DE102021101554A1 - Aircraft engine with integrated oil separator - Google Patents

Abstract

An aircraft engine (1) with an integrated oil separator and with at least two bearing chambers (12, 13) is proposed, in which bearing units are provided for the rotatable mounting of at least one engine shaft. Interior spaces (29) of the bearing chambers (12, 13) are each supplied with oil by an oil system (19) and are sealed against oil escaping. The oil system (19) has at least one oil reservoir (20) for storing oil. Oil is conveyed from the oil reservoir (20) to the bearing chambers (12, 13) and out of the bearing chambers (12, 13) into the oil reservoir (20). The oil separator (28) is designed to separate oil from air-oil volume flows (44) from the bearing chambers (12, 13). The oil separator (28) is designed as a cyclone and is arranged on one of the storage chambers (12), at least partially within one of the storage chambers (12) or completely within one of the storage chambers (12). Oil separated in the cyclone (28) is fed into the oil reservoir (20) via an oil outlet (30). In addition, an air-oil volume flow, which has a lower oil load than the air-oil volume flows (44) from the bearing chambers (12, 13), exits the cyclone (28) in the direction of the environment ( 32) of the aircraft engine (1).

Description

The present disclosure relates to an aircraft engine with an integrated oil separator and at least two storage chambers.

From the U.S. 2009/0133961 A1 a jet engine with a low-pressure shaft and a high-pressure shaft is known. During operation of the jet engine, oil-containing consumption air is supplied to a storage chamber of a device for separating oil, which is designed as a centrifugal oil separator and is also referred to as a breather. The device is non-rotatably connected to the low-pressure shaft of the jet engine and is thus driven by the low-pressure shaft about a central axis of the jet engine during operation of the jet engine. During operation of the jet engine, oil droplets are separated from the consumption air supplied to the device or the air-oil volume flow and are thus filtered out of the air. The oil separated by this procedure is fed back into the bearing chamber via recesses in the device, while the cleaned air is discharged to the environment through the low-pressure shaft designed as a hollow shaft. Cleaned air is understood to be a fluid volume flow discharged from the device, which has a lower oil load than the air-oil volume flow supplied to the oil separator.

Furthermore, in the EP 2 559 869 A1 describes a jet engine with a device for separating oil. The device is connected to an auxiliary gear shaft of the auxiliary gear in the area of an auxiliary gear arranged radially outside of bearing chambers of the jet engine. Due to correspondingly existing transmission ratios, the device is driven during operation of the jet engine by the accessory gear shaft at a speed required for a desired high separation efficiency.

However, jet engines of this type are characterized by high production costs and, in addition, have a high weight combined with large external dimensions, which results in undesirably high fuel consumption.

The object of the present disclosure can be seen as providing an aircraft engine that is of simple and inexpensive design and can be operated with low fuel consumption, in which oil can be separated to the desired extent from air-oil volume flows during operation.

This problem is solved with an aircraft engine having the features of patent claim 1 .

The aircraft engine according to the present disclosure comprises an integrated oil separator and at least two bearing chambers, in which bearing units are provided for rotatably supporting at least one engine shaft. Interiors of the bearing chambers are each supplied with oil by an oil system and are sealed against oil escaping. The oil system has at least one oil reservoir for storing oil. Oil is conveyed from the oil reservoir to the storage chambers by means of at least one feed pump and returned from the storage chambers into the oil reservoir via at least one return pump.

The oil separator is set up to separate oil from air-oil volume flows from the bearing chambers. The oil separator is designed as a cyclone. As a result, in comparison to oil separators that use rotating components for oil separation, oil can be separated without rotary drive units, which are known to cause high production costs and require additional installation space.

The cyclone can be installed directly on one of the storage chambers, i. H. be arranged on an outside of a wall of the storage chamber and thus outside of the storage chamber and be positioned directly adjacent to the storage chamber in a space-saving manner.

As an alternative to this, there is also the possibility that the cyclone is arranged partly inside and partly outside the storage chamber. This design of the aircraft engine represents a space-saving solution if the cyclone is implemented in existing aircraft engine systems in which a corresponding space is available in a storage chamber.

