Nov. 26, 1968
`
`3,412,560
`A. w. GAUBATZ
`JET PROPULSION ENGINE WITH COOLED COMBUSTION
`CHAMBER, FUEL HEATER, AND INDUCED AIR-FLOW
`Filed Aug. 5, 1966
`4 Sneets—Sheet
`
`
`
`."'.'.'.'.'.'.'.v_¢¢¢z£:.-_-.1’.-.-. .\ i
`:2
`\ '
`ll
`9
`:r:‘.‘,‘.‘:3=‘c‘p‘.‘2;;‘.';‘nr‘a";‘YS \\
`l:
`7
`y" §’/
`'"'.::::'--''''''~ 4:
`',\
`E
`-
`_-----....---
`3
`
`
`-:9:IV
`ll
`\
`\
`:..~;:.-.-.-::..‘.‘::.-::-.';=.--'\\\\
`
`
`
`1
`
`
`
`
`INVENTOR
`Q27‘/fa//'}I€41/&e&’
`
`A 7'70?/VE)’
`
`GE-1013.001
`
`GE-1013.001
`
`

`
`Nov. 26, 1968
`
`A.W.GAUBATZ
`3,412,560
`N ENGINE
`JET PROPULSIO
`WITH COOLED COMBUSTION
`C
`HAMBER, FUEL HEATER, AND INDUCED AIR-F
`Filed Aug. 5, 1966
`4
`
`eets—Sheet 2
`
`1I....1n.
`
`.......-IIIt
`llllllf.riflllflll....~I.1
`
`
`
`...
`
`.
`
`s
`
`/J.\,.\.n.\.
`
`DNINDQDVTOR.
`‘
`Q/-/fizzrféaadafiz
`
`“‘
`
`BY
`
`A77Z#®MEY
`
`GE-1013.002
`
`GE-1013.002
`
`

`
`Nov. 26, 1968
`
`3,412,560
`2
`A. w. GAUB
`OLED COMBUSTION
`JET PROPULSION ENGINE WITH
`CHAMBER, FUEL HEATER, AND INDUCED AIR-FLOW
`Filed Aug. 3, 1966
`4 Sneets—Sheet 3
`
` .3at
`
`M 95912
`"
`INVENTOR
`§/2‘/}zz.2'7/'éZ'z/Jet?
`
`flu/%§/azaé
`"”"’”‘”GE-1013.003
`
`GE-1013.003
`
`

`
`N0V- 25. 1968
`
`3,412,560
`A. w. GAUBATZ
`JET PROPULSION ENGINE WITH COOLED COMBUSTION
`CHAMBER, FUEL HEATER, AND INDUCED AIR-FLOW
`Filed Aug 3, 1966
`4 Sheets——Sheet 4
`
`COOLE RS
`
`PRECOMBUSTI ON
`
`REGENE RATOR
`
`COMBUSTION
`
`‘av...av'1pp.-pp4rpp.r::p.p...np..paa/ I..,‘~............./n\\\x\~..............
`
`
`
`AC TUATOR
`
`I NVENTOR.
`Qrz‘/.52//'7/.‘§4z/dazfz
`
`BY
`
`A 7‘TOR/VEY
`
`GE-1013.004
`
`GE-1013.004
`
`

`
` States Fatent G
`1 cc
`
`3,412,560
`
`Patented Nov. 26, 1968
`
` 1
`
`2
`
`3,412,560
`JET PROPULSION ENGINE WITH CQOLED COM-
`BUSTION CHAMBER, FUEL HEATER, AND
`INDUCED AIR-FLOW
`Arthur W. Gaubatz, Indianapolis, Ind., assignor to Gen-
`eral Motors Corporation, Detroit, Mich., a corporation
`of Delaware
`Filed Aug. 3, 1966, Ser. No. 570,964
`3 Claims. (Cl. 60—261)
`
`
`ABSTRACT OF THE DISCLOSURE
`
`A jet propulsion engine has a fuel cooled combustion
`chamber with a chamber outlet nozzle also fuel-cooled.
