Assembly comprising an equipment lubrication device, particularly for a turbomachine accessory housing
The fluid circuit with a strainer and rotating flow mechanism addresses particle-induced clogging in turbomachine lubrication systems, ensuring reliable oil supply by centrifuging and evacuating particles, thus maintaining turbomachine operation.
Patent Information
- Application Number
- FR2021012496
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2021-11-25
- Publication Date
- 2025-11-14
- Estimated Expiration
- 2041-11-25
AI Technical Summary
Existing lubrication systems in turbomachines are prone to clogging due to particle accumulation in the oil circuit, which cannot be detected and results in inadequate oil supply to components like pneumatic starters, affecting the starting process.
A fluid circuit with a strainer and a discharge portion that generates a rotating flow to centrifuge particles upstream, preventing clogging by evacuating them through a separate channel, and a turbulator or helical grooves to create turbulence and vortices to enhance particle removal.
Effectively prevents clogging of the strainer by centrifuging particles, ensuring consistent oil supply to turbomachine components and maintaining operational reliability.
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Abstract
Description
Title of the invention: Assembly comprising a lubrication device for equipment, in particular for a turbomachine accessory housing Technical field of the invention
[0001] The present invention relates to an assembly comprising an equipment lubrication device, in particular for a turbomachine accessory housing, such as for example a turbojet or an aircraft turboprop. Prior art
[0002] An accessory gearbox, also called an AGB (acronym for Accessory Gear Box), is designed to transmit mechanical power from the turbomachine to equipment such as a pump, an air / oil separator, an electricity generator, etc. The accessory gearbox comprises gears meshed with each other, at least some of which are fixed to coaxial tails designed to drive rotating moving parts or rotors of the equipment.
[0003] To start a turbomachine, a starter is used to deliver a motor torque to the shaft of said turbomachine. This motor torque is intended to overcome all the resistive torques applied to this shaft. The starter gradually accelerates the turbomachine and, when a predefined rotational speed is reached, the injection and ignition of fuel in the combustion chamber of the turbomachine are initiated. Then, at another predefined rotational speed, the action of the starter is stopped and the turbomachine continues to accelerate to its idle speed through fuel combustion.
[0004] Starters are generally pneumatic, i.e., consisting of a turbine powered by compressed air, or electrical. Figure 1 shows a pneumatic starter 1 fitted to an accessory drive (not shown) on a fan 2 of an aircraft turbomachine. The pneumatic starter 1 is designed to be supplied with compressed air via a pipe 3. Generally, air is pressurized by means of an auxiliary power unit (APU) located in the aircraft, by means of a ground-based unit, or by drawing air from another turbomachine that is already running. Regardless of the compressed air source, the pressurized air arrives at the upstream end 4 of the pipe, as illustrated by arrow 5, destined for the pneumatic starter 1.
[0005] A starter air valve 6 (SAV) regulates the flow of pressurized air in the pipe 3. Thus, regulating the valve 6 makes it possible to prevent or limit the flow of compressed air to the downstream side 7 of the pipeline 3 where the pneumatic starter 1 is located. When the turbomachine starts, the starting valve 6 is opened so as to supply the pneumatic starter 1. The pressurized air then enters the turbine of the starter 1, which transforms the pneumatic energy into mechanical energy to rotate the shaft of the turbomachine.
[0006] The pneumatic starter is also supplied with lubricating oil via an oil circuit equipped with a nozzle whose diameter is calibrated to deliver the correct amount of oil to the starter. In practice, the oil carries particles that can cause clogging of the oil circuit, particularly at the nozzle.
[0007] Such clogging results in an inability to supply oil to the pneumatic starter, regardless of the condition of the pneumatic starter. Furthermore, it is not possible to detect such clogging in the starter lubrication circuits downstream of the turbomachine lubrication device filter.
[0008] Of course, the invention is not applicable only to the case of a pneumatic starter but can be applied to any other oil circuit of an accessory housing of a turbomachine. Presentation of the invention
[0009] The invention aims to remedy this drawback in a simple, reliable and inexpensive way.
[0010] For this purpose, the invention relates to an assembly comprising a body comprising a fluid circuit comprising at least one fluid flow portion comprising a strainer suitable for filtering particles present in the fluid, and at least one discharge portion extending from an upstream area of the flow portion located upstream of the strainer, said flow portion comprising means for generating a rotating flow in said upstream area.
[0011] During operation, the oil flows from upstream to downstream in the flow section of the oil circuit, passing through the strainer. The strainer retains particles present in the oil flow in the upstream part of the flow section. Furthermore, some of the oil is discharged through the discharge section into the upstream area, carrying with it the particles retained by the strainer. The discharged oil can then be filtered or decanted in a container, for example, to remove these particles.
