior to introducing
the fuel in
the injector tip, directing the preswirl fuel tangentially into a first
annular passage to
provide a circular swirl to the fuel as it enters the injector tip, advancing
the swirling
fuel to a conical fuel swirl chamber with the apex of the cone downstream
thereof
and exiting the fuel from the conical swirl chamber through a nozzle such that
the
fuel is atomized as it exits from the nozzle.

15. A method as defined in claim 14, wherein air is passed into the
chamber in an annular array with each passage in the array having an axis at
an angle
to create a swirl for the air entering into the combustor and enhancing the
atomization
of the fuel.


-19-
16. A fuel injector for use in a combustor of a gas turbine engine, whereby
the combustor includes a combustor wall defining a combustion chamber
surrounded
by pressurized air, the injector comprising an injector tip adapted to
protrude, when
in use, through the combustor wall into the chamber, the injector tip having
an
injector body extending along an injector tip axis, a primary fuel nozzle
formed in the
injector tip concentrically of the injector tip axis and communicating with a
primary
fuel chamber formed as a cone upstream of the fuel nozzle and coaxial
therewith, a
first annular fuel channel defined in the injector body upstream of the
primary fuel
chamber concentric with the injector tip axis and communicating with the
primary
fuel chamber, a second annular fuel channel defined in the injector body
upstream of
the first annular fuel channel, passages communicating the second annular fuel

channel downstream to the first annular fuel channel, and an inlet conduit
defined in
the injector body to communicate the fuel under pressure tangentially into the
second
fuel channel so as to provide a swirl to the fuel in the second fuel channel,
and then to
the first annular fuel channel tangentially thereof in order to provide a
swirl to the
fuel flow in the second annular fuel channel, the first annular fuel channel,
the
primary fuel chamber, and thus to the injector tip, thereby atomizing the fuel
as it
exits the primary fuel nozzle.

17. The fuel injector as defined in claim 16, wherein an annular air swirl
member is provided mounted to the injector tip, the air swirl member including
an
annular array of first air passages communicating the pressurized air
surrounding the
combustor into the combustion chamber, the first air passages being concentric
with
the primary fuel nozzle and the tip axis whereby the first air passages are
arranged to
further atomize the fuel exiting from the primary fuel nozzle in order to
enhance the
atomization of the fuel exiting from the primary fuel nozzle and to provide a
cone-
shaped air and fuel spray within the combustion chamber.


-20-

18. The fuel injector as defined in claim 17, wherein a set of air passages
is arranged in an annular array in the air swirl member spaced radially
outwardly
from the first air passages and concentric with the injector tip axis whereby
the
second passages are arranged to shape the spray of a mixture of atomized fuel
and air
and to add supplemental air to the mixture.

19. The fuel injector for a combustor as defined in claim 16, wherein the
fuel injector is mounted to a stem containing at least one fuel flow passage
extending
from a stem fuel inlet to a fuel delivery outlet, a first annular fuel flow
chamber
provided in the stem near the fuel stem inlet, an inlet conduit extending from
the fuel
stem inlet to the first annular fuel chamber and being angled to provide a
tangential
flow direction to the fuel passing to the first annular fuel chamber, an
outlet conduit
extending at an acute angle from the first annular fuel chamber to receive the
fuel
therefrom in a tangential direction and deliver it to a linear fuel conduit
extending
axially of the stem and communicating with the inlet conduit.

20. The fuel injector as defined in claim 17, wherein the fuel injector body
sits within a concentric cylindrical extension of the air swirl member.

