Multiple-flow aircraft turbine engine

Abstract

The invention relates to a multiple-flow turbine engine (10) for an aircraft, said turbine engine comprising a gas generator (12) having geometric characteristics allowing it to have, on the periphery thereof, a cold compartment (C2) that is larger than its hot compartment (C1).

Description

[0001] DESCRIPTION

[0002] TITLE: MULTI-FLOW AIRCRAFT TURBOMACHINE

[0003] Technical field of the invention

[0004] The present invention relates to the field of multi-flow turbomachines, in particular for aircraft.

[0005] Technical background

[0006] The state of the art includes in particular documents FR3074476A1 and FR2981686A1, which relate in particular to turbomachines comprising at least one fan in the form of an unducted propeller. These documents disclose more particularly turbomachines in which certain air flow veins are suitable for improving the thermal management of the turbomachine, and in particular for cooling equipment or compartments which contain equipment.

[0007] As shown in Figure 1, an aircraft turbomachine 10 generally comprises a gas generator 12 comprising at least one compressor 14, an annular combustion chamber 16 and at least one turbine 18.

[0008] The turbomachine 10 further comprises at least one propulsion propeller 20 which is driven by a shaft of the turbine 18.

[0009] The gas generator 12 comprises an annular nozzle 22 for separating two annular veins V1, V2 of respective flow of an internal primary flow F1 inside the gas generator 12, and of an external secondary flow F2 around the gas generator 12.

[0010] When the propulsion propeller 20 is located upstream of the gas generator 12 as in the example shown, it is called a fan and its purpose is to accelerate the sucked air. A portion of the air flow leaving the fan flows around the gas generator 12 to form the secondary flow F2 which makes it possible to generate the majority of the thrust produced by the turbomachine 10. The remainder of the air flow leaving the fan enters the gas generator 12 to form the primary flow F1. This air is compressed in the or each compressor 14, then mixed with fuel and then burned in the combustion chamber 16. The combustion gases are then expanded in the or each turbine 18 in order to drive the rotor of the turbine and thus the propulsion propeller 20 in rotation.

[0011] The propeller 20 comprises blades 24 which generally have an angular position, called pitch, which is fixed around an axis Y perpendicular to the longitudinal axis X of the turbomachine 10. Even in low engine speed phases, such as idling, this pitch is configured so that the flow rate of the secondary flow F2 generated is sufficient to supply surface or non-surface fluid / air exchangers 26, installed in the flow path of the secondary flow F2. These exchangers 26 are necessary to cool equipment of the turbomachine.

[0012] To improve engine performance (greater thrust and lower fuel consumption), some engine architectures aim to increase the bypass ratio, also called BPR (which is the acronym for the Anglo-Saxon term Bypass Ratio), by increasing the diameter of the propeller 20. In order to limit the mass of the turbomachine 10, the fairing 28 located around the propulsion propeller 20 can be removed, and the blades 24 of the propeller 20 can be made orientable, and therefore variable-pitch, to control the thrust level of the turbomachine.

[0013] However, it happens that in certain phases such as ground idle, fixed point or thrust reversal phases, the flow rate of the secondary flow F2 is no longer sufficiently high for the thermal management of the turbomachine which needs heat exchange between fluids and air in order to ensure the cooling of its equipment and its optimal operation.

[0014] To address this problem, it has already been proposed to provide an additional bypass flow that is dedicated to the thermal management of the turbomachine. As shown in Figure 2, the turbomachine 10 then comprises a secondary propeller 30 driven in rotation by a shaft of the gas generator 10. This propeller 30 is located in the flow vein V1 of the primary flow F1 and upstream of a second annular nozzle 32 for separating two annular flow veins V11, V12 of respective flow of a first internal flow F11 and a second external flow F12.

[0015] The exchangers 26 are housed in the vein V12 and are supplied by the second external flow F12. The first internal flow F11 supplies the compressor 14, as mentioned above.

[0016] Figure 2 shows that the gas generator 12 comprises two annular compartments C1, C2 which extend around the axis X.

[0017] The first annular compartment C1 is called the hot compartment because it is relatively close to the flow path V11 and therefore more exposed to the heat generated by compression, by the combustion chamber 16 and by the combustion gases. This hot compartment C1 extends axially between the second nozzle 32 and a first nozzle 34 for ejecting the first internal flow F11 at the outlet of the turbine(s). This hot compartment C1 is furthermore delimited radially by first and second annular walls 36, 38, respectively internal and external, which extend coaxially around each other. The first wall 36 externally defines the flow path V11 of the first internal flow F11, and the second wall 38 internally defines the flow path V12 of the second external flow F12.

