AXIAL SWIRL DEVICE FOR TURBOMACHINE COMBUSTION CHAMBER.

Abstract

The invention relates to an axial swirling device (80') comprising: a first circular cylindrical ring (81') having a first diameter (D1) and extending about a longitudinal axis (L) so as to be traversed by said airflow (F) between an upstream longitudinal end and a downstream longitudinal end when said turbomachine (1) is in operation; a plurality of blades (83') extending longitudinally between a leading edge and a trailing edge, said leading edge being inclined with respect to said longitudinal axis (L) so as to define an inlet airflow angle, and said trailing edge being inclined with respect to said longitudinal axis (L) so as to define an outlet airflow angle, each of said blades extending radially over a height (h) between an inner surface of said first circular cylindrical ring. Figure 4.

Description

Title of the invention: AXIAL SWIRL DEVICE FOR CHAMBER TURBOMACHINE COMBUSTION. Scope of the invention

[0001] The present invention relates to the field of aircraft turbomachinery.

[0002] More particularly, the invention relates to a swirling device axial configured to be positioned close to the combustion chamber feed of an aircraft turbomachine. Prior art

[0003] Classically, a turbomachine comprises a gas generator on either side of which are arranged along a longitudinal axis of the turbomachine a low pressure compressor and a low pressure turbine, this gas generator comprising a high pressure compressor, a combustion chamber and a high pressure turbine.

[0004] The combustion chamber is, as is known, the element where a fuel mixes with an airflow passing through this turbomachine. Much work is being carried out to optimize this portion of the turbomachine, and in particular to improve the quality of combustion and to stabilize this combustion within the combustion chamber.

[0005] To achieve this, it is common to implement a swirling device at the combustion chamber feed to generate turbulence and a swirling burst.

[0006] Such a device thus makes it possible to improve many combustion parameters such as consumption or the space required to carry out this combustion, and also makes it possible to create a rotating flow in a more uniform way, which allows the combustion flame to be reduced in the combustion chamber and which thus offers the possibility of reducing the length of the combustion chamber along the longitudinal axis of this chamber.

[0007] However, the gyration, which is the ratio between the tangential velocity of the airflow introduced by the swirling device and the axial velocity of the airflow introduced by the swirling device, must be sufficiently high to generate a satisfactory level of turbulence. On the other hand, this satisfactory level of turbulence can cause vortex bursting near a fuel injector due to the axial velocity deficit at the center of the generated vortex. Such premature bursting can create a risk of backfire, particularly for certain fuel types that prove to be very reactive, and can also cause a high pressure drop, which is not acceptable.

[0008] There is therefore a need to provide a solution to address the problem of axial velocity deficit at the center of the generated vortex in order to limit or even eliminate the risks of premature vortex bursting. Description of the invention

[0009] The invention aims to remedy at least in part the aforementioned drawbacks relating to prior art techniques.

[0010] To this end, the invention relates to an axial swirl device for a turbomachine combustion chamber, said axial swirl device being configured to be positioned within said turbomachine in a mounting position in which said axial swirl device is traversed by an airflow F arriving axially on said axial swirl device and deviating axially downstream of said axial swirl device when said turbomachine is in operation, said axial swirl device comprising: - a first circular cylindrical ring having a first diameter DI and extending around a longitudinal axis L so as to be crossed by said axial airflow F between an upstream longitudinal end and a downstream longitudinal end when said turbomachine is in operation; - a plurality of blades extending longitudinally between a leading edge and a trailing edge, said leading edge being inclined with respect to said longitudinal axis L so as to define an angle of inlet airflow, and said trailing edge being inclined with respect to said longitudinal axis L so as to define an angle of outlet airflow, each of said blades extending radially over a height between an inner surface of said first circular cylindrical ring and a predefined distance from said longitudinal axis L.

[0011] Thus, the proposed solution makes it possible to push the vortex bursting downstream of the axial vortex device and therefore to reduce the level of gyration and thus the axial velocity deficit at the center of the vortex, which not only reduces the pressure loss, but also reduces the risk of flashback, while maintaining significant levels of gyration on the periphery, which are favorable to combustion quality.