21. A fuel injector for use in a combustor of a gas turbine engine, whereby
the combustor includes a combustor wall defining a combustion chamber
surrounded
by pressurized air, the injector comprising an injector tip adapted to
protrude, when
in use, through the combustor wall into the chamber, the injector tip having
an
injector body extending along an injector tip axis, a primary fuel nozzle
formed in the
injector tip concentrically of the injector tip axis and communicating with a
primary
fuel chamber formed as a cone upstream of the fuel nozzle and coaxial
therewith, at
least a first annular fuel channel defined in the injector body upstream of
the primary
fuel chamber concentric with the injector tip axis and communicating with the
primary fuel chamber, a plurality of slots to communicate the primary fuel
chamber,
wherein the slots are angled to provide a tangential delivery of the fuel flow
from the


-21-

first annular channel to the primary fuel chamber, and means for providing a
flow of
pressurized fluid to the first annular channel tangentially thereof in order
to provide a
swirl to the fuel flow in the first annular fuel channel, the primary fuel
chamber, and
thus to the tip nozzle, thereby atomizing the fuel as it exits the primary
fuel nozzle.
22. The fuel injector as defined in claim 21, wherein the slots are provided
with portions of reduced diameter in order to provide for the metering of the
fuel
flow between the various annular passages.

23. A fuel injector for use in a combustor of a gas turbine engine, whereby
the combustor includes a combustor wall defining a combustion chamber
surrounded
by pressurized air, the injector comprising an injector tip adapted to
protrude, when
in use, through the combustor wall into the chamber, the injector tip having
an
injector body extending along an injector tip axis, a primary fuel nozzle
formed in the
injector tip concentrically of the injector tip axis and communicating with a
primary
fuel chamber formed as a cone upstream of the fuel nozzle and coaxial
therewith, at
least a first annular fuel channel defined in the injector body upstream of
the primary
fuel chamber concentric with the injector tip axis and communicating with the
primary fuel chamber, and means for providing a flow of pressurized fluid to
the first
annular channel tangentially thereof in order to provide a swirl to the fuel
flow in the
first annular fuel channel, the primary fuel chamber, and thus to the tip
nozzle,
thereby atomizing the fuel as it exits the primary fuel nozzle; a secondary
fuel
delivery arrangement is provided which is concentric and radially outward of
the
primary annular fuel channel, the secondary fuel delivery arrangement
including a
secondary annular fuel channel, a secondary annular conical fuel chamber
provided
concentrically and outwardly of the primary fuel chamber, a secondary fuel
nozzle
provided concentrically and outwardly of the primary fuel nozzle in the
injector tip
axis, secondary fuel inlet conduit for directing fuel under pressure
tangentially into
the secondary annular fuel channel in order to provide a swirl to the fuel
flow in the
secondary annular fuel channel, the secondary annular conical fuel chamber and
the
secondary fuel nozzle.


-22-
24. In the injector as defined in claim 23, wherein conduits are provided to
communicate the secondary annular fuel channel with the secondary annular
conical
fuel chamber and the conduits include at least portions that have a cross-
sectional
diameter smaller than adjacent conduit portions in order to meter the fuel
flow
passing therethrough.

Description

Note: Descriptions are shown in the official language in which they were submitted.



CA 02335349 2000-12-15

WO 00/00770 PCT/CA99/00579
- 1 -

FUEL INJECTOR FOR GAS TURBINE ENGINE
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to gas turbine engines
and, more particularly, to a fuel injector for such
engines.
2. Description of the Prior Art
Many small gas turbine engines utilize fuel pressure
to atomize fuel at the fuel nozzle of an injector to
inject fuel into the combustion chamber. At low fuel
flows, such as starting conditions, the fuel flow rate is
too low to pressurize the fuel to produce adequate
droplet size for a particular injector. Such fuel
systems are designed for maximum pressure at full engine
power. Thus, the smallest flow number possible for a
given engine design is determined by the maximum pressure
available from the fuel pump at maximum power. At
starting conditions and low power, small quantities of
fuel are required, thereby developing low pressure drop.
This results in inadequate atomization at low power and
leads to poor emissions and combustion instability.
Furthermore, since the fuel injector is immersed in
a very hot environment of the gas turbine engine,
stagnation of the fuel in the delivery passages can be
detrimental to the injector in that the heat transfer
from the walls of the injector is reduced which can lead
to hot spots on the otherwise wetted wall. It has been
found that excessive wall temperatures can lead to fuel
coking and subsequent injector contamination. Low fuel
flows in these regions further aggravate the situation.


