Propulsion assembly for an aircraft, comprising a three-stream turbomachine and a mounting structure for said turbomachine
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- SAFRAN AIRCRAFT ENGINES SAS
- Filing Date
- 2026-01-21
- Publication Date
- 2026-07-30
Smart Images
Figure FR2026050048_30072026_PF_FP_ABST
Abstract
Description
[0001] DESCRIPTION
[0002] TITLE: PROPULSION ASSEMBLY FOR AN AIRCRAFT, COMPRISING A TRIPLE-FLOW TURBOMACHINE AND A MOUNTING STRUCTURE FOR THIS TURBOMACHINE
[0003] Technical field of the invention
[0004] The present invention relates to a propulsion assembly for an aircraft, comprising a triple-flow turbomachine and a structure in particular for attaching this turbomachine.
[0005] Technical background
[0006] The prior art includes in particular the documents WO-A1-2023 / 198962, US-B2-7444802 and US-A1-2018 / 156235.
[0007] An aircraft turbomachine, such as the one shown in Figure 1, comprises a gas generator 12 which conventionally includes, from upstream to downstream, with reference to the gas flow in the turbomachine 10, at least one compressor 14, 16, an annular combustion chamber 18 and at least one turbine 20, 22. In the case of a twin-spool turbojet engine, with low and high pressure respectively, the gas generator 12 successively comprises a low-pressure compressor 14, a high-pressure compressor 16, the combustion chamber 18, a high-pressure turbine 20 and a low-pressure turbine 22. The gas generator 12 defines an annular flow path V1 for a gas stream that passes through the compressors 14, 16, the combustion chamber 18 and the turbines 20, 22. This path V1 is called the primary path and the gas flow F1 that flows through it is called the primary stream.
[0008] The rotor of the high-pressure compressor 16 is connected to the rotor of the high-pressure turbine 20 by a high-pressure shaft 24. The rotor of the low-pressure compressor 16 is connected to the rotor of the low-pressure turbine 22 by a low-pressure shaft 26, which passes through the high-pressure shaft 24 and drives, either directly or via a reduction gear 28, a blower impeller S1, generally located upstream of the gas generator 12. The blower impeller S1 may be shrouded or unshrouded. When shrouded, it is enclosed by a nacelle 30, which is schematically represented in Figure 1 by dashed lines.
[0009] The blower propeller S1 generates an airflow F, part of which enters the gas generator 12 to form the primary flow F1, and part flows around the gas generator 12 to form a secondary flow F2 in a secondary vein V2.
[0010] In practice, this separation of the airflow F is obtained by means of a first annular separation nozzle 32 which is located downstream of the blower propeller S1 and which is able to separate the airflow F passing through the blower propeller S1 into two flows, respectively internal and external, able respectively to form the primary flow F1 and secondary flow F2 and to flow respectively into the veins V1 and V2.
[0011] The turbomachine 10 is attached to an aircraft component, such as a wing or fuselage, by means of a mounting structure or pylon 34. The assembly formed by the turbomachine 10 and the structure or pylon 34 is referred to as the propulsion assembly in the context of the present invention.
[0012] The pylon 34 constituting the structure in the embodiment illustrated in figure 1 generally has an elongated general shape and is located at a predetermined clockwise position relative to the longitudinal axis A of the turbomachine 10.
[0013] In the present invention, a time position is defined as a position, with reference to the dial of a watch or clock, that is centered on the axis A of the turbomachine 10 in a plane perpendicular to this axis. A 12 o'clock position corresponds to a high position in a vertical direction relative to the axis A, and located above the axis. A 6 o'clock position corresponds to a low position in a vertical direction relative to the axis A, and located below the axis, and the 3 o'clock and 9 o'clock positions correspond respectively to lateral positions in horizontal directions relative to the axis A, and on either side of this axis.
