US2760336A - Improvements in turbojet units, including means for by-passing air on its way from the compressor to the turbine of the unit - Google Patents

Description

Aug. 28, 1956 v REMGER 2,760,336

IMPROVEMENTS IN TURBOJET UNITS, INCLUDING MEANS FOR BY-PASSING AIR ON ITS WAY FROM THE COMPRESSOR TC THE TURBINE OF THE UNIT Filed July 17, 1951 3 Sheets-Sheet 1 INVENTDR g- 1956 v. RENIGER 2,750,336

IMPROVEMENTS IN TURBOJET UNITS, INCLUDING MEANS FOR BY-PASSING AIR ON ITS WAY FROM THE COMPRESSOR TO THE TURBINE OF THE UNIT Filed July 17, 1951 s Sheets-Sheet 2 Aug. 28, 1956 v. RENIGER 2,760,336

IMPROVEMENTS IN TURBOJET UNITS, INCLUDING MEANS FOR BY-PASSING AIR ON ITS WAY FROM THE COMPRESSOR TO THE TURBINE OF THE UNIT Filed July 17, 1951 3 Sheets-Sheet 3 toward c/aw/zsream al'oe of compressor-.5

lNVENTDR BY I 1 Unite tates Patent G INIPRGVEMENTS 1N TURBO-YET UNITS, INCLUD- ING BEANS FDR Edi-PASSING AIR ON ITS WAY FRQM THE COMPRESSGR T TIE TURBINE 015 THE UNIT Victor Reniger, Chatillon-sous-Bagneux, France, assignor to )fiice National dEtudes et de Recherches Aeronautiques (0. N. E. R. A.), Chatillon-sous-Bagneux, France, a society of France Application an 17, 1951, Serial No. 237,093

Claims. (21. 60-3554) The present invention relates to turbo-jet units in which air is by-passed on its way from the compressor to the turbine, for instance for feeding braking nozzles.

It is known that braking nozzles, used for reducing the speed of jet aircrafts, in particular for landing, may be supplied with air collected from the outlet of the compressor. However, if no precautions are taken, by-passing of air from the outlet of the compressor involves serious drawbacks concerning the efiiciency of the unit.

The object of the present invention is to provide a turbo-jet unit of the type above described which avoids these drawbacks.

Preferred embodiments of my invention will be hereinafter described with reference to the accompanying drawings, given chiefly by way of example, and in which:

Fig. l is a diagrammatic sectional view of a turbo-jet unit made according to my invention;

Fig. 2 is a corresponding diagram showing the air distribution, a portion of this view being a section on the line HH of Fig. l; v i

Fig. 3 is a diagrammatic plan view showing air distribution cut-oif means in two combustion chambers supposed for the sake of simplification to be located in the same plane;

Fig. 4 diagrammatically shows an automatic air by-pass control device according to my invention;

Figs. 5 and 6 are diagrammatic detail views on a larger scale.

, from the compressor toward the turbine.

In the example illustrated by Figs. 1 to 3, it is supposed that three combustion chambers, designated by 2a, 2b, 20, respectively, are thus brought out of action when the braking nozzles are to be operated.

My device includes, in this embodiment, a set of shutters 5 pivotally disposed between fixed partitions 6 and located ahead of said combustion chambers 2a, 2b and 20.

Fixed partitions 6a, 6b, 6c and 6d, Which also cooperate with shutters 5, limit said combustion chambers.

Shutters 5 are actuated through a ring 7 movable on an annular bearing surface 8 fixed on the outer casing of the unit. Between ring 7 and shutters 5 are provided links 9 rigid with the spindles 5a of said shutters 5 and the slotted ends 9a of which engage pins 7a carried by ring 7.

Ring 7 may be operated either manually or automatically. In the example shown, ring 7 is actuated by means of a jack 10 operated by oil under pressure supplied from a valve device 11 manually controlled by the Patented Aug. 28, 1956 operator by means of a lever L. Oil under pressure from a suitable source enters this valve 11 through a conduit 12 and it leaves it through conduits 13 and 14. This oil is fed to jack 10 through either of conduits 15 and 16 and it escapes therefrom through the other of these conduits.

The means for by-passing air from the stream flowing from the compressor toward the turbine and sending this by-passed air to the braking nozzles 17 include three by- pass pipes 18a, 18b, 18c, starting from the conduit leading from the compressor to said shutters 5, at points located upstream of said shutters, these by-pass pipes,

leading to a common conduit 19 connected through branch pipes 20 with the braking nozzles 17.

The inlet of each of these nozzles 17 is provided with a throttle valve 21. These throttle valves 21 are to be opened when shutters 5 are being closed. Advanta geously, the means for controlling shutters 5 and those for controlling throttle valves 21 are interconnected.

