PNEUMATIC DEVICE FOR RAPIDLY REACTIVATING A TURBINE ENGINE, ARCHITECTURE FOR A PROPULSION SYSTEM OF A MULTI-ENGINE HELICOPTER PROVIDED WITH SUCH A DEVICE, AND CORRESPONDING HELICOPTER

Abstract

The invention relates to a device for the rapid reactivation of a helicopter turbine engine (6), characterised in that it comprises a pneumatic turbine (7) mechanically connected to said turbine engine (6) so as to be able to rotate it and ensure reactivation thereof; a pneumatic storage (9) connected to said pneumatic turbine (7) by means of a pneumatic circuit (10) for supplying pressurised gas to said pneumatic turbine (7); a controlled fast-opening pneumatic valve (11) arranged on the pneumatic circuit (10) between said storage (9) and said pneumatic turbine (7) and suitable for being on demand placed at least in an open position in which the gas can supply said pneumatic turbine (7), or in a closed position in which said pneumatic turbine (7) is no longer supplied with pressurised gas.

Claims

1. A device for the rapid reactivation of a helicopter turbine engine, wherein it comprises: a pneumatic turbine mechanically connected to said turbine engine so as to be able to rotate it and ensure reactivation thereof; a pneumatic storage connected to said pneumatic turbine by means of a pneumatic circuit for supplying pressurised gas to said pneumatic turbine, a controlled fast-opening pneumatic valve arranged on the pneumatic circuit between said storage and said pneumatic turbine and suitable for being on demand placed at least in an open position in which the gas can supply said pneumatic turbine, thus allowing reactivation of said turbine engine, or in a closed position in which said pneumatic turbine is no longer supplied with pressurised gas.

2. The device according to claim 1, wherein it further comprises a pressure reducer arranged on said pneumatic circuit between said pneumatic valve and said pneumatic turbine and configured to regulate the pressure of said gas supplying said pneumatic turbine.

3. The device according to claim 1, wherein said pneumatic turbine is mechanically connected to said turbine engine by means of at least one free-wheel.

4. The device according to claim 1, wherein said pneumatic storage contains a mixture of gases comprising by mass at least 50% neutral gas, and a fire-extinguishing agent.

5. The device according to claim 1, wherein said pneumatic turbine comprises a low-pressure supply socket configured so as to be able to carry out an integrity test on the kinematic chain formed by the pneumatic turbine and the free-wheel.

6. The device according to claim 1, wherein said pneumatic valve is controlled for position by electronic equipment and controlled for opening by pyrotechnic equipment.

7. The architecture of a propulsion system of a multi-engine helicopter comprising turbine engines connected to a power transmission unit, wherein it comprises: at least one turbine engine among said turbine engines, referred to as a hybrid turbine engine, able to function in at least one standby regime during a stabilised flight of the helicopter, the other turbine engines functioning alone during this stabilised flight, at least one device for the rapid reactivation of a hybrid turbine engine according to claim 1, suitable for being able to bring this hybrid turbine engine out of said standby regime and to reach a so-called nominal regime in which it supplies mechanical power to said power transmission unit.

8. The architecture according to claim 7, wherein it comprises at least one fire-extinguishing device arranged in the vicinity of a turbine engine and connected to said pneumatic valve of a rapid reactivation device by means of so-called fire conduit, so that said gas in said pneumatic storage of this startup device can be conducted on command from said valve to said extinguishing device.

9. The architecture of a propulsion system of a multi-engine helicopter comprising turbine engines connected to a power transmission unit, wherein it comprises: at least one turbine engine among said turbine engines, referred to as a hybrid turbine engine, able to function in at least one standby regime during a stabilised flight of the helicopter, the other turbine engines functioning alone during this stabilised flight, at least one device for the rapid reactivation of a hybrid turbine engine according to claim 1, suitable for being able to bring this hybrid turbine engine out of said standby regime and to reach a so-called nominal regime in which it supplies mechanical power to said power transmission unit, said architecture including two said hybrid turbine engines and two said rapid reactivation devices, each said hybrid turbine engine being associated with a dedicated reactivation device.