[0012] According to a particular aspect of at least one embodiment of the invention, for each blade, the outlet airflow angle exhibits an angular variation in absolute value between 20° and 50° relative to the inlet airflow angle so that the inclination of said trailing edge differs from the inclination of said leading edge.

[0013] This angular variation may depend on the type of application and the need for the axial swirling device to impose a change of direction on the axial airflow F between upstream and downstream.

[0014] According to a particular aspect of at least one embodiment of the invention, for each blade, the angular variation is unequal over the height of the blade.

[0015] In other words, the inlet airflow angle varies along the vein height, and therefore the axial airflow deflection F of the inlet varies along the vein height. Furthermore, the outlet airflow angle varies along the vein height, and therefore the axial airflow deflection F of the outlet also varies along the vein height.

[0016] According to a particular aspect of at least one embodiment of the invention, for each blade the angular variation in the vicinity of a center of the axial swirling device is less than or equal to 20° in absolute value.

[0017] According to a particular aspect of at least one embodiment of the invention, the axial swirling device further comprises a second circular cylindrical ring concentric with said first circular cylindrical ring and having a second diameter D2 smaller than said first diameter Dl, said vanes extending radially from an inner surface of said first circular cylindrical ring to an outer surface of said second circular cylindrical ring.

[0018] According to a particular aspect of at least one embodiment of the invention, said second diameter D2 has a dimensional ratio with respect to said first diameter Dl of between 0.05 and 0.5.

[0019] According to a particular aspect of at least one embodiment of the invention, the axial swirling device further comprises a third circular cylindrical ring concentric with said first circular cylindrical ring and having a third diameter D3 lower than said second diameter D2, said vanes extending radially from an inner surface of said first circular cylindrical ring to an outer surface of said second circular cylindrical ring, said third circular cylindrical ring being connected to said second circular cylindrical ring by means of fins extending radially from an inner surface of said second circular cylindrical ring to an outer surface of said third circular cylindrical ring.

[0020] According to a particular aspect of at least one embodiment of the invention, the axial swirling device comprises a central body, said first circular cylindrical ring being positioned around said central body, and further comprising an auxiliary circular cylindrical ring positioned around said central body and in contact with said central body, axially downstream of said first circular cylindrical ring, and further comprising a plurality of auxiliary blades extending radially outwards from an outer surface of said auxiliary circular cylindrical ring.

[0021] According to a particular aspect of at least one embodiment of the invention, said plurality of auxiliary blades extends radially outwards so that said circular auxiliary cylindrical ring has a diameter less than said first diameter Dl.

[0022] According to a particular aspect of at least one embodiment of the invention, said ancillary circular cylindrical ring has a diameter D4 less than half of said first diameter Dl.

[0023] According to a particular aspect of at least one embodiment of the invention, said auxiliary blades are oriented with respect to said longitudinal axis L at an angle between -10° and 10°.

[0024] The invention also relates to a turbomachine comprising a combustion chamber assembly including at least one axial swirling device according to one of the aforementioned embodiments, said at least one axial swirling device being positioned within said turbomachine in a mounting position in which said axial swirling device is traversed by an airflow F arriving axially on said axial swirling device and moving away axially downstream of said axial swirling device when said turbomachine is in operation. Presentation of the figures

[0025] The invention, as well as its various advantages, will be more easily understood in the light of the following description of several illustrative and non-limiting embodiments thereof, and the accompanying drawings, among which: [Fig.1] is a schematic cross-sectional view of an aircraft turbomachine; [Fig.2] is a perspective view illustrating an assembly according to a first embodiment of the invention; [Fig.3A] and [Fig.3B] are respectively front and perspective views of an axial swirling device according to the first embodiment of the invention; [Fig.4A] and [Fig.4B] are respectively front and perspective views of an axial swirling device according to a second embodiment of the invention; [Fig.5A] and [Fig.5B] are respectively front and perspective views of an axial swirling device according to a third embodiment of the invention; [Fig.6A] and [Fig.6B] are respectively front and perspective views of an axial swirling device according to a fourth embodiment of the invention; [Fig.7A] and [Fig.7B] are respectively front and perspective views of an axial swirling device according to a fifth embodiment of the invention, and [Fig.8A] and [Fig.8B] are respectively front and perspective views of an axial swirling device according to a sixth embodiment of the invention.

