FR3042011A1 - PROPULSION ASSEMBLY OF AN AIRCRAFT EQUIPPED WITH A MAIN BLOWER AND AT LEAST ONE BLOW FAN - Google Patents

Abstract

The present invention relates to a propulsion assembly of an aircraft comprising: - at least one main turbine (5, 6) mounted along a longitudinal axis (XX); at least one main blower (8) disposed along the longitudinal axis (XX) and driven in rotation by said main turbine; - At least one auxiliary turbine (7) mounted along the longitudinal axis (XX), the auxiliary turbine being independent of the main turbine, - at least one auxiliary blower (9, 9 ') axis (XY, XY') offset from the longitudinal axis (XX) and driven by the auxiliary turbine.

Description

Propulsion unit for an aircraft equipped with a main blower and at least one remote blower

Field of the invention

The present invention relates to the aeronautical field and relates to a propulsion unit comprising at least two blowers driven by the same engine. In particular, it aims at a blower disposed along the gas generator and at least one blower offset relative to the axis of the gas generator.

State of the art

The present applicant has undertaken work on an overall propulsion architecture for at least two distributed blowers. These objectives are to seek an optimization of the propulsive performance through a high dilution rate, while maintaining an acceptable ground clearance and reduced size blowers with a different regime than that of the turbine.

One of the solutions to continue to increase the dilution rate without compromising the rules established in terms of integration is to distribute the propulsion on various smaller fan modules. A schematic diagram of such an assembly 1 is shown in FIGS. 1 and 2. A gas generator 3 conventionally comprises a compression assembly supplying air to an annular combustion chamber; the gases from the chamber drive one or more turbines mechanically connected to the compressor and here a power turbine 5. The latter is secured to a power shaft 6 coaxial with the gas generator 3. This power shaft 6 drives through of a suitable transmission system two intermediate radial shafts each driving a fan shaft 9, 9 'offset, that is to say of axis offset from the axis of the gas generator. The shafts of the blowers 9 and 9 'each drive a fan 10, 10' axis offset to that of the motor. Such an arrangement makes it possible to achieve the objectives referred to above.

However, the realization of a transmission system of this type is complex. The jet of the gas generator "shears" directly at room temperature and generates a loud noise typical of fighter aircraft with low dilution or single flow. Added to this is the fact that the gas generator is very exposed to the ingestion of foreign bodies unlike the case of a conventional architecture where it is protected by a fan.

The present invention aims to remedy this problem.

In particular, it aims at an arrangement that makes it possible to maintain a known architecture while increasing the dilution ratio.

Presentation of the invention

It is possible to achieve this objective with a propulsion unit of an aircraft comprising: at least one main turbine mounted along a longitudinal axis; at least one main blower disposed along the longitudinal axis and driven in rotation by said main turbine; at least one auxiliary turbine mounted along the longitudinal axis, the auxiliary turbine being independent of the main turbine; and at least one auxiliary blower with axis offset relative to the longitudinal axis and driven by the auxiliary turbine.

Thus, when the second power transmission system is arranged downstream of the driving turbine of the main fan, and when the driving of the main and auxiliary fans (s) is performed by different and independent turbines, these They are unloaded as a couple.

