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Патент USA US3020723

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Feb. 13, 1962
J. H. BERTIN ETAL
3,020,713
THRUST SPOILING DEVICE FOR JET PROPULSIQN UNITS
Filed Dec. 9, 1953
United States Patent Q?ice
_
1
3,020,713
3,020,713
Patented Feb. 13, 1962
2
*
THRUST SPOILING DEVICE FOR JET
PROPULSION UNITS
Jean H. Bertin, Neuilly-sur-Seine, and Marcel Kadosch,
Paris, France, assignors to Societe Nationale d’Etude
et de Construction de Moteurs d’Aviation, Paris,
France, a French company
Filed Dec. 9, 1953, Ser. No. 397,228
Claims priority, application France Dec. 12, 1952
1 Claim. (Cl. 60-3554)
It is known to provide reaction propulsion units with
a device for de?ecting the jet, whereby in particular a
braking effect is obtained or by reversal of the direction
of the thrust.
The applicants have themselves proposed, de?ection 15
arrangements which operate by means of a solid or ?uid
with a velocity component at right angles to the direction
of ?ow of this stream, forms a kind of marginal ?uid
screen which masks the openings and displaces the stream
away from them.
The'said discharge openings for the de?ected jet may
thus remain constantly open to the interior of the pro
pulsion unit, and it will suf?ce that the auxiliary gas under
pressure is blown permanently through the blowing ori
?ce or ori?ces during the periods when there is no de?ec
tion; the de?ection is produced by stopping the auxiliary
injection and may be furthered by the use of a mobile
obstacle ‘which may itself be either solid or ?uid. It
should furthermore be noted that the de?ection is facili
tated by the fact that the static pressure of the gases of
the stream at a point level with the openings tends to
produce naurally a ?ow through these openings as soon
as the auxiliary fluid screen is suppressed.
The description which follows below ‘in respect of the
obstacle (in the latter case, a jet of auxiliary gas is in
jected into the jet with a component at right angles to the
direction of ?ow of the jet) which by modifying the
attached drawings (which are given by way of example
forces which act on the jet, produce the desired change in 20 only, and not in any way in a limiting sense) will make it
direction. Means for guiding the jet thus de?ected, consti
quite clear how the invention is to be carried into effect.
tuted in most cases by a grid of blades, serve to re-enforce
FIG. 1 shows diagrammatically one form of embodi~
the de?ection created by the obstacle.
ment of the invention. The upper half and the lower
These de?ection devices have been most frequently
half of this ?gure are two axial cross-sections of the rear
placed at the end of the discharge nozzle, thus increasing 25 portion of a jet propulsion unit taken in two planes at
the maximum overall cross-section at this point, which
right angles to each other.
gives rise to the necessity of a supplementary fairing, ex
FIG. 2 is a transverse cross-section along the line II—II
tends the length of the casing and has generally an adverse
of FIG. 1. In this ?gure, the lines 01 and Ola represent
effect on the performance of the aircraft.
respectively the outlines of the cross-sectional planes of
It would be of great advantage to be able to house the 30 the ‘upper half and of the lower half of FIG. 1.
de?ection device in the space within the propulsion unit,
FIG. 3 is a diagrammatic view of an alternative em
forward of the exhaust discharge nozzle, in a portion of
the casing in which there is in general a large amount
In the drawing, there is shown at 1, the tubular rear
of room available, and this would avoid any increase in
portion of a reaction propulsion unit.
the maximum overall cross-section as compared with a 35
This tubular portion receives the gases coming from
propulsion unit which is not provided with a de?ection
the turbine 2. At 3, there is located the exhaust dis
device, and which also avoids any increase in the length
charge nozzle having a shape adapted for the expansion
of the casing, while enabling the provision of grids of
of the gases and the formation of the propulsive jet at
blades which are more developed in the radial direction,
high speed. This discharge nozzle is generally mounted
thus increasing the effectiveness of these blades. In order 40 by the aircraft manufacturer immediately after the tube
to achieve this, it is necessary to form openings for the
1 of the reaction propulsion unit, at the same time as
passage of the de?ected jet, both in the wall of the pro
the cowling 4 which surrounds the unit. This cowling
pulsion unit and also in the casing, at a point forward of
being adapted to the shape of the propulsion unit and of
the exhaust discharge nozzle. Since, however, in this
the discharge nozzle in order that it shall have a mini
zone, the expansion of the gases is not completed, the
mumaerodynamic drag, it will be seen that the arrange
gases thus having a static pressure higher than atmospheric
ment of a de?ection device aft of the discharge nozzle
pressure, the problem arises of closing these openings ’ has an adverse effect by varying the aerodynamic .qual
bodiment.
during normal operation and only causing them to open
at the moment when it is desired to de?ect the jet. The
ities of the casing.