CA 02335349 2007-07-12
-2-

In some cases, lack of adequate heat transfer in the stem may lead to
unacceptable temperature gradients and attendant stresses in the stem which
can
affect its fatigue life.
It has been found that by swirling a substantial quantity of air around a
nozzle
of a fuel injector, an improvement in low power performance can be obtained.
However, swirling the air can lead to flow separation around the face of the
injector,
resulting in carbon growth and overheating of the injector.
Air swirlers have been developed and are described in U.S. Patent
No. 5,579,645, Prociw et al., issued December 3, 1996, and U.S. Patent
No. 6,082,113 issued on July 4, 2000 for a Gas Turbine Injector by Prociw et
al. and
assigned to Pratt & Whitney Canada Inc. These air swirlers reduce flow
separation at
the injector. However, it is considered that other improvements are required
to
improve low power performance of the injector by improving fuel atomization at
the
injector.
The stem of the injector, that is, the elongated stem through which the
various
fuel conduits are contained, extends from the fuel source across the P3 air
envelope
surrounding the combustor wall. The stem is also subjected to high
temperatures
and, therefore, problems of fuel stagnation that can lead to fuel coking is
also
possible within the stem.


CA 02335349 2007-07-12

-3-
SUMMARY OF THE INVENTION
It is an aim of the present invention to provide an improved injector wherein
low power fuel atomization will be enhanced.

It is a further aim of the present invention to provide an improved simplex
pressure injector with improved low power performance.

It is yet a further aim of the present invention to provide an improved duplex
pressure injector with improved low power performance.
It is an aim of the present invention to provide a fuel flow path within the
stem and the injector tip which follows a circular path. Parts of the stem and
the
injector tip are provided with annuli which allow a circular and/or spiral
path for the
fuel.
It is yet a further aim of the present invention to provide an improved fuel
flow passage in the stem of the injector. It is known that the velocity of the
flow in
the annular channels is controlled by appropriately sizing the inlet orifice
to produce
the correct pressure loss for the heat transfer rate required. According to
the present
invention, much higher velocities than would occur in conventional designs are
attributable to the present method since a large portion of the fuel flow is
in the
tangential direction and not governed by the mass of fuel.


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In the present invention, this control of the flow
velocity to produce the correct pressure loss is
determined not by a single metering or trim orifice at
the inlet to the injector but by providing such metering
orifices throughout the stem prior to the fuel entering
the injector.
A construction in accordance with the present
invention comprises a fuel injector for a combustor in a
gas turbine engine, wherein the combustor includes a
combustor wall defining a combustion chamber surrounded
by pressurized air, the injector comprising an injector
tip adapted to protrude, when in use, through the
combustor wall into the chamber, the injector tip having
an injector body extending along an injector tip axis, a

primary fuel nozzle formed in the injector tip
concentrically of the injector tip axis and communicating
with a primary fuel chamber formed as a cone upstream of
the fuel nozzle and coaxial therewith, at least a first
annular fuel channel defined in the injector body
upstream of the primary fuel chamber concentric with the
injector tip axis and communicating with the primary fuel
chamber, and means for providing a flow of pressurized
fuel to the first annular channel tangentially thereof in
order to provide a swirl to the fuel flow in the first
annular fuel channel, the primary fuel chamber and thus
to the injector tip, thereby atomizing the fuel as it
exits the primary fuel nozzle.
More particularly, swirl slots communicate the first
annular channel to the primary fuel chamber.
In a more specific embodiment of the present
invention, there is provided a secondary fuel delivery


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- 5 -

arrangement whereby a secondary annular fuel channel is
provided concentrically and outwardly of the primary
fuel channel, a secondary annular conical fuel swirl
chamber.is provided concentrically and outwardly.of the
primary swirl fuel chamber, and a secondary fuel nozzle
is provided concentrically and outwardly of the primary
fuel nozzle and the injector tip axis, means for
providing a flow of pressurized fuel to the secondary
annular channel tangential thereof in order to provide a
swirl to the fuel flow in the secondary annular fuel
channel, the secondary annular fuel channel communicating
with the secondary fuel swirl chamber so as to provide a
swirl to the fuel whereby the secondary fuel will exit
the secondary fuel nozzle in an atomized fashion.
It has been found that when the tangential velocity
of the swirling fuel increases as it progresses in the
conical primary fuel chamber, external air is entrained
back into the primary fuel chamber along the tip axis,
resulting in the formation of a thin hollow spinning film
of fuel in the primary fuel chamber. As the fuel exits
from the nozzle, it forms a thin conical unstable film
that breaks down into droplets.
It is a further feature of the present invention to
provide the injector with an air swirl member defining
first air passages forming an annular array communicating
the pressurized air from outside the wall into the
combustion chamber, the first air passage being
concentric with the primary fuel nozzle and the tip axis
whereby the first air passages are arranged to further
atomize the fuel emanating from the primary fuel nozzle,
and a set of second air passages arranged in annular


