Note: Descriptions are shown in the official language in which they were submitted.
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VARIABLE AREA MEANS FOR AIR SYSTE~S
OF AIR ~LAST TYPE FUEL NOZZLE ASSEMBLIES
BACRGROUND AND SUMM~RY OF THE INVENTIOM
This invention relates to a variable area means ~or
air systems of air blast type fuel nozzle. The varia~le
area means is intended for use in the air systems o
sin~le fuel system and dual fuel system a.ir blast type
fuel nozzle assemblies or use in variable geometry (area)
combustion systems of advanced design gas turbine en~inesO
The purpose of controlling fuel/air ratios is to ~eet
emission standards over a wide range of engine op~rating
conditionsO
Present technology Lor accomplishing movement of
variable area air sys.ems of nozzles and combustors has
been through the use of elaborate mechanical linkage
systems with imput means through ~he engine case, such as
disclosed in U.S~ Patent NoO 3,905,19~. ~.S~ Patent ~o~
4,044,533 issued August 30, 1977 to Vaught discloses a
variable geometry swirler ln a combustion no~zle of a
fuel system.
It is an object of this invention to provide a
varla~le area air metering means connected with a pressure
responsive actuating means integral within a nozzle
assembly for controlling the air flow in the air systems
of single fuel system and dual fuel system air blast
type fuel nozzle and support assemblies used in gas
turbine engines. A :E~Irther object of the inven-tion is to
provide a p~ssaqe for a press~lrized actuating means, ei~her
li~uid o.r gas, through the nozz:l.e and su~port assembly -to
the inside of the engine case for the purpose of opera-ting
the variable area air system of the noæ-~le ancl combus-tor.
Broadly speaking, -the above objec-ts are met by
the present invention which provides an air blas-t type fuel
nozzle assembly having a fuel delivery system :Eor a gas -turbine
engine,.comprising: nozzle means having housing means wi-th
fuel supply means for supplying fuel to downstream orifice
means and having air supply means internal thereof -For
supplying air with respect -to fuel flow from the orifi.ce
means; and pressure responsive variable area air me-tering
means on an upstream end of the nozzle means, including air
inlet means in air flow communica-tion with the internal aîr
supply means, sleeve means wi-thin the nozz]e means Eorming a
piston-receiving means, piston means slidably received within
the sleeve means with the piston means having a downstream
face portion inside the nozzle means in fluid pressure commun-
ica-tion with a source of actuating fluid pressure, and pis-ton
rod means extending upstream of the face portion opera-tively
connected to valve means in the air inlet means for actuating
the valve means relative to the air inlet means, whereby
fuel/air ratio is controllable over a wide range oE operating
conditions.
BRIEF DESCRIPTION OF THE DRAWIN~S
Fig. 1 shows a typical external view of an air blast
-type fuel nozzle and suppor-t assembly with a variable area
air system means in the combustion system of a gas turbine
engine.
Fig. 2 shows a detail cross-sectional view of a
dual fuel system air blast fuel nozzle assembly with a
variable area air system means for controlling air flow to
both inner and outer air systems of a typical dual fuel system
air blast type fuel nozzle assembly.
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Fig. 3 shows a modif :iCd tion of the nozzle assembly
and var:iable area air sys-tem means as shown in Fig. 2 for
controlling a:ir flow -to the outer air system of applicants'
dual system air blast type Euel nozzle assembly.
Fig. 4 shows a further modifica-tion of -the nozzle
assembly and variable area air system means as shown in
Fig. 2 for controlling air flow -to -the inner air sys-tem of
applicants' dual fuel sys-tem air blast -type fuel nozzle
assembly.
Fig. 5 shows a detail cross-sec-tional view of a
single fuel system air blast type fuel nozzle assembly with
a variable area air system means for controlling air flow
to both inner and outer air systems of a typical single
fuel system air blast type fuel nozzle assembly.
Fig. 6 shows a further modifica-tion of the nozzle
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assembly and variable area air system means as shown for
controlling air flow to the outer air system of applicantls
single fuel system air blast type fuel nozzle assembly.
S Fig. 7 shows a modification of the nozzle assembly
and variable area air system means as shown in Fig. 5
for controlling air flow to the inner air system of
applicant's single fuel system air blast type fuel nozzle
assemblyc
Fig. 8 shows a detail cross-sectional view of a dual
fuel system air blast fuel nozzle assembly with a-variable
area air system means for controlling air flow to both
inner and outer air systems of a typical fuel system air
blast fuel nozzle assembly with the integral pressure
responsive actuating means connected to the primary nozzle
Euel passage.