`The combustion chamber discharges into a fuel-cooled
`convergent-divergent jet propulsion nozzle which has an
`air entry around the combustion chamber. Means are
`provided for variably admitting ambient boundary layer
`air into the jet propulsion nozzle. Fuel for combustion is
`also heated in a heat exchanger disposed between a pre-
`combustion chamber, in which some fuel is burned, and
`the main combustion chamber.
`
`
`My invention is directed to jet engines and particularly
`to jet propulsion nozzle systems of such engines. In its
`preferred form, the invention is embodied in a jet propul-
`sion device including a fuel-cooled combustion chamber
`with variable area outlet means also cooled by fuel, a
`fuel-cooled convergent-divergent
`jet propulsion nozzle
`downstream from the combustion apparatus, and variable
`means for admitting ambient air to the nozzle adjacent
`the throat of the convergent-divergent nozzle for induction
`into the nozzle by the discharge from the combustion
`chamber. In certain aspects, the invention is particularly
`suited to engines operating on gaseous fuel.
`The principal objects of the invention are to provide an
`eflicient jet propulsion device capable of operation at very
`high temperatures and suited for operation over a wide
`spectrum of jet propulsion with respect to altitude and
`speed of the vehicle in which the device is used. The
`nature of the invention and the advantages thereof will
`be clear to those skilled in the art from the succeeding
`detailed description of the preferred embodiment of the
`invention and the accompanying drawings thereof.
`FIGURE 1 is an elevation view, with parts cut away
`and in section, of the exhaust end of a jet propulsion
`engine having provision for fuel heating and fuel burning
`in the exhaust system.
`FIGURE 2 is an enlarged view of a portion of FIGURE
`1 illustrating the secondary air inlet doors.
`FIGURE 3 is a sectional View taken on the plane indi-
`cated in FIGURE 2 showing the arrangement of actuators
`for the air inlet doors.
`FIGURE 4 is a fragmentary cross section through an
`air inlet door indicated in the plane indicated in FIG-
`URE 2.
`
`10
`
`15
`
`20
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`FIGURE 5 is a rear elevation View of the discharge
`end of the exhaust system taken on the plane indicated
`in FIGURE 1.
`
`60
`
`FIGURES 6 and 7 are partial sectional views, taken
`on the planes indicated in FIGURE 5,
`illustrating the
`variable combustion chamber outlet means.
`FIGURE 8 is a longitudinal sectional view illustrating
`the cooling arrangement for the convergent-divergent jet
`nozzle, taken on the plane indicated in FIGURE 5.
`FIGURES 9, 10, 11, and 12 are fragmentary sectional
`views taken on planes indicated on FIGURE 8.
`FIGURE 13 is a schematic diagram of an engine show-
`ing the principal fuel circuits.
`
`65
`
`70
`
`FIGURE 14 is a somewhat simplified representation of
`a plug-type variable outlet for the combustion chamber.
`Referring flrst to FIGURES 1 and 13,
`the engine is
`enclosed in an outer housing 5 exposed to ambient
`boundary layer air, such as a fuselage or nacelle. Suit-
`ably supported within the housing, as by struts 6,
`is an
`annular air duct 7 inside which is mounted a turbine 9
`which is preferably of the type described and claimed in
`my U.S. Patent No. 3,368,794. The turbine drives a com-
`pressor 10 which is preferably of the type described and
`claimed in my U.S. Patent No. 3,365,125. The annular
`air duct 7 carries combustion air which may be com-
`pressed by the ram effect of forward motion of an air-
`craft, by the compressor, or both, and preferably by
`both when the aircraft is in rapid motion. This air serves
`to burn fuel supplied to the engine which is preferably
`originally a cold liquid and is vaporized in the engine.
`The air is supplied flrst from duct 7 to a precombustion
`chamber 11 within which a portion of the fuel may be
`burned, depending upon operating conditions. The air,
`or air and combustion products,
`then flows through a
`cylindrical heat exchanger 13 to which the fuel is sup-
`plied from a suitable source by pumping and control
`means (not illustrated). The heated air fiows from the
`regenerator into combustion chamber 22.
`As indicated in FIGURE 13, the fuel may flow from
`the controlled source through an inlet air cooler 14 which
`may be bypassed by a valve 15 to the heat exchanger 13
`-and then through a conduit 17 to the turbine 9 where it
`expands and is cooled.
