AIR-CONDITIONING SYSTEM FOR AN AIRCRAFT CABIN, COMPRISING A TURBOMACHINE PROVIDED WITH A RADIAL TURBINE DISTRIBUTOR

Abstract

The invention relates to an air conditioning system for an aircraft comprising a turbine engine comprising at least one radial turbine and a compressor, said radial turbine extending along a central axis (10) and comprising a wheel (20) equipped with vanes (21) mounted so as to be able to rotate about said central axis (10), a nozzle (30) arranged at the periphery of said wheel (20) comprising a plurality of variable-pitch blades (31) arranged around said central axis (10), and a volute (12) comprising an air inlet (12a) and an air outlet (12b) opening onto said plurality of variable-pitch blades (31), characterized in that said variable-pitch blades (31) are arranged around said central axis (10) between two nozzle casing walls (11a, 11b) delimiting an air passage section of said nozzle between them, each variable-pitch blade (31) further comprising means for axial displacement of the blade between the two casing walls (11a, 11b).

Claims

1. An air conditioning system for an aircraft comprising a turbine engine comprising at least one radial turbine and a compressor, said radial turbine extending along a central axis and comprising a wheel equipped with vanes mounted so as to be able to rotate about said central axis, a nozzle arranged at the periphery of said wheel comprising a plurality of variable-pitch blades arranged around said central axis, and a volute comprising an air inlet and an air outlet opening onto said plurality of variable-pitch blades, characterized in that said variable-pitch blades are arranged around said central axis between two nozzle casing walls delimiting an air passage section of said nozzle between them, each variable-pitch blade further comprising means for axial displacement of the blade between the two casing walls.

2. The system according to claim 1, wherein each variable-pitch blade of said nozzle further comprises means for pivoting the blade about a pivot axis which are coupled to said means for axial displacement of the blade between the two casing walls so that each blade can, upon actuation of said axial displacement means and said pivoting means by control means, be simultaneously pivoted about said pivot axis and displaced axially between the two casing walls, so as to be able to modify the air passage section from upstream to downstream of the nozzle.

3. The system according to claim 2, wherein each variable-pitch blade of said nozzle is secured to a threaded shaft extending parallel to said central axis along said pivot axis, and cooperating with at least one combined internal thread formed in one of said casing walls so that this blade can, upon actuation of said threaded shaft by said control means, be simultaneously pivoted about said pivot axis and displaced axially between the two housing walls, this threaded shaft forming said means for axial displacement of the blade and said means for pivoting of the blade.

4. The system according to claim 3, wherein said threaded shaft of each variable-pitch blade of said nozzle extends on either side of said blade so as to be able to cooperate with two combined internal threads which are formed respectively in each of the two nozzle casing walls.

5. The system according to claim 3, wherein said control means of said variable-pitch blades of said nozzle are configured to be able to simultaneously actuate the threaded shaft of each blade.

6. The system according to claim 3, wherein said threaded shaft of each blade of said nozzle has a non-regular thread so as to be able to define a law for controlling the displacement of the non-linear blade.

7. The system according to claim 1, wherein said nozzle comprises at least twelve variable-pitch blades which are evenly distributed around the central axis.

8. An aircraft comprising at least one cabin supplied with air at a temperature and pressure controlled by an air conditioning system, wherein said air conditioning system comprises a turbine engine comprising at least one radial turbine and a compressor, said radial turbine extending along a central axis and comprising a wheel equipped with vanes mounted so as to be able to rotate about said central axis, a nozzle arranged at the periphery of said wheel comprising a plurality of variable-pitch blades arranged around said central axis, and a volute comprising an air inlet and an air outlet opening onto said plurality of variable-pitch blades, characterized in that said variable-pitch blades are arranged around said central axis between two nozzle casing walls delimiting an air passage section of said nozzle between them, each variable-pitch blade further comprising means for axial displacement of the blade between the two casing walls.

Description

5. LIST OF FIGURES

[0034] Further aims, features and advantages of the invention will become apparent upon reading the following description, which is provided solely by way of non-limiting example, and which refers to the appended figures, in which:

[0035] FIG. 1 is a schematic perspective view of a turbine of an air conditioning system according to one embodiment of the invention equipped with a nozzle according to one embodiment of the invention,

[0036] FIGS. 2a and 2b are partial perspective schematic views of a portion of the nozzle of an air conditioning system according to one embodiment of the invention,

[0037] FIGS. 3a and 3b are schematic sectional views of a portion of the nozzle of an air conditioning system according to one embodiment of the invention,

[0038] FIG. 4 is a partial schematic sectional view of the nozzle of an air conditioning system according to one embodiment of the invention in a longitudinal plane of the turbine along its axis of rotation,

[0039] FIG. 5 is a schematic perspective view of a turbine wheel and of a turbine nozzle of an air conditioning system according to one embodiment of the invention.

6. DETAILED DESCRIPTION OF AN EMBODIMENT OF THE INVENTION

[0040] For the sake of illustration and clarity, the scales and proportions are not strictly adhered to in the figures. Throughout the detailed description which follows with reference to the figures, unless otherwise indicated, each element of the nozzle is described as it is arranged when the nozzle is mounted on a turbine. This arrangement is shown in particular in FIG. 1.

