FR3139357A1 - TURBOMACHINE WITH SECONDARY AIR PIPE INCLUDING AN OIL REMOVAL SYSTEM - Google Patents

Abstract

The invention relates to an aircraft turbomachine (10), comprising an internal pipe (40) for supplying a secondary air system of said turbomachine and a de-oiling system (50) arranged between an upstream end (44). and a downstream end (42) of said pipe (40), said de-oiling system (50) comprising an axial inlet (52) of potentially oil-laden air and a first outlet (54) of de-oiled air supplying air secondary an internal cavity (42) of the turbomachine (10), and a second oil outlet (56), characterized in that the de-oiling system (50) comprises an inertial separator (60), supplied by the inlet of axial air (52), mounted in the pipe (40) upstream of the first axial air outlet (54), and configured to eliminate by inertia the suspended oil potentially contained in the air intended to circulate in the internal pipeline to the second oil outlet (56). Figure for abstract: Figure 3

Description

TURBOMACHINE WITH SECONDARY AIR PIPE INCLUDING AN OIL REMOVAL SYSTEM

The present invention relates to the secondary air systems of aeronautical turbomachines, and more particularly a secondary air system comprising a pipe which includes de-oiling means.

Traditionally, turbomachines include a main air system which is associated with the circulation of an air flow in an internal vein of the gas generator passing through its compressors, its combustion chamber and its turbines.

Turbomachines also include a secondary air system, which is supplied with pressurized air, taken from the main air flow at the compressor(s), and which is intended to perform different functions. These functions mainly concern the cooling of parts located in areas subject to high temperatures of the turbomachine such as turbine disks, and the pressurization of various strategic areas of the turbomachine such as, for example, internal enclosures containing lubricated bearings of rotors of the turbomachine.

Turbomachines also include lubrication systems comprising internal circuits in which oil circulates under pressure which is intended, for example, to ensure the lubrication of the rotor bearings previously mentioned.

In certain configurations, the secondary air systems and the lubrication systems are arranged in the same area of the turbomachine. This solution has the advantage of compactness but it also has the disadvantage, in the event of a leak from the lubrication system, of risking polluting the air circulating in the secondary air system and consequently causing droplets of oil suspended in the pressurized air of the secondary air system towards strategic areas of the turbomachine where its presence is not desired. For example, oil can be entrained to strategic areas such as internal cavities containing inside turbine disks, which are areas subject to high temperatures since the turbine disks are heated by combustion gases, and the introduction of oil into these areas can cause fires causing damage to these rotating parts or, in the worst case, their breakage and, in this case, the release of high energy parts such as blades. turbine or bladed disks.

It is therefore necessary to avoid the introduction of oil into the air circulating in strategic areas of the secondary air system in order to avoid such disadvantages.

An objective of the present invention is to propose a turbomachine comprising a secondary air system provided with a supply pipe comprising an integrated de-oiling system.

To this end, the invention relates to an aircraft turbomachine, comprising an internal pipeline for supplying a secondary air system of said turbomachine and a de-oiling system arranged between an upstream end and a downstream end of said pipeline, said de-oiling system comprising an axial inlet of potentially oil-laden air and a first outlet of de-oiled air supplying secondary air to an internal cavity of the turbomachine, and a second oil outlet.

According to the invention, the de-oiling system comprises an inertial separator, supplied by the axial air inlet, mounted in the pipe upstream of the first axial air outlet, and configured to eliminate the suspended oil by inertia potentially contained in the air intended to circulate in the internal pipe towards the second oil outlet.

The invention thus makes it possible to achieve the aforementioned objective. In particular, such a turbomachine according to the invention is equipped with a static de-oiling system and arranged upstream of an internal cavity of the turbomachine containing rotors. Thus, the invention makes it possible to decontaminate the air of the secondary oil system to allow it to access these internal cavities containing rotors without the risk of generating a fire.

Advantageously, this de-oiling system has a high compactness compatible with the small space available in the turbomachine and does not require mechanical drive to carry out the de-oiling.

