FR3057614A1 - TURBOMACHINE EQUIPPED WITH TEMPORARY POWER INCREASE DEVICE - Google Patents

Abstract

A turbomachine (5A) comprising a control unit (19A) and a temporary power boost device (13A), said temporary power boost device (13A) comprising a non-pressurized reservoir (14) configured to hold a fluid refrigerant, and an injection circuit (16A) connected to said reservoir (14) and opening on at least one injector (22A), the injection circuit (16A) comprising a pump (18A) controlled by the control unit ( 19A).

Description

FIELD OF THE INVENTION The present invention relates to the field of turbomachinery and more particularly turbomachinery equipped with a device for temporarily increasing the power of a turbomachine, a propulsion unit comprising such a turbomachine, and an aircraft equipped with such a propulsion system.

The term "turbomachine" designates all of the gas turbine devices producing driving energy, among which there are in particular turbojets providing a thrust necessary for propulsion by reaction to the high speed ejection of hot gases, and turboshaft engines in which the driving energy is supplied by the rotation of a drive shaft. For example, turboshaft engines are used as an engine for helicopters, ships, trains, or even as an industrial engine. Turbopropellers (turboshaft driving a propeller) are also turboshaft engines used as an aircraft engine.

STATE OF THE PRIOR ART In certain circumstances, it may be desirable to temporarily increase the power of a turbomachine. For example, when taking off from an aircraft or under specific flight conditions, there may be a need for a temporary contribution of additional power. According to another example, in a propulsion unit comprising a plurality of turbomachines, the failure of one of them may require a temporary increase in the power of one or more others in order to compensate for the power lost by the faulty turbomachine.

One of the solutions known to the person skilled in the art for obtaining this temporary increase in power is the injection of a refrigerant, which can be, inter alia, water or a mixture of water and a antifreeze, such as methanol, ethanol or glycol, in the air stream upstream of the combustion chamber. On the one hand, this injection makes it possible to cool this air upstream of the combustion chamber, thereby increasing its density and therefore the mass flow rate of oxygen admitted into the combustion chamber. On the other hand, the vaporization of this coolant in the combustion chamber makes it possible to very significantly increase the pressure and / or the volume flow rate downstream of the combustion chamber, and therefore the mechanical work recovered in the turbine.

Such a solution is described by FR1262433, where the coolant is contained in a pressurized tank, and injected into the turbomachine by the activation of a valve. However, these pieces of equipment are heavy, expensive, and require regular maintenance. There is therefore a need in this sense.

PRESENTATION OF THE INVENTION One embodiment relates to a turbomachine comprising a control unit and a temporary power increase device, said temporary power increase device comprising a non-pressurized tank configured to contain a coolant. , and an injection circuit connected to said reservoir and leading to at least one injector, the injection circuit comprising a pump controlled by the control unit.

In the present description, the terms "downstream" and "upstream" are considered according to the normal direction of flow of the gases within the turbomachine.

The temporary power increase device allows, when necessary, to temporarily increase the power of said turbomachine by injecting the coolant upstream of the combustion chamber. The control unit is configured to detect such a situation and then to control the pump so as to inject coolant.

Thanks to the presence of the pump, it is not necessary to pressurize the tank, nor to use pipes and valves adapted to a pressurized circuit. Compared to known temporary power increase devices, this reduces the risk of leakage, the overall mass of the device and its cost, but also improves its reliability, its integrability and its testability.

In some embodiments, the pump is a variable flow pump.

It is understood of course that a variable flow pump is a pump whose flow can be controlled. Such a pump makes it possible to control and adapt the flow of refrigerant fluid according to the circumstances.

For example, the pump has a fixed displacement but a variable speed of rotation of the rotor, or else the speed of rotation of the rotor is fixed while the displacement is variable.

In some embodiments, the control unit is a digital electronic control system with full authority of the turbomachine.

Those skilled in the art also know the full electronic digital electronic regulation system under the acronym FADEC (for "Full Authority Digital Engine Control"). The use of the digital electronic regulation system with full authority of the turbomachine (hereinafter, and unless otherwise indicated, the “regulation system”) as a control unit of the power increase device makes it possible to integrate this function within a central control system, whereby the consistency of control with the other elements of the turbomachine is improved.

In certain embodiments, the turbomachine comprises an air inlet and a combustion chamber, the injector being disposed between the air inlet and the combustion chamber.

It is understood that the injector can be positioned at any location between the air inlet and the combustion chamber. For example, the turbomachine includes a low pressure compressor and a high pressure compressor. It is understood that the high pressure compressor compresses the air to a higher pressure than the low pressure compressor. Thus the terms "high pressure" and "low pressure" are to be considered relatively with respect to each other. Of course, the high pressure compressor is downstream of the low pressure compressor. For example, the injector can be arranged between the air inlet and the low pressure compressor, between the low pressure compressor and the high pressure compressor, or between the high pressure compressor and the combustion chamber.

In some embodiments, a safety valve is disposed between the pump and the injector.

