TEST BENCH FOR AN AIRCRAFT TURBOMACHINE
The test bench addresses measurement inaccuracies and durability issues by using a suction device with aligned orifices and sealing elements, ensuring precise thrust measurements and component longevity.
Patent Information
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2024-04-24
- Publication Date
- 2026-04-10
AI Technical Summary
Existing test benches for aircraft turbomachines face challenges in accurately measuring thrust due to disturbances from suction devices that generate static and dynamic forces, leading to measurement inaccuracies and accelerated deterioration.
A test bench design with a suction device connected via a conduit having aligned orifices and openings, featuring radial gaps and sealing elements to allow relative displacements, minimizing interference with weighing systems and reducing friction forces.
Ensures accurate thrust measurements by preventing piston effects and maintaining durability of the test bench components, while allowing for air aspiration without affecting the behavior and longevity of connected parts.
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Abstract
Description
Title of the invention: TEST BENCH FOR AN AIRCRAFT TURBOMACHINE Technical field of the invention
[0001] The present invention relates to a test bench for an aircraft turbomachine. Technical background
[0002] A test bench for an aircraft turbomachine makes it possible to carry out tests that are not always feasible in flight. This is particularly the case for thrust tests.
[0003] Indeed, knowledge of the thrust of aeronautical engines requires extremely precise measurements to be taken with different types of instrumentation, which it is not always possible to carry on a test engine on the ground or in flight.
[0004] One way to circumvent this constraint is to reconcile, on representative test benches, different sets of sensors.
[0005] In order to guarantee the accuracy of the measurements taken, it is essential to eliminate as much as possible anything that can disturb the observed phenomena or anything that can introduce noise into the measurement sensors.
[0006] In the present application, particular attention is paid to a test bench comprising a propeller and stator arm assembly. As is known, the propeller is a rotor element that compresses the airflow entering the turbomachine. This airflow then splits into a primary flow that passes through compressors, a combustion chamber, and turbines, and a secondary flow that circulates around the primary flow. The stator arms are stator elements located in the flow path of the secondary flow.
[0007] Performance and installation tests of the propeller and stator arm assembly on a reduced scale generally cannot incorporate compressors capable of capturing an airflow representative of a primary flow. The tests are therefore generally carried out with a smooth primary flow path, i.e., one that does not include any blades.
[0008] In order to ensure the representativeness of the flow at the inlet of the primary flow vein, between the propeller and the straightener arms, one solution may consist of connecting a suction device downstream of the primary flow vein.
[0009] This connection is likely to generate static piston and solid friction forces between the suction device and the primary flow path. Dynamic forces can also be transmitted along the same path. These forces are likely to alter the measurements in the test bench, and in particular the weighing systems associated with the various modules of the turbomachine.
[0010] Furthermore, during testing, the connection is subjected to constraints related to relative displacements by thermal deformation or under static or dynamic stresses, which can lead to accelerated deterioration of the test bench.
[0011] The present invention aims to provide a solution to at least some of the problems of the prior art, in a simple, efficient, and economical way. Summary of the invention
[0012] The invention relates to a test bench for an aircraft turbomachine, this test bench having a longitudinal axis and comprising:
[0013] - a rotor module centered on the axis and equipped with a propulsion propeller,
[0014] - a first weighing system for the rotor module,
[0015] - a stator module centered on the axis and located downstream of the rotor module, this module of stator comprising two coaxial annular veins: a first annular vein for primary flow, and a second annular vein for secondary flow, this second vein extending around the first vein and being crossed by straightening arms of the stator module,
[0016] - a second weighing system for the stator module, and
[0017] - a suction device located downstream of the stator module and comprising a conduit annular, one upstream end of which is connected to a downstream end of the first vein,
[0018] the downstream end of the first vein being delimited by two coaxial annular walls, respectively internal and external, whose downstream annular edges are connected to each other, a first of these walls comprising at least one annular row of through-holes for air passage, and
[0019] the upstream end of the duct comprises two coaxial annular walls, respectively internal and external, whose upstream annular edges are connected to each other, a first of these walls having at least one annular row of through-openings for air passage, the upstream end of the duct being engaged coaxially in or on the downstream end of the first vein so that the openings are aligned radially with the orifices of the downstream end of the first vein, so that the suction device can draw air from the first vein into the duct, passing through the orifices and openings,
[0020] a radial annular gap being provided between the first walls, and sealing elements being located in this gap, upstream and downstream of the orifices and openings, these sealing elements being configured to allow relative displacements in radial and axial directions between the upstream end of the conduit and the downstream end of the first vein.