[0014] If the turbomachine 10 is mounted under a wing of the aircraft, the pylon 34 is generally located at the 12 o'clock position. If the turbomachine 10 is mounted on the side of the aircraft fairing, the pylon may be located between 9 and 12 o'clock, or between 12 and 3 o'clock, for example. The pylon 34 is connected to the turbomachine 10 and may disrupt the flow of the gas it passes through.
[0015] In the context of the present invention, we are particularly interested in a triple-flow turbomachine 10.
[0016] A triple-flow turbomachine 10, as shown in Figure 1, includes in particular a secondary blower propeller S2 which is driven in rotation by a shaft of the gas generator, such as the low-pressure shaft 26, and which is located in the V1 channel.
[0017] The turbomachine 10 includes a third internal annular or tertiary V3 which is located inside the gas generator 12, and a second annular separation nozzle 36 which is located downstream of the secondary blower propeller S2 and which is suitable for separating the flow through the secondary blower propeller S2 into two flows, respectively internal and external, suitable respectively for forming the primary F1' and tertiary F3 flows and for flowing respectively into the V1 and V3 channels.
[0018] Figure 2 is an enlarged view of the secondary blower propeller S2, the separation nozzle 36 and the V3 stream whose upstream end opens into the V2 stream and whose downstream end opens into the V2 stream (see figure 1).
[0019] Figure 2 and Figure 3 show that a fixed stator blade 38 is located in the V3 channel, here near its upstream end. A fixed stator blade 38 comprises a plurality of stator blades 42 distributed around axis A and extending over the entire radial dimension of the V3 channel.
[0020] It can also be seen in these figures 2 and 3 that arms 40 are located in the V3 vein downstream of the fixed straightener blade 38, these arms 40 being axially intercalated between the fixed straightener blade 36 and a part of the pylon 34 which is located in the V2 vein.
[0021] This architecture has drawbacks. In particular, static pressure distortion occurs upstream of pylon 34, which then travels along the V2 flow path to the secondary fan propeller S2. This causes operability problems on this propeller at certain flight regimes, especially during takeoff. This distortion is caused by pylon 34, which completely traverses the V2 flow path and has relatively large dimensions. The present invention proposes an improvement to this architecture that is simple, efficient, and economical.
[0022] Summary of the invention
[0023] The invention relates to a propulsion system for an aircraft, comprising a triple-flow turbomachine and a structure, in particular a mounting structure for this turbomachine, the turbomachine having a longitudinal axis and the structure being located at a predetermined clockwise position relative to this longitudinal axis, the turbomachine comprising a gas generator and a main fan propeller driven in rotation by a shaft of the gas generator, the gas generator comprising:
[0024] - a first internal annular vein located inside the gas generator,
[0025] - a second external annular vein located outside the gas generator,
[0026] - a first annular separation nozzle located downstream of the main fan propeller and capable of separating an incoming air flow passing through the main fan propeller into two flows, respectively internal and external, capable of flowing respectively into the first and second streams,
[0027] - a rotor driven in rotation by a shaft of the gas generator, this rotor being located in the first vein,
[0028] - a third internal annular vein located inside the gas generator,
[0029] - a second annular separation nozzle located downstream of the rotor and capable of separating the flow passing through the rotor into two flows, respectively internal and external, capable of flowing respectively into the first and third channels,
[0030] - a fixed straightener blade located in the third vein,
[0031] - arms located in the third vein downstream of the fixed straightener blade, these arms being axially interposed between the fixed straightener blade and a part of the structure,
[0032] characterized in that the third vein comprises three consecutive axial sections: - a first upstream section comprising the fixed rectifier blade and having an annular-shaped passage section which has the same radial dimension all around the axis,
[0033] - a second intermediate section having an annular-shaped passage cross-section which exhibits a radial widening at said hour position, and
[0034] - a third downstream section comprising the arms and having an annular-shaped passage section which has the same radial dimension all around the axis.
