Testing machine

Abstract

The invention relates to a test machine (100) comprising an airflow channel in which is located at least one impeller that rotates about a longitudinal axis (X) of the airflow channel, said test machine comprising a flow distortion device (8) arranged upstream of the impeller that rotates along the direction of the airflow, said flow distortion device (8) being rotatably mounted about the longitudinal axis (X). Figure to be published with the abstract: [Fig. 4]

Description

Title of the invention: Testing machine Technical field of the invention

[0001] The invention relates to a testing machine, for example, an aeroacoustic testing machine for characterizing a moving blade wheel. State of the prior art

[0002] In the context of aero-acoustic testing, it is known to install a flow distortion device in the upstream part of a flow vein, so as to be able to simulate different aerodynamic phenomena, such as the presence of an aircraft wing, the ground or the aircraft fairing near the engine.

[0003] [Fig. 1] illustrates a part of a test machine 1 of the prior art. This comprises a vein 2 of axis X whose dimensions are reduced compared to the real dimensions of a turbomachine, for example of a ratio 4. The vein 2 is delimited by an external casing 3, a machine 4 comprising a rotating shaft 5 being mounted in the vein. This shaft is integral with a disc 6 carrying blades 7, simulating for example a fan rotor.

[0004] Upstream of the disk 6 and the blades 7 is mounted a flow distortion device 8. The latter is thus mounted in an area simulating an air intake sleeve of a nacelle of a turbomachine. The device 8, better visible in [Fig. 2], comprises a grid 9 extending in a radial plane, and a reinforcement 10 located downstream of the grid 9.

[0005] The grid 9 is for example formed from a mesh of braided or welded wires, the diameter of the wires, the shape and the dimensions of the mesh being a function of the aerodynamic phenomenon to be simulated.

[0006] The reinforcement 10 comprises a radially internal annular part 11 and a radially external annular part 12, connected by rectilinear arms 13 extending between the internal 11 and external 12 annular parts. The arms 13 each extend in the radial direction.

[0007] The reinforcement 10 makes it possible to hold the grid 9 in position in order to prevent it from being torn off under the effect of the stresses which may be applied during operation. The external annular part 12 of the reinforcement 10 is fixed using flanges to the external casing 3.

[0008] The reinforcement 10 is generally fixed and the grids are changed to test various influences on the flow flowing in the vein 2. By way of illustration, examples of flow distortion devices are shown in Figures 3a, 3b, 3c and 3d and can be used to disturb the inlet flow. Each distortion device comprises a solid or alternatively porous part 14 partially obscuring the grid 9. Each configuration of the solid or alternatively porous part 14 makes it possible to create a specific disturbance of the flow circulating in the vein 2. The solid or porous parts 14 are generally arranged asymmetrically.

[0009] The testing machine generally comprises instruments for measuring the characteristics of the flow at the level of the vein. The measuring instruments may be different sensors integrated in the external casing 3 and opening into the vein 2.

[0010] In the case of such non-axisymmetric distortion grids, it is necessary to take measurements in numerous azimuths of the vein 2 in order to be able to evaluate the disturbance of the flow generated at the level of the blades 7.

[0011] For this purpose, it is possible to multiply the sensors which is expensive and has a strong impact on integration into the testing machine.

[0012] It is also possible to integrate the sensors into a ring rotating around the vein 2, which makes it possible to multiply the measurements at different azimuths around the longitudinal axis. However, the integration of such a ring into the testing machine is complex due to the impact on rigidity, lack of space, the presence of fixing means, etc. In addition, it is difficult to ensure sealing at the interfaces between the stator and the rotating ring. Managing the wiring of the ring is also complex to achieve.

[0013] The invention aims in particular to provide a simple, effective and economical solution to the aforementioned problems. Summary of the invention

[0014] To this end, the invention proposes a testing machine comprising an air flow vein in which is located at least one bladed wheel movable in rotation along a longitudinal axis of the air flow vein, said testing machine comprising a flow distortion device arranged upstream of the bladed wheel movable along the direction of the air flow, said flow distortion device being mounted rotatably around the longitudinal axis.