[0021] The invention makes it possible to perform air aspiration downstream of the vein, without risk of affecting the behavior and durability of the parts connected to the aspiration device. This is made possible thanks to the particular configuration of the connection between the downstream end of the vein and the upstream end of the aspiration duct.
[0022] The relative displacements between the conduit and the vein are therefore not likely to generate a piston effect that could cause axial forces to interfere with the weighing systems. A weighing system includes, for example, a balance.
[0023] The test bench according to the invention may also have one or more of the following characteristics, taken alone or in combination with each other: • the downstream end of the first vein has a cross-sectional air passage which decreases from upstream to downstream, in particular between the upstream and downstream ends of the orifices, and / or the upstream end of the conduit has a cross-sectional air passage which increases from upstream to downstream, in particular between the upstream and downstream ends of the openings; • the orifices are separated from each other by bars of the first wall, which have a circumferential dimension less than a circumferential dimension of the orifices; • the openings are separated from each other by bars of the first wall, which have a circumferential dimension less than a circumferential dimension of the openings; • the bars carry guide fins or are connected to each other by guide fins; the fins help to limit the forces that could appear in the vein with variations in momentum of the fluid when passing from an axial movement to a centripetal or centrifugal movement depending on the connection assembly; • the openings are separated from each other by radial partitions which connect the internal and external walls of the upstream end of the conduit; • at least part of the partitions includes at least one internal balancing pipe which includes an upstream end opening upstream of the sealing devices and a downstream end opening downstream of the sealing devices; • the number of holes is identical to the number of openings, and / or the shape and dimensions of the holes are identical to the shape and dimensions of the openings; • Each of the organs has an elastically deformable bellows shape, the inner and outer peripheries of which are respectively fixed to the said first walls; this type of organ, for example made of metal, polymer or elastomer, has a stiffness that is easy to characterize according to the different directions; • each of the components forms a labyrinth seal, each of the components being fixed on one of the first walls and having annular flaps which cooperate with the other of these walls; this type of sealing presents a certain leakage rate, but does not transmit forces or moments between the connected parts; • Each component is a segmented seal; this type of seal generally exhibits a low leakage rate, but generates solid friction forces opposing movement between the inner and outer parts. These forces, which need to be characterized, are also relatively weak;
[0024] — the bars have a general axial orientation, that is to say they extend parallel and along the aforementioned axis; • the orifices and openings are distributed respectively over several annular rows arranged axially next to each other;
[0025] — the vein is closed downstream due to the joining of its walls;
[0026] — the conduit is closed upstream due to the joining of its walls. Brief description of the figures
[0027] Other features and advantages of the invention will become apparent upon reading the detailed description that follows, for an understanding of which reference should be made to the accompanying drawings in which:
[0028] [Fig-1] [Fig.1] is a very schematic view of a test bench according to the invention,
[0029] [Fig.2] [Fig.2] is a schematic perspective view of a bench connection test according to the invention,
[0030] [Fig.3] [Fig.3] is a partial schematic perspective and axial section view of the connection of [Fig.2],
[0031] [Fig.4] [Fig.4] is another partial schematic perspective and sectional view axial of the connection of the [Fig.2],
[0032] [Fig.5] [Fig.5] is a view similar to that of [Fig.3] and illustrates one embodiment of the sealing elements,
[0033] [Fig.6] [Fig.6] is a view similar to that of [Fig.3] and illustrates a variant embodiment of the sealing elements,
[0034] [Fig.7] [Fig.7] are schematic perspective views of a variant of construction of an annular conduit for the connection,
[0035] [Fig.8] [Fig.8] is a view similar to that of [Fig.3] and illustrates another embodiment of the sealing elements,
[0036] [Fig.9] [Fig.9] is a view similar to that of [Fig.3] and illustrates another alternative design for the sealing components, and
[0037] [Fig. 10] [Fig. 10] is a very schematic cross-sectional view of another variant embodiment of the connection. Detailed description of the invention
[0038] Fig. 1 illustrates a test bench 10 for an aircraft turbomachine.
[0039] This test bench 10 has a longitudinal axis A and comprises at least:
[0040] - a rotor module 12 centered on axis A and equipped with a propulsion propeller 14 which can be faired or unfaired,
[0041] - a first weighing system 16 for the rotor module 12,
[0042] - a stator module 18 centered on axis A and located downstream of the rotor module 12,
[0043] - a second weighing system 20 for the stator module 18, and
[0044] - a suction device 22 located downstream of the stator module 18.
[0045] The stator module 18 comprises two coaxial annular veins: a first annular vein VI of primary flow Fl, and a second annular vein V2 of secondary flow F2, this second vein V2 extending around the first vein VI and being crossed by straightening arms 24 of the stator module 18.
[0046] The test bench 10 allows in particular to measure the performance of the propeller 14 and straightener arm 24 couple.