When the second power transmission system is arranged upstream of the gas generator that facilitates integration is because it is an area where the constraints related to the thermal (operating temperature, expansion of parts, ... ) are much weaker. The assembly according to the invention may comprise one or more of the following characteristics, taken separately from one another or in combination with each other: the auxiliary turbine comprises a free power turbine driven by the gas generator and driving in rotating the auxiliary blower; the assembly comprises two auxiliary blowers and two auxiliary turbines independent of each other and from the main turbine; the auxiliary blowers are driven respectively by an auxiliary turbine; the assembly comprises a first power transmission system connected to the auxiliary blower and a second power transmission system connected to the first power transmission system, the second power transmission system being arranged: downstream of the turbine auxiliary between the auxiliary turbine and the auxiliary blower, or o upstream of the auxiliary turbine between the auxiliary blower and the main blower. the first and / or second power transmission system comprises a differential gear system; the differential gear system comprising a housing, an axial input shaft, a planet carrier driven by the input shaft, planet gears mounted on the planet carrier, at least one idler gear supported by the housing and radial shafts each perpendicular to the axial input shaft, the radial shafts being integral with the planet gears, the planet carrier and the input shaft being coaxial, the planet carrier forming a hub on which the axes of rotation of the satellites are arranged radially. the first and / or the second power transmission system comprises a speed reducer; the speed reducer is an epicyclic mechanism; the first and / or the second power transmission system comprises in series two homokinetic joints with a slide connection. - The first and / or the second power transmission system is located in a motor zone not thermally constrained, in particular upstream of the gas generator. - The first and / or second power transmission system is located downstream of the turbine. The invention also relates to a propulsion assembly comprising propulsion of an aircraft comprising: - at least one turbine mounted along a longitudinal axis; at least one main blower disposed along the longitudinal axis and driven in rotation by said turbine; at least one auxiliary turbine mounted along the longitudinal axis; at least one auxiliary blower with an axis offset relative to the longitudinal axis and driven by the auxiliary turbine, the auxiliary blower being connected to a first power transmission system; and a second power transmission system connected to the first power transmission system, the second power transmission system being arranged: downstream of the auxiliary turbine between the auxiliary turbine and the auxiliary blower, or upstream of the auxiliary power turbine; auxiliary turbine between the auxiliary blower and the main blower.

BRIEF DESCRIPTION OF THE DRAWINGS Other features and advantages will become apparent from the following description of one embodiment of the invention without limitation with reference to the accompanying drawings in which:

Figure 1 is a schematic representation of an aircraft propulsion assembly architecture according to the prior art;

Figure 2 shows schematically a first embodiment of the arrangement of an auxiliary blower module driven by an auxiliary turbine;

Figure 3 shows schematically a second embodiment of the arrangement of an auxiliary blower module in a standard architecture;

FIG. 4 shows a schematic representation of a variant of the first embodiment according to FIG. 3;

Figure 5 shows a schematic representation of the arrangement of the auxiliary blower module according to another embodiment of the invention;

Figure 6 schematically illustrates a variant of the embodiment according to Figure 5;

FIG. 7 illustrates in a diagrammatic representation another embodiment in which two remote auxiliary fan modules are arranged with respect to a gas generator upstream of which a main fan is installed;

Figure 8 schematically illustrates a variant of the embodiment according to Figure 7;

FIG. 9 is a schematic view of another embodiment of the invention in which two fan modules are offset with respect to the axis of a double-body gas generator upstream of which a main blower is installed;

Figure 10 is a variant of the embodiment according to Figure 9; Detailed description of an embodiment of the invention

In Figure 2 is shown a set 1 of propulsion of an aircraft according to a first embodiment. In this example the propulsion assembly 1 is shown mounted on the wing 20 of an aircraft. This assembly 1 comprises along a longitudinal axis XX from upstream to downstream a low pressure compressor 2 (BP), a high pressure compressor 3 (HP), a combustion chamber 4, a high pressure turbine 5 (BP) and a turbine 6 low pressure (HP). In the present invention, and in general, the terms "upstream" and "downstream" are defined with respect to the flow of gases in the propulsion assembly. The LP compressor and the LP turbine are connected by a LP shaft to form a low pressure body. The HP compressor and the HP turbine are mechanically connected by a high pressure shaft to form a high pressure body. The HP and LP bodies form the gas generator which is here a dual-body gas turbine engine. The BP and HP bodies are coaxial and are rotatably mounted independently. The combustion chamber 4 is supplied with compressed air from compressors 2 and 3 in series. The gases produced in the combustion chamber 4 successively move the turbine 5 HP and 6 BP which respectively drive the two compressors, 2 HP and 3 BP. The assembly includes a so-called main blower 8 upstream of the gas generator. The main blower 8 is careened by a housing 51C. The turbine 6 BP called main turbine here drives the fan 8. The main fan 8 comprises a rotor supported by the LP turbine shaft with vanes periphery of the rotor.

The secondary channel downstream of the fan 51 is in this embodiment, short. The secondary flow and the primary flow, the latter forming the gases produced by the combustion chamber, are separated, the two streams are ejected into the atmosphere by separate, concentric nozzles. The propulsion assembly could however be mixed flow, the two streams being mixed upstream of the gas ejection nozzle.