[0041] In addition, identical, similar or analogous elements are denoted using the same reference signs throughout the figures.

[0042] FIG. 1 schematically illustrates a radial turbine of an air conditioning system according to one embodiment of the invention which extends along a central axis 10 and comprises a wheel 20 which is movable in rotation about the central axis 10 and a nozzle 30 arranged at the periphery of the wheel 20 on casings 11a, 11b (of which only the casing 11a is shown in FIG. 1). The wheel 20 is equipped with a plurality of vanes 21.

[0043] The turbine also includes a volute 12 (a half-volute of which is shown in FIG. 1), the diameter of which decreases between an inlet 12a and an outlet 12b which opens onto the nozzle 30.

The nozzle 30 also comprises a plurality of variable-pitch blades 31, each variable-pitch blade 31 being secured to a threaded shaft 32 which extends parallel to the central axis 10.

[0044] FIG. 5 schematically illustrates, in perspective, the wheel 20 and the nozzle 30 of the turbine according to one embodiment.

[0045] In FIGS. 1 and 5, the blades 31 of the nozzle are shown with a threaded shaft arranged in the vicinity of the leading edge of the blades while FIGS. 2a and 2b illustrate the threaded shaft arranged in the middle of the blades. Both embodiments are possible, as is the embodiment, not shown in the figures, according to which the threaded shaft is arranged in the vicinity of the trailing edge of the blade.

[0046] As shown in FIGS. 2a and 2b, each threaded shaft 32 of each blade 31 cooperates with at least one internal thread 33 formed in one of the casing walls 11a, 11b so that this blade 31 can, upon command from control means 40 (shown schematically in FIG. 4), be simultaneously pivoted about its pivot axis and displaced axially between the two casings 11a, 11b within the air stream, so as to modify the air passage section from upstream to downstream of the nozzle. This threaded shaft 32 and the combined internal thread 33 can be of any type.

[0047] The thread of the shaft 32 and the combined thread of the internal thread can be regular or irregular threads. The characteristics of the thread condition the displacement law of the blade in the air stream of the nozzle.

[0048] FIGS. 2a and 2b schematically illustrate the displacement principle of the blades 31 relative to one of the walls of the casing 11a. FIG. 2a illustrates the blades 31 in a screwed position of the blades, that is to say, a position in which the threaded shaft 32 of each blade 31 is screwed into the combined internal thread formed in the wall of the casing 11 a arranged opposite. FIG. 2b illustrates the same blades 31 in a deployed position, that is to say, a position in which the blades are simultaneously pivoted with respect to the position of FIG. 2a and displaced axially relative to the casing 11a.

[0049] Thus, a single control of the blades 31 makes it possible both to modify the angle of the blade 31 and the position of the blade in the air stream of the nozzle delimited by the two casings 11a, 11b.

[0050] FIGS. 3a and 3b schematically illustrate the blades 31 in section according to two possible embodiments of the invention. FIG. 3a illustrates an embodiment in which the blade 31 is carried by a threaded shaft 32 which cooperates with a combined internal thread formed in a single wall of the casing. FIG. 3b illustrates an embodiment in which the blade 31 is carried by two threaded shafts 32 which extend on either side of the blade and which each cooperate with a combined internal thread respectively formed in each wall of the casing.

[0051] FIG. 4 schematically illustrates the blade 31 and the control means 40 for setting the blade. These control means 40 for example comprise a shaft 41 which is mechanically connected to the threaded shaft 32. This mechanical connection can for example comprise arms, pinions, bearings which are connected to electric or electromagnetic actuators 42 making it possible to mechanically connect the control shaft 41 and the displacement shaft 32 of the blade 31. According to a preferred embodiment, a single actuator can be configured for all of the blades 31 of the nozzle.

[0052] The actuators 42 are controlled by a central control unit 50. This control can be of any type. According to one embodiment, the control depends on the information supplied by a pressure sensor 45. Thus, depending on the pressure measurements, the opening or closing of the blades 31 of the nozzle can be controlled.

[0053] An air conditioning system may also comprise a set of members enclosed in a casing and having air inlet and outlet connection ports and a dynamic air circulation channel, better known under the term of RAM air, through one or more heat exchangers. Such a pack can be the subject of numerous variant embodiments which are compatible with the invention. For example, it can comprise at least one air-cycle turbine engine which comprises a compressor and a turbine connected to one another by a rotating shaft. The turbine engine may also comprise a fan configured to ensure dynamic air circulation through the heat exchangers.

[0054] According to another variant, the turbine engine can comprise an electric motor so as to form an electric air conditioning pack. The pack may also comprise a water extraction loop and a turbine engine outlet pipe connected to a mixing chamber which opens into the cabin to be supplied with air at a controlled temperature and pressure. The turbine of the air cycle machine is, according to the invention, equipped with a nozzle according to the invention, which allows the turbine to ensure a wide range of air flow rates while delivering the maximum possible power over the entire operating range.

[0055] The principle of the invention could also be applied to a variable diffuser of a centrifugal compressor.