[0035] The invention thus proposes a specific evolution of the tertiary flow channel cross-section, and in particular a non-axisymmetric section of the channel between the stator blade and the arms within this channel. Enlarging the cross-section upstream of the arm is equivalent to locally widening the channel in areas where there are objects that disrupt the upstream static pressure. This widening at constant flow rate causes a local deceleration of the flow, which in turn leads to an increase in static pressure. This therefore allows for a local increase in static pressure distortion, particularly between the blade and the arms. Conversely, upstream of the blade, the distortion decreases.
[0036] The idea is, firstly, to decrease the local Mach number upstream of the pylon to reduce static pressure and make it more difficult for the distortion generated by the pylon to travel upwards, and secondly, to do the opposite along the rest of the azimuth. To achieve this, the cross-section of the azimuth is locally increased at the pylon and narrowed along the remaining azimuths, resulting in a shape that resembles an ellipse rather than a circle.
[0037] The deformation of the duct is therefore carried out primarily in the middle of the duct, between the stator blade and the arms. The duct is circular at the stator blade and at the arms. In between, the duct is, for example, elliptical.
[0038] The propulsion assembly according to the invention may include one or more of the following features, taken individually or in combination with each other: - the second section extends between trailing edges of the blades of the fixed stator blade, and leading edges of the arms;
[0039] - the first section is delimited by two annular walls, respectively internal and external, each having a circular shape in section;
[0040] - the second section is delimited by two annular walls, respectively internal and external, each having an elliptical shape in section;
[0041] - the elliptical shapes of the walls of the second section have the same center aligned on the axis;
[0042] -- Alternatively, the elliptical shapes of the walls of the second section could be off-center from the axis;
[0043] - the third section is delimited by two annular walls, respectively internal and external, each having a circular shape in section;
[0044] - the walls of the second section are connected to the walls of the first and third sections by aerodynamic link zones ensuring continuity of the walls without steps;
[0045] - the passage section of the second segment includes a larger radial dimension at the widening, and a smaller radial dimension which is diametrically opposite to the larger radial dimension, the radial dimension of this passage section decreasing regularly and continuously between the larger radial dimension and the smaller radial dimension over a first half of the passage section extending around the axis, and increasing regularly and continuously between the smaller radial dimension and the larger radial dimension over a second half of the passage section extending around the axis;
[0046] - the arms are distributed in the third vein around the axis so that two of these arms, located on either side of said hour position, are separated from each other by a circumferential distance which is greater than the circumferential distances between the other arms;
[0047] - the third vein includes at least one heat exchanger;
[0048] - said at least one heat exchanger is located in said second section; - the enlargement represents a variation between 10 and 30%, and preferably between 15 and 25%, of an average radial dimension of the cross-section of the vein;
[0049] - the rotor is a secondary blower propeller.
[0050] Brief description of the figures
[0051] Other features and advantages of the invention will become apparent upon reading the detailed description that follows, for an understanding of which reference should be made to the accompanying drawings in which:
[0052] [Fig.1] Figure 1 is a schematic half-view in axial section of a propulsion assembly according to the invention;
[0053] [Fig.2] Figure 2 is a partial schematic view of part of the propulsion assembly of Figure 1;
[0054] [Fig.3] Figure 3 is a schematic top view, including unrolled flat section elements, of part of the elements located in the tertiary vein of the propulsion assembly of Figure 1;
[0055] [Fig.4] Figure 4 is a schematic cross-sectional view of a section of the tertiary vein, and shows a passage section with constant radial dimensions;
[0056] [Fig.5] Figure 5 is a schematic cross-sectional view of a section of the tertiary vein, and shows a passage section with a local enlargement;
[0057] [Fig.6] Figure 6 is a partial southern view of the tertiary vein and an enlargement of Figure 5;
[0058] [Fig.7] Figure 7 is another partial southern view of the tertiary vein of Figure 5;
[0059] [Fig.8] Figure 8 is a graph showing the azimuthal evolution of the passage section for an annular vein and for an elliptical vein;
[0060] [Fig. 9] Figure 9 is a graph showing the azimuthal distortion of static pressure upstream of a pylon in a circular vein and an elliptical vein at 50% of the vein height, and
[0061] [Fig. 10] Figure 10 is a graph showing the axial static pressure distortion in an axisymmetric vein and a widening vein. Detailed description of the invention
[0062] Figures 1 to 3 have been described above. These figures can be considered as illustrating the invention.