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- 6 -

array in the injector tip spaced radially outwardly from
the first air passages whereby the second passages are
arranged to shape the spray of thiE~ mixture of atomized
fuel and air and to add supplemental air to the mixture.
In a further embodiment of an injector in accordance
with the present invention including an injector tip that
has annular fuel flow passages, there is a stem
containing at least one fuel flow passage extending from
a stem fuel inlet to a fuel delivery outlet, a first
annular fuel flow cavity provided in the stem near the
fuel stem inlet, an inlet conduit extending from the fuel
stem inlet to the annular cavity, the inlet conduit being
angled to provide a tangential flow direction to the fuel
passing through the conduit to the annular cavity, an
outlet conduit extending at an acute angle from the first
annular cavity to receive the fuel therefrom in a
tangential direction, a first linear fuel conduit
extending from the outlet conduit and extending axially
of the stem and communicating with an injector inlet
conduit at the fuel delivery outlet, the injector inlet
conduit being angled to direct the fuel flow to a first
annular passage in the injector tip in a tangential
direction to provide a swirl to the fuel flow entering
the annular passage in the injector tip.
In a more specific embodiment of the present
invention, there is provided a metering of the fuel flow
in the various conduits in the stem where alternating
fuel flow conduits have differing cross-sectional areas
arranged to provide the proper velocity to the fuel flow
and result in the pressure loss to enhance the heat
transfer rate.


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As can be seen, throughout the injector tip and the
stem, care has been taken to ensure tangential injection
into the annular passages, thus maximizing the angular
momentum of the fuel flow into the annular channels. The
kinetic energy in the flow is dissipated at the stem and
injector walls enhancing the heat transfer of the
passages.
The passage metering and the fuel swirl slots in the
injector tip are designed to control injector temperature
and to eliminate fuel stagnation wherever possible.

BRIEF DESCRIPTION OF THE DRAWINGS
Having thus generally described the nature of the
invention, reference will now be made to the accompanying
drawings, showing by way of illustration, a preferred

embodiment thereof, and in which:
Fig. 1 is a fragmentary vertical cross-section of an
injector in accordance with an embodiment of the present
invention;
Fig. 2 is a front elevation of the injector in
accordance with Fig. 1;
Fig. 3 is a fragmentary axial cross-section in
accordance with another embodiment of the injector in
accordance with the present invention;
Fig. 4 is a perspective schematic view showing the
flow passages of the injector in accordance with the
present invention, including both the injector tip and
the stem;
Fig. 5 is a schematic view showing the fuel passages
within the injector tip of the embodiment shown somewhat
in Fig. 1; and


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Fig. 6 is a perspective schematic view showing the
flow passages based on the embodiment shown in Fig. 3 of
the injector tip but showing only the secondary fuel flow
passages.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present specification describes two embodiments
of the present invention. The first embodiment shown in
Figs. 1 and 2 is a simplex injector while the second

embodiment shown in Fig. 3 is a duplex injector.
Referring to the embodiment shown in Figs. 1 and 2,
the simplex injector is designated by the reference
numeral 30. The injector 30 is shown mounted in an
opening in the combustor wall 31. The injector 30
includes an injector body 32, an injector face 33, as
shown in Fig. 2, and an injector tip 34.
A tip axis X extends through the tip 34 and the
body 32, as shown in Fig. 1. A stem 40 is connected to
the body 32, and at least.a fuel passage 36 is formed in
the stem 40 which is also covered by protective
sleeve 38. The body 32 defines cavities, such as annular
channels 41, 42, and 44, that are concentric to the tip
axis X. The fuel line 36 communicates with the
channel 41 in a somewhat tangential manner in order that
the fuel under pressure will be provided a swirl in the
annular channel 41. The annular channels 42 and 44
communicate with each other by means of slots 46 which
are defined helically so as to provide a swirl or spin to
the fuel as it passes from the annular channel 42 and to
channel 44.


