U.S. patent number 3,667,221 [Application Number 04/816,985] was granted by the patent office on 1972-06-06 for fuel delivery apparatus.
This patent grant is currently assigned to General Electric Company. Invention is credited to Jack R. Taylor.
United States Patent |
3,667,221 |
Taylor |
June 6, 1972 |
FUEL DELIVERY APPARATUS
Abstract
Apparatus is disclosed for premixing air and fuel or carbureting
air prior to introduction thereof into the primary zone of a
combustor, said apparatus including a housing defining a spin
chamber therein; the spin chamber is adapted to receive air and
fuel and vaporize and/or atomize said fuel and deliver said air and
fuel into said combustor as a vortical flow.
Inventors: |
Taylor; Jack R. (Cincinnati,
OH) |
Assignee: |
General Electric Company
(N/A)
|
Family
ID: |
25222097 |
Appl.
No.: |
04/816,985 |
Filed: |
April 17, 1969 |
Current U.S.
Class: |
60/737; 261/79.1;
431/173 |
Current CPC
Class: |
F23R
3/12 (20130101); F23R 3/30 (20130101) |
Current International
Class: |
F23R
3/04 (20060101); F23R 3/30 (20060101); F23R
3/12 (20060101); F02c 007/22 () |
Field of
Search: |
;60/39.71,39.65,39.74
;431/9,173 ;261/78,79R ;123/119R |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
675,092 |
|
Jul 1952 |
|
GB |
|
726,538 |
|
Mar 1955 |
|
GB |
|
765,327 |
|
Jan 1957 |
|
GB |
|
Primary Examiner: Hart; Douglas
Claims
What is claimed is:
1. A combustion apparatus including, in combination:
a hollow body defining a combustion chamber therein, said hollow
body formed with an opening therein, and
a housing disposed outwardly of said combustion chamber, said
housing including a downstream wall formed with an outlet of
generally circular flow area in the fluid flow communication with
said hollow body opening, an upstream wall facing said outlet, an
involute outer wall extending between and joining said upstream and
downstream walls so as to define a spin chamber internally of said
housing and a generally tangential inlet to said spin chamber, an
annular array of swirl vanes extending between said upstream and
downstream walls around said outlet, and passage means in fluid
flow connection with said tangential inlet for delivery of liquid
fuel and air to said spin chamber at a point radially outwardly of
said vanes.
2. The apparatus of claim 14 further characterized in that said
passage means is formed with an upstream facing inlet for receiving
a generally axially directed flow of air and includes one side wall
formed as a generally streamline continuation of said involute
outer wall.
Description
This invention relates to combustion apparatus and, more
particularly, to apparatus for supplying fuel to a combustion
chamber.
Delivery of fuel into a continuous burning combustion apparatus, as
for example in gas turbine engines, in a highly dispersed manner so
as to achieve complete and efficient combustion of the fuel and, at
the same time, minimize the occurrence of fuel-rich pockets which,
upon combustion produce carbon or smoke, has posed a continuing
design problem. Solutions of this problem are further complicated
in applications such as gas turbine engines by the severe
temperature environment of the combustion chamber as well as
overall length limitations for the combustion apparatus.
While spray atomizing nozzles of the type adapted to deliver a
single or dual atomized conical fuel spray through a small
discharge orifice have heretofore enjoyed widespread usage, such
devices are generally complex and expensive in nature and generally
require a relatively expensive and complex high pressure fuel
delivery or distribution system. Furthermore, such spray atomizing
nozzles tend to produce local fuel-rich pockets and are sensitive
to fouling by carbon deposits or other deleterious matter.
Another approach which has been heretofore employed involves the
use of tubes which extend into the combustion chamber for delivery
of air and fuel to a cup which is disposed in the primary
combustion zone of the combustor and is adapted to extract energy
from the combustor flame to vaporize the fuel. With such an
approach, however, life problems are encountered with respect to
the elements protruding into the hot region of the combustor.
This invention, then, is concerned with an efficient fuel delivery
apparatus which overcomes the foregoing problems.
A primary object of this invention is to provide relatively simple
and economical means for delivery of fuel into a combustion chamber
in a highly dispersed manner.
Another object of this invention is a long life fuel delivery
apparatus adapted to receive air and fuel, atomize and/or vaporize
the fuel, and carburet the inlet air with such fuel or premix the
fuel and air prior to introducing the fuel into the primary zone of
the combustor.
A further object of this invention is an apparatus for supplying
fuel to a combustion chamber which is relatively insensitive to
fouling, does not require a high pressure fuel distribution system,
and is of relatively short axial length.
Yet another object of this invention is an apparatus which is
adapted to utilize the energy of the inlet air to effect delivery
of the fuel to the combustion chamber in a highly dispersed
manner.