In addition, it can also be provided that the cyclone is arranged entirely inside the storage chamber. This embodiment of the aircraft engine according to the present disclosure is particularly economical in terms of installation space and is to be preferred if a corresponding installation space is available inside the bearing chamber.

In the aircraft engine according to the present disclosure, oil separated in the cyclone is conducted from inside the cyclone into the oil reservoir via an oil outlet of the cyclone. In addition, an air-oil volume flow, which has a lower oil load than the air-oil volume flows from the storage chambers and is also referred to below as a cleaned air volume flow, exits the cyclone via an air outlet in the direction of the area surrounding the aircraft engine.

The storage chambers can be connected to one another. Then there is the possibility of conducting an air-oil volume flow from one of the storage chambers via the connection into the interior of the other storage chamber. The air-oil volume flow, which is guided from one storage chamber into the other storage chamber, can then be introduced into the cyclone together with an air-oil volume flow from the other storage chamber. With such an embodiment of the aircraft engine according to the present disclosure, oil can be separated from the air-oil volume flows of both storage chambers in a manner that is cost-effective and space-saving with just one cyclone.

The connection between the storage chambers can be designed with a throttle unit in order to avoid an undesired increase in pressure in the storage chamber into which the air-oil volume flow from the other storage chamber is introduced via the connection.

In addition, there is also the possibility that both storage chambers are directly connected to the cyclone. An air-oil volume flow from one storage chamber can then be introduced directly into the cyclone via the connection between the one storage chamber and the cyclone. Furthermore, an air-oil volume flow from the other storage chamber can then also be routed directly into the cyclone via the connection between the other storage chamber and the cyclone. This means that each bearing chamber only has a defined air-oil volume flow applied to it, which is independent of the air-oil volume flow in the other bearing chamber, and the oil can be separated from the air-oil volume flows in the bearing chambers using only a single cyclone is.

The connection between the storage chambers or the connection between one of the storage chambers and the cyclone can run through a strut which extends radially through an air-carrying area of the aircraft engine. Then, in a structurally simple manner, there is the possibility of appropriately tempering or cooling the air-oil volume flow before it enters the bearing chamber and also before it enters the cyclone in the area of the strut. The air-oil volume flow from the bearing chamber, which is arranged near a combustion chamber of the aircraft engine and therefore has high bearing temperatures when the aircraft engine is in operation, can be conducted through a strut. The strut can, for example, close to the engine inlet radially through the core flow of the aircraft engine, z. B. directly after a fan, be provided running.

The oil outlet of the cyclone can communicate with the interior of one of the bearing chambers. In addition, there is the possibility that the connection is set up to introduce oil separated from the air-oil volume flow from the cyclone into the bearing chamber. Then the cyclone itself does not have to be designed with its own return to the oil reservoir, which is complex in terms of design and must be sealed off from the environment.

In a further embodiment of the aircraft engine according to the present disclosure, return areas of the bearing chambers are connected to the oil reservoir. In addition, oil can be conveyed from the return areas of the bearing chambers into the oil reservoir via at least one return pump in a way that saves space and costs.

If the oil reservoir is designed with an air separator, by means of which air is separated from the oil volume flow which is introduced into the oil reservoir, it is ensured in a structurally simple manner that the bearing chambers are acted upon by the quantity of oil from the oil reservoir required for lubrication and cooling.

A connection between the oil reservoir and the storage chambers may include a heat exchanger. The heat exchanger can be designed to temper an oil volume flow, which is at least partially conducted via the connection into the storage chambers, with fuel with which the aircraft engine is operated.

An accessory gearbox may be provided which is connected to at least one of the bearing chambers. The connection can be set up to introduce an air-oil volume flow from the accessory gearbox into the bearing chamber. Then oil can also be separated from a ventilation flow or the air-oil volume flow from the auxiliary device transmission with only one cyclone before the cleaned air volume flow is discharged to the environment.