The turbomachine according to the invention may comprise one or more of the following characteristics, taken in isolation from each other or in combination with each other:
- the inertial separator comprises a first baffle forming an angle between 90° and 180° and arranged axially to the right of the second oil outlet, preferably an angle of approximately 180°;
- the inertial separator comprises a second baffle forming an angle of between 90° and 180° and arranged between the first baffle and the first axial air outlet in the direction of circulation of the air flow, preferably an angle of approximately 180°;
- the angle of the first baffle and the angle of the second baffle are configured so that the direction and direction of the air flow leaving the second baffle is identical to the direction and direction of the incoming air flow in the first chicane;
- the de-oiling system comprises a first section of conduit extending between the axial air inlet and the first baffle, a second section of conduit arranged between the first baffle and the second baffle and a third section of conduit arranged between the second baffle and the first de-oiled air outlet, the first and third duct sections extending substantially parallel to a longitudinal axis of the turbomachine;
- the de-oiling system comprises a radial drain opening at one end into the second oil outlet and configured to evacuate the oil out of the internal pipe at a second end;
- the first outlet communicates with the internal cavity via an injector.

The invention also relates to an aircraft comprising a turbomachine according to the invention and as described previously.

The present invention will be better understood and other details, characteristics and advantages of the present invention will appear more clearly on reading the description of a non-limiting example which follows, with reference to the appended drawings in which:
there is an axial (or longitudinal) sectional view of a turbomachine to which the invention applies;
- there is an enlarged view of the turbomachine of the in a zone of proximity to a secondary air system and a turbomachine lubrication system; And
- there is a schematic sectional view of an air supply pipe of a turbomachine secondary air system.

Elements having the same functions in the different implementations have the same references in the figures.

We represented at the a longitudinal sectional view of a turbomachine 10, which here is a helicopter turbine engine. It will be understood that this configuration is not limiting to the invention and that it can be applied to any type of turbomachine comprising a gas generator.

In known manner, the turbomachine 10 comprises a casing in which a gas generator is housed. The latter comprises, from upstream to downstream according to the direction of flow of the gases inside the turbomachine, at least one high pressure compressor 12, which is here a centrifugal compressor, a diffuser 14, an annular combustion chamber 16 , a high pressure turbine 18 with two stages 20 and 22, a low pressure turbine 24 with two stages 26 and 28, and an exhaust nozzle 30. The rotor of the high pressure compressor 12 and the rotor of the high pressure turbine 18 are connected by a high pressure shaft 32 and form with it a high pressure body (HP). They extend along a longitudinal axis A of the turbomachine. Upstream of the high pressure compressor 12, the turbomachine may include a low pressure compressor, which has not been shown here.

By convention, in the present application, the terms “upstream” and “downstream” are defined in relation to the direction of circulation of the gases in the turbomachine and here along the longitudinal axis A thereof. Likewise, by convention in the present application, the terms "internal" and "external", "interior" and "exterior" are defined radially with respect to the longitudinal (or axial) axis A of the turbomachine 10, which is in particular the axis of rotation of the rotors of the compressors and turbines of the gas generator.

The turbomachine 10 is crossed by a flow of primary gas P. As illustrated by the arrow in the , the flow path of the primary gas flow P thus successively passes through the high pressure compressor 12, the diffuser 14, the combustion chamber 16, the high pressure turbine 18, the low pressure turbine 24, and the exhaust nozzle 30 In fact, fresh air enters the turbine engine via an air inlet. It is then compressed by the compressor 12 before being sent to the combustion chamber 16 where it is mixed with fuel. The combustion of the compressed air/fuel mixture generates a gas flow which causes the rotation of the high pressure turbine 18 which itself drives the compressor 12.

The compressor 12 and the turbines 18, 24 of the turbomachine 10 are made up of rotors which are mounted to rotate in a casing 34 of the turbomachine via bearings. For example, we see in particular on the an upstream bearing 36 allowing the rotation of the low pressure turbine 24.

The turbomachine 10 comprises a secondary air system, which has the function of supplying secondary air to the internal cavities of the turbomachine 10, for example to ensure the cooling of certain members such as the disks of the turbine stages such as the stages 26 , 28 of the low pressure turbine 24 housed in cavities of the casing 34, or to ensure the pressurization of cavities such as enclosures containing bearings by which the compressor and the turbines are mounted in rotation.

In particular, the bearings are housed in internal cavities which are pressurized enclosures supplied with pressurized air, taken upstream of the combustion chamber 16 in the primary air flow, and routed through the secondary air system until in these enclosures, in order to prevent bearing lubricating oil from escaping from these enclosures.

