Power plant having a two-stage cooler device for cooling the admission air for a turboshaft engine

Abstract

A power plant having at least one compressor, at least one fuel-burning engine, and a cooler device for cooling admission air for the engine, the engine being provided with a combustion chamber. The cooler device is constituted by a heat engine having three heat sources arranged between two compression stages of the compressor and including a refrigerant fluid and two evaporators. The admission air flows in succession through the two evaporators between the two compression stages firstly to cool the admission air between the two compression stages prior to being injected into the combustion chamber, and secondly to vaporize the refrigerant fluid.

Claims

1. A power plant comprising at least one compressor, at least one fuel-burning engine, and a cooler device for cooling admission air for each fuel-burning engine, each fuel-burning engine being provided with a combustion chamber, each compressor having at least two compression stages in order to compress the admission air prior to injecting the compressed admission air into the combustion chamber of each fuel-burning engine, the cooler device including a refrigerant fluid, first pipes and second pipes and also two evaporators, a pump, an expander, and a condenser, the first pipes connecting a first compression stage to a first evaporator, the first evaporator to a second evaporator, and the second evaporator to a second compression stage, the second pipes connecting the condenser to the pump, the pump to the first evaporator, the condenser to the expander, and the expander to the second evaporator, the refrigerant fluid circulating in the second pipes and the cooler device, while the compressed admission air flows through the first pipes and successively through the two evaporators in order firstly to vaporize the refrigerant fluid and secondly to cool the compressed admission air between the two compression stages, wherein the cooler device is a heat engine having three heat sources including a compression and drive means, the refrigerant fluid circulating through the compression and drive means, the second pipes connecting the compression and drive means to the first evaporator, to the second evaporator, and to the condenser.

2. The power plant according to claim 1, wherein the compression and drive means is an ejector.

3. The power plant according to claim 1, wherein the compression and drive means comprise a positive displacement expander connected to the first evaporator by the second pipes and a positive displacement compressor connected to the second evaporator by the second pipes, the positive displacement expander and the positive displacement compressor being connected by the second pipes to the condenser, the positive displacement expander and the positive displacement compressor being mechanically constrained together in rotation, the positive displacement expander being driven in rotation by the refrigerant fluid leaving the first evaporator, and the refrigerant fluid leaving the second evaporator circulating through the positive displacement compressor.

4. The power plant according to claim 3, wherein the cooler device includes a mechanical transmission shaft, the positive displacement expander being mechanically connected in rotation with the mechanical transmission shaft.

5. The power plant according to claim 4, wherein the cooler device includes clutch means constraining the positive displacement expander in rotation with the mechanical transmission shaft.

6. The power plant according to claim 4, wherein the cooler device includes a fan system for ventilating the condenser, the fan system being mechanically constrained in rotation with the mechanical transmission shaft.

7. The power plant according to claim 1, wherein the power plant includes third pipes, the third pipes being suitable for connecting the second pipes between the condenser and the pump to an additional system, the refrigerant fluid circulating in the third pipes and the additional system.

8. The power plant according to claim 7, wherein the power plant includes at least one main power transmission gearbox, the additional system is the main gearbox, the refrigerant fluid circulating through the third pipes and the main gearbox in order to cool the main gearbox.

9. The power plant according to claim 7, wherein the power plant is for fitting to a rotary wing aircraft having at least one cabin and at least one heat exchanger for cooling the cabin, the additional system is each heat exchanger, and the third pipes are suitable for connecting the second pipes between the condenser and the pump to each heat exchanger, the refrigerant fluid circulating in the third pipes and each heat exchanger in order to cool the cabin.

10. The power plant according to claim 1, wherein the condenser is a heat exchanger for exchanging heat between the refrigerant fluid and a secondary fluid, and the power plant includes fourth pipes connected to the condenser in order to channel and direct the secondary fluid to an auxiliary device.

11. The power plant according to claim 10, wherein the power plant is for a rotary wing aircraft having at least one cabin, and the fourth pipes are suitable for channeling and directing the secondary fluid to the cabin in order to heat the cabin.

12. The power plant according to claim 1, wherein the condenser is a heat exchanger for exchanging heat between the refrigerant fluid and ambient air surrounding the power plant.

13. A cooling method for cooling admission air to a fuel-burning engine of a power plant, the method comprising the following steps: compressing the admission air in a compressor of the power plant, the compressor having two compression stages; causing a refrigerant fluid to circulate in a cooler device for cooling the compressed admission air for the fuel-burning engine; and causing the compressed admission air to flow in succession through first and second evaporators of the cooler device between the two compression stages in order firstly to vaporize the refrigerant fluid and secondly to cool the compressed admission air; the method further comprising the following steps: condensing the refrigerant fluid by exchanging heat energy with a first heat source; compressing a first portion of the refrigerant fluid; vaporizing the first portion of the refrigerant fluid by exchanging heat energy with a second heat source, the second heat source being the compressed admission air flowing through the first evaporator; expanding a second portion of the refrigerant fluid; vaporizing the second portion of the refrigerant fluid by exchanging heat energy with a third heat source, the third heat source being the compressed admission air flowing through the second evaporator; and compressing and driving the second portion of the refrigerant fluid by means of energy in the first portion of the refrigerant fluid, and then mixing together the second portion of the refrigerant fluid and the first portion of the refrigerant fluid.