DESCRIPTION OF TF[E PREFERRED EM~3ODIMENT
Referring to Fig. 1~ the fuel feeding system for the
invention disclosed is most particularly adapted for gas
turbine engines as indicated by the fragmentary represen-
tation thereon. In such engines, air is compressed by
compressor and is discharged through an opening 10.
portion of the air enters a combusti~n chamber 12 for
ignition with fuel discharged from nozzles 14O The
remainder of ~he air passes on opposite sides of the
combustion chamber 12 through passage 16 defined by the
outer engine case 18 and an inner engine case 20 not
shown. The products of combustion are discharged ,rom
the combustion cham~er 12 on to a turbine (not shown) in
a known fashion to drive the compressor and to generate a
power output such as a propulsive jet forceO
The amount of fuel supplied to the nozzle 14 varies
for different engine operating conditions. Pressurized
fuel is supplied to the nozzle 14 through the support
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assembly 22 by means of the primary nozzle fuel inlet
fitting 24, and the secondary nozzle fuel inlet fitting
26. A primary nozzle fuel passage 28 provides pressur-
ized fuel to the primary fuel system. A secondary nozzle
S fuel passage 30 provides pressurized ~uel to the second-
ary fuel system. The variable area air system actuating
means 32, using either liquid or gas, comprises an inlet
fitting 34 and passage 36 to the interior of nozzle 14 in
a manner to ~e herein described.
It is apparent as shown in Fig. 1, the nozzle and
support is a unitary assembly and mounted to the outer
engine casing 18 by bolts 33, with a typical prechamber
40 at the end of nozzle 14 mounted within an opening 42
of the combustion chamber 12. An engine spark igniter 44
is mounted to the outer engine case 18 and extends
through the combustion chamber liner wall 19 to provide
ignltion in the combustion chamber 12 ~o the combustible
mixture emanating from the nozzle 14O
~ eferring to Fig. 2, the passages 28, 30 and 36
through the nozzle suppor~ 22 ar~ shown in broken cross-
section view of the nozzle 14.
The nozzle support 22 is fabricatQd to the nozzle
adaptor or housing 48 by means of brazing rings 50l and
the nozzle adaptor 48 is ~abricated to the prechamber 40 ~y
brazing ring 52, in a manner to be described hereinafterO
3~ The nozzle adaptor 48 comprises the main body section
of the nozzle 14 in that it includes passases 28l, 30' and
36l which join the passages 28, 30 and 36 in the nozzle
suppo~t 22.
The primary nozzle fuel passages 28, 28' extend into
a chamber 54, which includes a primary nozzle fuel filter
56. Pr'mary fuel is thus adapted to flow into the
primary nozzle means 55 ~hrough the fuel filter 56 into a
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recess 58, through slots 60 of the primary no~zle swirler
62, through recessed area 6~ and through the primary
nozzle swirl holes 66 into the primary nozzle swirl
chamber 68. The primary fuel is discharged through the
primary nozzle orifice 70 of the primary nozzle swirl
chamber in a hollow cone spray out of the primary nozzle
orifice 70.
Around the e~it portion of the primary nozzle an
air shroud 72 is welded a~ 74 to the primary nozzle body
76~ The primary nozzle body 76 has passages 78 to supply
air from the inner air system under the air shroud 72 and
wash~s across the nozzle face to prevent carbon ~ormations
on the face of the nozzleO
The secondary nozzle fuel passages 30~ 30' extend
into an area 90 and is adapted to provide fuel flow
through angled secondary swirl slots 92, through area 94,
past slots 95 of secondary nozzle swirler 96 and exits
through annulus 98.