[0012] The rotating flow prevents clogging of the strainer by generating a vortex upstream of the strainer, the particles thus centrifuged by such a vortex or whirlpool being then evacuated by the evacuation part.
[0013] The said invention is particularly applicable to oil or fuel circuits.
[0014] The means for generating a rotating flow may include a turbulator mounted in the upstream area of the flow part.
[0015] The turbulator can be formed by a part separate from the body.
[0016] The turbulator may comprise a central part and a peripheral propeller limiting a helical channel, with the surface of the body forming said upstream zone of the flow portion.
[0017] The propeller and said central part of the turbulator can be formed from a single piece.
[0018] The turbulator may include an annular part placed in the flow part and delimiting a central fluid passage, the annular part having surfaces oblique to the axis of the annular part.
[0019] The oblique surfaces can be oriented in opposite directions in pairs, so as to define a general circular zigzag shape. The oblique surfaces can be flat or curved. The oblique surfaces can be oriented upstream, that is, away from the strainer.
[0020] The means for generating a rotating flow may include at least one helical groove formed in the body and opening into the upstream area of the fluid flow part.
[0021] The upstream zone of the flow part can extend along a first axis, the discharge part extending along a second axis, forming an angle between 45° and 135° with respect to the first axis.
[0022] In general, the second direction can form a non-zero angle with the first direction. This angle can be between 45 and 90°.
[0023] The upstream zone of the flow part may be of circular cross-section, the discharge part opening tangentially at the radially external periphery of said upstream zone.
[0024] Such a characteristic facilitates the evacuation of particles.
[0025] The cross-section of the flow portion may be greater than the cross-section of the discharge portion.
[0026] The ratio of the cross-section of the flow part to the cross-section of the discharge part can be between 5 and 30.
[0027] The invention also relates to an accessory housing comprising an assembly of the aforementioned type.
[0028] The invention also relates to a turbomachine, such as a turbojet or an aircraft turboprop, characterized in that it comprises an accessory relay box, which includes a support flange for equipment and an assembly of the aforementioned type, disposed in the flange. At least one area of the flow portion and the strainer may belong to a nozzle of the oil circuit.
[0029] The nozzle may be formed by a separate element mounted on a housing or on a component of the turbomachine, such as, for example, a starter. The nozzle may have a calibrated cross-section. The calibrated cross-section may be the nozzle passage cross-section at the strainer or may be formed by a portion located downstream of the strainer.
[0030] The evacuation part can open into the flow part directly upstream or near the strainer.
[0031] The strainer may have a dome shape or a portion of a sphere, for example, a hemispherical shape. Alternatively, the strainer may have a conical shape. The strainer may have a grid shape. The strainer may have oil passage openings smaller than the average particle size. The strainer may have oil passage openings smaller than 0.4 mm.
[0032] The evacuation part can open into the flow part axially opposite the strainer.
[0033] The nozzle can be fixed by screwing, crimping or fitting onto the housing or the relevant component of the turbomachine.
[0034] A similar nozzle, but without a particle evacuation part upstream of the strainer, is notably known from US document 3,109,459.
[0035] The nozzle can be mounted, for example by screwing or crimping, in a support called a coil, itself fixed to a housing or component of the turbomachine. The coil can be fixed, for example by screwing or crimping, to the housing or relevant component of the turbomachine. The coil can be mounted by fitting between two fixed elements, with sealing achieved by means of gaskets, for example O-rings. At least one area of the flow portion and / or the discharge portion can be formed in the support and / or in the housing or relevant component.
[0036] The discharge section may open into the flow section at a distance, for example, less than 2 mm from the strainer. This distance may be measured along the longitudinal axis of the flow section.
[0037] In operation, the ratio between the oil flow rate in the discharge section and the oil flow rate in the flow section, downstream of the strainer, can be between 5 and 15.
[0038] The oil flow rate in the discharge section is, for example, between 10 and 30 L / h. The oil flow rate in the flow section, downstream of the strainer, is, for example, between 0.5 and 3 L / h.
[0039] The coil may include a main channel, called a flow channel, comprising the strainer and extending along an axis, and a secondary channel, called a discharge channel.
[0040] The coil can be mounted in a housing having a supply conduit opening into the coil's discharge channel. The housing can also have an outlet conduit, with the coil's discharge channel opening into the housing's outlet conduit.
[0041] The flow channel may include an upstream part, in the upstream zone, and a downstream part, located downstream of the screen or screens.
