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Патент USA US3080724

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Maul‘ 12, 1963
Filed Jan. s, 1960
4 Sheets-Sheet 1
March 12, 1963
3,080,71 1
Filed Jan. 6, 1960
4 Sheets-Sheet 2
March 12, 1963
J. F. coNNQRs
4 Sheets-sheet 5
Filed Jan~_ 6’ 196°
March 12, 1963
Filed Jan. 6, 1960
4 Sheets-Sheet 4
_ ‘Stats
rear,“ Ice
Patented .“Mam ,12, 19.63:
Meyer ?ow expansion and its application to the penshape
exhaust nozzle exit.
FIG. 2 is a penshape exhaust nozzle exit having a
James F. Connors, North Olmsted, Ohio, assignor to the
" United States of America as represented by the Admin
' istrator of the National Aeronautics and Space Ad
Filed Jan. 6, 1960, Ser. No. 914
7 Claims.
(Cl. 60-3555)
- (Granted under Title 35, U.S. Code (1952), see. 266)
-- The invention described herein may be manufactured
and used by or for the Government of the United States
of America for governmental purposes without the pay
ment of any royalties thereon or therefor.
— The present invention relates, to internal external ex
pansion exhaust nozzles for supersonic air-breathing and
rocket-type jet engines.
clamshell element.
FIG. 3 is a cross-section view of the exhaust nozzle
shown in FIG. 2.
FIG. 4 is a cross-section view of a penshape exhaust
nozzle having a variable ramp.
FIG. 5 is a pictorial view of the exhaust exit shown in
4 wherein the ramp is in a closed position.
_ FIG. 6 is a pictorial view of the exhaust nozzle shown
in FIG. 4 having the ramp in an open position.
FIG. 7 is a partly~sectioned pictorial view of a pensha'pe
exhaust nozzle exit having a two-dimensional variable
15 ramp.
FIG. 8 is a cross-section taken along line 8-8 0t
FIG. 7.
I Previous to the present invention, conventional nozzle
FIG. 9 is an end view of FIG. 7.
Referring now to the drawings wherein like reference
con?gurations consisted of the convergent-divergent noz
zle, the plug-type nozzle, and the ejector nozzle. Each 20 characters designate like or corresponding parts through
out the several views. The design approach of the pen
of these‘ three nozzles has serious disadvantages. The
convergent-divergent nozzle exhibits good performance
at design conditions, but the “oil-design” characteristics
shape nozzle exit is illustrated in FIGS. la-lc. The well
known Prandtl-Meyer theory for determining ?ow ex,
indicate severe thrust losses at less than the design pres
pansion around a corner, as shown in FIG. 1a, is the
basis for calculating the nozzle contours. If the ?ow is
expanded all externally, as seen in the nozzle exitof
FIG. 1b, the focal point of the wayesf is located at
ambientupressure, thereby creating drag on the nozzle
one end of the sonic line M=1, where M represents
,while the plug-type nozzle geometryv utilizes external ex
the Mach number. The particular engine condition for
;p_ansionq and maintains, at- least in quiescent air, a high
level at performance independent of the pressure ratio. 30 which the nozzle is to be designed corresponds to some
nozzle pressure ratio which, in turn, determines the out
{It appears havefan extremely difficult cooling prob
let Mach number M1. The sonic line is then inclined
lem because of the large centerbody which is completely
sure' ratio. v,InIthe over-expanded nozzle condition, the
‘(local pressures, along, the-expansion surface drop below
.su-bmerged ingthe= hot gases emitted. in the jet stream.
to the vertical by the amount of' the Prandtl angle M
.iExternaljstream effects‘ and base. drag due to high lip
by varying the lip 11 angle, so that the exiting jet is
in the axial direction. ‘By incorporating some internal
,angleslare excessive with this type of geometry. The
.ejector; nozzle gives good performance but tends to be
heavy and requires?additional ducting of secondary or
tertiary air around the engine}
The present inventiomconcerns a. novel exhaust noz
zle having circular end projections more particularly de
?ned asa penshape exhaust nozzle- having excellent off
dcsign characteristics. vThe instant invention also admits
tof'leacil'y' controllable throat area modulation which is
,iijeguiredito-satisfy .a wide range of . engine operating
expansion, as seen in FIG. 1c, the total expansion can
be split in twodirections about two focal points fly-and
jg located on opposite surfaces. Thisftechnique permits
lower base angles on the cowl, particularly for extremely
40 high pressure ratios.
