FR2570765A1 - Jet engine unit for vertical take off aircraft - Google Patents

Abstract

THE INVENTION RELATES TO A TURBOREACTOR UNIT FOR A VERTICAL OR SHORT TAKE-OFF AIRCRAFT COMPRISING A MAIN GAS TURBINE ENGINE 12 TO 20, OF THE DUCTED BLOWER TYPE, SUPPLYING THE MAIN ORIENTABLE TUBES 22, 23, AND ONE OR MORE GAS TURBINE ENGINES. AUXILIARIES 24, ACTIVATED BY THE PRESSURIZED AIR COMING FROM THE BLOWER CHANNEL 14 OF THE MAIN MOTOR, AND ACTING BY ORIENTABLE AUXILIARY TUBES 28 PROVIDED UPstream OF THE MAIN TUBES. THE GROUP ACCORDING TO THE INVENTION IMPROVES THE BALANCE OF THRUST AND REDUCES FUEL CONSUMPTION.

Description

The present invention relates to turbojet engines and, in p)

  specific, those applicable; -ble to type aircraft

vertical or short takeoff.

  We know how to equip these aircraft with a single turbojet coinm-

  carrying a plurality of pivoting ejection nozzles. Sphering so as to vary the direction of the thrust produced by the engine. The aircraft can be propelled forward for normal flight, the nozzles discharging rearward, or float or move vertically, the nozzles discharging downward. The nozzles can be adjusted so as to give the

  Pois a certain vertical lift and a certain propulsion-

  horizontal zion to ensure the transition between normal flight

  sore forward and lift.

  The best known of these engines has four jet nozzles

  pivoting, the two located downstream are supplied with hot exhaust gas and the two located upstream

  are supplied with relatively cold branch air.

  Several solutions have been proposed to increase the thrust of these engines, but all have drawbacks. These types of engines have a low bypass rate and thought has been given to proportionally increasing the characteristics of such a motor or to increasing its bypass rate. But

  this obliges to give to the anterior nozzles and to the piping-

  associated with exaggerated dimensions to admit the large flow of diverted air at low pressure. This increases the

  weight of the engine and complicates the installation of the aircraft.

  It has also been proposed to increase the thrust of the two previous nozzles by combustion of additional fuel in the bypass air reaching the nozzles (solution usually

  dcdnomriwe reheating or combustion in an accumulation chamber).

  This solution has two main drawbacks: the combustion of fuel in the air derived from fairly low

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  pressure is insufficient and leads to a specific consumption

  high fuel efficiency. 2 the increase in power

  thrust of the front nozzles poses problems of

  push release. In order for an engine of this type to function satisfactorily in an airframe, it must be ensured that the bottom-up thrust resulting from all

  the nozzles pass through the center of gravity of the mo-

  tor / cell when the nozzles are pointed downwards.

  So, unless you apply a reheater to the front nozzles

  permanent fage, the balance of the thrust is not maintained.

  The object of the present invention is to produce a turbo-jet unit for aircraft with vertical or short takeoff

  eliminating the above drawbacks.

  The turbo-reactor unit according to the invention comprises a main gas turbine engine having at least one propellant nozzle, and at least one auxiliary gas turbine engine capable of being supplied with pressurized air, as the driving fluid, coming from the main engine, this at least unique auxiliary engine having

  at least one outwardly orientable ejection nozzle.

  Preferably, the device will include two auxiliary motors.

  res arranged in the blower channel of the main engine where they will be supplied with pressurized air, the remainder of pressurized air from the blower channel mixing with the gas stream

  hot leaving the main engine turbine.

  In addition, the propellant nozzle of the main engine may include two sectionally vectorable nozzles

  variable, one on each side of the motor axis.

  The vectorally adjustable ejection nozzles of the auxiliary motors may be arranged, one on each side of the axis of the motor, in front of the propulsion nozzles of the main motor.

  Preferably, flow guidance members will be available.

  placed in the blower channel in order to direct towards the

  auxiliary teurs a determined fraction of pressurized air

crossing the fan channel.

  Preferably, these flow guide members comprise an annular divider arranged in the blower channel in

  upstream of the air intakes of the auxiliary engines.

  The invention is described below in detail with reference to a preferred, nonlimiting example of embodiment shown.

  in the accompanying drawings in which: -

  - Figure 1 is a schematic perspective view, in partial section, of a turbojet engine according to the invention; - Figure 2 is a schematic axial section of the turbojet engine according to the invention; - Figure 3 is a schematic cross section of the turbo-reactor group along line 2-2 of Figure 2; and - Figure 4 is a comparative graph of the fuel consumption curve as a function of the thrust, in

  a conventional motor heated with vectorial thrust o-

  rientée and in an engine according to the present invention.

  The turbo-reactor group 10 shown comprises, in the direction of flow of the gases, a fan. before 12 rotary climb

  on a low pressure shaft 13 and housed in the blowing channel

  flowering 14; a medium pressure compressor 15 fixed on a medium pressure shaft 13a; and a high pressure compressor 16 disposed downstream of the medium pressure compressor 15 and mounted

  rotary on a high pressure shaft 17. A com-

  annular bust 18 is arranged downstream of the high pressure compressor 16 with fuel supply members and

burners not shown.