The oil reservoir may communicate with the accessory gearbox. The connection can be set up to introduce both an air-oil volume flow and an oil volume flow from the oil reservoir into the auxiliary gear. Then the accessory gearbox can be charged with oil for lubrication and cooling from the oil reservoir and the oil reservoir can be vented, for example via the accessory gearbox in the direction of the cyclone and from there in the direction of the environment.

In addition, downstream of the air outlet of the cyclone and upstream of the area surrounding the flight an electrostatic oil separator must be provided for the engine. Oil separated in the area of the electrostatic oil separator can run off into one of the storage chambers, driven by gravity, and from there it can be fed back into the oil reservoir.

In the area of the electrostatic oil separator, the remaining oil droplets are electrostatically charged. In a so-called collector of the electrostatic oil separator, the charged oil droplets settle on oppositely charged collector plates. The remaining oil drains off the plates and flows back towards the oil reservoir due to the gravity acting on the oil.

If the bearing chambers are sealed off from a sealing air system by brush and/or carbon seals, the air-oil volume flows from the bearing chambers, from which oil is to be separated in the cyclone, are advantageously low due to the high sealing effect of the brush and/or carbon seals.

The oil outlet of the cyclone can be provided with a device for preventing air from entering the interior of the cyclone via the oil outlet. This ensures that the cyclone functions in a structurally simple manner.

In a structurally simple embodiment of the aircraft engine according to the present disclosure, the cyclone is designed as a tangential cyclone separator. Then there is the possibility of introducing an air-oil volume flow from a bearing chamber laterally into an inlet cylinder. The oil outlet of the cyclone may be part of a central lower portion of a cone that connects to the inlet cylinder. Furthermore, the air outlet can be designed as a dip tube which engages into the interior of the cyclone from above.

Both the features specified in the patent claims and the features specified in the following exemplary embodiments of the aircraft engine according to the present disclosure are each suitable, alone or in any combination with one another, to further develop the subject matter according to the invention.

Further advantages and advantageous embodiments of the aircraft engine according to the present disclosure result from the patent claims and the exemplary embodiments described in principle below with reference to the drawing, the same reference numbers being used for structurally and functionally identical components for the sake of clarity.

• 1 eine stark schematisierte Längsschnittansicht eines Flugtriebwerks;
• 2 ein vereinfachtes Schema eines Ölsystems des Flugtriebwerks gemäß 1;
• 3 eine vereinfachte Teilschnittansicht des Flugtriebwerks gemäß 1, wobei im Bereich einer vorderen Lagerkammer ein Ölabscheider angeordnet ist; und
• 4 eine vergrößerte Teilschnittansicht eines in 3 näher gekennzeichneten Bereiches IV, der einen Ölauslass des Ölabscheiders umfasst.

It shows:

• 1 a highly schematic longitudinal sectional view of an aircraft engine;
• 2 a simplified scheme of an oil system of the aircraft engine according to 1 ;
• 3 a simplified partial sectional view of the aircraft engine according to FIG 1 , wherein an oil separator is arranged in the area of a front bearing chamber; and
• 4 an enlarged partial sectional view of an in 3 more specifically identified area IV, which includes an oil outlet of the oil separator.

1 shows an aircraft engine or jet engine 1 in a longitudinal sectional view. The aircraft engine 1 is designed with a bypass duct 2 and an inlet area 3, with a fan 4 adjoining the inlet area 3 downstream in a manner known per se. Again downstream of the fan 4, the fluid flow in the aircraft engine 1 is divided into a bypass flow B and a core flow A, with the bypass flow B flowing through the bypass duct 2 and the core flow A into an engine core 5, which in turn flows in a manner known per se a compressor device 6, a burner 7 and a turbine device 8 is executed.