Thus, from a known ?ow. ?eld,
nozzle contours for an arbitrary cross-sectional" shape of
the jet stream tube can be determined by tracing strfea'r‘n
lines back to the throat or sonic area. In FIGS. la‘—l‘c,
the angle zxMl is the Mach angle at Mach M1.
conditions; Theythrloat area modulation is caused in the 45 FIG. 2 shows the exhaust nozzle 23 withra clarnshell
element 21 which serves as a varying lip and'thus achieves
,invéntionyby either a movable single or double-ramp
'the desired throat area modulation. As seen in FIGQQ,
‘structureisituated. within the nozzle exit'or a movable
lithe clamshell element 21 can be actuated by'_,any con
fqclamshellelement, situated v. at the lip of the nozzle exit.
,ventional means, such as 22 shown. The‘ nozzlejis
any meanswof the movable structures within the nozzle exit
or tlieclarnshell element, the disadvantages present in the 50 readily cooled by bringing cooling air ‘into [the area
bounded by the outer shell or surface 17, of the nozzle
‘prior’ nozzle con?gurations have been eliminated. '
23, and the inner surface 18 and exits through opening 20.
An object of the invention is to provide‘ a nozzle exit’
v 7 As can be seen in FIG. 3, the exhaust from the .after
[capable of attaining high nozzle e?jcie'ncies. ’
burner enters to the left of the exhaust. nozzle ‘23, and
1, Another, object of the invention is a nozzle exit designed
" to obtain high thrust coe?icients‘ over a wide range of 55 when the afterburner is on, the temperature increasesand
-mass ?ow decreases at a given outletvjcondition? To'ac
_ nozzle pressure. ratios :and ?ightconditions.
‘An. additional .objectof .the. invention-is a nozzle that‘ ' count for the corresponding decrease in'xde'nsity and‘ to
avoid decrease in mass ?ow, it is necessary toope‘nfthe
iuachieves the favorable externalexpansion of features of a
lthroat area. by moving the, clamshell ‘element 21.] By
jplug nozzle withoutthe cooling dii?culties of a submerged
60 having such modulation the exhaust‘ stream will be "con
;-centrall, body. _
tinually split about two focal points and the drag Will
A further objectof theinvention is an exhaust nozzle
-~with a exit wherein the afterbody lift drag is considerably ' be kept to‘a minimum throughout varying operating con
less than any other conventional nozzle.
FIGS. 4, 5, and 6 ‘are illustrative ofran alternative
r." ‘A’ still 'fufther 'objectof the invention is a nozzle with
65 method of varying the throat area of a penshape nozzle
Ya" exit particularly suited for high Mach number turbojet
‘1 and rocket applications.v
23. The tear-shapedv member 28 ‘is situated‘on theex
pansion surface 48,v saidptear shaped‘ member 28 ‘being
Other objects and many attendant advantages of the
actuated 'by' conventional .means 29‘ shown. ' The‘. near
§fpifesent invention 'will be ‘apparent? "from the following - shaped member 28 beingis actuated from an’op‘en posi
detailed description when taken together with the accom 70: tron in the exhaust nozzle v2.3 wherein said member 28
“panying' drawings in 'which:'
-1s flush with the expansion surface 48, as seen in'FIG..6,
FIGS. 1a-1c diagrammatically shows the- Prandtl-j‘ ‘ to a closed'position, as seénin IFI'G.»-5‘r'estricting the-clich
tive throat area. Cooling air is readily admitted between
the area bounded by the inner surface 18 and the outer
shell 17 of the nozzle 23; the cooling air exiting through
an opening 20, in the outer shell 17.