[0047] The suction device 22 includes an annular conduit 26, an upstream end 28 of which is connected to a downstream end 30 of the first vein VL. The downstream end of the conduit 26 can be connected to a pump, for example.
[0048] Figures 2 to 5 illustrate a first embodiment of the connection between the suction device 22 and the VL vein
[0049] The downstream end 30 of the first vein V1 is delimited by two coaxial annular walls, respectively internal 30a and external 30b, whose downstream annular edges 30al, 30bl are connected to each other. The vein VI is therefore closed downstream. A first of these walls 30a, 30b, namely the internal wall 30al in the example shown, includes an annular row of through air passages 32.
[0050] The upstream end 28 of the duct 26 comprises two coaxial annular walls, respectively internal 28a and external 28b, whose upstream annular edges 28a1, 28b1 are connected to each other. The duct 26 is therefore closed upstream. One of these walls 28a, 28b, namely the external wall 28b in the example shown, has an annular row of through-holes 34 for air passage.
[0051] The upstream end 28 of the conduit 26 is coaxially engaged here in the downstream end 30 of the first vein VI so that the openings 34 are aligned in radial direction with the orifices 32, and so that the suction device 22 can draw air from the first vein VI into the conduit 26, passing through the orifices 32 and the openings 34.
[0052] In the example shown, the downstream end 30 of the first vein Via a cross-section of air passage which can decrease from upstream to downstream, in particular between the upstream and downstream ends of the orifices 32.
[0053] Similarly, the upstream end 28 of the duct 26 has an air passage cross-section which can increase from upstream to downstream, in particular between the upstream and downstream ends of the openings 34.
[0054] In the example shown, the orifices 32 are separated from each other by bars 37 of the inner wall 30a. The bars 37 have a generally axial orientation. These bars 37 may have a circumferential dimension E1 smaller than a circumferential dimension E2 of the orifices 32.
[0055] The openings 34 can also be separated from each other by bars 39 of the outer wall 28b. The bars 39 have a generally axial orientation. These bars 39 can have a circumferential dimension E3 smaller than a circumferential dimension E4 of the openings 34.
[0056] The number of orifices 32 may be identical to the number of openings 34. The shape and / or dimensions of the orifices 32 may be identical to the shape and dimensions of the openings 34.
[0057] A radial annular gap J is provided between the walls 28b, 30a. Sealing elements 38, 40 are located in this gap 36, upstream and downstream of the orifices 32 and the openings 34. These sealing elements 38, 40 are configured to allow relative displacements in the radial and axial directions between the upstream end 28 of the conduit 26 and the downstream end 30 of the first vein VL
[0058] In the example shown, each of the components 38, 40 has an elastically deformable bellows shape. The inner periphery of each bellows is fixed to the outer wall 28b and the outer periphery of each bellows is fixed to the inner wall 30a. Each bellows has a corrugated or accordion-like wall that is elastically deformable in the radial and axial directions to allow relative displacements between the ends 28, 30.
[0059] Fig. 6 illustrates an alternative embodiment of the sealing elements 38, 40.
[0060] In the example shown, each of the components 38, 40 forms a labyrinth seal. Each of the components 38, 40 is fixed to the inner wall 30a in the example shown, and includes annular grooves 42 that cooperate with the outer wall 28b. The reverse would of course be conceivable: each of the components 38, 40 would be fixed to the outer wall 28b and would include annular grooves 42 that would cooperate with the inner wall 30a.
[0061] In yet another variant not shown, each of the organs could be a segmented joint.
[0062] Figure 7 illustrates another variant in which the openings 34 are separated from each other by radial partitions 44 which connect the internal and external walls 28a, 28b of the upstream end 28 of the duct 26. In this configuration, the upstream end 28 of the duct 26 may include an annular groove 46 at the level of which the partitions 44 would delimit the air passage openings 34.
[0063] In the embodiment shown in [Fig. 8], at least part of the partitions 44 includes at least one internal balancing channel 48. These channels 48 are formed within the thickness of the partitions 44. Each of these channels 48 comprises an upstream end 48a which opens upstream of the sealing element 38 and a downstream end 48b which opens downstream of the sealing element 40. The channels 48 thus ensure pressure balancing between the upstream and downstream sides of the elements 38, 40 and therefore between the upstream and downstream sides of the ports 32 and the openings 34.
[0064] Figure 7 illustrates another variant in which the bars 37 of the inner wall 28b carry guide fins 50 or are connected to each other by guide fins 50. The fins 50 can then have an annular shape and extend around the axis A. In the same way, the bars 39 of the outer wall 30a could carry similar guide fins or be connected to each other by similar guide fins.