A free power turbine 7 called auxiliary turbine is also mounted downstream of the turbine 6 BP. The free power turbine 7 is rotated by the gases of the primary flow of the gas generator independently of the BP and HP bodies. This free power turbine 7 is integral with a power shaft 13 coaxial with the longitudinal axis XX.

Another fan 9 said auxiliary is mounted along an axis XY offset with respect to the longitudinal axis XX. We understand by the term "offset" or "offset" that the XX and XY axes are not coaxial. The fan has a housing 91. In the present embodiment, the axis of the fan 9 is parallel to that of the gas generator. The rotor of the fan is rotated by an intermediate shaft 10. This is, in this example, made in two parts. A lower part 10i and an upper part 10s. The two parts are connected to each other by a suitable coupling 10a. Of course, the rotor can be driven by intermediate shaft 10 in a single part 0.

The upper part 10s of the intermediate shaft 10 is rotated by the output shaft 13 of the free power turbine 7 through a first power transmission system 11. Advantageously but without limitation, this first transmission system power 11 comprises a conical gear 11 ic. At the other end the lower part 10i cooperates with a second power transmission system 12. Advantageously, but not exclusively, the second power transmission system comprises a conical gear 12sc meshing with the drive shaft 92a of the fan 9 through.

Conical wheel meshes make it possible to simplify the integration of the different modules. The internal angle return to the auxiliary blower allows speed transformations between input shafts and output shafts with a multiplication ratio between 0.5 and 1.5.

The turbine engine formed by the turbojet provides part of the thrust on the aircraft by the entire primary and secondary flow that is produced. The free power turbine 7 rotates the rotor of the fan 9 via the intermediate shaft 10 and the first and second power transmission system.

This propulsion assembly 1 is shown mounted on the wing 3 of an aircraft with the auxiliary blower above the area and the main blower below the wing. The aircraft comprises at least two such propulsion units, one on each wing. The assembly comprises a turbojet engine suspended from a pylon under the wing forward with respect to the leading edge of the wing. Of course, the fan is mounted on the wing by means of a pylon 11 or any other equivalent structure forming the support of the fan on the wing. Of course, the auxiliary blower and the main blower can be arranged in a horizontal rather than vertical plane.

According to a non-illustrated embodiment, the first power transmission system further comprises a link comprising a first and a second constant velocity joint type joints connected by a slide connection. The first seal is connected to the intermediate shaft while the second seal is connected to the fan rotor. This combination makes it possible to make up for the angular displacements between the axial and radial displacements of the intermediate shaft.

Advantageously, but not exclusively, the seal (s) may be a Rzeppa seal. Such a seal comprises a drive shaft and a driven shaft; a bowl is secured to one axis and a nut is integral with the other axis with the interposition of balls. The arrangement between these elements is made so as to allow a drive of the driven axis at the same speed of rotation as the input axis while admitting an angular misalignment between them.

Advantageously, but not exclusively, the seal or joints may be a sliding VL seal known per se. This seal comprises a drive shaft and a driven shaft. Balls retained in a cage are movable inside cross grooves, respectively outer and inner. The grooves allow axial displacement of one axis relative to the other while ensuring the transmission of torque. The second seal can also be a Rzeppa seal. The connection between the two joints then being sliding, for example by means of sliding splines. The connecting shaft between the main blower and the auxiliary blower module can be inclined at an angle between -45 ° and + 45 ° relative to the axes of the driving and receiving members. This configuration allows to play on the axial position of the auxiliary blower module relative to the main blower and gas generator.

According to yet another alternative embodiment, the first power transmission system may comprise a differential gear system.

According to yet another embodiment of the invention, the first power transmission system may comprise a speed reducer. In particular, the auxiliary blower 9 is driven by its fan shaft which is itself driven through a speed reducer supported by the shaft 10. The gearbox is preferably epicyclic gear with a sun gear, a ring gear and satellites. The satellites are supported by a fixed frame, attached to the casing of the propulsion unit. The wheels forming the satellites mesh on the one hand on the teeth of the sun gear and on the other hand on the teeth of the crown. The sun gear meshes with the set of satellites, the number of which depends on the size of the gearbox, the gear ratio and the input torque.

These satellites are, according to one embodiment, double helical helical gears. In this case, there is a blockage of the degree of freedom in translation on the axis of the blower between the various components of the gearbox. In order not to undergo significant internal stresses during the axial expansion of the environment under thermal load, restores the degree of freedom in axial translation between each component. For example, it is possible for this purpose to use a guide of the satellites by plain bearings without axial stop and a fan / crown rotor connection made using a spline which is not locked axially and therefore slippery on the axis of the blower.