The outer air system 100 is adapted to exit through
outer air swirl vanes or helical slots 101 to prechamber
area 41 while the inner air system 102 is adopted to exit
through the inner air swirl vanes 103 to prechamber area
4t via chamber 104O The actuating means to control the
metering for the outer and inner air syst.ems 100 and 102,
respectively comprises, either air, gas~ or liquid~
through the passages 36 and 36' to control metering of the
air to the outer and inner air systemsO For examplef air
is adopted to enter the bore lOS and is adapted to move
the piston 107 against the bia~ of spring 109. That isl
the piston 107 is a spring biased pressure responsive valve
meansa The piston 107 is slidable in the actuating piston
sleeve 111 that is fabricated by means of brazing ring 113
to the rear portion of the housing or nozzle adaptor 48~
A spring retainer 115 holds the concentricity of the spring
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i~ the piston sleeve 111 with a snap ring 117 mounted in
recess 119 o~ the sleeve 111 to hold the actuating piston
107 and spring 109 within the sleeve l110
',
T~e piston is biased against the spring and moves
against it. The piston face comprises an ef~ective area~
with an operating pressure ~lowing ~hrough the passages
36, 36' operating against the piston 107 which in turn
moves two valves which are attached to the piston rod 1210
- lO That ist bo~h outer and inner air systems are controlled
by the movement o~ the piston 107~ The outer air system
me~ering valve 123 is mounted on to the end 125 of the
piston rod 1~1 and held in place by a retaining ring 127
. secured in a recessed Dortion 12g of the piston rod end
; 15 125. The outer air system metering valve 123 and the
-~ inner air system metering valve 141 is adapted to move
.~ axially or longitudinally as indicated by arrow 131. The
.~ opening 133 is adapted to be opened to allow more air to
enter the outer air system chamber 1350 That is, the
. 20 outer air system 1Q0 i9 adapted to flow through the
. openin~ 133 through the chamber 135, which is between the
.'.' body o~ the nozzle adaptor 48 and the member 137, and is
adapted to ~low past the outer air swirl vanes 101 to exit
': into the prechamber area 41. The member 137 separates the
outer air system 100 from the inner air system 102~
.~ Simultaneous with the movement o~ air through ~he outer
air systemr the inner air system air metering valve 141 is
~ adapted to move to allow air to enter the inner air system
: c~amber 155 via openings 143 in the closed end portion 145
o~ the outer air system air metering valve 123 and through
the opening 149 that exists between the inner air system
air metering valve 141 and the end of the outer air systern
air metering valve sleeve 1510 The inner air system 102
thus is adapted to flow through the openings 143 of the
`.: 35 outer alr system air meterin~ valve 123, past the opening
149 through chambers 153 and 155, past the inner air swirl
i vanes 103 on the primary nozzle ~ody and through chamber
104 to ex1t into the prechamber area 41 through annulus
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1564 An air scoop 157 is fabricated to the air metering
valve 123 by means of brazing ring 1S9 in a manner to be
described hereinafter.
S It is thus apparent that in the dual fuel system air
blast type nozzle having a variable area air system actu-
`atin~ means that the piston is adapted to move both
valves; that is, the outer air system air metering valve
123 and the inner air system air metering valve 141 is
moved to control the ratio of air in relation to the fuel
in the nozzleO
The nozzIe and support is a unitary structure in
that all the parts are fitted together and brazing rings
are placed within the annular recesses of the various
members and the completely assembled unit is then placed
in a furnace. The elevated temperature in the furnace
melts the brazing rods, such as shown in Fig. 2 namely,
50, 113, 16lt 162, 163~ and 167, to the mating members to
form a unitary assembly. A brazing method similar to the
method disclosed herein is disclosed in U.S. Patents
3,827,538 issued August 6, 1974 and 3,871,063 issued ~arch
18, lg75 to Robert M~ Halvorsen~
BRIEF DESCRIPTION OF THE MODIFICATIONS
Fig~ 3 shows a modification of the nozzle assemblv
showing essentially the same elements as in Fig. 2, with
the exception of the inner air system air metering valve~
That is, movement o~ ~he piston 307 longitudinally along
the direction of arrow 331 moves the piston rod 325. The
outer air metering valve 323 is attached to the end of the
piston rod 32S by a retaining ring 3~7 which is secured
thereto in annular recess 329. It is thus apparen~ that
as the pressure in the variable alr system actuating means
increases, the piston moves axially to allow more air to
enter the outer air system 300 through the onening 333,
while the inner air system 302 has a constan~ flow of air
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throuyh the open vent means 343 of the closed end portion
345 of air metering valve 323.