[0026] Detailed description of an embodiment of the invention

[0027] With reference to [Fig. 1], a twin-spool, high-bypass turbofan engine 1 is shown. As described previously, a turbofan engine 1 conventionally comprises a gas generator 2 on either side of which are arranged a low-pressure compressor 4 and a low-pressure turbine 12. This gas generator 2 includes a high-pressure compressor 6, a combustion chamber 8, and a high-pressure turbine 10. Hereafter, the terms "front" and "rear" are considered in a direction 14 opposite to the main gas flow direction within the turbofan engine, this direction 14 being parallel to its longitudinal axis 3. Conversely, the terms "upstream" and "downstream" are considered in the main gas flow direction within the turbofan engine.

[0028] The low-pressure compressor 4 and the low-pressure turbine 12 form a low-pressure unit and are connected to each other by a low-pressure shaft 11 centered on the axis 3. Similarly, the high-pressure compressor 6 and the high-pressure turbine 10 form a high-pressure unit and are connected to each other by a high-pressure shaft 13 centered on the axis 3 and arranged around the low-pressure shaft 11. The shafts are supported by rolling bearings 19, which are lubricated by being arranged in oil chambers. The same applies to the blower hub 17, which is also supported by rolling bearings 19.

[0029] The turbojet 1 also includes, at the front of the gas generator 2 and the low-pressure compressor 4, a single fan 15 which is arranged here directly at the rear of an engine air inlet cone. The fan 15 is rotatable about axis 3 and surrounded by a fan housing. In [Fig. 1], it is not driven. directly by the low-pressure shaft 11, but only indirectly driven by this shaft via a reduction gear 20, which allows it to rotate at a slower speed. Nevertheless, a solution with direct drive of the blower 15, by the low-pressure shaft 11, falls within the scope of the invention.

[0030] Furthermore, the turbojet 1 defines a primary stream 16 configured to be traversed by a primary flow, and a secondary stream 18 configured to be traversed by a secondary flow located radially outwards with respect to the primary flow, the fan flow thus being divided. As is known to those skilled in the art, the secondary stream 18 is delimited radially outwards in part by an outer shell 23, preferably metallic, extending rearwards from the fan casing.

[0031] Although not shown, the turbojet 1 is equipped with a set of equipment, for example, a fuel pump, hydraulic pump, alternator, starter, variable stator timing (VSV) actuator, wastegate actuator, and a power generator. This includes equipment for lubricating the gearbox 19. This equipment is driven by an accessory gearbox or AGB (not shown), which is also lubricated.

[0032] Downstream of the blower 15, in the secondary channel 18, a ring of guide vanes is provided, which are in this case outlet guide vanes 24 (or OGVs, from the English "Outlet Guide Vane"). These stator vanes 24 connect the outer shell 23 to a housing 26 surrounding the low-pressure compressor 4. They are spaced circumferentially from each other and allow the secondary flow to be straightened after it passes through the blower 15. In addition, these vanes 24 can also fulfill a structural function, as is the case in the embodiments described herein. They ensure the transfer of forces from the reducer and bearings 19 of the motor shafts and the fan hub, to the outer shell 23. Then, these forces can pass through a motor attachment 30 fixed to the shell and connecting the turbojet to a mounting mast (not shown) of the aircraft.

[0033] Finally, the outlet guide vanes 24 provide a third heat exchanger function between the secondary airflow passing through the vane ring, and the lubricant circulating inside these vanes 24. The lubricant intended to be cooled by the outlet guide vanes 24 is that used in particular for the lubrication of the reducer 19.

[0034] As discussed previously, the combustion chamber is where fuel mixes with an airflow passing through this turbomachine. To improve combustion quality and stabilize combustion within the combustion chamber, the invention provides for the implementation of at least an axial swirling device within a turbomachine combustion chamber assembly 1.

[0035] A first embodiment of the invention is now presented in relation to Figures 2 to 3B.

[0036] The combustion chamber assembly therefore comprises at least one axial swirl device 80 which is positioned within the turbomachine, here around a central body 100 in a mounting position. In this mounting position, the axial swirl device 80 is traversed by an airflow F arriving axially on the axial swirl device 80 and moving axially away downstream of the axial swirl device 80 when the turbomachine is in operation.