[0042] The cross-section of the casing supply conduit may be greater than the cross-section of the upstream part of the coil flow channel.
[0043] The cross-section of the upstream part of the coil's flow channel may be greater than the cross-section of the coil's discharge channel.
[0044] The cross-section of the coil discharge channel may be smaller than the cross-section of the housing outlet conduit.
[0045] The cross-section of the crankcase supply conduit may be greater than the cross-section of the crankcase outlet conduit.
[0046] The invention also relates to a method of operating an assembly of the aforementioned type, characterized in that the ratio between the flow rate of oil circulating in the evacuation part and the flow rate of oil circulating in the flow part, downstream of the strainer, is between 5 and 20. Brief description of the figures
[0047] [Fig. 1] represents part of a prior art turbomachine,
[0048] [Fig.2] is a cross-sectional view of part of a relay equipment support accessories equipped with a nozzle, according to one embodiment of the invention,
[0049] [Fig.3] is a view corresponding to [Fig.2], illustrating another embodiment,
[0050] [Fig.4] is a perspective view of a turbulator,
[0051] [Fig.5] is a cross-sectional view of the upstream area of the flow portion, according to a form of embodiment of the invention,
[0052] [Fig.6] is a view corresponding to [Fig.6], illustrating another embodiment,
[0053] [Fig.7] is a perspective view of a turbulator according to another embodiment. Detailed description of the invention
[0054] Fig. 2 illustrates part of an assembly 1 equipping an accessory relay of an aircraft turbomachine, such as, for example, an aircraft turbojet or turboprop.
[0055] The assembly comprises a housing 8 having internal conduits belonging to a oil circuit, including a supply conduit 9 intended to supply oil to moving parts to be lubricated, and an outlet conduit 10 opening into or connected directly or indirectly to an enclosure.
[0056] A support 11, called a coil, is mounted in an opening 12 in the housing 8. The support 11 is, for example, attached to the housing 8 by a press fit and retained by a retaining ring. The support 11 has an elongated shape and extends along an axis X. The support 11 includes a main channel, called a flow channel 13, extending along said axis X, and a secondary channel, called a discharge channel 14. The supply conduit 9 opens into the flow channel 13, in particular into a portion or zone called the upstream 13a of said flow channel 13. The upstream zone 13a is generally cylindrical in shape and has peripheral grooves 13b with a helical shape about axis X, designed to create turbulence or a vortex within said upstream zone 13a. The discharge channel 14 opens into the outlet duct 10. The cross-section of the outlet duct 10 is greater than the cross-section of the discharge channel 14.
[0057] A nozzle 15 is further mounted in the support 11, the nozzle 15 being formed by a tubular part of axis X, the upstream end of which has a strainer 16.
[0058] The strainer 16, for example, has a general hemispherical or conical shape extending axially opposite the discharge channel 14. The nozzle 15 is fixed by crimping. The hollow internal portion 17 of the nozzle 15 forms a downstream extension of the upstream zone 13a of the flow channel 13, that is to say, a zone located downstream of the strainer 16. The internal portion 17 of the nozzle 15 also opens, downstream, into a downstream portion 13c of the flow channel 13 of the support 11.
[0059] The support 11 includes a section reduction lia forming a stop, suitable for cooperating with a complementary stop of the nozzle 15 so as to facilitate its axial positioning in the support 11 when mounting the nozzle 15 in the support 11.
[0060] During operation, oil arriving through conduit 9 enters the upstream zone 13a of the flow channel 13. The cross-section of the upstream zone 13a may be smaller than the cross-section of conduit 9.
[0061] The oil may be laden with particles 18, which are retained by the strainer 16. The oil flow entering the flow channel is divided into two flows: a first flow (illustrated by a dashed arrow 19) passing through the strainer 16 and flowing into the flow channel 13 downstream of the strainer 16, and a second flow 20 (illustrated by a solid arrow 20) passing through the discharge channel 14 and the outlet conduit 10, carrying with it all or part of the particles 18 retained by the strainer 16 so as to clean it and prevent clogging. The oil flow entering the upstream zone 13a is rotated around the X-axis by the helical grooves 13b, so as to centrifuge the particles 18 and prevent them from aggregating on the strainer 16.
[0062] The oil flow rate entering the flow channel 13, upstream of the strainer 16, is typically between 10 L / h and 30 L / h. The oil flow rate passing through the strainer 16 is between 0.5 L / h and 3 L / h. The oil flow rate passing through the outlet conduit 10 is between 10 L / h and 29.5 L / h.