In the present case, the aircraft engine 1 has two shafts with a first shaft, which is a low-pressure shaft 10 , and a second shaft, which is a high-pressure shaft 9 . The low-pressure shaft 10 and the high-pressure shaft 9 are each mounted so as to be rotatable about a central axis 18 . In addition, the low-pressure shaft 10 is non-rotatably connected to the fan 4 and rotates during operation of the aircraft engine 1 at a lower speed about the central axis 18 than the high-pressure shaft 9. To mount the shafts 9, 10 to one another and to a housing area 11 of the aircraft engine 1, there are several bearing devices 14, 15, 16, 17 provided. The bearing devices 14, 15, 16, each designed as a roller bearing, are arranged in a front bearing chamber 12 in the axial direction of the aircraft engine 1, while the bearing device 17, also designed as a roller bearing, is mounted in a rear bearing chamber 13 in the axial direction of the aircraft engine 1.

2 shows a schematic of an oil system 19 with an oil reservoir 20 for storing oil. Oil is conveyed from the oil reservoir 20 to the bearing chambers 12, 13 by means of a feed pump 21 and from the return line via return pumps 22, 23 Chen 24, 25 of the storage chambers 12, 13 back into the oil reservoir 20 out.

During operation of the aircraft engine 1, an air volume flow taken from the core flow A, which is also referred to as compressor bleed air, is applied to the bearing chambers 12, 13 via a so-called sealing air system. In this way, the bearing chambers 12, 13, in conjunction with seals 50, 51, such as labyrinth seals, are intended to be opposite to adjacent chambers 26, 27, some of which are in 3 are shown to be sealed. In order to keep the air volume flow entering the bearing chambers 12, 13 from the chambers 26, 27 low, the bearing chambers 12, 13 can be sealed off from the sealing air system using brush and/or carbon seals instead of labyrinth seals.

The compressor bleed air mixes in the bearing chambers 12, 13 with the oil provided for lubricating the bearing devices 14, 15, 16, 17, resulting in an air-oil volume flow or an oil mist in the area of the bearing chambers 12, 13. Before used air is discharged from the aircraft engine 1, the oil content of the air used in the aircraft engine 1 must be reduced to a required level at which oil consumption by the aircraft engine 1 and unwanted emissions are low.

An oil separator 28 is provided for this purpose, which is set up to separate oil from air-oil volume flows from the bearing chambers 12, 13. The oil separator 28 is designed as a cyclone and can be installed in the 3 , which shows an enlarged view of the front storage chamber 12, can be arranged in the interior space 29 of the front storage chamber 12 in the manner illustrated. Oil separated in the cyclone 28 is conducted via an oil outlet 30 of the cyclone 28 into the return area 24 of the front bearing chamber 12 and from there into the oil reservoir 20 . In addition, an air-oil volume flow, which has a lower oil load than the air-oil volume flows from the bearing chambers 12, 13, exits the cyclone 28 via an air outlet 31 in the direction of the environment 32 of the aircraft engine 1. There is the possibility that the air outlet 31 of the cyclone 28 opens into the bypass duct 2 and the air cleaned in the cyclone 28 reaches the environment 32 via the bypass duct 2 .

The storage chambers 12, 13 are presently connected to one another via a ventilation line 33. An air-oil volume flow is conducted from the rear bearing chamber 13 into the interior 29 of the front bearing chamber 12 via the connection or the ventilation line 33 . The air-oil volume flow then flows out of the rear bearing chamber 13 into the cyclone 28 . In order to be able to limit the air-oil volume flow from the rear bearing chamber 13 into the front bearing chamber, a throttle unit 34 is provided in the ventilation line 33 between the bearing chambers 12, 13.

Furthermore, the aircraft engine 1 includes an auxiliary gear 35 which is connected to the front bearing chamber 12 via a further ventilation line 36 . Via the connection or the further ventilation line 36 , an air-oil volume flow is conducted from the auxiliary gear 35 into the front bearing chamber 12 , which flows from there into the cyclone 28 . In addition, the oil reservoir 20 is connected to the interior space 37 of the auxiliary device transmission 35 . The connection includes an additional ventilation line 38 via which an air-oil volume flow is conducted from the oil reservoir 20 into the interior 37 of the auxiliary gear 35 arranged adjacent in the aircraft engine 1 . In addition, the connection between the oil reservoir 20 and the interior 37 of the accessory gearbox 35 includes an oil line 39 via which an oil volume flow from the oil reservoir 20 into the accessory gearbox 35 is introduced.