[0037] In order to push the vortex bursting downstream of the axial vortex device and thus reduce the level of gyration and therefore the axial velocity deficit at the center of the vortex, the assembly further includes an axial vortex device 80 positioned around the central body 100 so as to be traversed by an axial airflow F.

[0038] It should be noted that the central body may, for example, have a circular cylindrical shape, or an ogival shape.

[0039] As can be seen more particularly in Figures 3A and 3B, the axial swirling device 80 according to this embodiment comprises: - a first circular cylindrical ring 81 having a first diameter DI and extending around the longitudinal axis L so as to be crossed by the axial airflow F between an upstream longitudinal end and a downstream longitudinal end when the turbomachine is in operation; - a plurality of blades 83 extend longitudinally between a leading edge and a trailing edge and extend radially over a height h between an inner surface of the first circular cylindrical ring 81 up to a predefined distance from the longitudinal axis L.

[0040] More specifically, in this embodiment, the blades are uniformly distributed around the circumference of the first circular cylindrical ring. They are inclined with respect to the axial direction of the flow F in order to deflect it. More specifically, the leading edge is inclined with respect to the longitudinal axis L so as to define an inlet airflow angle. Furthermore, the trailing edge is inclined with respect to the longitudinal axis L so as to define an outlet airflow angle.

[0041] As illustrated, in this embodiment, the axial swirling device further comprises a second concentric circular cylindrical ring 82 with the first circular cylindrical ring 81 and having a second diameter D2 smaller than the first diameter Dl.

[0042] This second circular cylindrical ring is positioned here so that an inner surface of this second cylindrical ring 82 is in contact with the central body.

[0043] Furthermore, in this embodiment, the blades 83 extend radially from an inner surface of the first circular cylindrical ring 81 to an outer surface of the second circular cylindrical ring 82.

[0044] Therefore, in this embodiment, the predefined distance from the longitudinal axis L corresponds to the radius of the second circular cylindrical ring 82.

[0045] In addition, the height h of each of the blades 83 corresponds in this embodiment to the radial distance between the first circular cylindrical ring and the second circular cylindrical ring.

[0046] In this embodiment, the second diameter D2 has a dimensional ratio, otherwise called dimensional ratio, with respect to the first diameter which is between 0.05 and 0.5.

[0047] In other words, the second diameter D2 has a dimension between 5% of the first diameter Dl and 50% of the first diameter Dl.

[0048] A second embodiment of the invention is now presented in relation to Figures 4A and 4B.

[0049] As illustrated in these figures, in this embodiment, the axial swirling device 80' comprises: - a first circular cylindrical ring 81' having a first diameter Dl and extending around the longitudinal axis L so as to be crossed by the axial airflow F between an upstream longitudinal end and a downstream longitudinal end when the turbomachine is in operation; - a plurality of blades 83' extend longitudinally between a leading edge and a trailing edge and extend radially over a height h between an inner surface of the first circular cylindrical ring 81' up to a predefined distance from the longitudinal axis L.

[0050] More particularly in this embodiment, the blades 83' are uniformly distributed around the circumference of the first circular cylindrical ring. They are inclined with respect to the axial direction of the flow F so as to deflect it. More specifically, the leading edge is inclined with respect to the longitudinal axis L so as to define an inlet airflow angle. Furthermore, the trailing edge is inclined with respect to the longitudinal axis L so as to define an outlet airflow angle.

[0051] In this embodiment, for each blade, the outlet airflow angle has an angular variation in absolute value of 20° to 50° with respect to the inlet airflow angle so that the inclination of said trailing edge differs from the inclination of said leading edge.

[0052] More precisely, here, the angular variation is included, in absolute value, between 20° and 50°, between the angle of inlet air flow and the angle of outlet air flow.

[0053] This angular variation may in particular depend on the type of application and the need of the axial swirling device to impose a change of direction on the axial airflow F between upstream and downstream.

[0054] Moreover, and as can be seen more particularly in [Fig.4B], the angular variation is uneven over the height of the blade.

[0055] In other words, the inlet airflow angle varies along the vein height, and therefore the axial airflow deflection F of the inlet varies along the vein height. Furthermore, the outlet airflow angle varies along the vein height, and therefore the axial airflow deflection F of the outlet also varies along the vein height.