The above and other objects are achieved in the present invention
by providing a housing having a central or core outlet in flow
communication with the combustion chamber and defining a spin
chamber around the outlet. The spin chamber is adapted to receive
and circulate pressurized air and fuel around the outlet and
generate a vortical discharge of air from the outlet. In this
manner, the fuel is vaporized and/or atomized and delivered into
the combustion chamber with the air vortex. The spin chamber is
preferably formed with an involute or spiral shaped outer wall and
generally planar upstream and downstream end walls. Inlet passage
means may be provided for receiving a generally axially directed
flow of pressurized air and directing such air in a generally
streamline manner into the spin chamber. The inlet passage means
may also be adapted to receive and direct the fuel into the swirl
chamber although separate passage means may be used. Swirl vanes
may be employed to enchance the rotational velocity of the vortex
discharge as well as accurately locate the vortex centrally of the
outlet.
While the specification concludes with claims particularly pointing
out and distinctly claiming the subject matter of this invention,
it is believed the invention will be better understood upon reading
the following description of the preferred embodiment in
conjunction with the accompanying drawing wherein:
FIG. 1 is a fragmentary axial cross section view of an exemplary
gas turbine engine combustion apparatus embodying the present
invention;
FIG. 2 is a front elevational view, in partial cross section, of
the fuel delivery apparatus of this invention;
FIG. 3 is a side view, in partial cross section, of the apparatus
of FIG. 2; and
FIG. 4 is a cross sectional view taken along lines 4--4 of FIG.
2.
Referring now to the drawings, and particularly to FIG. 1, a
continuous burning combustion apparatus of the type suitable for
use in a gas turbine engine has been shown generally at 10 as
comprising a hollow body 12 defining a combustion chamber 14
therein. The hollow body 12 includes a domed upstream end 16 having
an opening 18 therein for receiving a fuel/air mixture. As will be
understood by those skilled in the art, the combustion chamber 14
may be of the annular type, the cannular type or the can type, with
the apparatus 10 having a plurality of circumferentially spaced
openings 18.
An outer shell 20 may be provided to enclose the hollow body 12 and
define passages 22 and 24 in cooperation with the hollow body 12
and a snout assembly 26. As will be understood, the passages 22 and
24 are adapted to deliver a flow of pressurized air from a suitable
source, such as a compressor 28, into the combustion chamber 14
through suitable apertures or louvers 30 for cooling of the hollow
body 12 and dilution of the gaseous products of combustion.
The snout assembly 26 is suitably secured to the upstream end of
the hollow body 12 and is adapted to function as a flow splitter to
divide the pressurized air delivered from the compressor 28 between
passages 22, 24 and a passage 32 formed through the snout
assembly.
The fuel injection or carbureting apparatus of this invention has
been shown generally at 34 as comprising a housing having inlet
passage means 36 for receiving pressurized air from snout assembly
passage 32, a central or core outlet 38 in flow communication with
the hollow body opening 18 for delivery of an air/fuel mixture into
the combustion chamber 14 as a vortical flow 40, and means 42 for
receiving fuel from a suitable conduit 44 which extends through the
snout assembly 26 and outer shell 20 and communicates with a source
of pressurized fuel. Although the fuel injection apparatus 34 is
particularly suited for use with liquid fuel and will be
hereinafter described in connection with a liquid fuel, it will be
appreciated that fuel in the liquid state, gaseous state,, solid
state or a combination thereof may be employed.
As will be understood, suitable ignition means (not shown) of well
known construction are provided within the combustion chamber 14 to
provide initial ignition of the combustible air/fuel mixture
discharged through outlet 38.
Referring now to FIG. 2, the housing comprises an involute outer
wall 48 and generally planar, spaced, upstream and downstream end
walls 50 and 52, respectively, peripherally joining the outer wall
and defining, in cooperation therewith, an air vortex generator or
spin chamber 46 within the housing outwardly of the core opening
38. As shown in FIG. 2, the outer wall 48 is generally involute or
spiral in shape with a progressively decreasing radius from the
inlet passage 36 to a terminal edge or lip 54 which defines, in
part, the inlet opening from the passage 36 to the spin chamber 46.
The inlet passage 36 is formed with a generally axially facing,
upstream end opening for receiving the flow of pressurized air from
passage 32 and has one wall formed as a streamline continuation of
the involute outer wall 48 so as to deliver the inlet air in a
generally streamline manner into the spin chamber 46. In this
manner, pressurized air is directed into the spin chamber 46 in a
circular motion of ever-decreasing radius so as to generate the
vortical or cyclonic discharge 40 having a hollow core 56. To
further enhance the swirling motion of the air as well as
accurately position the vortical flow 40 relative to the opening
38, a plurality of swirl vanes 58, each of which extends between
the upstream and downstream walls 50 and 52, may be provided in a
peripheral array about the outlet 38 as shown in FIG. 2. Such an
array of swirl vanes may also be adapted to throttle the air
passing therethrough so as to increase the rotational velocity of
the vortical flow 40.