’
'
.
In carrying out the invention, the openings for the de
provision of movable mechanical shutters leads to great 50 ?ected jet are formed at a point forward of the discharge
complication and di?iculties because of the necessity of
nozzle 3. In the form of embodiment shown in the draw
causing these shutters to operate in the center of gases
ing, these openings are formed by two indentations which
at a high temperature.
are diametrically opposite and extend parallel to the
The object of the present invention is to solve this
axis of the propulsion unit, the said indentations being
55 formed both at 5 on the internal Wall of the gas conduit
hitherto unsolved problem.
forward of the discharge nozzle, and also at 6 in the wall
In accordance with the invention, the openings formed
of the cowling of the unit. Between the wall of the
in the wall of a jet propulsion unit, and in the casing in
propulsion unit and the wall of the cowling, they are
front of the exhaust discharge nozzle, for the exit of the
closedvin by two parallel partitions 7, 8 (see FIG. 2).
gases during the de?ection period, are combined with
an arrangement of slots or ori?ces formed in the wall 60 They form with these partitions and the walls 9, 10, which
are joined to the casing, two channels through which
of the jet propulsion unit forward of the said openings,
and which are themselves connected to a source of aux
iliary gas at a suitable pressure, in particular to the de
the gases ofythe jet may escape in the direction shown
by the arrows F1 with a component of speed directed
towards the front of the unit in order to give a braking
livery side of the air compressor of the unit, the said 65 effect.
'
ori?ces having a direction such that the auxiliary gas under
In these channels, there are arranged grids of blades
pressure, injected into the center of the gases of the stream
11, suitably curved’ from the interior of the propulsion
3,020,713
3
unit towards the exterior and forming as many individ
ual channels which assist in directing the de?ected jet in
the direction F1. Forward of each of the grids of blades,
there is provided a curved surface 12 which is connected
tangentially both to the internal wall of the gas conduit
and to the external wall of the cowling, and which may
have an ejector-shaped cross-section as shown in the
drawing. Forward of this point, the surface 12 is sepa
A.
obstacle to the ?ow of the jet of gas towards the dis
charge nozzle, and the jet is thus de?ected into the chan
nels of the grids of blades, which cause it to escape to
the exterior in the direction of the arrows P1.
In order to ensure the maximum elfect of the de?ecting
jets which are discharged through the ori?ces '14, 15, it
is an advantage to provide holes such as 11341, 15a in the
wall of the gas conduit aft of the ori?ces 14, 15; these
holes enable air to enter and supply the wake created by
slot 13, the function of which will be explained in the 10 the de?ecting jets.
In order to close-in the channels on each side of the
description below.
rated from the internal wall of the gas conduit by a
Two diametrically opposite holes 14, 15, formed on
the wall of the propulsion unit in the plane Ola, perpen
grids of blades, the form of embodiment described in
cludes the walls 7, 8, which are parallel to each other.
This has the advantage that all the portions of the de
?ected jet are directed parallel to these walls, without any
lateral component of speed at right angles to the plane
of the upper half of FIG. 1. The detachment of the jet
from the walls is thus avoided and the jet retains the max
shape in the direction of the periphery of the propulsion
imum of kinetic energy whilst producing a powerful
unit. On the internal wall of the gas conduit, and im
mediately forward of the surface 12 respectively, of the 20 counter-thrust.
Other arrangements of the outlet channel of the de
ori?ces 13 which precede these surfaces, there is formed
?eoted jet may, however, be adopted.
a continuous annular slot 18 which connects the interior
The ?uid obstacle formed by the jets of air escaping
of the propulsion unit with an annular collector 19, the
through the ori?ces 14, 15, could be replaced by a solid
latter being in turn connected to the delivery side of the
obstacle. There could, for example, be provided a di
air compressor through a pipe 20 with a wave 21.
ametrical support with an aerodynamic pro?le which
The operation is as follows:
could extend into the discharge nozzle between the points
It is ?rst of all supposed that the valves 17 are closed,
occupied on the drawing by the ori?ces 14, 15 and which
so that the ori?ces 14, 15, are not supplied with air. The
would carry movable screens which could be withdrawn
gases issuing from the tube 1 of the propulsion unit and
into this support, or be caused to project from it; the said
proceeding towards the discharge nozzle 3 pass in front
solid screens could, furthermore, be replaced by jets of
of the passages 5. Since at that point, the gases have a
auxiliary gas escaping from slots in the said support.