14. The cooling method according to claim 13, including the step of compressing and driving the second portion of the refrigerant fluid by means of the energy in the first portion of the refrigerant fluid, and mixing together the second portion of the refrigerant fluid and the first portion of the refrigerant fluid by means of an ejector.

15. The cooling method according to claim 13, including the step of compressing and driving the second portion of the refrigerant fluid by means of the energy in the first portion of the refrigerant fluid by using a positive displacement expander and a positive displacement compressor that are mechanically constrained together in rotation, the positive displacement expander being driven in rotation by the first portion of the refrigerant fluid, and the second portion of the refrigerant fluid circulating through the positive displacement compressor, and then mixing together the second portion of the refrigerant fluid and the first portion of the refrigerant fluid.

16. The cooling method according to claim 15, including the step of using a portion of the mechanical energy available from the positive displacement expander, the positive displacement expander being mechanically connected in rotation with a mechanical transmission shaft.

17. The cooling method according to claim 13, including the step of using heat discharged while condensing the refrigerant fluid for an auxiliary heating function.

18. The cooling method according to claim 17, wherein the auxiliary heating function is heating a cabin of an aircraft.

19. The cooling method according to claim 13, including the step of using a portion of heat energy of the refrigerant fluid for at least one additional heat exchange function.

20. The cooling method according to claim 19, wherein the additional heat exchanger function is cooling a main power transmission gearbox of the power plant.

21. The cooling method according to claim 19, wherein the cooling method is used for cooling compressed admission air for the fuel-burning engine forming part of a rotary wing aircraft, the additional cooling function being cooling a cabin of the rotary wing aircraft.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) The invention and its advantages appear in greater detail from the context of the following description of examples given by way of illustration and with reference to the accompanying figures, in which:

(2) FIG. 1 shows a rotary wing aircraft having a power plant of the invention; and

(3) FIGS. 2 and 3 show two embodiments of the power plant of the invention.

(4) Elements shown in more than one of the figures are given the same references in each of them.

(5) In FIG. 1, a rotary wing aircraft 2 is shown, which aircraft 2 has a main rotor 28 located above a fuselage 3 and an anti-torque tail rotor 29 situated at the rear end of a tail boom.

(6) The aircraft 2 also has a power plant 1 and a cabin 30 located inside the fuselage 3.

DETAILED DESCRIPTION OF THE INVENTION

(7) The power plant 1 comprises a compressor 21, a fuel-burning engine 20, a main power transmission gearbox 24, and a cooler device 10 for cooling the air admitted into the engine 20. The engine 20 is mechanically connected to the main gearbox 24 in order to set both the main rotor 28 and the tail rotor 29 into rotation.

(8) Two embodiments of the power plant 1 are shown, respectively in FIGS. 2 and 3.

(9) In common to both of these embodiments of the power plant 1, each engine 20 is a turboshaft engine having a combustion chamber 22 and an expansion turbine 23. Each compressor 21 has two compression stages 25 and 26 so as to compress the admission air prior to injecting into the combustion chamber 22.

(10) The cooler device 10 is constituted by two loops. A primary loop comprises a pump 11, a first evaporator 12, a condenser 16, together with compression and drive means 15. A secondary loop comprises an expander 13, a second evaporator 14, the condenser 16, and the compression and drive means 15.

(11) The cooler device 10 also comprises first and second pipes 27 and 17. The first pipes 27 connect the first compression stage 25 to the first evaporator 12, the first evaporator 12 to the second evaporator 14, and the second evaporator 14 to the second compression stage 26.

(12) The second pipes 17 serve firstly in the primary loop to connect the condenser 16 to the pump 11, the pump 11 to the first evaporator 12, and the first evaporator 12 to the compression and drive means 15, and secondly, in the secondary loop, to connect the condenser 16 to the expander 13, the expander 13 to the second evaporator 14, and the secondary evaporator 14 to the compression and drive means 15. A second pipe 17 also connects the compression and drive means 15 to the condenser 16 in order to close the primary loop and the secondary loop.

(13) The cooler device 10 thus forms a heat engine with three heat sources, having its primary loop operating in the Rankine cycle.

(14) A refrigerant fluid circulates through the cooler device 10 and more precisely in the primary loop and the secondary loop, passing through all of the components 11, 12, 13, 14, 15, and 16 of the cooler device 10, and also through the second pipe 17.