[0056] Furthermore, this variation in the inclination of the leading edge and trailing edge is evolutionary so that the curve tilts more and more in the same direction without twisting.

[0057] In other words, the variation of the inclination is achieved by increasing the inclination in the same direction along the entire height of the blade.

[0058] Here, for each blade the angular variation at the location of a center of the axial swirling device is less than or equal to 20° in absolute value so as to limit the disturbances near the central body.

[0059] Here, the axial swirling device further comprises a second circular cylindrical ring 82' concentric with the first circular cylindrical ring 81' and having a second diameter D2 smaller than the first diameter Dl.

[0060] This second circular cylindrical ring is positioned here so that an inner surface of this second cylindrical ring 82' is in contact with the central body (not shown).

[0061] Furthermore, in this embodiment, the blades 83' extend radially from an inner surface of the first circular cylindrical ring 81' to an outer surface of the second circular cylindrical ring 82'.

[0062] Therefore, in this embodiment, the predefined distance from the longitudinal axis L corresponds to the radius of the second circular cylindrical ring 82'.

[0063] In addition, the height h of each of the blades 83' corresponds in this embodiment to the radial distance between the first circular cylindrical ring 81' and the second circular cylindrical ring 82'.

[0064] Thus, the angular variation in the vicinity of the second cylindrical ring is less than or equal to 20° in absolute value.

[0065] In this embodiment, the second diameter D2 has a dimensional ratio with respect to the first diameter which is between 0.05 and 0.5.

[0066] A third embodiment of the invention is now presented in relation to Figures 5A and 5B.

[0067] As illustrated in these figures, in this embodiment, the axial swirling device 80'' comprises: - a first circular cylindrical ring 81” having a first diameter DI and extending around the longitudinal axis L so as to be crossed by the axial airflow F between an upstream longitudinal end and a downstream longitudinal end when the turbomachine is in operation; - a plurality of blades 83” extend longitudinally between a leading edge and a trailing edge and extend radially over a height h' between an inner surface of the first circular cylindrical ring 81” up to a predefined distance from the longitudinal axis L.

[0068] In this embodiment as well, the 83” blades are uniformly distributed around the circumference of the first circular cylindrical ring. They are inclined relative to the axial flow direction F in order to deflect it. More specifically, the leading edge is inclined relative to the longitudinal axis L so as to define an inlet airflow angle. Furthermore, the trailing edge is inclined relative to the longitudinal axis L so as to define an outlet airflow angle.

[0069] As illustrated, in this third embodiment the axial swirling device does not include another circular cylindrical ring.

[0070] This axial swirling device also does not include a central body.

[0071] Therefore, in this third embodiment, the 83” blades have a free end and extend up to a predefined distance from the longitudinal axis L between 90% of the first diameter DI and 55% of the first diameter Dl.

[0072] In addition, the height h' of each of the 83” blades is equivalent for each of the 83” blades and is between 10% of the first diameter Dl and 45% of the first diameter Dl.

[0073] A fourth embodiment of the invention is now presented in relation to Figures 6A and 6B.

[0074] As illustrated in these figures, in this embodiment, the axial swirling device 80' ' ' comprises: - a first circular cylindrical ring 81"' having a first diameter DI and extending around the longitudinal axis L so as to be crossed by the axial airflow F between an upstream longitudinal end and a downstream longitudinal end when the turbomachine is in operation; - a plurality of blades 83'" extend longitudinally between a leading edge and a trailing edge and extend radially over a height h' between an inner surface of the first circular cylindrical ring 81'" up to a predefined distance from the longitudinal axis L.

[0075] More particularly in this embodiment, the blades 83" are uniformly distributed around the circumference of the first circular cylindrical ring 81". They are inclined with respect to the axial flow direction F in order to deflect the flow. More specifically, the leading edge is inclined with respect to the longitudinal axis L so as to define an inlet airflow angle. Furthermore, the trailing edge is inclined with respect to the longitudinal axis L so as to define an outlet airflow angle.

[0076] Here, the axial swirling device further comprises a second circular cylindrical ring 82”’’ concentric with the first circular cylindrical ring 81’” and having a second diameter D2’ lower than the first diameter Dl.