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  Downstream of the combustion chamber is arranged a high pressure turbine 19 mounted on the high pressure shaft 17. A medium pressure turbine 19a is arranged on the medium pressure shaft 13a downstream of the high pressure turbine 19 and a low pressure turbine 20 is arranged downstream of the turbine 19a. A plurality of mixing conduits, one of which 21 is shown, are arranged downstream of the low pressure turbine. The air entering the engine is completely pre-pressurized by the blower 12 and then is divided into three flows.

  The first air flow enters the medium compressor.

  pressure 15 then gains high pressure compressor 16,

  the combustion chamber 18 and lems turbines 19, 19a and 20.

  The second flow enters the space located radially outside the compressor 15 but radially inside the flow divider 26 and emerges at the downstream part of the blower channel 14a where the mixing conduits 21 mix it

  to the flow of hot gases leaving the low turbine near

  sion 20. This mixed flow crosses a tubing in the form of breeches from which it is led to section ejection nozzles

  variable 22 and 23 À These latter also include or-

  ganes allowing to rotate them by at least 90 in order to

  be able to allow both vertical takeoff and horizontal flight

  zontal. The pivoting or vectorially orientable parts of the two nozzles 22 and 23 are shown diagrammatically in FIG. 2 only by the lines 22a and 23a

  The third flow enters the annular part deli-

  placed radially between the flow divider 26 and the envelope

  external engine hood and splits into two penetrating branches

  trant in the two auxiliary gas turbine engines 24 and

  arranged in the fan channel 14. These motors can

  wind be jet engines with one or two shafts whose combined volumetric flow will be significantly higher than that of the main part of the main engine identified by the

compressors 15 and 16.

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  The exhaust of the two auxiliary motors 24 and 25 is led to the ejection nozzles

  tion 27 and 28. The two anterior ejection nozzles 27 and 28 are both pivotally mounted relative to the rest of the turbojet group so as to be vectorially orientable to allow both vertical takeoff and horizontal flight. In operation, the auxiliary motors 24 and 25 operate under various regimes depending on the thrust required by the aircraft. Each of the two downstream nozzles has members making it possible to vary the section thereof. The variable section nozzles of the

  main motor are used to adjust this section, when modifying

  relies on the speed of auxiliary gas turbine engines to increase thrust, so that the outlet pressure of the blower discharging in channel 14 is

  in accordance with the pre-established theoretical report: blower pressure / speed rate.

  These variable section nozzles will therefore be coupled, by an appropriate system

  control, distributors or butterflies of auxiliary motors to satisfy

  make this blower pressure / speed ratio.

  Figure 4 is a comparative graph of the efficiency of a vector-driven thrust gas turbine engine, equipped with a heating system, with the efficiency of an engine according to the present invention, showing the economy of

fuel made possible.

  The legend of this graph is as follows

A = conventional engine.

B = motor according to the invention.

C = fuel consumption.

E = fuel economy.

P = thrust in flight.

R = reinforcement by reheating.

X = reinforcement by auxiliary motor.

  It is understood that, although the main motor described above is a bypass, blower and three-shaft motor, the invention is not limited to such a motor and that it may as well be of the blower type. with two trees or in fact

to any number of trees.

  RI V tNDICAlIvNS 1. Turbo-reactor unit comprising a main gas turbine engine having at least one propellant nozzle, and at least one auxiliary gas turbine engine, characterized in that said at least one auxiliary gas turbine engine is suitable for being supplied with pressurized air as the driving fluid from the main engine, said auxiliary engine

  at least unique having at least one vector exhaust nozzle

rially orientable.

Claims (6)

2. belon turbo-reactor group lJe Claim 1, characterized   in that it comprises two auxiliary motors arranged in the blower channel of the main engine from which they are supplied with pressurized air, the remainder of pressurized air from the blower channel mixing with the stream of hot gas   leaving the main engine turbine.   3. turbo-reactor unit according to claim 1, characterized in that the propellant nozzle of the main engine comprises two vectorially adjustable nozzles of variable section   arranged one on each side of the motor axis.   4. Turbo-reactor unit according to any of the Claims-   1 or 2, characterized in that the at least single auxiliary motor has two vectorally adjustable auxiliary motor ejection nozzles arranged one from each side of the axis of the main motor, in front   propellant nozzles of the main engine.   5. turbo-reactor unit according to claim 1, characterized in that flow guide members are arranged in the blower channel in order to direct towards the auxiliary engines a determined fraction of the pressurized air crossing the blower channel.   6. turbo-reactor group according to claim 5, characterized in that these flow guide members com:> return an annular divider disposed in the soufi'lante channel   upstream of the air intakes of the auxiliary engines.   7. Turbo-reactor group according to any of the levendica-   1, 2, 3, 4, 5 or 6, characterized in that it is suitable for   pr, required for propulsion of a vertical takeoff aircraft or over a short distance.