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WO 00/00770 PCT/CA99/00579
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A conical fuel swirl chamber 48 is defined
downstream of the channel 44, and slots 49 communicate
the channel 44 to the chamber 48. As the diameter in the
conical chamber 48 decreases, the velocity of the
spinning fuel increases until it reaches the cylindrical
nozzle 50. It is believed that the spinning fuel flow
will create a film on the conical walls of the chamber 48
by centrifugal force, and external air may be drawn into
the chamber to flow back along the tip axis X into the
chamber 48. This separation effect results in a thin,
hollow, spinning film which develops at the nozzle 50.
As the fuel leaves the nozzle, it forms a thin conical
sheet which stabilizes into droplets.
An annular air swirl member 52 is connected to the
injector tip 34, as shown in Figs. 1 and 2. The air
swirl member 52 comprises a series of annular spaced-
apart passages 54 distributed around the nozzle 50. As
described in U. S. Patent Application 09/083,199, the air
flow from P3 air into the combustor passes through the
holes or passages 54 in such a way as to avoid flow
separation and to develop a conical fuel spray pattern
within the combustor.
A second set of annularly spaced-apart passages 56
may be provided to shape the fuel air cone and to augment
the combustion air into the combustor. Both sets of
passages 54 and 56 are specifically sized to admit a
predetermined quantity of air at the engine design point.
Referring now to the embodiment of Fig. 3, the
duplex injector 60 is described which includes an
injector body 62 and an injector tip 64. The tip axis X2
passes through the injector tip 64 as shown.


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The injector body 62 fits in a stem cavity 74. In
this embodiment, the air swirl member 66 includes a
cylindrical portion which has a greater diameter than the
injector body 62.
The injector body 62 defines, with the cavity 74 of
the stem 72, a primary fuel channel 68. The fuel
channel 68 is annular because of the valve device 73
within the cavity so formed. The fuel annular channel 68
communicates with the primary fuel line 86 which is
arranged to deliver the pressurized fuel tangentially of
the channel 68 so as to create a fuel swirl within the
primary fuel channel 68.
A primary fuel swirl chamber 70 is defined as a
conical chamber downstream of the channel 68 and
communicates with the nozzle 71. Slots 75 are defined
between the valve 73 and the conical wall of the
chamber 70. These slots are designed to enhance the
spinning effect of the primary fuel from the primary fuel
channel to the primary fuel chamber 70 and ultimately

through the nozzle 71.
A secondary fuel channel 76 is formed between the
injector body 62 and the cylindrical portion 67 of the
air swirl member 66. Passages are provided in the
cylindrical member 67 to communicate with the secondary
fuel line 88 in the stem 72. The fuel line and the
passages will provide a swirl to the secondary fuel as it
enters the secondary annular channels 76. The annular
channel 76 communicates with the downstream annular
secondary fuel channel 78 by means of slots 80 which are

designed to enhance the swirl of the secondary fuel. A
conical secondary fuel chamber 82 is also provided which