[0018] The second annular compartment C2 is called the cold compartment because it is less exposed to heat, in particular because it is separated from the hot compartment by the flow path V12. This cold compartment C2 extends axially between the first nozzle 22 and a second nozzle 40 for ejecting the second external flow F12. This cold compartment C2 is furthermore delimited radially by third and fourth annular walls 42, 44, respectively internal and external, which extend coaxially around each other. The third wall 42 externally defines the flow path V12 of the second external flow F12, and the fourth wall 44 internally defines the flow path V2 of the secondary flow F2.

[0019] Many pieces of equipment in the turbomachine 10 are installed in the hot compartment C1, which is large. The cold compartment C2 is relatively small and reserved for equipment that cannot withstand the temperatures of the hot compartment C1, in particular electronic equipment.

[0020] This type of installation has several consequences:

[0021] - Equipment in the hot compartment C1 must be thermally protected. These thermal protections constitute additional volumes and masses to be installed in an already very constrained environment, which tends to hinder accessibility for inspections and maintenance of the turbomachine.

[0022] - Localized ventilation must be added in the hot compartment C1 for certain equipment (in particular electronic equipment) which is more sensitive to heat and cannot be installed in the cold compartment C2 since space there is too limited.

[0023] - The equipment has a reduced lifespan in the hot compartment C1 and this restrictive environment has consequences on its design: the choice of its technologies is limited and its mass is increased.

[0024] The invention proposes a solution to solve all or part of these problems.

[0025] Summary of the invention

[0026] The invention relates to a multi-flow turbomachine for an aircraft, this turbomachine having a longitudinal axis and comprising:

[0027] - a gas generator comprising at least one compressor, an annular combustion chamber, and at least one turbine,

[0028] - at least one main propeller driven in rotation by a shaft of the gas generator, the gas generator comprising:

[0029] - a first annular nozzle for separating two annular flow streams of an internal primary flow inside the gas generator and an external secondary flow around the gas generator,

[0030] - a secondary propeller driven in rotation by a shaft of the gas generator, this propeller being located in the flow vein of the primary flow and upstream of a second annular nozzle separating two respective annular flow veins of a first internal flow and a second external flow,

[0031] - a first ejection nozzle for the first internal flow,

[0032] - a second nozzle for ejecting the second external flow,

[0033] - a first annular compartment, called the hot compartment, extending axially between the second nozzle and the first nozzle, and between first and second annular walls, respectively internal and external, which extend coaxially around each other, the first wall externally defining said flow vein of the first internal flow, and said second wall internally defining said flow vein of the second external flow,

[0034] - a second annular compartment, called the cold compartment, extending axially between the first nozzle and the second nozzle, and between third and fourth annular walls, respectively internal and external, which extend coaxially around each other, the third wall externally defining said flow vein of the second external flow, and said fourth wall internally defining said flow vein of the secondary flow, characterized in that

[0035] - Rmaxparoi42 is between 0.8.Rmax30 and 1.5.Rmax30,

[0036] - Rmaxparoi44 is greater than or equal to 1,3.Rtuyère40,

[0037] - Rtuyère40 is between 1,2.Rtuyère34 and 1,5.Rtuyère34, and

[0038] - Vcompfroid is greater than or equal to 1.3.Vcompchaud, with: Rmaxparoi42 which is the maximum radius of the third wall, Rmax30 which is the maximum radius of the secondary propeller, Rmaxparoi44 which is the maximum radius of the fourth wall, Rtuyère40 which is the radius of the second nozzle, Rtuyère34 which is the radius of the first nozzle, Vcompfroid which is the volume of the cold compartment, and Vcompchaud which is the volume of the hot compartment.

[0039] In the present application, the expressions "upstream" and "downstream" refer to the direction of flow of the gases in the turbomachine.

[0040] The radii are measured relative to the longitudinal axis of the turbomachine. The invention thus proposes to optimize the geometric characteristics of the turbomachine and in particular of the gas generator, to optimize the dimensions of its hot and cold compartments and facilitate the integration of equipment, even heat-sensitive equipment, in these compartments. Advantageously, the cold compartment is longer and larger in diameter than a cold compartment of the prior art. Furthermore, this cold compartment is protected in the event of a fire by the flow vein of the second external flow which also protects the cold compartment from thermal radiation linked to combustion.