[0077] As illustrated, the blades 83” extend radially from an inner surface of the first circular cylindrical ring 81”’ to an outer surface of the second circular cylindrical ring 82”’.

[0078] Therefore, in this embodiment, the predefined distance from the longitudinal axis L corresponds to the radius of the second circular cylindrical ring 82”’.

[0079] Furthermore, the height h' of each of the blades 83'” corresponds in this embodiment to the radial distance between the first circular cylindrical ring 81'” and the second circular cylindrical ring 82'”.

[0080] In this embodiment, the second diameter D2' has a dimensional ratio with respect to the first diameter Dl which is between 0.05 and 0.5.

[0081] Thus, in this embodiment, the axial swirling device is similar to the axial swirling device of the third embodiment but with the presence of a second circular cylindrical ring.

[0082] Also, in this embodiment, the axial swirling device is similar to the axial swirling device of the first embodiment but with the second circular cylindrical ring having a larger diameter D2' and blades having a smaller radial height h', and without a central body.

[0083] A fifth embodiment of the invention is now presented in relation to Figures 7A and 7B.

[0084] As illustrated in these figures, in this embodiment, the axial swirling device 80”” comprises: - a first circular cylindrical ring 81”” having a first diameter DI and extending around the longitudinal axis L so as to be crossed by axial airflow F between an upstream longitudinal end and a downstream longitudinal end when the turbomachine is in operation; - a plurality of blades 83”” extend longitudinally between a leading edge and a trailing edge and extend radially over a height h' between an inner surface of the first circular cylindrical ring 81”” up to a predefined distance from the longitudinal axis L.

[0085] More particularly in this embodiment, the blades 83”” are uniformly distributed around the circumference of the first circular cylindrical ring 81””. They are inclined with respect to the axial direction of the flow F so as to deflect it. More specifically, the leading edge is inclined with respect to the longitudinal axis L so as to define an inlet airflow angle. Furthermore, the trailing edge is inclined with respect to the longitudinal axis L so as to define an outlet airflow angle.

[0086] Here, the axial swirling device further comprises a second circular cylindrical ring 82”” concentric with the first circular cylindrical ring 81”” and having a second diameter D2' lower than the first diameter Dl.

[0087] As illustrated, the blades 83”” extend radially from an inner surface of the first circular cylindrical ring 81”” to an outer surface of the second circular cylindrical ring 82””.

[0088] Therefore, in this embodiment, the predefined distance from the longitudinal axis L corresponds to the radius of the second circular cylindrical ring 82”.

[0089] Furthermore, the height h' of each of the blades 83”” corresponds in this embodiment to the radial distance between the first circular cylindrical ring 81”” and the second circular cylindrical ring 82””.

[0090] In this embodiment, the second diameter D2' has a dimensional ratio with respect to the first diameter Dl which is between 0.05 and 0.5.

[0091] As can be seen in Figures 7A and 7B, the axial swirling device further comprises a third circular cylindrical ring 84”” concentric with the first circular cylindrical ring 81”” and having a third diameter D3 smaller than the second diameter D2' of the second circular cylindrical ring 82’”.

[0092] An inner surface of this third cylindrical ring 84”” is configured to be in contact with the central body (not shown).

[0093] This third circular cylindrical ring 84” is connected to the second circular cylindrical ring 82”” by means of fins 85”” extending radially from an inner surface of the second circular cylindrical ring 82”” to an outer surface of the third circular cylindrical ring 84””.

[0094] More particularly, in this embodiment, the third circular cylindrical ring 84”” is connected to the second circular cylindrical ring 82”” by means of three circumferentially uniformly distributed fins 85”” extending radially from an inner surface of the second circular cylindrical ring 82”” to an outer surface of the third circular cylindrical ring 84”””.

[0095] Thus, in this fifth embodiment, the axial swirling device is similar to the axial swirling device of the fourth embodiment but with the presence of a third circular cylindrical ring, and with a central body (not shown).

[0096] A sixth embodiment of the invention is now presented in relation to Figures 8A and 8B.