For this purpose, each of the throttle valves 21 is operated, as shown for one of them, by means of a hydraulic jack 22 supplied with oil in parallel with jack 10, for instance through branch pipes 15a and 16a in com- .munication with pipes 15 and 16 respectively (Figs. 2

and 6).

Fuel is fed to each combustion chamber 2 through a pipe 23 controlled by a valve 24. Valves 24 are, same as throttle valves 21, operated through hydraulic jacks 24a supplied with oil through conduits 15b and 16b connected with distributing pipes 15a, 16a respectively (Figs. 2 and 5)., t

Braking nozzles 17 are to be supplied, simultaneously with compressed air, with fuel fed through pipes 25 controlled by valves 26 respectively. Each valve 26 is operated through a hydraulic jack 26a supplied with oil through conduits 15c, 16c branching off from conduits 15a, 16a respectively.

Advantageously, the, turbo-jet unit is provided, in its jet nozzle, with a cone 27 slidable longitudinally in the -jet nozzle'for varying the outlet section of said jet nozzle.

Control of the longitudinal displacements of this come is preferably interconnected with that of shutters 5. For this purpose, cone 27 carries a nut 28]: prevented from rotating about its axis and in mesh with a screw 28a rotatable about itsaXis but prevented from sliding longitudinally, rotation of this screw being obtained from a shaft 29 actuated by a pinion 30, which may be the gear of a hydraulic motor 31 inserted in the oil circuit constituted by pipes 15d and 16d.(Figs. 1 and 2).

In the above described example of a device according to my invention, a certain amount of air can therefore be by-passed from the compressor 3 to the braking nozzles 17 by operating lever L to place a given number of combustion chambers temporarily out of action.

I may also, according to my invention, vary the relative amount of air which is thus by-passed. This result can be obtained by providing means for bringing the various elements above referred to (such as shutters 5, throttle valves 21, etc.) into any of a plurality of positions intermediate between the fully closed one and the fully open one..

However, I consider that it is more advantageous to vary the number of combustion chambers brought out of action, the number of braking nozzles brought into action being simultaneously and correspondingly varied.

According to a preferred embodiment of my invention,

the supply of air from the compressor to the respective braking nozzles is automatically controlled in response to variations of the compressed air pressure downstream I of the compressor, these variations being produced by the operator by varying the number of combustion chambers that are out of service. a

Fig. 4 shows automatic control means complying with this condition. This arrangement corresponds to the case of an airplane p'rovidedwith fourbraking nozzles adapted tobe operated independently; Fig. 4 shows the means forcontrolling the feed of air to only two of these nozzles,

' a by means of hydraulicjacks' 32a and 320. i The two other nozzles would be controlledsimilarly.

These jacks are controlled'by means-of an automatic valve system including-a casing 33, a diaphragm '34, a

spring 3 5 and a slide valve 3 6. One of the faces of diaphragm 34 is connected through a conduit 37 with the ment it would be only 2.24 kgs. per sq. cm. Thus, the thrust I can obtain by means of the braking nozzles. is about one half of the thrust developed by the turbo-jet under normal working conditions, whereas, with the conventional arrangement, it is about one fourth thereof.

In a general manner, while I have, in the above description, disclosed what I deem to be practical and efficient embodiments of my invention, it should be well'under stood that I do not wish to be limited thereto as there might be changes made inthe arrangement; disposition and form ofthe parts without departing from the principle of the present invention as comprehended within the scope of the accompanying claims;

space on the downstream side of compressor 3 and is 7 therefore subjected to the pressure of theeompresscd air,

and the other face is subjected to the atmospheric pressure, J

owing to the provision of ports 38. Spring 35 balances the difference between these pressures.

'The casing 36:; of slide valve 36 is supplied with oil under pressure througha conduit 39. The discharged oil escapes through either of conduits 4i) and 41.

Valve 3636a operates a relay, valve device 42, through two conduits 43 and 44. a

This relay valve device 42 is supplied with oil under pressure through conduit 45, whereas the discharged oil escapes through either of conduits 46 and 47.