10. The architecture of a propulsion system of a multi-engine helicopter comprising turbine engines connected to a power transmission unit, wherein it comprises: at least one turbine engine among said turbine engines, referred to as a hybrid turbine engine, able to function in at least one standby regime during a stabilised flight of the helicopter, the other turbine engines functioning alone during this stabilised flight, at least one device for the rapid reactivation of a hybrid turbine engine according to claim 1, suitable for being able to bring this hybrid turbine engine out of said standby regime and to reach a so-called nominal regime in which it supplies mechanical power to said power transmission unit, said architecture including two said hybrid turbine engines and a single said reactivation device that comprises two pneumatic turbines connected respectively to each said hybrid turbine engine, said pneumatic valve being a three-way valve controlled so as to orient the gas to said pneumatic turbine of the hybrid turbine engine to be reactivated.

11. A helicopter comprising a propulsion system wherein said propulsion system has an architecture according to claim 7.

12. A method for the reactive reactivation of a turbine engine of a helicopter, wherein it comprises: a step of controlling the opening of a pneumatic valve arranged on a pneumatic circuit between a pneumatic storage and a pneumatic turbine mechanically connected to said turbine engine, a step of conveying the gas taken off to said pneumatic turbine, a step of transformation, by said pneumatic turbine, of the pneumatic power of said pressurised gas into mechanical power in order to reactivate the turbine engine.

Description

5. LIST OF FIGURES

[0058] Other aims, features, and advantages of the invention will emerge from a reading of the following description given solely non-limitatively and which refers to the accompanying figures, in which:

[0059] FIG. 1 is a schematic view of a device for reactivating a turbine engine according to one embodiment of the invention,

[0060] FIG. 2 is a schematic view of an architecture of a propulsion system of a helicopter according to one embodiment of the invention,

[0061] FIG. 3 is a schematic view of an architecture of a propulsion system of a helicopter according to another embodiment of the invention,

[0062] FIG. 4 is a schematic view of an architecture of a propulsion system of a helicopter according to another embodiment of the invention,

[0063] FIG. 5 is a schematic view of an architecture of a propulsion system of a helicopter according to another embodiment of the invention,

[0064] FIG. 6 is a schematic view of helicopter comprising a propulsion system having an architecture according to the invention.

6. DETAILED DESCRIPTION OF AN EMBODIMENT OF THE INVENTION

[0065] In the figures, the scales and proportions are not complied with, for purposes of illustration and clarity.

[0066] FIG. 1 is a schematic view of a device for reactivating a turbine engine 6 according to one embodiment of the invention.

[0067] Such a device comprises a pneumatic turbine 7 connected mechanically to the turbine engine 6 by means of a free-wheel 8. This pneumatic turbine 7 may be a radial or axial turbine, with one or more stages. Its function is to transform the pneumatic power that it receives into a mechanical power for reactivating the turbine engine 6.

[0068] This pneumatic turbine 7 is preferably mounted on the turbine engine 6 by means of an accessory box, not shown in FIG. 1.

[0069] The device further comprises a pneumatic storage 9 connected to the pneumatic turbine 7 by means of a pneumatic circuit 10 supplying this pneumatic turbine 7 with pressurised gas.

[0070] The supply to the pneumatic turbine 7 is dependent on a controlled fast-opening pneumatic valve 11 that is arranged on the pneumatic circuit 10 between the storage 9 and the pneumatic turbine 7.

[0071] This pneumatic valve 11 is, in the embodiment in FIG. 1, a two-way valve controlled by a control device 12, which is preferably the computer controlling the turbine engine 6, which also makes it possible to define the operating regime of the turbine engine.