The penshape nozzles shown in FIGS. 2»6 may be
cording to the expansion and contraction of the section
of the double-ramp structure 34. Said movable section
more particularly de?ned as comprising an outer shell or
outer surface 17 which coacts with inner surface 18 to
structure 34 expands, the guide rods 41 move in a di
form a penshape exhaust nozzle 23. The forward end
to one another at a constant distance by guide runners
of said double-ramp structure 34 is caused to contract or
expand by any conventional means 36 placed within the
area enveloped by the ramp structure 34. As the ramp
rection towards the trailing edge 38 and are kept parallel
37. As the ramp structure 34 contracts, said guide rods
19 of outer surface 17 and the forward end 24 of inner
surface 18 are of generally circular cross section, al 10 41 move in a direction opposite from the trailing edge
38. The guide rods 41 may be spring loaded (not
though not limited thereto, and concentric about longi
shown) so as to facilitate the return from the position
tudinal centerline or axis 25 of the exhaust nozzle 23.
when the ramp is expanded back to the position of said
In the penshape nozzle shown in FIG. 3 the inner surface
rods 41 when the ramps are in a contracted position.
18 and outer surface 17 cooperate to form in part a solid
It is pointed out that it is not necessary to use ?exible
portion 45. The forward end 24 of inner surface 18 de 15
ramps in this double-ramped structure. The same effect
?nes an exhaust gas passage 42 which is substantially
could be created through the use of ?xed pivot pins and
cylindrical and concentric about centerline axis 25.
a slide joint using rigid ramps.
Inner surface 18’ and inner surface 18" converge to~
It can be seen in FIG. 8 that the exhausting gases are
ward each other downstream of front end 24 to form a
converging exhaust passage, the passage terminating as 20 split into two separate streams by means of the airfoil
shape ramp 34, the effect being created by two penshape
a tipped minimum area nozzle throat 43 near the middle
nozzles, similar to the one shown in FIG. 4, mounted side
portion 46 of nozzle 23. The nozzle throat 43 is sub
by side. As has been previously pointed out, it is highly
stantially, maximally positioned, diametrically opposite
desirable to have a variable control of the throat area of
the longest straight portion 44 of the outer shell 17, and
is tipped with respect to centerline 25 and longest straight 25 the penshape exhaust nozzle. This is accomplished, as
shown in FIGS. 7, 8, and 9 by means of the expandable
‘portion 44 so that the extension of throat plane 43 de
air-foil shaped double-ramp structure 34, which structure
?nes acute angle a therewith and the downstream por
tions thereof. Surface 18" terminates as an exit lip 47
downstream of middle portion 46. The rearward or
creates a convergent-divergent effect on the exhaust gases
and thus serves as an internal expansion surface.
As can be readily seen, the effect of the variable ramp
downstream expansion surface 48 of inner surface 18 30
nozzle is that there are two semi-circular jets and a back
diverges with respect to the exit lip 47 and terminates
to-back nozzle effect. Side force components, therefore,
downstream of the throat 43 as inner surface point por
at less than the design pressure ratio would be cancelled
tion 49. Downstream of the throat 43, straight portion
by this back-to-back nozzle approach. It should be noted
44 terminates in outer end portion 51 which has a com
mon trailing end 52 with inner surface point portion 49. 85 that cooling air can be readily admitted to the interior of
the ramp structure 34.
In other words, the straight portion 44 terminates as a
Obviously, many modi?cations and variations of the
trailing end 52 in cooperation with downstream inner
present invention are possible in the light of the above
surface 49 of inner surface 18. Inner surface 18 also
teachings. It is, therefore, to be understood that within
includes connecting portions 53 and 54 which smoothly
the scope of the appended claims, the invention may be
join the inner surface 18' to the inner surface 18" and
practiced otherwise than as speci?cally described.
which connecting portions also smoothly join exit lip 47
In the claims:
with end 52. By virtue of this construction, inner sur
face 18 de?nes gas passage 42 concentric about centerline
25 at its forward end, eccentric to centerline 25 at its
middle portion 46 diametrically positioned with respect
1. An exit nozzle comprising
an exit lip,
a trailing end, said end being diametrically and longi
tudinally positioned with respect to said lip,
to straight portion 44 and then de?ning a divergent gas
expansion surface with respect to lip 47 terminating in a
an outer shell joining said lip and said end, said outer
substantially elliptic gas outlet 55, thus providing pen
shape nozzle 23. For the penshape con?guration shown
respect to the longitudinal centerline ‘of said shell,
shell comprising a surface which is symmetrical‘with
in FIGS. 2 and 3, the throat area and plane location
thereof is varied by actuation of a clamshell member 21.