`The fuel exhausted from the turbine is burned, ordi-
`narily most of it in the combustion chamber 22, although
`part of it may be burned in the precombustion chamber
`11. Before reaching these, however, the turbine exhaust
`is circulated through a line 18 and the hollow wall of
`the combustion chamber 22 and through a second inlet
`air precooler 19 to which fuel is directed through a con-
`duit 20 and returned by way of a conduit 21. A valve 23
`provides for bypassing the second inlet cooler to the ex-
`tent desired.
`
`The combustion chamber 22 discharges through a con-
`vergent outlet section into the throat of a convergent-
`divergent jet propulsion nozzle 25. The area of the com-
`bustion chamber outlet is variable as by a ring of mov-
`able flaps 26 or an axially movable plug, as will be de-
`scribed in connection with FIGURE 14.
`The provision for admission of secondary air to the
`jet nozzle involves four doors 27 which swing in from a
`position coincident with the outer wall 5 to the position
`indicated at the upper part of FIGURE 1 to admit bound-
`ary layer air into an annular entry 29 around the com-
`bustion chamber 22. Struts 30 support the rear end of the
`combustion apparatus. The combustion chamber flaps
`26 and the secondary air doors 27 may have their posi-
`tion varied over the range from maximum opening to
`minimum opening in accordance with the operating con-
`ditions of the jet propulsion engine and the vehicle.
`My invention is not concerned with the means for con-
`trolling these, but rather with the provision of structure
`providing for flexibility of operation and including pro-
`visions for cooling such that the mechanism is capable
`of resisting hot combustion gases. The details of the pre-
`heating and combustion apparatus also -are immaterial
`to this invention.
`Returning to the fuel circuit; as previously pointed out,
`the fuel after passing through the regenerator, turbine,
`combustion chamber cooling jacket, and second precooler,
`is supplied to a line 21. Some of the fuel exhausting from
`the first precooler bypasses the regenerator, -combustion
`chamber jacket, and second precooler under control of a
`turbine control valve 28. The total fue
`i
`i
`ti?-itt‘1§.oo5
`
`GE-1013.005
`
`

`
`3,412,560
`
`3
`through double walls, to be described, of the convergent-
`divergent jet nozzle 25 and is returned to a valve 29 which
`divides the flow between a line 30 to the precombustion
`chamber and a line 31 to the main combustion chamber.
`A small portion of this fuel is tapped olf ahead of valve
`29 into a line 32 by which it is directed to cool
`the
`variable jet nozzle 26 and is burned. The fuel line from
`valve 28 to the regenerator is indicated as 33 in FIGURES
`1 and 13.
`The line 31 leading to the combustion chamber com-
`municates by way of a manifold 35 with fuel nozzles 36,
`and the combustion air flows from the regenerator 13
`through spaces 37 between the fuel nozzles. The combus-
`tion takes place wi-thin the generally cylindrical chamber
`22. Suitable ignition means
`(not
`illustrated) may be
`provided. The casing of the combustion chamber 22 com-
`prises a forward portion 39 and a rear portion 41 coupled
`at the bolting flange 43. These two sections are double-
`walled so as to provide a cooling jacket the length of the
`combustion chamber. Fuel admitted through line 18 is
`caused to flow between the outer wall 46 and the inner wall
`47 of the rear portion of the combustion chamber except
`for the extreme rear portion beyond a barrier 49 (FIG-
`URE 6). After circulating in through this jacket, the fuel
`is transferred through a line 59 to the cooling jacket of
`the forward portion of the combustion chamber between
`the outer wall 51 and the inner wall 52 and is discharged
`through line 20 for further control and utilization. The
`extreme rear end of the combustion chamber is sur-
`rounded by a manifold 55 to which gaseous fuel is sup-
`plied through line 32 and from which it is discharged
`to cool the segments or flaps 26 of the combustion cham-
`ber outlet control.