On the , we see the upstream bearing 36 of the low pressure turbine housed in its enclosure 38. We also see an internal cavity 42 in which the disk of the first stage 26 of the high pressure turbine 24 is housed, this internal cavity 42 also being intended to be supplied by the secondary air system to ensure the cooling of the first stage 26 of the low pressure turbine 24.

The secondary air system has different internal pipes and/or cavities. There represents in particular in detail an internal supply pipe 40 which is intended to bring secondary air to the internal cavity 42 in which the disk of the first stage 26 of the low pressure turbine 24 is housed, to ensure its cooling. In particular, in the example illustrated on the , the internal supply pipe 40 comprises a cavity fluidly connected to the internal cavity 42.

For this purpose, the internal supply pipe 40 comprises, in the axial direction of the pipe 40, an upstream end 44 which is supplied with air under pressure and a second downstream end 45, opposite, which communicates with the internal cavity 42.

The turbomachine 10 is also equipped with an oil supply system which is intended to ensure the lubrication of internal organs such as the bearing 36 of the low pressure turbine 24. For this purpose, the supply system The oil comprises for example an oil supply pipe 50 which is arranged upstream of the upstream end 44 of the pipe 40. The oil supply pipe 50 and the internal supply pipe 40 are in communication fluidic with each other, for example they are connected directly to each other or via at least one pipe not shown on the .

On the , this pipe 50 radially crosses the primary flow stream P and it radially crosses the casing 34 upstream of the upstream end 44 of the pipe 40 but it will be understood that it could be arranged upstream of the upstream end 44 of the pipe 40 in another orientation, without limitation of the invention. The pipe 50 is intended in particular to bring the oil to the bearing 36. The pipe 50 is therefore a pipe attached to the casing 34, with the risks of leakage that this implies.

In certain configurations, the oil supply line 50 may leak. In the event of a leak, oil escaping from the line 50 can pollute the air introduced into the supply line 40 through its first end 44, which has the effect of conducting oil-laden air. in areas of the turbomachine where it is precisely not desirable for oil to be introduced.

Indeed, oil which would for example be introduced into cavity 42, which is a high temperature cavity due to the heating of the turbine 24 caused by the combustion gases, could ignite spontaneously and cause a start of fire inside the casing 34 of the turbomachine, and thus cause damage, going as far as the destruction of certain parts such as the turbine disks, which could lead to the release of high energy elements such as blades turbine or bladed discs.

It is therefore imperative, when it is not possible to avoid air pollution from the secondary air system, to ensure rapid depollution for safety reasons before its introduction into the above-mentioned areas of the turbomachine.

In reference to the , the invention remedies this drawback by proposing a turbomachine 10 whose secondary air system comprises an improved air supply pipe 40 comprising a de-oiling system 50 making it possible to eliminate by inertia the suspended oil potentially contained in the air circulating in the air supply pipe 40.

The de-oiling system 50 is arranged between the upstream end 44 and the downstream end 45 of the pipeline 40 and preferably near the downstream end 45 of the pipeline 40.

The de-oiling system 50 comprises an axial inlet of air 52 potentially loaded with oil and a first air outlet 54 supplying de-oiled secondary air to an internal cavity 42 of the turbomachine 10. It also comprises a second oil outlet 56. The first air outlet 54 is axial, that is to say that the air flow leaving through this first air outlet 54 is directed parallel to the longitudinal axis A of the turbomachine.

Furthermore, as illustrated by , the de-oiling system 50 comprises an inertial separator 60 mounted in the pipe 40 upstream of the first axial air outlet 54. The inertial separator 60 is supplied by the axial air inlet 52, and configured to eliminate by inertia the suspended oil potentially contained in the air intended to circulate in the internal pipe 40. The inertial separator 60 is configured to eliminate the oil by inertia and direct it towards the second oil outlet 56.

The second oil outlet 56 is produced in the form of a radial drain 58 which opens into the pipe 40 and which is capable of evacuating the oil out of the pipe 40. For this purpose, the radial drain 58 opens to a first end into the second oil outlet 56 and is configured to discharge oil out of the internal pipeline 40 through a second end.

The inertial separator 60 consists of a conduit having a shape of revolution around an axis which coincides with the longitudinal axis A of the turbomachine

The inertial separator 60 comprises a first chicane 62 forming an angle at least between 90° and 180° and arranged axially to the right of the second oil outlet 56. In the example illustrated in , the first chicane forms an angle of approximately 180°.