[0072] When the valve 11 is controlled for opening, the gas in the storage 9 is ejected towards the pneumatic turbine 7 so that it can transform the pneumatic power of the gas received into an output mechanical power.

[0073] The pneumatic circuit 10 further comprises a pressure reducer 14 arranged between the storage 9 and the pneumatic turbine 7 to regulate the pressure of the gas supplying the pneumatic turbine 7.

[0074] The pneumatic storage 9 further comprises a pressure sensor 40 and a safety valve 41. The pneumatic storage 9 has for example a 250 bar nitrogen capacity.

[0075] The reactivation device of FIG. 1 advantageously equips an architecture of a propulsion system of a twin-engine helicopter as shown in FIG. 2.

[0076] According to the embodiment in FIG. 2, the propulsion system comprises two turbine engines 6, 16 connected to a power transmission box 22, which itself drives a rotor of the helicopter (not shown in the figures). Each turbine engine is a hybrid turbine engine, able to be put in at least one standby regime during a stabilised flight of the helicopter, from which it can emerge quickly by means of a reactivation device according to the invention. A turbine engine comprises in a known fashion a gas generator, a combustion chamber and a free turbine.

[0077] The standby regime is for example one of the following operating regimes: [0078] a standby regime, referred to as normal tickover, in which the combustion chamber is ignited and the shaft of the gas generator turns at a speed of between 60% and 80% of the nominal speed, [0079] a standby regime, referred to as normal super-tickover, in which the combustion chamber is ignited and the shaft of the gas generator turns at a speed of between 20% and 60% of the nominal speed, [0080] a standby regime, referred to as assisted super-tickover, in which the combustion chamber is ignited and the shaft of the gas generator turns, assisted mechanically, at a speed of between 20% and 60% of the nominal speed, [0081] a standby regime, referred to as turnover mode, in which the combustion chamber is extinguished and the shaft of the gas generator turns, assisted mechanically, at a speed of between 5% and 20% of the nominal speed, [0082] a standby regime, referred to as stoppage, in which the combustion chamber is extinguished and the shaft of the gas generator is completely at rest.

[0083] The reactivation device comprises, in addition to the elements described in relation to FIG. 1, a pneumatic turbine 17 connected to the turbine engine 16 by means of a free-wheel 18. Furthermore, the pneumatic circuit 10 extends from the pneumatic storage 9 as far as the pneumatic turbine 17 and the pneumatic turbine 7.

[0084] The controlled valve 11 is, according to this embodiment, a three-way valve suitable for allowing, on command, either the supply to the pneumatic turbine 17 connected to the turbine engine 16, or the supply to the pneumatic turbine 7 of the turbine engine 6. The control is a function of the turbine engine on standby that is to emerge in emergency from its standby regime.

[0085] The operating principle of the reactivation device of this architecture is, for each turbine engine 6, 16, identical to the one described in relation to FIG. 1.

[0086] FIG. 3 is an architecture according to another embodiment of the invention. According to this embodiment, a separate reactivation device is provided for each turbine engine. In other words, a pneumatic storage 29, 39 is associated with each pneumatic turbine 7, 17 and a two-way valve 11, 21 is associated with each storage 29, 39 in order to provide the supply to the turbines and the restarting of the corresponding turbine engine. The valves 11, 21 are controlled respectively by computers 12, 13, one computer per device. In a variant, a single computer may control the two valves. Furthermore, each turbine is associated with a dedicated pressure reducer 14, 24 intended to regulate the pressure of the gas supplying the corresponding turbine.