[0015] Thus, in the case of an asymmetric flow distortion device, it is possible to orient it along different azimuths in order to carry out measurements relating to the flow in the air flow vein. In addition, this arrangement is simple to implement.

[0016] The testing machine may comprise means for actuating the flow distortion device and means for transmitting rotation from the actuating means to said flow distortion device. Such actuating means may be an electric motor, for example associated with an azimuth position sensor, and the rotation transmission means may comprise a first pinion connected to the electric motor and a second pinion or a toothed wheel meshing with the first pinion. The second pinion or the toothed wheel may be configured to drive rotation of the flow distortion device.

[0017] The testing machine may further comprise a means for determining the azimuthal position of the distortion support. Such a means may be an angular sensor, for example integrated into the electric motor.

[0018] The flow distortion device may comprise a grid mounted on a grid support. The grid support may comprise an inner annular portion and an outer annular portion connected by reinforcing arms. The outer annular portion may be coaxial with, and surrounding said inner annular portion and said reinforcing arms may extend radially and be distributed circumferentially around an axis of said inner and outer annular portions.

[0019] The flow distortion device may comprise between 3 and 12 reinforcing arms.

[0020] The testing machine may comprise a housing defining the air flow path and in which the movable impeller and the flow distortion device are arranged.

[0021] According to one embodiment, the actuating means of the flow distortion device and the rotation transmission means may be arranged in a housing of the casing arranged upstream of the movable impeller. In particular, the housing may be arranged in an upstream portion of the casing, in particular upstream of the movable impeller.

[0022] The housing may be delimited by an outer annular wall and by an inner annular wall. The outer annular wall may extend radially outwardly from the inner annular wall, forming a "c". The housing may be closed downstream in part by a downstream wall of the casing and by an annular fairing surrounding the downstream wall.

[0023] Furthermore, sealing means may be arranged at the outlet of the housing into the air flow stream.

[0024] A radially outer portion of the flow distortion device may be inserted into the housing through an opening provided in the inner annular wall forming the outlet of the housing into the air flow stream.

[0025] A first seal, for example of the lip seal type, may be arranged upstream of the flow distortion device. This first seal may be arranged in an annular groove provided in an axial end of the inner annular wall. A second seal, for example of the O-ring type, may be arranged downstream of the flow distortion device. This second seal may be arranged in an axial end of the downstream wall.

[0026] The rotation transmission means may comprise a rotating support, in particular integral with the second pinion or the toothed wheel. The radially external part of the flow distortion device may be removably mounted on said rotating support.

[0027] The testing machine may comprise a bearing for guiding the device in rotation. flow distortion, said radially external part being removably mounted on the guide bearing.

[0028] The guide bearing may comprise an inner ring on which the flow distortion device is fixed and an outer ring fixed to the fairing and / or to the downstream wall. Rolling elements may be arranged between the inner ring and the outer ring. The outer ring may comprise a channel provided for the circulation of lubricant intended for example for the rolling elements.

[0029] The testing machine may include at least one sensor arranged at the air flow duct, said sensor being configured to detect a characteristic of the flow circulating in the air flow duct. The sensor may be configured to measure a pressure, a temperature, a velocity or any other physical characteristic of the flow circulating in the air flow duct. At least one sensor may be arranged downstream of the movable impeller.

[0030] The invention also relates to a method for characterizing the flow circulating in a testing machine according to one of the examples discussed above, the method comprising the steps of: a) mounting the flow distortion device in the air flow vein, (b) orienting the flow distortion device around the longitudinal axis in a given orientation, and (c) carry out measurements of the characteristics of the flow circulating in the air flow vein.

[0031] The method may comprise repeating steps b) and c). Brief description of the figures

[0032] [Fig-1] represents a schematic half-sectional view of a testing machine of the art prior,

[0033] [Fig.2] represents a perspective view of an example of a flow distortion device of the prior art,

[0034] [Fig.3] shows front views of other examples of prior art flow distortion devices,

[0035] [Fig.4] represents a schematic half-view of an upstream part of a testing machine according to the invention. Detailed description of the invention

[0036] [Fig. 4] represents an upstream part of a testing machine 100 according to the invention. The testing machine 100 comprises the same elements as the testing machine 1 of [Fig. 1] and is configured for aerodynamic tests. In contrast, the testing machine 100 comprises in its upstream part means for actuating in rotation a flow distortion device 8 such as that of [Fig. 2] or 3a to 3d. In par In particular, the testing machine 100 comprises an air inlet sleeve 102 forming the upstream portion of the casing 3 of the testing machine. The air inlet sleeve 102 is annular and in which an air flow circulates. In its upstream portion, the air inlet sleeve 102 comprises a portion curved radially outwards in order to channel the incoming air flow.