`
`Secondary air inlets
`
`We may now proceed to a description of the secondary
`air inlet doors 27 shown principally on FIGURES 1 to
`5. There are four of these doors which are of slightly
`curved generally rectangular shape. Each door is hinged
`to the nacelle wall 5 by a hinge connection 61 at
`its
`forward edge. The trailing or downstream edge ‘62 of
`the door can be moved between the positions shown in
`solid and in broken lines in FIGURES 1 and 5. A
`portion 63 of the nacelle wall of generally quadrantal
`cross section occupies each of the four gaps between
`the doors 27. The doors are held in any desired position
`-between the outer -or closed inlet position and the inner
`or wide open inlet poritions by a pneumatic cylinder 65
`and linkage 66 at each door. The open position is illus-
`trated in solid lines in FIGURES 1 and 2 and the closed
`position in broken lines.
`'67
`links
`Each parallelogram linkage 66 includes
`pivoted on brackets 68 fixed on the outer wall 39 of the
`combustion chamber. Links 69 likewise pivoted on these
`brackets are pivoted to a head 70 on the piston rod 71
`of the cylinder 65. Links 73 parallel to links 67 and links
`74 parallel to links 69 are pivoted on the head 70 and
`cylinder
`'65,
`respectively, and have a common pivot
`axis at 75 on a bracket extending inwardly from the wall
`of the door 27. As shown in FIGURE 4, the outer wall
`of door 27 is a double wall having an outer sheet 76, an
`intermediate corrugated spacer 77, and an inner sheet
`78, and is reinforced by flanged ribs 79 which taper
`towards the ends of the door. The cylinder 65 is supported
`by the parallelogram linkage and «therefore moves in
`operation. The assembly includes a swivel pipe con-
`nection to the fixed structure of the regenerator case. As
`shown in FIGURE 3, the cylinder is double-walled and
`has two fluid supply connections 81 which have a swivel
`connection to telescoping tubes 82 which in turn are
`swiveled on a hollow shaft 83 mounted in a bracket 84
`on the wall of regenerator 19. The hollow shaft is plugged
`at its center and has fluid connections 85 and 86 at
`its ends which connect through lateral openings in the
`
`4
`shaft to the interior of tubes 82. Tubes 82 are maintained
`in engagement with the inlets 81 by a clamp 87.
`Variable combustion chamber outlet
`
`The arrangement of variable flaps 26 to vary the area
`of the combustion chamber outlet is shown principally
`in FIGURES 1, 5, 6, and 7. There are eight flaps 26,
`each of generally rectangular outline and arcuate cross
`section as seen clearly in FIGURES 5 and 7. The flaps
`are double—walled, having an outer sheet 91 and inner
`sheet 92 suitably connected as by a corrugated inter-
`mediate sheet. Brackets 93 projecting from the two for-
`ward corners of the flap are pivoted on the fixed structure
`of the engine. This fixed structure comprises eight inter-
`mediate wall elements 95 which have an outer wall 97,
`side walls 98 converging at a 45° angle, and an inner
`wall 99. Walls 97 and 99 diverge from a ring 100 at
`the forward edge of the intermediate members at which
`they are joined at the walls of the manifold 55. The side
`edges of the flaps 26 slide over the side walls 98 of
`the intermediate members as the flaps are moved in
`and out. Each intermediate member bears a longitudinal
`sheet metal rib 101 upon which a flap actuating ring
`103 is sli-dable. Ring 103 mounts eight brackets 105 each
`bearing a pin 106 which slides in a cam slot 107 of a
`cam 108. The cams 108 extend radially from the outer
`surface of the flaps 26. As shown clearly by the solid
`and broken line views in FIGURE 7, reciprocation of
`ring 103 moves the flaps between their wide open and
`minimum open position. The flaps are pivoted by pins
`110 which are received in brackets 111 extending from the
`forward corners of the intermediate members 97. The
`ring 103 is reciprocated by four fixed hydraulic cylinders
`113, spaced around the circumference of the combustion
`chamber, the piston rods 115 of which are connected to
`the rod by brackets 114. A hoop 116 limits outward
`movement of flaps 26.
`As indicated by FIGURE 13, a line 32 brings gaseous
`fuel to the ring manifold 55 at the rear end of combustion
`chamber 22. This gas is discharged through holes 117 in
`the wall of combustion chamber 22 so as to flow over
`the inner surface of the variable flaps 26, cooling the
`flaps and shielding them by the reducing fuel rich gas
`from the hot combustion products which may contain
`oxygen. Means (not illustrated) may also be provided to
`circulate some of this gas through the fixed structure of
`the intermediate wall 95.