(15) The condenser 16 enables the refrigerant fluid to be condensed into a liquid phase, delivering heat energy to a first heat source constituted by the ambient air surrounding the power plant 1. Thereafter, the refrigerant fluid splits into two portions in the secondary pipe 17.

(16) In the primary loop, the pump 11 compresses the refrigerant fluid, which then transforms into the gaseous phase at high pressure in the first evaporator 12, absorbing heat energy from a second heat source constituted by the admission air leaving the first compression stage 25.

(17) In the secondary loop, the expander 13 expands the refrigerant fluid, which is then transformed into a gaseous phase at low pressure in the secondary evaporator 14 by absorbing heat energy from a third heat source constituted by the admission air leaving the first evaporator 12.

(18) The compression and drive means 15 compress and drive the refrigerant fluid circulating in the secondary loop by means of the refrigerant fluid circulating in the primary loop. The compression and drive means 15 also mix together the refrigerant fluid flowing in the primary and the secondary loops, prior to directing the fluid to the condenser 16.

(19) Finally, the refrigerant fluid circulates once more through the condenser 16 and restarts a new three-heat source cycle.

(20) The admission air flows through the compressor 21 and the cooler device 10. The admission air passes in succession through the two evaporators 12, 14, between the two compression stages 25 and 26, firstly so as to vaporize the refrigerant fluid and secondly so as to cool the admission air between the two compression stages 25 and 26.

(21) This cooling of the admission air between the two compression stages 25 and 26 serves to increase the power delivered by the turboshaft engine 20.

(22) In the first embodiment of the power plant 1, as shown in FIG. 2, the compression and drive means 15 comprise an ejector, e.g. in the form of a convergent-divergent nozzle.

(23) In the second embodiment of the power plant 1, as shown in FIG. 3, the compression and drive means 15 comprise a positive displacement expander 18 connected to the first evaporator 2 by a second pipe 17 and a positive displacement compressor 19 connected to the second evaporator 14 by a second pipe 17. The positive displacement expander 18 and the positive displacement compressor 19 are mechanically constrained together in rotation and they are connected by a second pipe 17 to the condenser 16. The positive displacement expander 18 is thus driven in rotation by the refrigerant fluid leaving the first evaporator 12, the positive displacement expander 18 driving the positive displacement compressor 19 in rotation, thereby serving to compress and drive the refrigerant fluid leaving the second evaporator 14. Thereafter, the refrigerant fluid coming from the primary and secondary loops is mixed together and directed to the condenser 16.

(24) In this second embodiment of the power plant 1, the cooler device 10 also has a mechanical transmission shaft 32, clutch means 31, an inlet pipe 53, a fan system 33, and a fourth pipe 52.

(25) The clutch means 31 are constituted by a magnetic coupling constraining the positive displacement expander 18 in rotation with the mechanical transmission shaft 32. The fan system 33 is constrained in rotation with the mechanical transmission shaft 32.

(26) The input pipe 53 and the fourth pipe 52 are connected to the condenser 16. The inlet pipe 53 serves to channel and direct a portion of the ambient air surrounding the power plant 1 to the condenser 16, and the fourth pipe 52 serves to channel the ambient air leaving the condenser 16.

(27) The fan system 33 serves to activate the flow of ambient air through the inlet pipe 53, thus improving the thermal effectiveness of the condenser 16.

(28) Furthermore, as shown in FIG. 1, the fourth pipe 52 serves to direct the ambient air leaving the condenser 16 to the cabin 30 of the aircraft 2 in order to heat it.

(29) In this second embodiment of the power plant 1, the cooler device 10 has a separator 35 located after the condenser 16 on a second pipe 17. The separator 35 serves to separate the liquid and gaseous phases of the refrigerant fluid and at its outlet it delivers only the liquid phase of the refrigerant fluid. Thus, after the separator 35, only the liquid phase of the refrigerant fluid circulates in the second pipe 17 to the pump 11 and the expander 13. This absence of gaseous phase in the second pipe 17 is of importance in particular for effective operation of the pump 11.

(30) In this second embodiment of the power plant 1, the power plant 1 has a third pipe 51 connected to a second pipe 17 situated between the condenser 16 and the pump 11. This third pipe 51 is also shown in FIG. 1, and it serves to connect the second pipe 17 to the main gearbox 24 and to a heat exchanger 50 situated in the cabin 30 of the aircraft 2.

(31) The refrigerant fluid thus circulates in a third pipe 51 from a second pipe 17 so as to pass through the main gearbox 24 and the heat exchanger 50 and return to the second pipe 17 via a third pipe 51.

(32) The refrigerant fluid thus serves to cool the main gearbox 24 and also the cabin 30 of the aircraft 2.

(33) Naturally, the present invention may be subjected to numerous variations as to its implementation. Although several embodiments are described, it will readily be understood that it is not conceivable to identify exhaustively all possible embodiments. It is naturally possible to envisage replacing any of the means described by equivalent means without going beyond the ambit of the present invention.