By “baffle”, we mean here a device modifying the direction of the path of gases/fluids, here air potentially laden with oil. A chicane forming an angle of 90° thus corresponds to a turn at approximately a right angle, while a chicane forming an angle of 180° will cause a half-turn of the throttle.

The inertial separator 60 further comprises a second baffle 64 of the same angle as the first baffle 62 arranged between the first baffle 62 and the first air outlet 54 in the direction of circulation of the air flow. Thus, the second chicane 64 forms an angle at least between 90° and 180°. In the example illustrated in , the first chicane forms an angle of approximately 180°.

Preferably, the angle of the first baffle and the angle of the second baffle are configured so that the direction and direction of the air flow leaving the second baffle is identical to the direction and direction of the air flow. air entering the first chicane.

In the example illustrated on the , the baffles have equal angles measuring 180° relative to the longitudinal axis A of the turbomachine in the section plane presented, which is also the axis of the axial air inlet 52.

Alternatively, the baffles can be oriented azimuthally relative to the axial air inlet 52.

In the context of the invention, the baffles are advantageously produced by the arrangement of the pipe itself, by making the latter follow a winding path.

Thus, in the example illustrated on the , the conduit of the de-oiling system 50 comprises a first section of conduit 72 extending between the axial air inlet 52 and the first baffle 62, a second section of conduit 74 arranged between the first baffle 62 and the second baffle 64 and a third section of conduit 76 arranged between the second baffle 64 and the first deoiled air outlet 54.

Thus, the air entering the internal pipe 40 enters the deoiling system 50 via the air inlet 52 in communication with the first section of conduit 72. The air thus successively passes through the first section of pipe 72, the first baffle 62, the second section of conduit 74, the second baffle 64 and the third section of conduit 76 up to the first outlet 54 of deoiled air.

Preferably, the first, second and third sections of conduit 72, 74, 76 extend substantially parallel to the longitudinal axis A of the turbomachine 10.

In the first section of conduit 72, the air flow F propagates from the front of the turbomachine (to the left on the ) towards the rear of the turbomachine (to the right on the ) then its direction of circulation is modified by the first chicane 62 so that the air flow F propagates from the right to the left on the , that is to say from the rear towards the front of the turbomachine in the second section of conduit 74. Finally, the second chicane 64 restores the “initial” direction of circulation of the air flow so that the air flow F propagates from the front to the rear of the turbomachine (from left to right on the ) in the third section of conduit 76.

The internal wall 72A of the first section of conduit 72, that is to say the wall closest to the longitudinal axis A of the turbomachine, is constituted by a portion of an internal wall 40A of the internal pipe 40.

The outer wall 72B of the first section of conduit 72 is formed of a lip 80 which extends in the general downstream direction from an upstream edge 81 of an outer wall 40B of the internal pipe 40 radially towards inside then substantially parallel to the longitudinal axis A towards the downstream. The lip 80 comprises an end 82 arranged opposite the first baffle 62 and at a distance therefrom so as to create a passage for the air flow.

The first baffle 62 has a wall 63 forming a curve practically reaching an angle of 180° in the example illustrated which first extends downstream from a downstream edge of the internal wall 72A of the first section of conduit 72 to then take the upstream direction. The wall 63 is preferably arc-shaped and substantially concave in a transverse plane so as to guide towards its central part 65 defining a zone for capturing the oil droplets present in the air flow potentially loaded with oil hitting it . This shape also makes it possible to minimize the pressure loss generated on the air in the secondary circuit. The second oil outlet 56 is arranged to the right of the capture zone 65 of the oil droplets.

The internal wall 74A of the second section of conduit 74 is constituted by the lip 80 up to the second baffle 64.

The outer wall 74B of the second section of conduit 74 is formed by a wall 85 extending upstream to a first end 85A in a direction substantially parallel to the longitudinal axis A from a circumferential edge 65 of the first baffle 62. The end 85A of the wall 85 is arranged opposite the second baffle 64 and at a distance from it so as to create a passage for the air flow.

In addition, the wall 85 also extends downstream from the first end 85A to a second end 85B in a direction substantially parallel to the longitudinal axis A and forming the internal wall 76A of the third section of conduit 76.

The external wall 76B of the third section of conduit 76 is constituted by a portion of the wall 40B of the internal pipe 40.