[0065] Figure 8 shows that the orifices 32 and the openings 32 can be distributed respectively over several annular rows arranged axially next to each other. Each of the rows of orifices 32 and associated openings 34 is associated with a pair of sealing elements 38, 40. Furthermore, in this embodiment, the end 28 of the conduit 26 is engaged on the end 30 of the vein.
Claims
1. Demands Test bench (10) for an aircraft turbomachine, this test bench (10) having a longitudinal axis (A) and comprising: - a rotor module (12) centered on the axis (A) and equipped with a propulsion propeller (14), - a first weighing system (16) for the rotor module (12), - a stator module (18) centered on the axis (A) and located downstream of the rotor module (12), this stator module (18) comprising two coaxial annular channels: a first annular channel (VI) for the flow of a primary flow (F1), and a second annular channel (V2) for the flow of a secondary flow (F2), this second channel (V2) extending around the first channel (VI) and being crossed by straightening arms (24) of the stator module (18), - a second weighing system (20) for the stator module (18), and - a suction device (22) located downstream of the stator module (18) and comprising an annular conduit (26) whose upstream end (28) is connected to a downstream end (30) of the first vein (VI), the downstream end (30) of the first vein (VI) being delimited by two coaxial annular walls, respectively internal (30a) and external (30b), whose downstream annular edges (30a1a, 30b1) are connected to each other, a first of these walls (30a) having at least one annular row of through-holes (32) for air passage, and the upstream end (28) of the conduit (26) comprising two coaxial annular walls, respectively internal (28a) and external (28b), whose upstream annular edges (28a1a, 28b1) are connected to each other, a first of these walls (28b) having at least one annular row of through-holes (34) for air passage, the upstream end (28) of the conduit (26) being coaxially engaged in or on the downstream end (30) of the first vein (VI) such that the openings (34) are aligned radially with the orifices (32) of the downstream end (30) of the first vein (VI),and so that the suction device (22) can draw air from the first vein (VI) into the duct (26), passing through the orifices (32) and the openings (34), A radial annular gap (J) is provided between the first walls (30a, 28b), and sealing elements (38, 40) are located within this gap. (J), upstream and downstream of the orifices (32) and openings (34), these sealing elements (38, 40) being configured to allow relative displacements in radial and axial directions between the upstream end (28) of the conduit (26) and the downstream end (30) of the first vein (VI).
2. Test bench (10) according to claim 1, wherein the downstream end (30) of the first vein (VI) has an air passage cross-section which decreases from upstream to downstream, in particular between the upstream and downstream ends of the orifices (32), and / or the upstream end (28) of the conduit (26) has an air passage cross-section which increases from upstream to downstream, in particular between the upstream and downstream ends of the openings (34).
3. Test bench (10) according to claim 1 or 2, in which the orifices (32) are separated from each other by bars (37) of the first wall (30a), which have a circumferential dimension (El) less than a circumferential dimension (E2) of the orifices (32).
4. Test bench (10) according to any one of the preceding claims, wherein the openings (34) are separated from each other by bars (39) of the first wall (28b), which have a circumferential dimension (E3) less than a circumferential dimension (E4) of the openings (34).
5. Test bench (10) according to claim 3 or 4, wherein the bars (37, 39) carry guide fins (50) or are connected to each other by guide fins (50).
6. Test bench (10) according to any one of claims 1 to 3, in which the openings (34) are separated from each other by radial partitions (44) which connect the internal and external walls (28a, 28b) of the upstream end (28) of the conduit (26).
7. Test bench (10) according to claim 6, wherein at least a portion of the partitions (44) comprises at least one internal balancing channel (48) which includes an upstream end (48a) opening upstream of the sealing members (38, 40), and a downstream end (48b) opening downstream of the sealing members (38, 40).
8. Test bench (10) according to any one of the preceding claims, wherein the number of orifices (32) is identical to the number of openings (34), and / or the shape and dimensions of the orifices (32) are identical to the shape and dimensions of the openings (34).
9. Test bench (10) according to any one of the preceding claims, wherein each of the components (38, 40) has an elastically deformable bellows shape, the internal and external peripheries of which are respectively fixed to said first walls (30a, 28b).
10. Test bench (10) according to any one of the preceding claims, wherein each of the members (38, 40) forms a labyrinth seal, each of the members being fixed on one of the first walls (30b, 28a) and comprising annular strips (42) which cooperate with the other of these walls (28a, 30b).
11. Test bench (10) according to any one of the preceding claims, wherein each of the components (38, 40) is a segmented joint.
12. Test bench (10) according to any one of the preceding claims, in which the orifices (32) and the openings (34) are distributed respectively over several annular rows arranged axially next to each other.