US2865170A

US2865170A - Method of jet deflection and apparatus therefor

Info

Publication number: US2865170A
Application number: US599593A
Authority: US
Inventors: Kadosch Marcel
Original assignee: SNECMA SAS
Current assignee: Safran Aircraft Engines SAS
Priority date: 1955-08-12
Filing date: 1956-07-23
Publication date: 1958-12-23
Anticipated expiration: 1975-12-23

Description

M. KA'DOSCH Dec. 23, 1958 METHOD OF JET DEFLECTION AND APPARATUS THEREFOR Filed July 23, 1956 INVE NTOR Mmaceu. KADoscH MMMPWW ATTOR NEYs United States Fatent METHOD or. JET DEFLECTION AND APPARATUS THEREFOR Marcel Kadosch, Paris, France, assignor td Siiciete Nationale dEtudes et de Construction de Moteurs dAviation, Paris, France, a French company Application July 23, 1956, Serial No. 599,593

Claims priority, application France August 12, 1955 Claims. (Cl. 60-3554) The present invention relates to arrangements for deflecting jets, and especially jets produced by reactionpropulsion devices. It is more particularly concerned with a thermal method of causing the deflection of a jet at the outlet of a discharge nozzle.

In accordance with the invention, the deflection of the jet is initiated by creating in the flow of gas on the upstream side of the outlet orifice of the discharge nozzle, an asymmetry in the transverse distribution of pressures by heating the part of the jet located at the side towards which the deflection is required, the opposite part of this jet remaining at a lower temperature. There are thus obtained two parallel streams of different temperatures in the jet.

The deflection thus started is strengthened and stabilised by adequate means for guiding the jet laterally, such as a convex edge or a grid of deflecting blades.

The present invention has a particularly advantageous application in the case of reaction propulsion devices provided with an after-burning system. There can then be created a transverse gradient of temperatures either by supplying only the fuel injectors situated on the side towards which deflection is desired, or by increasing the supply of fuel to these injectors, and/or by reducing the supply of fuel to the injectors located on the side opposite to that at which deflection is to be produced.

Thus, in the case in which retractable flame-holders are used, for example holders of the fluid-screen type, it is possible to put out of use the flame holders in that part of the jet opposite to the side towards which deflection is desired, thus rendering the combustion incomplete in this portion.

Instead of effecting an internal combustion for the asymmetric heating of the jet, it is clearly possible to heat one wall on the side towards which deflection is to be effected, for example, by means of an external source of heat.

The description which follows below with reference to the attached drawings (which are given by way of example only and not in any sense by way of limitation) will make it quite clear how the invention may be carried into effect.

Fig.1 is an axial diagrammatic cross-section of the rear part of a reaction unit provided with a post-combustion device. 7

Fig. 2 is a cross-section along the line II-II of Fig. 1.

There can be seen on the drawings, the casing 1 of a turbo-jet unit, the exhaust cone of which is shown at 2. This propulsion unit comprises an after-burning chamber *3 which terminates in an exhaust nozzle 4, the crosssection of which can be varied, in known manner, for example by means of pivotally-mounted flaps 5.

The outlet orifice of the exhaust nozzle is extended by :a convex deflecting edge 6 of circular shape, the front portion 6a of which forms an ejector, drawing-in the ambient air under the effect of the flow of gas passing out of the discharge nozzle 4. A grid of annular deice fleeting blade 7 is fixed at the rear of the deflecting edge 6.

The after-burning device comprises two oppositelyarranged groups of injectors 8, 9, connected to sepai ate manifolds 10, 11, which are supplied with fuel through valves 12, 13, enabling the rate of flow to be regulated. Flame holders 14,-of annular shape, are provided in the centre of the jet, close to the forward portion of the postcombustion chamber 3.

In order to obtain a deflection of the jet, one of the groups of injectors 8, 9 is fed with fuel, say the group 8; the valve 12 is opened, the valve 13 remaining closed. The introduction of fuel through the off-centered injectors 8 produces an asymmetric heating of the flow, and by this means a transverse gradient of temperature is created which has the effect of deflecting the jet towards the hotter side, i. e. towards the side adjacent the injectors 8. i The jet therefore is urged to flow along the path illustrated by the arrows and is thus applied against the adjacent part of the deflecting edge 6 and engages the adjacent part of the grid of blades 7.

The deflection of the jet thus produced gives rise to a transverse thrust which creates a moment which can be employed for steering in aircraft.

In order to obtain a deflection in the opposite direction, the procedure is reversed: the valve 13 is opened instead of the valve 12. The directional effect produced is opposite to that obtained in the preceding case.

It will be understood that it is possible to obtain a deflection of the jet in a plane at right angles to that of Fig. 1 (that is to say towards the left-hand or the righthand side of Fig. 2) by arranging two other groups of injectors displaced by with respect to those which are shown in the drawings. The groups of injectors could also be distributed over quarters of the circumference, for example by dividing the manifolds 10 and 11 into two halves and using separates valves for each of these halves.

In the case in which the after-burning device is in operation at the moment when it is desired to deflect the jet, that is to say if all the injectors are simultaneously and uniformly supplied with fuel, the operation is carried out in the following manner.

The supply of fuel to the injectors located at the side towards which deflection is desired to be made is increased, or the supply is reduced to the injectors located in the opposite side or again, these two operations are preferably carried out simultaneously, by providing a suitable valve system for that purpose.

What I claim is:

1. In a jet propulsion unit having a propulsive nozzle and a tail pipe for leading a continuous stream of motive gas thereto, a jet deflecting device comprising jet guiding means positioned downstream of said nozzle and extending outside and laterally of the normal undeflected path of the jet, and controllable means in said tail pipe which increases the temperature of an eccentric portion of said stream relatively to the remainder thereof whereby said stream is dissymmetrically heated and a transverse temperature gradient is established thereacross.

2. Jet deflecting device as claimed in claim 1, wherein the controllable means comprise means which effects a dissymmetrical combustion within the stream.

3. Jet deflecting device as claimed in claim 2, wherein the controllable means comprise means which effects a dissymmetrical injection of fuel into the stream.

4. Jet deflecting device as claimed in claim 3, wherein the fuel injecting means comprise a plurality of fuel injectors distributed symmetrically in the tail pipe, separate fuel supply lines which feed at least two groups of said References Cited in the file of this patent UNITED STATES PATENTS Forsyth Sept. 23,1947 10 4 FOREIGN PATENTS 161,402 Australia Feb. 22, 1955 1,057,271 France Oct. 28, 1953 OTHER REFERENCES Publication: Chandler-Aero Digest Magazine, vol. 60, No. 4, pages 100-102, April 1950.