[0063] The invention relates to a propulsion assembly for an aircraft, comprising a triple-flow turbomachine 10 and a pylon 34 for attaching this turbomachine 10.
[0064] The turbomachine 10 has a longitudinal axis A and the pylon is located at a predetermined clockwise position relative to this longitudinal axis A.
[0065] In the rest of the description, we will consider that this time position is 12h (12 hours) but only as a non-limiting example, this time position can be any position with respect to axis A.
[0066] The turbomachine 10 includes a gas generator 12 and a main blower propeller S1 driven in rotation by a shaft of the gas generator, either directly or via a reduction gear 28.
[0067] The gas generator 12 includes:
[0068] - a first internal annular vein V1 located inside the gas generator 12,
[0069] - a second external annular vein V2 located outside the gas generator 12,
[0070] - a first annular separation nozzle 32 located downstream of the propeller S1 and capable of separating an incoming air flow F passing through the propeller S1 into two flows, respectively internal F1 and external F2, capable of flowing respectively into the first and second veins V1, V2,
[0071] - a rotor, such as a secondary blower propeller S2, driven in rotation by a shaft of the gas generator, this rotor or propeller S2 being located in the first stream V1,
[0072] - a third internal annular vein V3 located inside the gas generator 12,
[0073] - a second annular separation nozzle 36 located downstream of the rotor or propeller S2 and suitable for separating the flow passing through the rotor or propeller S2 into two flows, respectively internal F1' and external F3, suitable for flowing respectively into the first and third veins V1, V3,
[0074] - a fixed stator blade 38 located in the third channel V3, and - arms 40 located in the third channel V3 downstream of the fixed stator blade 38, these arms 40 being axially interposed between the fixed stator blade 38 and a portion of the pylon 34, which is itself located in channel V2. The fixed stator blade 38 comprises a plurality of stator blades 42 which are distributed, preferably regularly, around the axis A and which extend over the entire radial dimension of channel V3. Each of these blades 42 comprises a leading edge 42a and a trailing edge 42b of the flow F3. The arms 40 are distributed around the axis A and extend over the entire radial dimension of channel V3. Each of the arms 40 includes a leading edge 40a and a trailing edge 40b of the F3 flow.
[0075] The distinctive feature of the invention lies in the fact that the third vein V3 comprises three consecutive axial sections T1, T2, T3:
[0076] - a first upstream section T1 comprising the fixed rectifier blade 38 and having an annular-shaped passage section which has the same radial dimension R1 all around the axis A (see figure 4),
[0077] - a second intermediate section T2 having an annular-shaped passage section which has a widening H1 at the hour position of pylon 34, i.e. at 12 o'clock in the example shown (see figure 5), and
[0078] - a third downstream section T3 comprising arms 40 and having an annular-shaped passage section which has the same radial dimension R2 all around the axis A (see figure 4).
[0079] We can thus understand that figure 4 represents the annular shape and the radial dimension passage section R1, R2 constant of the first and third segments T1, T3.
[0080] Figures 5 to 7 show the annular shape and the widened passage section of the second segment T2. In this embodiment, the passage section of segment T2 comprises a larger radial dimension R4 at the widening H1, and a smaller radial dimension R3 which is preferably diametrically opposite the larger radial dimension R4. The radial dimension of this passage section decreases regularly and continuously between the larger radial dimension R4 and the smaller radial dimension R3 over the first half of the passage section extending around axis A, and increases regularly and continuously between the smaller radial dimension R3 and the larger radial dimension R4 over the second half of the passage section extending around axis A.