[0097] As illustrated in these figures, in this embodiment, the axial swirling device 800 comprises: - a first circular cylindrical ring 81 having a first diameter DI and extending around the longitudinal axis L so as to be crossed by the axial airflow F between an upstream longitudinal end and a downstream longitudinal end when the turbomachine is in operation; - a plurality of blades 83 extend longitudinally between a leading edge and a trailing edge and extend radially over a height h between an inner surface of the first circular cylindrical ring 81 up to a predefined distance from the longitudinal axis L.

[0098] More specifically, in this embodiment, the blades are uniformly distributed around the circumference of the first circular cylindrical ring. They are inclined with respect to the axial flow direction F in order to deflect it. More specifically, the leading edge is inclined with respect to the longitudinal axis L so as to define an inlet airflow angle. Furthermore, the trailing edge is inclined with respect to the longitudinal axis L so as to define an outlet airflow angle.

[0099] As illustrated, in this embodiment, the axial swirling device further comprises a second circular cylindrical ring 82 concentric with the first circular cylindrical ring 81 and having a second diameter D2 smaller than the first diameter Dl.

[0100] This second circular cylindrical ring is positioned here so that an inner surface of this second cylindrical ring 82 is in contact with the central body.

[0101] Furthermore, in this embodiment, the blades 83 extend radially from an inner surface of the first circular cylindrical ring 81 to an outer surface of the second circular cylindrical ring 82.

[0102] Therefore, in this embodiment, the predefined distance from the longitudinal axis L corresponds to the radius of the second circular cylindrical ring 82.

[0103] In addition, the height h of each of the blades 83 corresponds in this embodiment to the radial distance between the first circular cylindrical ring and the second circular cylindrical ring.

[0104] In this embodiment, the second diameter D2 has a dimensional ratio with respect to the first diameter Dl which is between 0.05 and 0.5.

[0105] In this sixth embodiment, and as illustrated in Figures 8A and 8B, the axial swirling device 800 further comprises an auxiliary circular cylindrical ring 86 to be positioned around the central body 100 and in contact with this central body 100, axially downstream of the first circular cylindrical ring 81.

[0106] This circular cylindrical ring 86 annex can for example be positioned downstream of the first circular cylindrical ring 81 at a distance between 1% of the first diameter Dl and 300% of the first diameter Dl.

[0107] Furthermore, and as illustrated, the axial swirling device 800 comprises a plurality of auxiliary blades 87 extending radially outwards from an outer surface of the auxiliary circular cylindrical ring 86.

[0108] These auxiliary blades 87 can for example have a height h which is between 5% of the first diameter Dl and 50% of the first diameter Dl from an external surface of this auxiliary circular cylindrical ring.

[0109] In other words, the plurality of auxiliary blades 87 can extend radially outwards so that the circular cylindrical auxiliary ring 86 has a diameter less than half of the first diameter Dl.

[0110] These auxiliary blades 87 can for example be oriented with respect to the longitudinal axis L at an angle between -10° and 10° and Y.

[0111] As for the circular cylindrical crown annexed 86, it has a diameter D4 which is less than the first diameter Dl.

[0112] In this embodiment, the diameter D4 of the circular cylindrical ring annexed 86 is equal to the second diameter D2 of the second circular cylindrical ring 82.

[0113] However, embodiments could be envisaged in which the radius of the central body is not axially constant, with therefore a diameter D4 that is not axially constant.

Claims

1.

2. Demands Axial swirl device (80, 80', 80”, 80'”, 80””, 800) for a turbomachine combustion chamber (1), said axial swirl device (80, 80', 80”, 80'”, 80””, 800) being configured to be positioned within said turbomachine (1) in a mounting position in which said axial swirl device (80, 80', 80”, 80'”, 80””, 800) is traversed by an airflow F arriving axially on said axial swirl device (80, 80', 80”, 80'”, 80””, 800) and departing axially downstream of said axial swirl device (80, 80', 80”, 80”', 80””, 800) when said turbomachine (1) is in operation, said axial swirl device (80, 80', 80”, 80'”, 80””, 800) including: - a first circular cylindrical ring (81, 81', 81”, 81'”, 81””) having a first diameter (Dl) and extending around a longitudinal axis (L) so as to be crossed by said air flow (F) between an upstream longitudinal end and a downstream longitudinal end when said turbomachine (1) is in operation; - a plurality of blades (83, 83', 83”, 83”', 83””) extending longitudinally between a leading edge and a trailing edge, said leading edge being inclined with respect to said longitudinal axis (L) so as to define an inlet airflow angle, and said trailing edge being inclined with respect to said longitudinal axis (L) so as to define an outlet airflow angle, each of said blades extending radially over a height (h) between an inner surface of said first circular cylindrical ring (81, 81', 81”, 81”', 81””) up to a predetermined distance from said longitudinal axis (L). Axial swirling device (80, 80', 80”, 80'”, 80””, 800) according to claim 1, characterized in that, for each blade (83'), the outlet airflow angle has an angular variation in absolute value of 20° to 50° with respect to the inlet airflow angle so that the inclination of said trailing edge differs from the inclination of said leading edge.