`
`Jet propulsion nozzle
`The combustion chamber 22 and the air inlet doors
`27 supply combustion products and induced nacelle
`boundary layer air into the convergent-divergent jet pro-
`pulsion nozzle 25. This is a metal structure through which
`some of the fuel on its way to the combustion chamber
`and the precombustion chamber is circulated to keep
`the nozzle sufficiently cool in spite of the hot combustion
`gases discharged through it. This nozzle is shown in
`FIGURES 1, 5, and 8 to 12. In general, it comprises an
`outer wall 131 which is of biconical shape with a waist
`at 132 which is reinforced by a circumferential strip 133.
`It also comprises an inner wall 134 spaced from the
`outer wall and terminating short of it at 135 near the exit
`end of the nozzle. A circumferential ring 137 extending
`between the two walls is the rear boundary of a fluid
`outlet manifold 138 extending around the forward end
`of the nozzle. The interior of the nozzle is lined with
`axially extending tubes 141 which are cooled by fuel
`circulating from the exit end of the nozzle to the manifold
`138. This fuel is supplied by one or more ducts 21 into
`the forward end of the space 145 between the two walls
`through which it flows to the rear end of the nozzle and
`back through tubes 141. Most of the tubes 141 terminate
`just ahead of wall 137 and discharge into manifold 138.
`The inner wall of manifold 138 is defined by a third sheet
`147 which is disposed withiréficffiyafi rfifieéayer
`
`10
`
`30
`
`to til
`
`40
`
`45
`
`50
`
`55
`
`60
`
`70
`
`75
`
`GE-1013.006
`
`

`
`5
`of tubes 141. A U-shaped metal strip 148 extending be-
`tween the sheets 134 and 147 defines a space around the
`inlet pipe 143.
`The tubes which are aligned with the barriers 148
`terminate short of it. The fuel which is circulated through
`the cooled jet nozzle wall discharges from manifold 133
`through a pipe or pipes 149 to the valve 29 which controls
`its admission to the combustion apparatus.
`Plug type combustion chamber
`FIGURE 14 illustrates an alternative form of combus-
`tion chamber with variable outlet which may be used
`instead of the corresponding structure shown in FIGURE
`1. FIGURE 14 illustrates the rear portion of a combus-
`tion chamber 170 which terminates in a converging noz-
`zle 171. Air and fuel may be supplied to the combustion
`chamber by any suitable means such as those illustrated
`in connection with FIGURE 1. A plurality of struts, in-
`cluding struts 173 and 174, extend inwardly from the wall
`of the combustion chamber to define a supporting spider
`for a double—walled nozzle plug support 175. Cooling
`fluid, such as gaseous fuel,
`is supplied through line 32
`and strut 173 to the passage 177 between the walls of the
`support 175 .
`The plug 179 which acts to vary the combustion cham-
`ber outlet includes a hollow stem 181, the forward end
`of which is slidable upon the support 175, a sliding seal
`182 being provided between the two. The support 175 in-
`cludes a rear portion 183 of reduced diameter on which
`is slidable a collar 185 connected to the interior of plug
`179 by an open-work spider 186. A ball screw actuating
`device 187 is mounted within the portion 183 of the
`support and supported rotatably in a thrust bearing 189.
`The inner member or screw 191 of the ball screw ac-
`tuator connects to web 190 in the rear end of plug 179.
`Rotation of the body or nut 192 of the actuator causes the
`plug to reciprocate on its support, as previously described.
`The body is rotated by a shaft 194 connected through
`bevel gears 196 to a radial shaft 195 extending through
`strut 174 and rotatable by any suitable power actuating
`device 197.