The oil line 39 branches off downstream of a heat exchanger 40 in the direction of the interior 37 of the auxiliary gear 35 . The heat exchanger 40 is provided in an oil line 52 of a connection between the oil reservoir 20 and the bearing chambers 12,13. In the area of the heat exchanger 40, an oil volume flow, which is sucked in by the feed pump 21 from the oil reservoir 20 and is fed by the feed pump 21 through the heat exchanger 40 to the bearing chambers 12, 13 and into the interior 37 of the auxiliary gear 35, with fuel, with which the aircraft engine 1 is operated, tempered or cooled.

An electrostatic oil separator 41 is provided downstream of the air outlet 31 of the cyclone 28 and upstream of the environment 32 of the aircraft engine 1 , oil separated in the region of the electrostatic oil separator 41 draining into the bearing chamber 12 under the force of gravity.

The oil reservoir 20 is designed with an air separator 42, by means of which air is separated from the oil volume flow, which is introduced into the oil reservoir 20 from the bearing chambers 12, 13 and from the auxiliary device gearbox 35 via a further return pump 43 and the return pumps 22, 23. Both the further return pump 43 and the return pumps 22, 23 are driven by the auxiliary gear 35.

The cyclone 28 is in the in 3 shown embodiment as a tangential cyclone separator educated. The air-oil volume flow 44 entering the cyclone 28 from the bearing chamber 12 flows laterally into an inlet cylinder 45 . The oil outlet 30 of the cyclone 28 is part of a central lower area of a cone 46 adjoining the inlet cylinder 45. Furthermore, the air outlet 31 is designed with an immersion tube 47 that engages into the interior of the cyclone 28 from above, through which the oil cleaned in the cyclone 28 Air is discharged from the cyclone 28.

In order to ensure the functioning of the cyclone 28, the oil outlet 30 of the cyclone 28 comprises an in 4 device 48 shown as an example, by means of which an undesired entry of air via the oil outlet 30 into the interior of the cyclone 28 is prevented. For this purpose, the device 48 comprises a U-shaped tube 49 in which a defined volume of oil collects, which forms a barrier between the interior 29 of the front bearing chamber 12 and the interior of the cyclone 28 and counteracts air entering the cyclone 28 through the oil outlet 30 .

In addition to this or as an alternative to this, there is also the possibility that the air-oil volume flow entering the front bearing chamber 12 from the rear bearing chamber 13 develops a certain suction or ejector effect in the interior 29 of the front bearing chamber 12, which prevents undesirable air entry from the Interior 29 of the front bearing chamber 12 through the oil outlet 30 into the interior of the cyclone 28 prevented.

Reference List

1

aircraft engine

2

bypass channel

3

inlet area

4

horns

5

engine core

6

compression device

7

burner

8th

turbine setup

9

high pressure wave

10

low pressure wave

11

housing area

12

front storage chamber

13

rear storage chamber

14

storage facility; roller bearing

15

storage facility; roller bearing

16

storage facility; roller bearing

17

storage facility; roller bearing

18

central axis

19

oil system

20

oil reservoir

21

feed pump

22.23

return pump

24

Return area of the first storage chamber

25

Return area of the second storage chamber

26.27

chamber

28

Oil separator, cyclone

29

Interior of storage chamber 12

30

Cyclone oil outlet

31

Cyclone air outlet

32

vicinity

33

vent line

34

throttle unit

35

Auxiliary gears

36

further ventilation line

37

Interior of the auxiliary gear

38

additional vent line

39

oil line

40

heat exchanger

41

electrostatic oil separator

42

air separator

43

another return pump

44

air-oil flow rate

45

inlet cylinder

46

cone

47

dip tube

48

furnishings

49

u-shaped tube

50, 51

poetry

52

oil line

QUOTES INCLUDED IN DESCRIPTION

This list of the documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• US 2009/0133961 A1 [0002]
• EP 2559869 A1 [0003]

Claims (11)