3. Axial swirling device (80, 80', 80”, 80'”, 80””, 800) according to the preceding claim, characterized in that the angular variation is unequal over said height (h) of said blade (83').

4. Axial swirling device (80, 80', 80”, 80'”, 80””, 800) according to any one of claims 1 to 3, characterized in that it further comprises a second circular cylindrical ring (82, 82', 82”', 82””) concentric with said first circular cylindrical ring (81, 81', 81”', 81””) and having a second diameter (D2) smaller than said first diameter (D1), said vanes (83, 83', 83”', 83””) extending radially from an inner surface of said first circular cylindrical ring (81, 81', 81’”, 81””) to an outer surface of said second circular cylindrical ring (82, 82', 82”', 82””).

5. Axial swirling device (80, 80', 80”, 80'”, 80””, 800) according to claim 4, characterized in that said second diameter (D2) has a dimensional ratio with respect to said first diameter (Dl) between 0.05 and 0.

5.

6. Axial swirling device (80, 80', 80”, 80'”, 80””, 800) according to any one of claims 4 or 5, characterized in that it further comprises a third circular cylindrical ring (84””) concentric with said first circular cylindrical ring (81””) and having a third diameter (D3) smaller than said second diameter (D2), said vanes (83””) extending radially from an inner surface of said first circular cylindrical ring (81””) to an outer surface of said second circular cylindrical ring (82””), said third circular cylindrical ring (84””) being connected to said second circular cylindrical ring (82””) by means of fins (85””) extending radially from an inner surface of said second circular cylindrical ring (82””) to an outer surface of said third circular cylindrical ring (84””).

7. An axial swirling device (80, 80', 80”, 80'”, 80””, 800) according to any one of the preceding claims, characterized in that it comprises a central body (100), said first circular cylindrical ring (81) being positioned around said central body (100), and in that it further comprises an auxiliary circular cylindrical ring (86) positioned around said body central (100) and in contact with said central body (100), axially downstream of said first circular cylindrical ring (81), and in that it comprises a plurality of auxiliary blades (87) extending radially outwards from an outer surface of said auxiliary circular cylindrical ring (86).

8. Axial swirling device (80, 80', 80”, 80'”, 80””, 800) according to the preceding claim, characterized in that said plurality of auxiliary blades (87) extends radially outwards so that said auxiliary circular cylindrical ring (86) has a diameter less than said first diameter (Dl).

9. Axial swirling device (80, 80', 80”, 80'”, 80””, 800) according to the preceding claim, said ancillary circular cylindrical ring (86) having a diameter (D4) less than half of said first diameter (Dl).

10. Axial swirling device (80, 80', 80”, 80'”, 80””, 800) according to any one of claims 7 to 9, said auxiliary vanes (87) being oriented with respect to said longitudinal axis (L) at an angle between -10° and 10°.

11. Turbomachine comprising a combustion chamber assembly including at least one axial swirl device (80, 80', 80”, 80”', 80””, 800) according to any one of claims 1 to 10, said at least one axial swirl device (80, 80', 80”, 80”', 80””, 800) being positioned within said turbomachine (1) in a mounting position in which said at least one axial swirl device (80, 80', 80”, 80”', 80””, 800) is traversed by an airflow F arriving axially on said at least one axial swirl device (80, 80', 80”, 80”', 80””, 800) and deviating axially downstream of said at least one axial swirl device (80, 80', 80”, 80'”, 80””, 800) when said turbomachine (1) is in operation.

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