These satellites are according to another embodiment with straight teeth. The degree of freedom in axial translation is maintained between planet / satellites and satellites / crown. In this case, it is not necessary to use sliding splines and it is possible to favor, for example, the use of spherical roller bearings for the guidance of satellites. The shaft element of the fan 9 is engaged, at the input of the gearbox, with the sun gear and, at the output, the fan shaft is driven by the ring of which it is integral. The shafts arranged along the axis XY, supported by sets of ball or roller bearings with the fixed structure of the propulsion unit, are here coaxial in the direction XY which is parallel and offset with respect to the direction XY of the tree 13.

The reducer may be a planar or spherical reducer.

In Figure 3 is illustrated another embodiment of a propulsion assembly. The elements identical to those of FIG. 2 are designated by the same reference numerals. The propulsion assembly comprises a BP body and an HP body rotatably mounted along the longitudinal axis XX independently. The BP body comprises a LP compressor and a LP turbine connected by a low pressure shaft. Between these are arranged an HP compressor and an HP turbine forming the HP body. The HP and BP bodies form the gas generator. This is a double-body gas turbine engine. In this example another auxiliary fan 9 is also mounted upstream of the compressor BP. This auxiliary blower 9 is disposed along an axis XY offset with respect to the longitudinal axis XX. The auxiliary blower 9 is driven by the power shaft of the free power turbine 7 via a first power transmission system 12 arranged between the main blower and the auxiliary blower 9. The first power transmission system 12 and the blower auxiliary 9 forms a fan module.

The main blower 8 is also driven by the free power turbine 7 by means of a second power transmission system 12. In other words, the auxiliary blower and the main blower are driven here by the same free power turbine. .

The first power transmission system 12 and the second power transmission systems are similar to those disclosed in the first embodiment illustrated in FIG.

According to a variant of the previous embodiment illustrated in Figure 4, the main fan 8 is disposed upstream of the compressor BP. The second power transmission system is disposed downstream of the free power turbine 7 and is connected to the auxiliary fan 9 offset along the axis XY with respect to the longitudinal axis XX. The second power transmission system is mechanically connected to the first power transmission system.

In Figure 5 is shown another embodiment of a set of propulsion. In this figure, identical elements to those of Figures 1 and 2 are designated by the same reference numerals. The propulsion assembly comprises a BP body and an HP body rotatably mounted along the longitudinal axis XX independently. The BP body comprises a LP compressor and a LP turbine connected by a low pressure shaft. Between these are arranged an HP compressor and an HP turbine forming the HP body. The HP and BP bodies form the gas generator. This is a double-body gas turbine engine. Upstream of the compressor BP 2 is arranged a main blower 8 which comprises a blower rotor integral with the LP shaft of the compressor BP. The main blower 8 is rotated by the turbine BP said main turbine.

An auxiliary blower 9 is also arranged along an axis XY offset with respect to the longitudinal axis XX of the gas generator. The auxiliary blower 9 is driven by the LP shaft of the LP turbine via the first transmission system 12. Between the LP compressor 2 and the main fan rotor 8 is arranged the second power transmission system. The intermediate shaft 10 mechanically connects the first and the second power transmission systems.

The first and / or the second power transmission system are similar to those presented in the first embodiment.

According to a variant of this previous embodiment illustrated in Figure 6, the main fan rotor 8 is disposed upstream of the compressor BP. The rotor of the blower 8 is integral with the shaft of the LP compressor and is driven directly by the LP turbine. An auxiliary blower 9 is disposed along an axis XY offset with respect to the longitudinal axis XX of the gas generator. The second power transmission system 11 is arranged downstream of the LP turbine. This is mechanically connected to the first power transmission system 12 via the intermediate shaft 10.