[0081] Preferably, this second section T2 extends between the trailing edges 42b of the blades 42 of the fixed straightener blade 38, and the leading edges 40a of the arms 40.
[0082] Each of the sections T1 and T3 is preferably delimited by two annular walls 44, 46, respectively internal and external, each having a circular shape in section.
[0083] The second section T2 is preferably delimited by two annular walls 48, 50, respectively internal and external, each having an elliptical cross-section. The ellipses preferably have the same center aligned with axis A. The walls 48, 50 of section T2 are advantageously connected to the walls 44, 46 of sections T1, T2 by aerodynamic link zones 52 which do not generate a step in the third channel V3 to avoid pressure losses in the flow F3.
[0084] Figure 3 shows that the arms 40 can be distributed in the V3 vein around the axis A so that two of these arms 40, located on either side of the hour position at 12 o'clock, are separated from each other by a circumferential distance C1 which is greater than the circumferential distances C2 between the other arms 40.
[0085] H1 enlargement represents an increase of between 10 and 30%, and preferably between 15 and 25%, of an average radial dimension of the V3 vein passage section. This increase is for example 20%.
[0086] The third vein V3 may include at least one heat exchanger 50, for example at its second section T2 (figure 2).
[0087] Figure 8 shows the azimuthal evolution of the cross-section for an annular vein (curve X1) and for an elliptical vein (curve X2). Figure 9 shows the azimuthal static pressure distortion upstream of pylon 34 in a circular vein (curve X1) and an elliptical vein (curve X2) at 50% of the vein's radial height or dimension.
[0088] A significant distortion of the static pressure is observed in the circular channel, which is generated by the pylon at 12 o'clock. Under the same operating conditions, less distortion is observed with an elliptical channel conforming to the invention, with a more uniform static pressure trace in the azimuth. These results stem from the fact that the local cross-section of the channel changes according to the increase in static pressure.
[0089] In Figure 10, the widening of the vein at 12 o'clock causes an increase in distortion locally between the blades 42 and the arms 40 (curve X2). Conversely, the distortion is slightly reduced upstream of the blades 42 compared to the axisymmetric vein or the vein without narrowing (curve X1).
[0090] Upstream of the 42 blades, this change in distortion is explained as resulting from a reduction in the flow's difficulty in passing through the intermediate section (T2) at 12 o'clock. This facilitated flow at 12 o'clock in this section, on the one hand, compensates for the effect of the downstream pylon, which impedes the flow at 12 o'clock, and on the other hand, allows the flow to distribute itself more uniformly along the azimuthal axis. Between the 42 blades of the fixed straightener and the 40 arms, the explanation lies in a local change in the Mach number. In fact, at 12 o'clock, the flow is decelerated due to the increased cross-sectional area, and the effect of opening the channel at 12 o'clock facilitates the flow's passage through this section and implies an increase in static pressure (Ps). In areas such as 3H, 6H and 9H, we have the opposite effect, which goes against a uniform distribution of static pressure (Ps) on the azimuthal axis in these areas and locally.When the vein returns to an axisymmetric vein, this distortion variation is lost.
[0091] In the preceding description, the invention has been described in relation to a structure that is a support pylon, but the invention can be used in relation to another type of structure. Generally, the structure is capable of causing a local increase in static pressure.