The downstream surface 48 of inner surface 18 which
includes the surface of tear-shaped member 28 of the
the symmetry occurring in planes which are perpen
dicular to the longitudinal centerline of said shell,
said surface providing an‘exhaust outlet having ‘a
con?guration shown in FIGS. 4-6 is selectively varied
said end at the limits of the major axis thereof,
an upstream inner surface disposed within said “shell,
by actuation of the tear-shaped member actuating 55
means 29.
Outer surface 17 has surface 56 converging
longitudinally toward centerline 25 to join with surface
18" and terminates as lip 47 and de?nes substantially
pointed boattail 57. The convergence of surface 56 is
of equal or greater angularity than the convergence of 60
substantially elliptical edge and having said lip and
said inner surface effecting a convergent ?ow area
terminating as a nozzle throat diametrically and
longitudinally positioned with respect to said end,
an expansion surface disposed in said shell down
surface 48. Connecting portions 58 and 59 of outer sur
face 17 join exit lip 47 to end 52 as best shown in FIGS.
2, 5 and 6 so that outer surface 17 and inner surface
18 coact to de?ne substantially elliptical exhaust gas out
stream of said throat, said expansion surface
comprising a concave central surface interconnecting
said throat and said trailing end and symmetrical
concave surfaces with respect to the shell centerline
let edge 55.
Shown in FIGS. 7, 8, and 9 is another embodiment of
interconnecting the exhaust outlet elliptical edge of
an exhaust nozzle 32.
The nozzle 32 has an outer shell
33 which encloses a double-ramp structure 34, said
‘double-ramp structure 34 being an envelope having an
airfoil pro?le. The trailing edge 38 of said double-ramp
structure 34 comprises the trailing edge of said exit noz
zle 32. A portion of said double-ramp structure 34 is
flexible and extends from two hinges 35 that are adja
cent the trailing edge 38 to two guide rods 41 adjacent t
,the leading edge whereby the guide rods 41 move ee
said outer shell with said concave central surface
and said throat.
2. An exhaust nozzle, according to claim '1, wherein the
said lip has an inward curvature toward said trailing end.
3. A penshape exhaust nozzle comprising‘ an outer
said outer surface being substantially straight-on one
longitudinal line thereof and extending for thefull
exhaust nozzle length and terminating in a trailing
said outer surface further having a curved surface
diammetrically and longitudinally positioned with
respect to said end converging gradually toward said
straight surface and terminating in an exit lip sub
stantially short of the trailing end, and
said outer surface still further having connecting sur
faces joining said straight outer surface and said
curved surface so that said outer surface has a sub
stantially rearward elliptical edge outlet, and
an inner surface,
4. Apparatus, according to claim 3, and including a
member pivotally attached to said curved surface and be
ing pivotable toward said straight outer surface thereby
permitting selective variation of the exit throat area.
5. Apparatus, according to claim 4, and including actu
ating means to selectively pivot said pivotable member
toward said straight outer surface.
6. Apparatus, according to claim 3, and including a
movable member disposed in said expansion surface and
10 being movable toward said exit lip thereby permitting
said inner surface de?ning an exhaust gas passage hav
ing a substantially circular cross section at its for
selective variation of the exit throat area.
7. Apparatus, according to claim 6, and including actu
ward end and converging to a minimum area exit
ating means to selectively move said movable member
throat, said throat being diammetrically positioned
toward said lip.
with respect to said straight outer surface at a sub 15
stantially maximum distance therefrom and terminat
ing upstream of said trailing end,
said inner surface throat further having the plane there
References Cited in the ?le of this patent
of de?ning an acute angle to said straight outer sur
trailing end, said expansion surface also terminating
face with respect to said trailing end, and
20 2,788,635
said inner surface still further having an expansion sur
face rearward of said throat and converging toward
said straight outer surface and terminating at said
in communication with the elliptical edge outlet and 25 2,956,759
said throat.
Gri?ith ______________ __. July 20,
Ford ________________ -_ Apr. 16,
Price et a1 ____________ __ Aug. 13,
Johnson ____________ .. Mar. 15,
Olson ________________ _- June 7,
Pearson ______________ .._ Sept. 13,
Creasey et a1 ___________ __ Oct. 18,
Sens _________________ ..- Feb. 6,
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