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WO 00/00770 PCT/CA99/00579
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is annular to the axis X2 and the primary fuel chamber 70.
The secondary fuel chamber 82 has the same effect on the
secondary swirling fuel as has the primary chamber 70.
An annular nozzle 84 is also provided in order to allow
the secondary fuel to form a conical spray with the
primary fuel in the combustion chamber defined by
combustor wall 94.
The air swirl member 66 is provided with air swirl
passages 90 so as to focus the air flow from the P3 air
into the combustion chamber just outside the fuel
injector face. Auxiliary air passages 92 are also
provided in the swirl component 66 and have a similar
effect to those described with the simplex injector 30.
It is noted that another difference between the
duplex injector 60 and the prior art is the absence of
core air passages and the primary injector heat shield.
The elimination of these elements reduces the
manufacturing complexity as well as its cost. A duplex
injector 60 is more compact for a given fuel flow rate.
This injector does not have to be concerned with the heat
transfer problems arising from the presence of core air
in the interior passage of the injector. The integration
of the air swirler component 66 with the fuel nozzles 71
and 84 helps reduce the overall size of the injector
tip 64. The swirl component 66 design with the duplex
injector 60 aids atomization particularly at low power
when the fuel pressure in the secondary annular channel
is too low to generate the thin film required for
adequate atomization.
Referring now to Fig. 4, the stem 172 is shown
generally in dotted lines. However, primary passage 174


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and second passage 176 are illustrated in this drawing.
The injector 160 is a duplex injector similar to that
described in relation to Fig. 3. Thus, the injector
tip 160 includes a primary fuel channel 168 and a
secondary fuel channel 176.
The remote end of the stem is provided with a
primary fuel inlet 140 which communicates with a circular
cylindrical primary fuel chamber 142 by means of the
inlet conduit 144. As noted in the drawings, the
conduit 144 is angled so that it delivers the fuel in a
tangential direction within the cylindrical chamber 142.
The primary fuel chamber 142 is shaped to allow the
primary fuel flow to swirl therein and exit through an
outlet conduit 146 which is of somewhat smaller diameter
than the chamber in order to provide a first metering
passage. The conduit 146 communicates with a linear
conduit 148 which has a larger cross-sectional area than
the conduit 146.
The linear conduit 148 communicates with a delivery
conduit 186 which is angled to deliver the primary fuel
into the annular channel 168 tangentially. The delivery
conduit 186 is also of a smaller cross-sectional area
than the conduit 148 in order to meter the fuel flow into
the channel 168.
The secondary fuel passage 175 of the stem 172 has a
secondary fuel inlet conduit 150 which is angled to
deliver the fuel to the annular channel 152 at the entry
end of the stem 172. An outlet conduit 154 delivers the
fuel flow from the annular channel 152 at a somewhat
tangential angle to deliver the fuel to the linear
conduit 156 which is of a larger cross-sectional area


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than the conduit 154. At the injector end of the stem,
an angled two-part delivery conduit 188 is provided for
delivering the fuel to the annular channel 176 in a
tangential direction so as to provide a swirl to.the fuel

flow within the annular channel 176.
Figs. 5 and 6 correspond generally with the injector
tip of Fig. 1, and although there are some constructional
differences, they do resemble each other in principle.
Thus, the reference numerals used in Fig. 5 will
correspond to the reference numerals used in Fig. 1 but
have been raised by 200.
Thus, the fuel is delivered by means of the delivery
conduit 236 into the annular channel 241. The slots 246
are all angled to deliver the fuel from the channels 241
and 242 into the annular channel 244. Angled slots 249
deliver the fuel tangentially to the chamber 248.
The schematic depiction of the fuel flow passages
shown in Fig. 6 resembles the duplex injector shown in
Fig. 3. The drawing represents the secondary fuel
distribution in the injector tip (the primary flow is not
shown) and that will now be described with similar
reference numerals to those used in Fig. 3 but raised
by 300.
Thus, the delivery conduit 388 is shown here with
its two components 388a and 388b. As noted, the cross-
sectional diameter of the conduit portion 388a is larger
than the cross-sectional diameter of the portion 388b,
thereby providing the metering effect mentioned
previously in order to provide the proper pressure drop.
The delivery conduits 388a and 388b are so arranged
in the stem that the portion 388b is directed


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tangentially to the annular channel 375 or 376. The so-
called angular slots 380 are, in fact, as shown in
Fig. 6, in two parts, one being a first outlet
portion 380a delivering the fuel from the channel 376,-
and the second part 380b is of a smaller diameter and is
angled to provide the fuel flow tangentially to the
conical fuel swirl chamber 382.