Figv 4 shows a further modirication of the noxzle
: 5 assembly showing a pressure responsive variable area
~: metering means for con~rolling air ~low to the inner air
system of a dual fuel system air blast type fuel nozzle
` assembly. That is, ~he outer air metering valve is
removed and only the inner air system air me~ering valve
is adapted to be moved longi~udinally along the direction
of arrow 4310 As the pressure in the variable area air
system actuating means increases~ the piston 407 moves
axially, moving the inner air system air metering valve
441, allowing more air to enter the inner air sys~em 402
through.the opening 449. The air metering valve 441 i5
connected to the end portion 425 of pis~on rod 421 by
means of a retaining ring 427 sitting in recess 429 of the
piston rod. It is apparent tha~ the outer air system 400
is adapted to flow through the chamber 435 of nozzle
adaptor 44a without hindrance at a constant flowO
. Fig. 5 shows another modification of the nozzle
- assembly showing a pressure responsive variable area air
metering means for controlling air flow to both inner and
: 25 outer air systems of a typical single fuel system air
blast ~vpe uel noz~le assembly. This is evident by the
view o Flg. 5 in cross-section showing the deletion of
~he primary noæzle system, and showing lnstead a nozzle '~
514 and support assemb].y S22 with the fuel passages 530
and 530' adapted to supply fuel to chamber 590~ through
angled swirl slots 592, through area 594, past slots 595
: of nozzle swirler 596 to exit through annulus 598. Piston
507 is adapted to move longitudinally in the direction of
arrow 531 when pressurized through passages 536 and 536'
: 35 to move bo~h inner air metering valve S41 and outer air
metering valve S23 and allow more air ~o flow through
openings 549 and 533 of the inner and outer air systems
500 and 50Z respectivelv~ The inner air system 502 flows
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` through chambers 553, 555, past the inner air swirl vanes
503 through chamber 504 and exits into the prechamber area
through annulus 556. The annulus 556 is an opening formed
between the core 571 and the orifice of nozzle swirler 5960
Fig. 6 is a ~urther modification of the nozzle
assembly showing a pressure responsive variable area air
'~ metering means for controlling air flow to the outer air
system of a typical sîngle fuel system air blas~ type fuel
~ 10 nozzle assemblyO The single nozzle fuel system shown in
.- Fig. 5 is modified to include the outer air system 600
~hich is adapted to be moved longitudinally along the
direction of arrow 631 by piston 607~ The actuating means
to control the movement of the metering valve 623 for the
outer air system is adapted to flow through passage 636
~- and 636' into piston chamber 605 ~o move piston 607.
Movement o~ piston 607 will effect movement o~ the outer
air metering valve 623 allowing more air to enter through
opening 633. The outer air metering valve 623 is connected
`~ 20 to the end portion 6~5 of piston rod 621 by a retaining
rinq 6274 The inner air flow 602 is adapted to be constantO
.
3' Fig. 7 shows a further modification of the nozzle
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assem~ly showing a pressure responsive variable area air
metering means for controlling air flow to the inner air
system of a typical single fuel system air blast type fuel
nozzle assembly. The single system air blast type ~uel
nozzle shown in ~ig~ S is modified to lnclude the inner
air system 702 adapted to flow through opening 749 when
the inner air metering valve 741 is moved longi.udinally
~ in the direction o~ arrow 73l~ The piston 707 is adapted
; to be moved axially in the piston sl~eve 711 by an increas2
of a pressure medium flowing through passage~ 730 and 730'
into piston chamber 705. The inner air metering valve 741
is connected to the end portion 725 of piston rod 721 by a
`~ retaining ring 727. It is thus apparent tnat the outer
air ~low 700 remains constant while the inner air rlow 702
is variable.
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Fig. 8 is a modification ~f the noæzle assembly shown
in Fis~ 2, showing a pressure responsive variable area air
metering means for controlling outer and inner air flow as
a function of the fuel pressure. That is, by increasing
S the supply of fuel through the primary nozzle passages
828 and 828' to the chamber 854, the fluid is divided
between the piston area chamber 805 and the primary no2æle
exit ori~ice 870 o~ the primary nozzle means 855~ Thus,
increasing the fuel pressure in chamher 805 is adapted to
move the piston 807 in the direction of arrcw 831 and thus
simultaneously move the outer air metering valve 823 and
the inner air metering valve 841~ Movement of the outer
and inner alr metering valves 823 and 841, allows more air
to ~low ~hrough openings 833 and 849, in the outer and
inner air flow systems 800 and 802, respectivelyO
While the best mode for practicing the invention
has been described in detail, and other modes have been
descri~ed generally in detail, those familiar with the
!.' 20 art will recognize various alternative designs and
embodiments ~or practicing the invention as defined by
the claims:
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