According to another embodiment illustrated in FIG. 7, the propulsion unit 1 comprises an HP body and a BP body along the longitudinal axis XX. A free power turbine 7 is also disposed along the axis XX and downstream of the LP turbine. The free power turbine 7 is rotated by the gases of the gas generator independently of the BP and HP bodies. Three blowers are arranged upstream of the compressor of the gas generator formed by the BP and HP bodies. In particular, the propulsion unit 1 comprises a main blower 8 mounted along the axis of the gas generator and driven by the free power turbine 7 and two auxiliary blowers 9, 9 'arranged on either side of the blower 8. The auxiliary blowers 9, 9 'are each respectively mounted along an axis XY and XY' offset with respect to the longitudinal axis XX. The auxiliary blowers 9, 9 'are rotated by the free power turbine 7. Each auxiliary blower rotor 9, 9' is mechanically connected to a first power transmission system. The main fan rotor 8 is mechanically connected to the second power transmission system arranged upstream of the LP compressor 2. First and second radial intermediate shafts connect respectively the first power transmission systems to the second power transmission system.

The first and / or the second power transmission system are similar to those presented in the first embodiment.

According to a variant of the previous embodiment illustrated in FIG. 8, the propulsion assembly also comprises three blowers. The main blower is arranged upstream of the gas generator and is rotated by the free power turbine 7 along the longitudinal axis XX. The two auxiliary blowers 9, 9 'are respectively mounted along the axes XY, XY' offset with respect to the axis XX. The second power transmission system 12 is arranged downstream of the free power turbine 7. The first power transmission systems of the remote auxiliary blowers 9, 9 'are mechanically connected to the second power transmission system via intermediate shafts 10 , 10 '.

In Figure 9 is shown another embodiment of a propulsion assembly. Here, the assembly comprises an HP body and a BP body forming a gas generator. The rotor of the main blower 8 is integral with the BP shaft of the LP compressor and is driven by the LP turbine. The second power transmission system is mounted upstream of the LP compressor and is connected to two remote auxiliary blowers 9, 9 '. In particular, each auxiliary blower 9, 9 'is connected to a first power transmission system which is itself connected to the second power transmission system via intermediate shafts 10, 10'.

The first and / or the second power transmission system are similar to those presented in the first embodiment.

According to a variant of this previous embodiment illustrated in FIG. 10, the main fan rotor is disposed upstream of the compressor BP. The second power transmission system is arranged downstream of the LP turbine. This is mechanically connected to two auxiliary blowers 9,9 'mounted on an axis offset from the axis XX of the gas generator via first power transmission system.

Thus, these different configurations make it possible to simplify the design of a propulsion system with distributed propulsion by keeping a known architecture on which at least one additional fan module is integrated. The ejection flow of the generator is covered by the ejection flow of the main blower, the reduced speed delta between the two ejection flows makes it possible to reduce the shear effect of the air layers and considerably reduce the perceived jet noise. This configuration also meets current and future aeronautical noise standards.

Claims (7)

claims An assembly (1) for propelling an aircraft comprising: - at least one main turbine (5, 6, 7) mounted along a longitudinal axis (XX); at least one main blower (8) disposed along the longitudinal axis (XX) and driven in rotation by said main turbine; - At least one auxiliary turbine mounted along the longitudinal axis (XX), the auxiliary turbine being independent of the main turbine; and - at least one auxiliary blower (9, 9 ') with axis (XY, XY') offset relative to the longitudinal axis (XX) and driven by the auxiliary turbine. 2. Assembly (1) according to claim 1, characterized in that the auxiliary turbine comprises a free power turbine (7) driven by the gas generator and rotating the auxiliary blower. 3. Assembly (1) for propulsion according to any one of the preceding claims characterized in that it comprises two auxiliary blowers (9, 9 ') and two auxiliary turbines independent of each other and the main turbine. 4. assembly (1) propulsion according to any one of the preceding claims, characterized in that it comprises a first power transmission system (11) connected to the auxiliary blower (9, 9 ') and a second system of power transmission (12) connected to the first power transmission system, the second power transmission system being arranged: - downstream of the auxiliary turbine between the auxiliary turbine and the auxiliary blower, or - upstream of the auxiliary turbine between the auxiliary blower and the main blower. 5. The assembly (1) according to claim 4, characterized in that the first and / or the second power transmission system comprises a differential gear system. 6. Assembly (1) according to any one of claims 4 to 5, characterized in that the first and / or the second power transmission system comprises a speed reducer, the speed reducer being an epicyclic mechanism. 7. The assembly of any one of claims 4 to 6, characterized in that the first and / or the second power transmission system comprises in series two homokinetic joints with a slide connection.