high static pressure, they would have a tendency to es
dicular to the median plane OI of the grids of blades, are
connected by pipes 16 provided with a valve 17 to the
delivery side of the air compressor (not shown) of the
propulsion unit. The holes 14, 15, have an extended
cape to the exterior if nothing were provided to prevent
this. The valve 21 is open and a jet of air passes through
the annular slot 18 and penetrates into the interior of
There could also be provided a diametrical obstacle 25
turning about a diametrical axis 26 as shown in FIG. 3,
the said obstacle occupying either the position shown in
full lines for which it presents a pro?led form to the jet
of gas, or the position shown in dotted lines, for which
angles to the direction of ?ow of the gases. This aux
it produces a symmetrical de?ection through the oppo
iliary jet compresses the jet of gases ?owing through the
sitely-disposed notches in the gas conduit, or any inter
tube. It forms around this jet a kind of convergent
mediate position giving rise to an asymmetrical de?ection
divergent ?uid wall which prevents the gases from escap
through the said notches and, in consequence, to a varia
ing through the notches 5 and the channels of the grids
of blades. The gases are thus led into the discharge
tion in the direction of ‘the thrust.
The arrangement of the channels for the passage of
nozzle 3 without losses, in spite of the absence of any
the de?ected jet may be varied. For example the two
mechanical shutter on the notches 5.
In this phase of the operation, the ori?ces 13 serve to 45 diametrically—opposed channels described, could be re
supply the low-pressure zones, or “wake zones” which
placed by a single annular channel.
Externally, the continuity of the cowling 4, or at least
tend to be formed on the outside of the ?uid screen.
a part of that continuity, may be restored by' a grid of
The ori?ces 13 may be supplied with air by the cooling
circuit of the jet propulsion unit or by the special air
cross stays in the form of a honeycomb for example, fol
inlet openings 22 formed in the cowling.
lowing the line 6 outlined in chain-dotted lines in FIG. 1.
The operation described naturally supposes that the
There could also be provided along this line 6, a movable
auxiliary jet is discharged from the annular slot 18 with
hood which would only be opened during the de?ection
the propulsion unit with a component of speed at right
a suitable total pressure. This pressure must be su?icient
for the ?uid screen formed around the gases to ensure
a balance between the high pressure of the gases and
periods; during periods of no de?ection, this hood could
not be subjected to the action of the hot gases by virtue
of the interposition of the screen formed by the con
the ambient atmospheric pressure, until the jet of gas
strictive jet.
again reaches the full wall of the discharge nozzle. On
What we claim is:
the other hand, it must not be too high, since in this case,
In a jet propulsion unit ending with a propulsive nozzle
the excessive contraction of the jet of gas would lead
designed for expanding motive gas and having a pipe con
to an aspiration of the exterior air through the channels 60 meeting said propulsive nozzle for conducting thereto a
of the grids of blades. As, at the delivery of the com
stream of motive gas, a thrust spoiling device comprising
pressor of the jet propulsion unit there is available a
passage means at the periphery of said pipe upstream of
pressure very much higher than the pressure of the gases
said propulsive nozzle, said passage means extending
laterally of the normal axial ?ow path of said stream and
in the portion 1, the gases having passed through their
?rst expansion in the turbine, it will be possible to vary 65 opening into the atmosphere at a substantial angle with
the axis of said nozzle, to provide an auxiliary de?ected
the pressure and/or the output of the gases passing
exhaust path for said stream, blowing means extending at
through the slot 18 in order to achieve the desired effect.
the periphery of said pipe and opening thereinto upstream
If now it is desired to de?ect the jet, the valve 21 is
of said passage means, said blowing means being designed
?rst closed in order that the ?uid screen shall cease to
exist and the gases already have a tendency to pass out to 70 for forming a screen-like ?uid partition about the motive
gas stream past the passage means, means for supplying
the exterior through the channels of the grids of blades.
pressure ?uid to said blowing means, controllable means
The valves 17 of the conduits 16 are opened. Two jets
for cutting off the supply of pressure ?uid, means for col
of air thus pass out through the opposed ori?ces 14 and
lecting ambient air and means for leading said ambient
15 in the diametrical plane at right angles to the median
plane of the grids of blades. These jets tend to form an 75 air to a point of the pipe located between the blowing
5
3,020,713
8
means and the passage means, whereby the low-pressure
wake zone which tends to arise at the side of the fluid
partition opposite to the screen is ?lled with air.
2,7 02,986
2,793,4931
Kadosch et a1. ________ __ May 28, 1957
1,020,287
France ______________ __ Nov. 12, 1952
Kadosch et a1. ________ __ Mar. 1, 1955
FOREIGN PATENTS
References Cited in the ?1e of this patent
UNITED STATES PATENTS
2,418,488
2,692,800
Thompson __________ __ April. 18, 1947
Nichols et a1 ___________ __ Oct. 26, 1954
6
OTHER REFERENCES
“Anti-Bomber Rocket Missiles,” by Chandler Aero
Digest, April 1950, pages 100—102.
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