[0063] [Fig.3] illustrates another embodiment, which differs from that illustrated in [Fig.2], in which the upstream zone 13a is devoid of helical grooves 13b. A turbulator 21, schematically illustrated in [Fig.3] by dashed lines, is mounted in the upstream zone 13a.
[0064] In the embodiment illustrated in [Fig. 4], the turbulator 21 comprises an elongated central body 22 extending along the X-axis and a peripheral helix 23 fixed to or formed from the material of the central body 22, said helix 23 having an external diameter corresponding substantially to the internal diameter of the upstream zone 13a. The body 22 and the helix 23, together with the cylindrical internal surface 24 of the upstream zone 13a, define helical channels or passages upstream of the strainer 16. The helix 23 can extend downstream of the body 22, that is to say, between the body 22 and the strainer 16 along the X-axis.
[0065] The turbulator 21 can be fixed by screwing or by pressing it into the support 11.
[0066] As illustrated in [Fig.5], the discharge channel 14 can open opposite the X axis. The axis of the discharge channel 14 thus passes through the X axis.
[0067] Alternatively, as illustrated in [Fig.6], the discharge channel 14 can open radially outward from the upstream zone 13 and tangentially to the internal surface 24 of the upstream zone 13a. This variant makes it easier to recover the particles 18 that have been centrifuged by the rotating oil flow.
[0068] In operation, the oil flow entering the upstream zone 13a passes through said helical channels and is driven in rotation around the X axis, so as to generate turbulence or vortex to prevent clogging of the strainer 16 by particles 18.
[0069] Figure 5 illustrates an alternative embodiment in which the turbulator 21 is in the form of a ring and comprises an annular portion 25 having an upstream face formed of oblique surfaces 26 with respect to the axis of the annular portion 25. The diameter of the oblique surface 25 is substantially the same as the diameter of the internal surface 24 of the upstream zone 13a. The oblique surfaces 26 are oriented in opposite pairs, so as to define a general circular zigzag shape. The oblique surfaces 26 may be flat or curved. The oblique surfaces 26 face upstream, i.e., away from the strainer 16.
[0070] The annular portion 25 defines a central passage or orifice 25a allowing the passage of oil. Said annular portion 25 can be fixed by screwing or by- handle by pressing into the support 11.
[0071] In operation, the oil flow entering the upstream zone 13a is disturbed or driven into rotation around the X axis by the oblique surfaces 26 and their orientations, so as to generate disturbances or vortices downstream of the turbulator 21 and upstream of the turbulator 21, thus preventing the clogging of the strainer 16 by the particles 18.
Claims
Demands
1. Assembly comprising a body (11) comprising a fluid circuit comprising at least one fluid flow portion (13) comprising a strainer (16) capable of filtering particles (18) present in the fluid, and at least one discharge portion (14) extending from an upstream area (13a) of the flow portion (13) located upstream of the strainer (16), said flow portion (13) comprising means (13b, 21) for generating a rotating flow in said upstream area (13a), the upstream area (13a) of the flow portion (13) being of circular cross-section, the discharge portion (14) opening tangentially at the radially external periphery of said upstream area (13a).
2. Assembly according to the preceding claim, characterized in that the means for generating a rotating flow comprise a turbulator (21) mounted in the upstream zone (13a) of the flow part (13).
3. Assembly according to the preceding claim, characterized in that the turbulator (21) comprises a central part (22) and a peripheral helix (23) delimiting a helical channel, with the surface (24) of the body (11) forming said upstream zone (13a) of the flow part (13).
4. Assembly according to claim 2, characterized in that the turbulator (21) comprises an annular part (25) placed in the flow part (13) and delimiting a central fluid passage (25a), the annular part (25) comprising surfaces (26) oblique with respect to the axis (X) of the annular part (25).
5. Assembly according to claim 1, characterized in that the means for generating a rotating flow comprise at least one helical groove (13b) formed in the body (11) and opening into the upstream zone (13a) of the flow part (13).
6. Assembly according to any one of the preceding claims, characterized in that the upstream zone (13a) of the flow part (13) extends along a first axis (X), the discharge part (14) extends along a second axis forming an angle between 45° and 135° with respect to the first axis (X).
7. Assembly according to any one of the preceding claims, characterized in that the cross-section of the flow portion (13) is greater than the cross-section of the discharge portion (14).
8. Accessory housing comprising an assembly according to one of the claims previous instructions.
9. Turbomachine, such as an aircraft turbojet or turboprop, characterized in that it comprises an accessory relay box, which includes a support flange for equipment and an assembly according to any one of claims 1 to 7, disposed in the flange.