, The four braking nozzle control jacks are suppliedwith oil under pressure respectively through conduits 48a, 48b,

48c, 48d for displacement in one direction and through conduits 49a, 49b, 49c, 49d for displacement in theother direction. 7

Whenthe operator actuates shutters 5, and forinstance when he opens only those corresponding to one combustion chamber, the compressedair pressure on the downstream side of the compressortends to rise, whereby slide valve 36 moves downwardly. Qilunder pressure from 1 'conduit39 is then supplied to cylinder 42 through con- "What fl claim is:

1. In combination with a turbo-jet unit including a com: pressor, a turbine, a jet nozzle atthe outlet of saidturbine,

means for driving said compressor operative by saidturbine, a piurality of combustion chambers mounted inparallelbetween the outlet of said compressor' and the 2. in combination, on an aircraft, a plurality of brak 7 ing nozzles, a turbo-jet unit including a compressor, a turduit 43. Piston 42a move's down and causes slide valve 42b to connect conduit 49a with feed conduit 45. The

piston of jack 32a is'thus moved down, which opens the r I throttle valve 21 of'the corresponding braking nozzle. 7

The throttle valves of the other braking nozzles are closed.

However, theamount of air by-passed fromthe downstream side of the compressor causes to restore the downstream compressed air pressure to its normal value. When this value is reached, slide valve 36 cuts off the connection between conduits? and the source of oil under pressure (conduit 39). fiston 42a and slide valve 42b remain stationary in the position they now occupy.

If the operator increases the number of combustion chambers placed out of service, piston 42a is again moved sively bringing the braking nozzles into action.

When the number of combustion chambers placed out f @5011 s e e operations above described are reversed.

' 'Of course, instead of 'closing some of the combustion .chambersl might as well reduce the section of flow thr ugh a o mi ,Theadvantage of my device is as follows: 7

Considering the case of a turbo-jet unit working under normal conditions (for instance the pressure on the down stream side or" the compressor being 5 kgs; per sq. cm.

and the temperature upstream of the turbine 800 Cl), calculation shows that with my device, the. maximum amount of air that can be lay-passed (in the limit, case where the propulsion energy of the'turbo-jet becomes zero) is about 31% of the airflow rateunder normal working conditions, whereas with the conventional arrangement, it was only 22%, which corresponds to a gain of 50% over the results previously obtained. Furtherm r yt i by'p s d ith m device s the normal pressure existing downstream of the compressor, i. e. 5

kgs. per sq. -cm whereas; with the conventional arrangedownwardly, together withi'slid e valve 42b, thus succes bine, a jet nozzle at the outlet ofsaid turbine, meansfor driving said compressor operativeiby said turbine, a plurality of combustion chambers mounted in' parallel between theoutletEof saidcempresscr and the inlet of said 7 turbine, and means 'for feeding fuel to saidcombustion chambers respectively, and adevice for feeding air'under pressure frorn'said compressor to said braking nozzles which comprises means for cutting oif communication between theoutlet of said compressor and any number i of said chambers smaller than the total number thereof,

means for cutting off the fuel feed means of said chamber, conduitmeans for by-passing a portion of the;com-: pressed airfed at the outlet of said compressor'tolsaid brakingnozzle, valve means in'said conduit means for controlling said nozzles, means responsive tovariations of the pressure at the outlet Said-compressor for succes-.

sivcly opening said'valve means as said outlet pressure rises, 'andmeans operatiyely connectedwith said valve means for operating said communication cut-off means 7 and said fuel feed cut-of means simultaneously and corl sra r nsl ith the i br s s f se il 3. in cornbination, on an aircraft, at least one braking nozzle, a turbo-jet unitincluding a compressor, a turbine, I a jet nozzle at the outlet of said turbine, a cone coaxial with said nozzle slidable therein so, that longitudinal movethem thereofvaries the outlet section of said jetnozzle,

means for driving said compressor operative by said turbine, a plurality of combustion chambers mounted in parallel between the ,outlet of said compressor and the inlet of said turbine, and means for feeding fuel to said combustion chambers respectively, and adevice for feed ing air under pressure fro-m said compressor to said brakinertia-ads w i h mor e esa Pu 0E m ni a en b ween t r u st fsai cam e nd least'one of said charnbers, means-for cutting off the fuel feed means of said chamber, means for sliding said cone in said jet nozzle to reduce the, outlet'section thereof,

conduit means for by-passing toward said braking nozzle V V a portion of .the compressed air fed at the outlet of said compressor, and 'means forfsimultaneously and coneispondingly opcratingthe four'last mentionedmeans,

7 4. In a device as claimed in claim. 1,,means tori-vary ingytheoutletsection.of said'iiet, nozzle, and meansflrespon sive to operation of said bypassing means to operate said nozzle section varying means.

5. In a device as claimed in claim 1, having a braking nczzle, said conduit means conducting the bypassed air to said braking nozzle.

References Cited in the file of this patent UNITED STATES PATENTS 1,986,435 Heinze Jan. 1, 1935 6 ONeil June 24, 1947 Martin May 30, 1950 Imbert Oct. 31, 1950 Roy Dec. 11, 1951 Marchant Nov. 10, 1953 Rennie et al Dec. 15, 1953

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