[0087] The architecture in FIG. 4 is based on the architecture in FIG. 3 and comprises, in addition to the elements described in relation to FIG. 3, a fire-extinguishing system. This extinguishing system comprises one fire-extinguishing device per turbine engine. The architecture in FIG. 4 therefore comprises two extinguishing devices. Each device comprises a fire conduit 25, 35 arranged between the corresponding valve 21, 31 and a fire nozzle 26, 36 arranged in the vicinity of, and in the direction of, the corresponding turbine engine 6, 16 so as to be able to spray gas towards the turbine engine in the event of fire. According to this embodiment, the valves 11, 21 are three-way valves. In the event of the detection of a fire in the vicinity of a turbine engine, for example the turbine engine 6, by a fire sensor, the unit 12 demands the opening of the valve 11 corresponding to the turbine engine 6 so that the gas stored in the storage 29 (formed by a mixture of a neutral gas and a fire-extinguishing agent of the halon type) is propelled towards the fire nozzle 26 in order to extinguish the fire in the turbine engine 6.

[0088] The architecture in FIG. 5 is a variant of the architecture in FIG. 4 in which each fire nozzle 26, 36 can be supplied by each pneumatic storage 29, 39 on demand from the valves 11, 21, which are four-way valves. To do this, each fire nozzle is supplied by two separate fire conduits. Such an architecture makes it possible to use the gases of each reactivation device in order to deal with a fire in one or other of the turbine engines.

[0089] FIG. 6 is a schematic view of a twin-engine helicopter comprising a propulsion system having an architecture according to the invention. The propulsion system comprises in particular two turbine engines 6, 16 suitable for rotating a rotor by means of the power transmission unit 22. In this figure, the reactivation devices are not shown, for reasons of clarity. Only the turbine engines 6, 16 are shown, it being understood that each turbine engine is equipped with a reactivation device according to the invention.

[0090] The principle of use of a device for reactivating a turbine engine in a twin-engine architecture as shown by FIG. 2 is as follows: [0091] when the flight conditions are favourable, an instruction is issued to put a turbine engine on standby in order to save on fuel (a standby regime chosen from the standby regimes mentioned above), [0092] the computers of the turbine engines then determine which turbine engine can be put on standby and demand the putting on standby thereof (hereinafter, it is considered that the turbine engine 6 is put on standby and that only the turbine engine 16 supplies power to the power transmission unit 22), [0093] the turbine engine 6 is in standby regime (this standby regime may be one of the aforementioned standby regimes, with a chamber ignited or extinguished, mechanically assisted or not), [0094] during the flight, the turbine engine 16 suddenly fails or the pilot decides to quickly reactivate the turbine engine 6 for a particular emergency manoeuvre, [0095] the combustion chamber of the turbine engine 6 is then quickly reignited (the case of a standby regime with chamber extinguished), [0096] after a predetermined period, the control unit 12 demands the opening of the valve 11 to the turbine engine 6, [0097] the pneumatic turbine 7 then quickly goes (within a period of less than one second) from 0 rev/min to the coupling speed of the gas generator initially in standby regime by transforming the pneumatic power into a mechanical power making it possible to drive the gas generator of the turbine engine 6 by means of the free-wheel 8, [0098] the pneumatic turbine 7 continues the driving of the turbine engine 6 for a short period, for example less than 3 seconds, during which the turbine engine has reached its emergency regime, [0099] rapid reactivation of the turbine engine 6 is therefore obtained.

[0100] The coupling speed corresponds to the standby speed of the gas generator divided by the speed reduction ratio between the shaft of the gas generator and the input of the accessory box of the turbine engine on which the pneumatic starter is mounted.

[0101] A device according to the invention therefore makes it possible to quickly reactivate a turbine engine on standby, using only inexpensive components that are simple to use and install and can be tested on benches.

[0102] The invention is not limited solely to the embodiments described. In particular, the architecture may comprise three turbine engines for equipping a triple-engine helicopter, and persons skilled in the art would easily determine, on the basis of the teachings of the present text, how to adapt the embodiments described to a multi-engine propulsion system, in particular a triple-engine one.

[0103] Although dedicated to rapid reactivation phases, the invention can also be used during rapid starting on the ground or during rapid restarting in flight.