The safety valve is configured to prevent the flow of coolant between the pump and the injector when the pump is inactive, and to allow the flow of fluid between the pump and the injector when the pump is activated . This safety valve thus improves the tightness of the device by preventing a leak, and therefore an undesired emptying of the tank in the turbomachine when the pump is inactive. Safety is thus improved by ensuring that the reservoir actually contains the volume of refrigerant required when it is desired to temporarily increase the power.

In some embodiments, the non-pressurized tank comprises a level detector configured to determine the level of coolant within the tank, said level detector being connected to the control unit of the turbomachine.

The level detector is arranged in the nonpressurized tank, and makes it possible to determine the level of refrigerant fluid therein, and to send the corresponding information to the control unit. This level detector thus makes it possible, via the control unit, to signal a level of refrigerant fluid too low to be able to supply the injection circuit.

An embodiment also relates to a propulsion unit comprising several turbomachines, at least one turbomachine among said several turbomachines being a turbomachine according to any one of the embodiments described in the present description.

Thus, the temporary increase in the power of said turbomachine according to the present description allows for example to compensate for a possible anomaly, for example when one or more of the other turbomachines of the propulsion unit fails. The overall power of the propulsion unit can thus be maintained at a predetermined value for a given period, for example a critical period such as the take-off or the landing of an aircraft. If several turbomachines include a temporary power increase device, there may be a single common tank, or several common tanks or not. Thus, each turbomachine can be connected to a single tank, or to several separate tanks.

In certain embodiments, the propulsion unit comprises at least two turbomachines according to any one of the embodiments described in the present description, the coolant reservoir being common to said two turbomachines.

It is understood that the reservoir common to the two turbomachines, is connected to an injection circuit specific to each turbomachine. The presence of a single tank makes it possible to simplify the integration of the tank and to minimize the overall weight of the propulsion unit without compromising safety, the probability that two turbomachines are simultaneously failing being very low.

In certain embodiments, the propulsion unit comprises at least two refrigerant tanks, each of the at least two tanks being connected to a single turbomachine.

In this case, each turbomachine is connected to a single tank which is specific to each turbomachine. Each of these tanks thus being independent of the tanks of the other turbomachines, it can therefore be arranged as close as possible to the corresponding turbomachine, or even integrated into said turbomachine, which makes it possible to obtain a compact assembly, of reduced bulk.

An embodiment also relates to an aircraft, in particular a helicopter, comprising an assembly according to any one of the embodiments described in the present description.

BRIEF DESCRIPTION OF THE DRAWINGS The invention and its advantages will be better understood on reading the detailed description given below of various embodiments of the invention given by way of nonlimiting examples. This description refers to the pages of attached figures, on which:

- Figure 1 schematically shows an aircraft comprising a propulsion unit;

- Figure 2 shows a block diagram of the propulsion unit of the aircraft of Figure 1 according to a first embodiment;

- Figure 3 shows a block diagram of the propulsion unit of the aircraft of Figure 1 according to a second embodiment.

DETAILED DESCRIPTION OF EXAMPLES OF EMBODIMENT FIG. 1 illustrates an aircraft 1 with rotary wing, more specifically a helicopter with a main rotor 2 and an anti-torque tail rotor 3 coupled to a propulsion unit 4 for their actuation. The propulsion unit 4 illustrated comprises two turbomachines, namely in this example a first turboshaft engine 5A and a second turboshaft engine 5B whose output shafts 6 are both connected to a main gearbox 7 for actuating the main rotor 2 and the tail rotor 3.

The propulsion unit 4 is illustrated diagrammatically in FIG. 2. In order to at least temporarily compensate for a drop in power due to a possible failure of one of the turboshaft engines 5A or 5B, the latter are equipped, respectively, with a first device 13A for temporary power increase (hereinafter "the first device") and a second device 13B for temporary power increase (hereinafter "the second device"). The broken lines in FIG. 2 schematically represent the first and second turbine engines 5A and 5B respectively.

The first turbine engine 5A comprises a first device 13A which comprises a first pump 18A controlled by a first control unit 19A, while the second turbine engine 5B comprises a second device 13B which comprises a second pump 18B controlled by a second control unit 19B. The first turbine engine 5A and the second turbine engine 5B each comprise a low pressure compressor 50A, 50B, a high pressure compressor 52A, 52B, an air inlet 53A, 53B, a combustion chamber 54A, 54B and turbines 56A, 56B, the gases flowing within each turbine engine from the compressors to the turbines (from upstream to downstream).

The control units 19A and 19B are in this example digital electronic control systems with full authority of a turbomachine (or FADEC) of the turboshaft engines 5A and 5B respectively. In this example, the pumps 18A and 18B are positive displacement displacement pumps, but could of course, according to a variant, be of fixed and variable displacement speed. The first device 13A comprises a first injection circuit 16A of coolant for the first turbine engine 5A, and the second device 13B comprises a second injection circuit 16B of coolant for the second turbine engine 5B.