In operation, the pressurized air loaded with oil hits the capture zone 63 of the first chicane 62. The heaviest particles of the air-oil mixture, here the oil, are captured by inertial effect by the zone of capture 63 of the first baffle 62. Consequently, the oil in the form of droplets condenses on the capture zone 63 of the first baffle 62 and is evacuated by the second oil outlet 56 communicating with the drainage system 58 towards other areas of the turbomachine. The pressurized air which carried the oil, now free of the oil, continues its path and crosses the second section of conduit 74 and the third section of conduit 76 via the second chicane 64. It exits through the air outlet axial 54 communicating with the downstream end 45 of the internal pipe 40, from where it continues its journey in the secondary air system in particular towards the internal cavity comprising the rotors.

Furthermore, according to another embodiment not illustrated, the de-oiling system may include an additional oil outlet similar to the second oil outlet 56. In this case, the second baffle 64 has a preferably D-shaped wall. arc, that is to say shaped to guide towards its central part the oil droplets present in the air flow potentially loaded with oil hitting it. As with the first baffle, this central part defines a collection zone for residual oil droplets, that is to say those which may still be present in the air after the first baffle.

The additional oil outlet is then arranged to the right of this area for capturing the oil droplets of the second baffle. Like the second oil outlet 56, the additional oil outlet is produced in the form of a radial drain which opens into the pipe and which is capable of evacuating the oil still present in the air after the first chicane outside of line 40.

This second capture zone and this additional oil outlet ensure complete recovery of the oil in the event that part of it has not been captured in the first baffle.

Thus, the invention allows the decontamination of the air/oil mixture present in the secondary air system upstream of the system in the event of a leak from the lubrication system. The system therefore makes it possible to eliminate the risk of fire in the rotor cavities by allowing only de-oiled air to pass to the downstream cavities.

On the , the first outlet 54 of the de-oiling system 50 communicates with the internal cavity 42 via an injector 90 in order to cool the turbine 24. It will be understood that this arrangement is not limiting of the invention, particularly in the case of direct power supply to an enclosure containing bearings.

The invention is therefore applicable to any turbomachine 10 comprising a secondary air system whose air supply pipe 40 is placed downstream of an internal oil supply conduit 50, and which risks as such to be exposed to oil leaks. It makes it possible to reinforce the safety of the turbomachine by dissociating the oil from the air of the secondary air system and therefore thus avoiding the risks of fire which could have serious repercussions on the airworthiness of the turbomachines.

Claims (7)

Aircraft turbomachine (10), comprising an internal pipe (40) for supplying a secondary air system of said turbomachine and a de-oiling system (50) arranged between an upstream end (44) and a downstream end ( 42) of said pipe (40), said de-oiling system (50) comprising an axial inlet (52) of potentially oil-laden air and a first outlet (54) of de-oiled air supplying secondary air to an internal cavity ( 42) of the turbomachine (10), and a second oil outlet (56), characterized in that the de-oiling system (50) comprises an inertial separator (60), supplied by the axial air inlet (52). ), mounted in the pipe (40) upstream of the first axial air outlet (54), and configured to eliminate by inertia the suspended oil potentially contained in the air intended to circulate in the internal pipe towards the second oil outlet (56). Aircraft turbomachine (10) according to claim 1, in which the inertial separator (60) comprises a first baffle (62) forming an angle of between 90° and 180° and arranged axially to the right of the second oil outlet ( 56), preferably an angle of approximately 180°. Aircraft turbomachine (10) according to claim 2, in which the inertial separator (60) comprises a second baffle (64) forming an angle of between 90° and 180° and arranged between the first baffle (62) and the first outlet axial air flow (54) in the direction of circulation of the air flow, preferably an angle of approximately 180°. Aircraft turbomachine (10) according to claim 3, in which the de-oiling system (50) comprises a first section of conduit (72) extending between the axial air inlet (52) and the first baffle (62). ), a second section of conduit (74) arranged between the first baffle (62) and the second baffle (64) and a third section of conduit (76) arranged between the second baffle and the first outlet (54) of deoiled air , the first and third conduit sections extending substantially parallel to a longitudinal axis (A) of the turbomachine. Aircraft turbomachine (10) according to any one of the preceding claims, in which the deoiling system (50) comprises a radial drain (58) opening at one end into the second oil outlet and configured to evacuate the oil out of the internal pipe at a second end. Aircraft turbomachine according to any one of the preceding claims, in which the first outlet (54) communicates with the internal cavity via an injector (90). Aircraft comprising a turbomachine (10) according to any one of the preceding claims.