[0041] The turbomachine according to the invention may comprise one or more of the following characteristics, taken in isolation from one another, or in combination with one another:

[0042] - Rminparoi42 is between 0.8.Rmax30 and 1.5.Rmax30, with Rminparoi42 being the minimum radius of the third wall;

[0043] - Rtuyère40 is between 1.95.Rmaxparoi42 and 1.05.Rmaxparoi42;

[0044] - said at least one main propeller is located upstream of the gas generator;

[0045] - said at least one main propeller is located downstream of the gas generator;

[0046] - the turbomachine comprises two counter-rotating main propellers located downstream of the gas generator; - said at least one main propeller is unducted.

[0047] Brief description of the figures

[0048] Other characteristics and advantages will emerge from the following description of a non-limiting embodiment of the invention with reference to the appended drawings in which:

[0049] [Fig.1] Figure 1 is a schematic axial sectional view of a dual-flow turbomachine for an aircraft,

[0050] [Fig.2] Figure 2 is a half schematic axial sectional view of a dual-flow turbomachine for an aircraft, which provides an additional airflow diverted for cooling equipment,

[0051] [Fig.3] Figure 3 is a view similar to Figure 2 and showing the prior art of the present invention,

[0052] [Fig.4] Figure 4 is a view similar to Figure 2 and showing an embodiment of the present invention, and

[0053] [Fig.5] Figure 5 is a view similar to Figure 2 and showing an alternative embodiment of the present invention.

[0054] Detailed description of the invention

[0055] Figures 1 and 2 have been described in the above.

[0056] Figure 3 represents an aircraft turbomachine 10 according to the art prior to the present invention and which is similar to the turbomachine 10 of Figure 2.

[0057] In this application, several parameters are defined which are illustrated in Figure 3, and which are:

[0058] Rminparoi42: this is the minimum radius of the third wall 42, Rmaxparoi42: this is the maximum radius of the third wall 42, Rmax30: this is the maximum radius of the secondary propeller 30, Rmaxparoi44: this is the maximum radius of the fourth wall 44, Rtuyère40: this is the radius of the second nozzle 40, Rtuyère34: this is the radius of the first nozzle 34, Vcompfroid: this is the volume of the cold compartment C2, and

[0059] Vcompchaud which is the volume of the hot compartment C1.

[0060] The radii are measured relative to the longitudinal axis X of the turbomachine 10.

[0061] In the prior art illustrated in Figure 3, the turbomachine 10 is such that:

[0062] - Rmaxparoi42 is greater than or equal to 1.6.Rmax30,

[0063] - Rtuyère40 is greater than or equal to 1.6. Rtuyère34, and

[0064] - Vcompfroid is lower than Vcompchaud.

[0065] Figure 4 illustrates an embodiment of a turbomachine 10 according to the invention.

[0066] The foregoing description made with reference to the preceding figures applies to figure 4 to the extent that it does not contradict what follows.

[0067] The turbomachine 10 of Figure 4 differs from the prior art in that:

[0068] - Rmaxparoi42 is between 0.8.Rmax30 and 1.5.Rmax30,

[0069] - Rmaxparoi44 is greater than or equal to 1,3.Rtuyère40,

[0070] - Rtuyère40 is between 1,2.Rtuyère34 and 1,5.Rtuyère34, and

[0071] - Vcompfroid is greater than or equal to 1.3. Vcompchaud.

[0072] Furthermore, preferably:

[0073] - Rminparoi42 is between 0.8.Rmax30 and 1.5.Rmax30, and / or

[0074] - Rtuyère40 is between 1.95.Rmaxparoi42 and 1.05.Rmaxparoi42, that is to say that the radius of the nozzle 40 is substantially equal to the maximum radius of the wall 42 (within + / - 5%).

[0075] As illustrated in Figure 4, the propeller 20 may be located upstream of the gas generator 12.

[0076] In the variant shown in Figure 5, the propeller 20 is located downstream of the gas generator 12. As illustrated, the turbomachine 10 may comprise a double propeller downstream of the gas generator 12, namely for example two successive and counter-rotating main propellers 20. The turbomachine 10 of Figure 5 has the same geometric characteristics (Rmaxparoi42, Rmaxparoi44, Rtuyère40, Vcompfroid, etc.) as the turbomachine 10 of Figure 4.