Claims
DEMANDS 1. Propulsion assembly for an aircraft, comprising a triple-flow turbomachine (10) and a structure (34), in particular for attaching this turbomachine (10), the turbomachine (10) having a longitudinal axis (A) and the structure (34) being located at a predetermined clockwise position relative to this longitudinal axis (A), the turbomachine (10) comprising a gas generator (12) and a main fan propeller (S1) driven in rotation by a shaft of the gas generator (12), the gas generator (12) comprising: - a first internal annular duct (V1) located inside the gas generator (12), - a second external annular vein (V2) located outside the gas generator (12), - a first annular separation nozzle (32) located downstream of the main blower propeller (S1) and capable of separating an incoming air flow (F) passing through the main blower propeller (S1) into two flows, respectively internal (F1) and external (F2), capable of flowing respectively into the first and second veins (V1, V2), - a rotor driven in rotation by a shaft of the gas generator (12), this rotor being located in the first vein (V1), - a third internal annular vein (V3) located inside the gas generator (12), - a second annular separation nozzle (36) located downstream of the rotor and suitable for separating the flow through the rotor into two flows, respectively internal (F1') and external (F3), suitable for flowing respectively into the first and third veins (V1, V3), - a fixed straightener blade (38) located in the third vein (V3), - arms (40) located in the third vein (V3) downstream of the fixed straightener blade (38), these arms (40) being axially intercalated between the fixed straightener blade (38) and a part of the structure (34), characterized in that the third vein (V3) comprises three consecutive axial sections (T1, T2, T3): - a first upstream section (T1) comprising the fixed rectifier blade (38) and having an annular-shaped passage section which has the same radial dimension (R1) all around the axis (A), - a second intermediate section (T2) having an annular-shaped passage section which presents a radial widening (H1) at said hour position, and - a third downstream section (T3) comprising the arms (40) and having an annular-shaped passage section which has the same radial dimension (R2) all around the axis (A).
2. Propulsion assembly according to claim 1, in which the second section (T2) extends between trailing edges (42b) of the blades (42) of the fixed stator blade (38), and leading edges (40a) of the arms (4).
3. Propulsive assembly according to claim 1 or 2, in which the first section (T1) is delimited by two annular walls (44, 46), respectively internal and external, each having a circular cross-section.
4. Propulsive assembly according to any one of the preceding claims, in which the second section (T2) is delimited by two annular walls (48, 40), respectively internal and external, each having an elliptical shape in section.
5. Propulsive assembly according to the preceding claim, in which the elliptical shapes of the walls (48, 50) of the second section (T2) have the same center aligned on the axis (A).
6. Propulsive assembly according to any one of the preceding claims, in which the third section (T3) is delimited by two annular walls (44, 46), respectively internal and external, each having a circular cross-section.
7. Propulsion assembly according to all claims 3, 4 and 5, in which the walls (48, 50) of the second section (T2) are connected to the walls (44, 46) of the first and third sections (T1, T3) by aerodynamic link zones ensuring continuity of the walls without step.
8. Propulsive assembly according to any one of the preceding claims, wherein the passage section of the second section (T2) comprises a larger radial dimension (R4) at the level of the widening (H1), and a smaller radial dimension (R3) which is diametrically opposite to the larger radial dimension (R4), the radial dimension of this passage section decreasing regularly and continuously between the larger radial dimension (R4) and the smaller radial dimension (R3) over a first half of the passage section extending around the axis, and increasing regularly and continuously between the smaller radial dimension (R3) and the larger radial dimension (R4) over a second half of the passage section extending around the axis.
9. Propulsive assembly according to any one of the preceding claims, wherein the arms (40) are distributed in the third vein (V3) around the axis (A) such that two of these arms (40), located on either side of said hour position, are separated from each other by a circumferential distance (C1) which is greater than the circumferential distances (C2) between the other arms (40).
10. Propulsive assembly according to any one of the preceding claims, wherein the third vein (V3) comprises at least one heat exchanger (50).
11. Propulsion assembly according to claim 10, wherein said at least one heat exchanger (50) is located in said second section (T2).
12. Propulsion assembly according to any one of the preceding claims, wherein the enlargement (H1) represents a variation of between 10 and 30%, and preferably between 15 and 25%, of an average radial dimension of the cross-section of the flow path (V3).
13. Propulsion assembly according to any one of the preceding claims, wherein the rotor is a secondary blower propeller (S2).