`
`Cooling gas admitted through line 173 and flowing rear-
`wardly through the passage 177 is discharged into the in-
`terior of
`the support and flows
`rearwardly through
`openings in the spider 186 into the interior of the plug
`179. The plug is also double-walled and the inner wall has
`an opening 201 at the rear end of the plug. The cooling
`gas entering between the double walls of the plug flows
`from the entrance 201 through the annular passage 202 to
`the forward end of the plug where it is discharged from
`the annular open end of the double wall at 203 and is
`burned in the flame from the combustion chamber. Thus
`the nozzle plug 179 and its support 175 are cooled by
`fuel subsequently burned.
`As will be apparent, the combustion apparatus of FIG-
`URE 14 and likewise that of the previously described
`form of the invention may have the area of the outlet
`varied in accordance with the operating condition of the
`engine to provide most eflicient propulsion under various
`conditions of speed and altitude. Also, the total fuel flow,
`the control of fuel flow through the two inlet precoolers,
`the adjustment of the air inlet doors 27, and the alloca-
`tion of fuel between the precombustion chamber and the
`main combustion chamber are variable to provide a broad
`spectrum of effective operation of the engine. However,
`my invention is not concerned primarily with the en-
`
`3,412,560
`
`6
`gine overall but rather with the improved combustion
`chamber and propulsion jet nozzle arrangement,
`two
`forms of which have been described.
`The description of the preferred embodiments of the
`invention for the purpose of explaining the principles
`thereof is not to be considered as limiting or restricting
`the invention, since many modifications may be made by
`the exercise of skill in the art.
`I claim:
`1. A jet propulsion device comprising, in combination,
`an air duct for conducting combustion air under pres-
`sure, a precombustion device supplied with air through
`the air duct, a heat exchanger supplied with air from
`the air duct through the precombustion device, a fuel
`circuit through the heat exchanger, a main combustion
`chamber supplied with air for combustion from the air
`duct through the precombustion device and the heat ex-
`changer,
`the chamber having an outlet for combustion
`products, a jet propulsion nozzle aligned with the outlet,
`the nozzle having a throat larger than the said outlet, the
`nozzle having an entrance passage disposed around the
`combustion chamber, means including movable air inlet
`doors operable to admit ambient boundary layer air to or
`exclude it from the entrance passage, means operable to
`move the doors and to hold them in desired positions
`through a range from closed to open, the main combustion
`chamber and jet propulsion nozzle including double walls
`adapted for circulation of a cooling medium through the
`walls, and means for circulating fuel for combustion
`through the said heat exchanger fuel circuit and the said
`double walls to the main combustion chamber and the
`precombustion device for combustion therein.
`2. A device as recited in claim 1 including controllable
`means for varying the area of the combustion chamber
`outlet.
`
`3. A device as recited in claim 1 including also a com-
`pressor connected to supply the said air duct, a turbine
`connected to drive the compressor, and means to cir-
`culate the fuel from the heat exchanger to the turbine as
`motive fluid for the turbine.
`
`3,048,973
`3,237,401
`3,323,304
`3,302,889
`3,346,193
`2,390,161
`2,589,215
`2,866,313
`2,937,494
`3,002,340
`3,018,626
`3,024,606
`3,052,431
`3,172,253
`
`1,019,176
`
`References Cited
`UNITED STATES PATENTS
`8/1962 Benedict _______ __ 239—265.17
`3/1966 Peters et al. ____ -_ 60-260 XR
`6/1967 Llobet et al.
`2/1967 Di Sabato ______ __ 60——-264 XR
`10/1967 Tumicki _______ __ 239--265.17
`12/1945 Mercier ________ __ 60——264 XR
`3/1952 Atwood ___________ __ 60-267
`12/1958 Hall ___________ __ 60—264 XR
`5/1960 Johnson _______ __ 60-267 XR
`10/1961 Landerman _____ __ 60—26O XR
`1/1962 Chester ________ __ 60-267 XR
`3/1962 Adams et al _____ __ 60-267 XR
`9/1962 Compton _______ __ 60—267 XR
`3/1965 Schelp et al. ____ __ 60-267 XR
`FOREIGN PATENTS
`10/ 1952 France.
`
`OTHER REFERENCES
`
`SAE Transactions, 1958, vol. 66, pp. 318, 319 relied
`on.
`
`CARLTON R. CROYLE, Primary Examiner.
`
`10
`
`[0 D1
`
`30
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`GE-1013.007
`
`GE-1013.007