Representative Drawing
A single figure which represents the drawing illustrating the invention.
Administrative Status

For a clearer understanding of the status of the application/patent presented on this page, the site Disclaimer , as well as the definitions for Patent , Administrative Status , Maintenance Fee  and Payment History  should be consulted.

Administrative Status

Title Date
Forecasted Issue Date 2008-10-07
(86) PCT Filing Date 1999-06-22
(87) PCT Publication Date 2000-01-06
(85) National Entry 2000-12-15
Examination Requested 2003-11-12
(45) Issued 2008-10-07
Expired 2019-06-25

Abandonment History

There is no abandonment history.

Payment History

Fee Type Anniversary Year Due Date Amount Paid Paid Date
Registration of a document - section 124 $100.00 2000-12-15
Application Fee $300.00 2000-12-15
Maintenance Fee - Application - New Act 2 2001-06-22 $100.00 2001-05-15
Maintenance Fee - Application - New Act 3 2002-06-24 $100.00 2002-04-23
Maintenance Fee - Application - New Act 4 2003-06-23 $100.00 2003-05-26
Request for Examination $400.00 2003-11-12
Maintenance Fee - Application - New Act 5 2004-06-22 $200.00 2004-05-28
Maintenance Fee - Application - New Act 6 2005-06-22 $200.00 2005-05-10
Maintenance Fee - Application - New Act 7 2006-06-22 $200.00 2006-03-06
Maintenance Fee - Application - New Act 8 2007-06-22 $200.00 2007-06-22
Maintenance Fee - Application - New Act 9 2008-06-23 $200.00 2008-03-11
Final Fee $300.00 2008-07-24
Back Payment of Fees $200.00 2008-08-22
Maintenance Fee - Patent - New Act 10 2009-06-22 $250.00 2009-05-07
Maintenance Fee - Patent - New Act 11 2010-06-22 $250.00 2010-05-11
Maintenance Fee - Patent - New Act 12 2011-06-22 $250.00 2011-05-11
Maintenance Fee - Patent - New Act 13 2012-06-22 $250.00 2012-05-10
Maintenance Fee - Patent - New Act 14 2013-06-25 $250.00 2013-05-08
Maintenance Fee - Patent - New Act 15 2014-06-23 $450.00 2014-05-15
Maintenance Fee - Patent - New Act 16 2015-06-22 $450.00 2015-05-25
Maintenance Fee - Patent - New Act 17 2016-06-22 $450.00 2016-05-27
Maintenance Fee - Patent - New Act 18 2017-06-22 $450.00 2017-05-23
Maintenance Fee - Patent - New Act 19 2018-06-22 $450.00 2018-05-23
Owners on Record

Note: Records showing the ownership history in alphabetical order.

Current Owners on Record
PRATT & WHITNEY CANADA CORP./PRATT & WHITNEY CANADA CIE.
Past Owners on Record
PRATT & WHITNEY CANADA INC.
PROCIW, LEV A.
SAMPATH, PARTHASARATHY
SHAFIQUE, HARRIS
Past Owners that do not appear in the "Owners on Record" listing will appear in other documentation within the application.
Documents

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Document
Description 
Date
(yyyy-mm-dd) 
Number of pages   Size of Image (KB) 
Representative Drawing 2001-03-30 1 27
Claims 2007-07-12 8 319
Description 2007-07-12 14 567
Representative Drawing 2007-12-05 1 24
Abstract 2000-12-15 1 66
Description 2000-12-15 14 593
Claims 2000-12-15 6 237
Drawings 2000-12-15 5 229
Cover Page 2001-03-30 2 86
Cover Page 2008-09-19 2 70
Assignment 2000-12-15 6 233
PCT 2000-12-15 5 205
Prosecution-Amendment 2000-12-15 1 21
Correspondence 2001-03-28 1 15
Prosecution-Amendment 2003-11-12 3 115
Prosecution-Amendment 2003-12-01 1 27
Prosecution-Amendment 2007-07-12 13 459
Prosecution-Amendment 2007-01-12 2 52
Correspondence 2007-03-12 2 62
Correspondence 2007-05-11 1 15
Correspondence 2007-05-11 1 18
Correspondence 2008-07-24 2 67
Correspondence 2008-09-17 1 19