Aircraft engine (1) with an integrated oil separator and with at least two bearing chambers (12, 13) in which bearing units (14 to 17) are provided for the rotatable mounting of at least one engine shaft (9, 10), interior spaces (29) of the bearing chambers (12, 13) each having oil applied to them by an oil system (19) and being sealed against oil escaping, the oil system (19) has at least one oil reservoir (20) for storing oil, wherein oil is conveyed from the oil reservoir (20) to the bearing chambers (12, 13) and is conducted from the bearing chambers (12, 13) into the oil reservoir (20), the oil separator (28) being set up to separate oil from air Separating oil volume flows (44) from the bearing chambers (12, 13), wherein the oil separator (28) is designed as a cyclone and is arranged on one of the storage chambers (12), at least partially within one of the storage chambers (12) or completely within one of the storage chambers (12), and wherein the oil separated in the cyclone (28) is fed into the oil reservoir (20) via an oil outlet (30) and an air-oil volumetric flow which has a lower oil load than the air is fed out of the cyclone (28) via an air outlet (31). -Oil volume flows (44) from the storage chambers (12, 13) exits in the direction of the environment (32) of the aircraft engine (1). aircraft engine after claim 1 , characterized in that the bearing chambers (12, 13) are connected to one another, with an air-oil volume flow being guided from one of the bearing chambers (13) into the interior (29) of the other bearing chamber (12) via the connection (33). and with both the air-oil volume flow from one storage chamber (13) and the air-oil volume flow from the other storage chamber (12) flowing into the cyclone (28) from the interior of the other storage chamber (12). aircraft engine after claim 1 , characterized in that both storage chambers (12, 13) are connected directly to the cyclone (28), with an air-oil volume flow from one storage chamber (12) via the connection between the one storage chamber (12) and the cyclone ( 28) directly into the cyclone (28) and an air-oil volume flow from the other bearing chamber (13) via the connection between the other bearing chamber (12) and the cyclone (28) directly into the cyclone. Aircraft engine according to one of the preceding claims, characterized in that the connection (33) between the bearing chambers (12, 13) or the connection between one of the bearing chambers (12, 13) and the cyclone (28) for cooling the air-oil volume flow runs through a strut which radially extends through an air-carrying area of the aircraft engine (1). Aircraft engine according to one of the preceding claims, characterized in that the oil outlet (30) of the cyclone (28) is connected to the interior (29) of one of the bearing chambers (12), the connection being set up to allow the air-oil Introduce volume flow of separated oil from the cyclone (28) into the bearing chamber (12). Aircraft engine according to one of the preceding claims, characterized in that an auxiliary gear (35) is provided, the auxiliary gear (35) being connected to at least one of the bearing chambers (12), and the connection (36) being set up for the auxiliary gear (35) to introduce an air-oil volume flow into the bearing chamber (12). Aircraft engine according to one of the preceding claims, characterized in that the oil reservoir (20) is connected to the accessory gearbox (35), the connection (38, 39) being set up for both an air-oil volume flow and an oil Introduce volume flow from the oil reservoir (20) into the auxiliary gear (35). Aircraft engine according to one of the preceding claims, characterized in that an electrostatic oil separator (41) is provided downstream of the air outlet (31) of the cyclone (28) and upstream of the environment (32) of the aircraft engine (1), with in the region of the electrostatic oil separator ( 41) Separated oil drains into one of the bearing chambers (12) driven by gravity. Aircraft engine according to one of the preceding claims, characterized in that the bearing chambers (12, 13) are sealed off from the sealing air system by brush and/or carbon seals. Aircraft engine according to one of the preceding claims, characterized in that the oil outlet (30) of the cyclone (28) is designed with a device (48) for preventing entry of air via the oil outlet (30) into the interior of the cyclone (28). Aircraft engine according to one of the preceding claims, characterized in that the cyclone (28) is designed as a tangential cyclone separator, with an air-oil volume flow (44) from a storage chamber (12, 13) laterally in each case an inlet cylinder (45), the oil outlet (30) of the cyclone (28) being part of a central lower area of a cone (46) adjoining the inlet cylinder (45), and the air outlet (31) having a top immersion tube (47) engaging in the interior of the cyclone (28).

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