While the outer wall 48 of the spin chamber 46 and the passage
means 36 have been shown and described as being involute, and such
is the preferred construction, it should be understood that other
vortex generator or spin chamber and passage means configurations
may be employed. For example, the spin chamber may be circular and
the passage means may be adapted to deliver the inlet air in a
tangential manner.
In order to maintain a generally uniform rotational velocity of the
inlet air within the spin chamber 46, outwardly of the vanes 58,
the outlet 38 and swirl vanes 58 are preferably positioned with
respect to the outer wall 48 so that the cross sectional flow area
between the outer wall 48 and the vanes 58 or opening 38
progressively decreases from the inlet 36 to the lip 54.
The apparatus 34 may be secured in the position of FIG. 1 by any
suitable means, such as by welding to the snout assembly 26 and/or
the hollow body 12 or by employing suitable bracketry (not
shown).
In operation, liquid fuel 60 is delivered to inlet passage 36
through means 42. Some of this fuel is immediately vaporized and/or
atomized and picked up by or entrained within the high velocity
inlet air and carried into the combustion chamber 14. The remaining
fuel lands on the interior surface of the inlet passage 36 and is
driven or pushed by the high velocity inlet air into the spin
chamber 46 and centrifugally along the outer wall 48. During such
flow, a portion of the fuel may be vaporized and entrained within
the inlet air flow. A portion of the fuel flow along outer wall 48
which is not so evaporated is then sheared off the lip 54, as at
62, and again passes across the high velocity, generally high
temperature, inlet air flow which results in more fuel being
vaporized and/or atomized and entrained within the inlet air. Since
the inlet air from the compressor 28 may be at an elevated
temperature of 700.degree. F. or higher, it will be appreciated
that significant vaporization may occur during such flow through
the vortex generator or spin chamber 46. In addition to the above
and with reference to FIG. 4, it has been found that the liquid
fuel circulating within spin chamber 46 is carried in a swirling
flow along the inner surface of upstream wall 50 by the swirling
air flow. This swirling flow liquid fuel is carried through vanes
58 and forms a ring of fuel 64 where the fuel velocity forces are
balanced by the centrifugal forces. During such flow along the
inner surface of upstream wall 50 to the ring 64, some of the fuel
may be vaporized from the surface by the high temperature inlet air
and by radiant heat from the flames within the combustion chamber
14. It has been found that the liquid fuel within the ring of fuel
64 is spun off and atomized into extremely small fuel droplets by
the high velocity vortical flow of air 40 and directed toward the
combustion chamber 14 as a generally conical spray 66. Since these
atomized fuel droplets are extremely small, they quickly vaporize
and mix with the air vortex 40.
Since the vortex core 56 is at a reduced pressure, a reverse or
recirculation flow is established from the combustion chamber 14
into the apparatus 34 as generally shown by the flow arrows 68 in
FIGS. 2 and 4. This recirculation of high temperature gas from the
chamber 14 into the central or core portion of the spin chamber 46
further enhances vaporization of the liquid fuel from the spin
chamber surfaces, as well as vaporization of any atomized fuel
droplets carried by the intake air or the atomized droplets
expelled from the fuel ring 64.
Since the outlet 38 is relatively large as compared, for example,
with the discharge orifice of prior fuel spray atomizing nozzles of
the well known type, the apparatus of this invention is relatively
insensitive to tolerance variations in construction and to problems
of deteriorated performance due to clogging by carbon or other
deleterious matter. Additionally, since the apparatus of this
invention utilizes the energy of the inlet air and does not relay
on fuel pressure to effect its atomized spray, lower fuel delivery
pressures and, consequently, simplified and more economical fuel
delivery or distribution systems may be employed. It will also be
noted that since the apparatus of this invention is positioned
externally of and does not project into the combustion chamber 14,
it is not subjected to the severe environmental stresses of the
chamber 14 and, accordingly, may readily be adapted to yield long
and reliable service life.
From the foregoing, it will be appreciated that the present
invention provides compact and economical means for carbureting air
or premixing air and fuel prior to introduction thereof into the
primary zone of combustor and, hence, for delivery of the fuel into
a combustion chamber in a highly effective and dispersed
manner.
While an exemplary embodiment of this invention has been depicted
and described as including an involute outer wall 48, involute
passage means 36 for introducing air and fuel into spin chamber 46,
and a circular array of swirl vanes 58, it should be understood
that the swirl vanes 58 may be eliminated and other suitable
geometrical housing and inlet passage constructions may be employed
to generate the circulation of fuel and air about outlet 38 and the
vortical flow discharge 66. Additionally, although the passage 36
has been shown as being adapted to deliver both the fuel and the
air to the spin chamber 46, and while such is the preferred
construction, separate passages may be employed. Accordingly,
although one embodiment of the present invention has been depicted
and described, it will be appreciated by those skilled in the art
that many modifications, substitutions and changes may be made
thereto without departing from the invention's fundamental
theme.
* * * * *