[0077] An advantage of the invention is the obtaining of a larger cold compartment C2 so as to be able to accommodate more equipment, whatever the dimensions of the turbomachine 10.

[0078] Another advantage is to have a cold compartment C2 protected from fire and thermal radiation by the flow vein V12 of the flow F12, which makes it possible to increase the lifespan of the equipment installed in this compartment C2 while optimizing their design without very high temperature resistance constraints.

[0079] Furthermore, from an aerodynamic point of view, the diameter of the V12 vein being relatively small compared to the prior art, the radial dimension of the vein is larger for the same passage section compared to the current art, which facilitates the integration of heat exchangers.

[0080] Furthermore, controlling the mach in the V12 vein is easier (the mach in the vein being directly linked to the passage section). Indeed, with a larger diameter vein, a very small deviation in the radial dimension of the vein has a strong impact on the passage section.

Claims

DEMANDS 1. A multiflow turbomachine (10) for an aircraft, this turbomachine having a longitudinal axis (X) and comprising: - a gas generator (12) comprising at least one compressor (14), one annular combustion chamber (16), and at least one turbine (18), - at least one main propeller (20) driven in rotation by a shaft of the gas generator (12), the gas generator (12) comprising: - a first annular spout (22) separating two annular veins (V1, V2) with respective flow of a primary flow (F1) internal to the inside of the gas generator (12) and a secondary flow (F2) external around the gas generator (12), - a secondary propeller (30) driven in rotation by a shaft of the gas generator (12), this propeller (30) being located in the flow vein (V1) of the primary flow (F1) and upstream of a second annular nozzle (32) separating two annular veins (V11, V12) of respective flow of a first internal flow (F11) and a second external flow (F12), - a first nozzle (34) for ejecting the first internal flow (F11), - a second nozzle (40) for ejecting the second external flow (F12), - a first annular compartment (C1), called the hot compartment, extending axially between the second nozzle (32) and the first nozzle (34), and between first and second annular walls (36, 38), respectively internal and external, which extend coaxially around each other, the first wall (36) defining externally said flow vein (V11) of the first internal flow (F11), and said second wall (38) defining internally said flow vein (V12) of the second external flow (F12), - a second annular compartment (C2), called the cold compartment, extending axially between the first nozzle (22) and the second nozzle (40), and between the third and fourth annular walls (42, 44), respectively internal and external, which extend coaxially around each other, the third wall (42) externally defining said flow vein (V12) of the second external flow (F12), and said fourth wall (44) internally defining said flow vein (V2) of the secondary flow (F2), characterized in that - Rmaxparoi42 is between 0.8.Rmax30 and 1.5.Rmax30, - Rmaxparoi44 is greater than or equal to 1.3.Rtuyère40, - Rtuyère40 is between 1.2.Rtuyère34 and 1.5.Rtuyère34, and - Vcompfroid is greater than or equal to 1.3Vcompchaud, where: Rmaxparoi42 which is the maximum radius of the third wall (42), Rmax30, which is the maximum radius of the secondary helix (30), Rmaxparoi44 which is the maximum radius of the fourth wall (44), Rtuyère40 which is the radius of the second nozzle (40), Rtuyère34 which is the radius of the first nozzle (34), Vcompfroid which is the volume of the cold compartment (C2), and Vcompchaud which is the volume of the hot compartment (C1).

2. Turbomachine (10) according to claim 1, wherein: - Rminparoi42 is between 0.8.Rmax30 and 1.5.Rmax30, with: Rminparoi42 which is the minimum radius of the third wall (42).

3. Turbomachine (10) according to claim 1 or 2, wherein: - Rtuyère40 is between 1.95.Rmaxparoi42 and 1.05.Rmaxparoi42.

4. Turbomachine (10) according to any one of claims 1 to 3, wherein said at least one main propeller (20) is located upstream of the gas generator (12).

5. Turbomachine (10) according to any one of claims 1 to 3, wherein said at least one main propeller (20) is located downstream of the gas generator (12).

6. Turbomachine (10) according to the preceding claim, comprising two counter-rotating main propellers (20) located downstream of the gas generator (12).

7. Turbomachine (10) according to any one of the preceding claims, wherein said at least main propeller (20) is unshod.

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