In the example illustrated in Figure 2, the devices 13A and 13B comprise a single common non-pressurized tank 14 containing the coolant, said tank 14 therefore being common to the first and second turbine engines 5A and 5B. This reservoir 14 is connected to the first and second injection circuits 16A and 16B via a circuit for

Ί sampling 15. In this example, the reservoir 14 is not disposed within a turbine engine, but outside the turbine engines, within the aircraft.

The reservoir 14 is equipped with a level detector 17, making it possible to monitor the level of coolant in the reservoir

14. The signal indicating the level of coolant is sent directly or indirectly to the control unit 19A, 19B. In this example, the detector 17 is connected to the control unit 19A and 19B via the electronic control unit of the aircraft 40, also known to those skilled in the art under the term "avionics". Each of the first and second injection circuits 16A and 16B leads to a plurality of injectors 22A, 22B (represented diagrammatically by an arrow) arranged between the air inlet 53A, 53B and the combustion chamber 54A, 54B. In the example of FIG. 2, the injectors 22A, 22B are arranged downstream of the high pressure compressor 52A, 52B (and therefore downstream of the low pressure compressor 50A, 50B). Each of these injection circuits 16A and 16B comprises a safety valve 23 for blocking the passage of the coolant from the pump 18A, 18B to the injectors 22A, 22B, below a certain pressure threshold within the circuit 16A , 16B, to prevent any untimely leakage towards the injectors 22A, 22B when the pump 18A, 18B is not operating. Strainers 34 in the injection circuits 16A and 16B make it possible to filter out any impurities present in the refrigerant.

In case of failure of a 5A or 5B turbine engine, the control unit of the other engine detects, via the electronic control unit of the aircraft 40, a situation requiring the increase in power. Thus, if the first turbine engine 5A fails, the control unit 19B detects the need to increase the power of the second turbine engine 5B (or, of course, vice versa). For example, it may be the detection of a 30s OEI situation (from the English “One Engine Inoperative”, meaning “one engine inoperative”), which requires the increase for 30 seconds of the power of one turbine engine in the event of failure of the other turbine engine.

Thus, if necessary, the device for temporarily increasing the power of the turbine engine which is not faulty detects a situation requiring a temporary increase in power, and controls the injection of coolant by controlling the flow of the pump appropriately.

3 shows a second embodiment which differs from the first embodiment shown in Figure 2 only by the tanks 114A, 114B. Thus, the other unchanged elements are not described again, while the reference signs are incremented by 100.

In this embodiment, the propulsion unit comprises two separate tanks: a first tank 114A integrated into the first turbine engine 105A, and a second tank 114B integrated into the second turbine engine 105B. The first and second tanks 114A and 114B are therefore distinct and specific to each turbine engine 105A and 105B respectively while the first and second injection circuits 116A and 116B are respectively connected directly to the first and second tanks 114A and 114B (ie without the via a sampling circuit).

In the event of a failure of one of the two turbine engines, the refrigerant is drawn from the tank of the turbine engine which is not broken down.

Although the present invention has been described with reference to specific embodiments, it is obvious that modifications and changes can be made to these examples without departing from the general scope of the invention as defined by the revendications. In particular, individual features of the various illustrated / mentioned embodiments can be combined in additional embodiments. Therefore, the description and the drawings should be considered in an illustrative rather than restrictive sense.

Claims (9)

1. Turbomachine (5A) comprising a control unit (19A) and a temporary power increase device (13A), said temporary power increase device (13A) comprising a non-pressurized tank (14) configured to contain a refrigerant, and an injection circuit (16A) connected to said reservoir (14) and leading to at least one injector (22A), the injection circuit (16A) comprising a pump (18A) controlled by the command (19A). 2. Turbomachine (5A) according to claim 1, in which the pump (18A) is a variable flow pump. 3. Turbomachine (5A) according to claim 1 or 2, wherein the control unit (19A) is a digital electronic control system with full authority of the turbomachine. 4. Turbomachine (5A) according to any one of claims 1 to 3, comprising an air inlet (53A) and a combustion chamber (54A), the injector (22A) being arranged between the air inlet (53A) and the combustion chamber (54A). 5. Turbomachine (5A) according to any one of claims 1 to 4, in which a safety valve (23) is arranged between the pump (18A) and the injector (22A). 6. Propulsion unit (4) comprising several turbomachines, at least one turbomachine among said several turbomachines being a turbomachine according to any one of claims 1 there. 7. propulsion unit (4) according to claim 6 comprising at least two turbomachines (5A, 5B) according to any one of claims 1 to 5, the reservoir (14) of coolant being common to said at least two turbomachines (5A, 5B). 8. Propulsion unit (4) according to claim 6 comprising at least two refrigerant tanks (114A, 114B), each of the at least two tanks (114A, 114B) being connected to a single turbomachine (105A, 105B). 9. Aircraft, in particular a helicopter, comprising an assembly according to claim 7 or 8. ³ ° S7614 1/3