[0037] The air inlet sleeve 102 comprises a housing in which means for rotating the flow distortion device 8 are arranged. The housing is delimited by an outer annular wall 101 and by an inner annular wall 103. The outer annular wall 101 extends radially outwards from the inner annular wall 103, forming a “c”. The housing is partially closed downstream by a downstream wall 104 of the casing 3 and by an annular fairing 105 surrounding the downstream wall 104. The axis of revolution of the flow distortion device 8 coincides with a longitudinal axis X of the testing machine 100.

[0038] To rotate the flow distortion device 8, the testing machine 100 comprises an electric motor 108 provided with a pinion 110, for example a bevel gear. The electric motor 108 is inserted through the outer annular wall 101. The testing machine 100 also comprises an annular rotating support 112 and comprising an annular toothed wheel 114, engaged with the pinion 110 to drive the rotation of the rotating support 112. The flow distortion device 8 is mounted on the rotating support 112 and is fixed there by screws for example.

[0039] The testing machine 100 further comprises a means for determining the azimuthal position of the distortion support. Such a means may be an angular sensor, for example integrated into the electric motor 108.

[0040] The testing machine 100 further comprises a bearing for guiding the flow distortion device 8 in rotation. The guide bearing comprises an inner ring 116 on which the flow distortion device 8 is fixed and an outer ring 118 fixed to the fairing 105 and to the downstream wall 104. Rolling elements 120 are arranged between the inner ring 116 and the outer ring 118, either in contact with each other or spaced apart by a cage or separators not shown here. The outer ring 118 comprises a channel 122 in which lubricant circulates, for example intended for the rolling elements 120. The flow distortion device 8 is fixed to the inner ring 116 by screwing. The rolling elements 120 may be of the doublet ball crown type. The outer ring 118 may include a clearance 122 provided to apply a preload to the ball crown doublet so as to consume any clearance therein.

[0041] A radially outer portion of the flow distortion device 8 is inserted into the housing through an opening provided in the inner annular wall 103. In order to ensure sealing at said opening, two seals are arranged upstream and downstream of the radially outer portion of the flow distortion device 8. A seal 126, for example of the lip seal type, is arranged upstream of the flow distortion device 8. A seal 124, for example of the O-ring type, is arranged downstream of the flow distortion device 8. The seal 126 is arranged in an annular groove provided in an axial end of the inner annular wall 103. The seal 124 is arranged in a groove provided in an axial end of the downstream wall 104. Upstream and downstream are defined relative to the flow of the flow in the vein 2.

[0042] The testing machine 100 comprises, downstream of the flow distortion device 8, sensors configured to characterize the flow circulating in the vein 2. The sensors are capable of measuring a pressure, a temperature, a speed or any other physical characteristic of the flow circulating in the air flow vein 2. At least one sensor is arranged downstream of the movable bladed wheel 7.

[0043] In operation, a flow distortion device 8 is mounted in the testing machine 100 and is attached to the rotating support 112. The testing machine 100 is operated and the flow characteristics in the vein 2 are recorded. When the flow distortion device 8 is not symmetrical about the longitudinal axis X, the electric motor 108 is operated to change the orientation of the flow distortion device 8 about the longitudinal axis X and the flow characteristics in the vein 2 are recorded for this orientation. The orientation of the flow distortion device 8 is changed as necessary to record the flow characteristics in the vein 2. Thus, the disturbances produced by the orientation of the flow distortion device 8 can be tested in a simple and inexpensive manner.

Claims

Claims

1. Testing machine (100) comprising an air flow vein (2) in which is located at least one bladed wheel (7) movable in rotation along a longitudinal axis (X) of the air flow vein (2), said testing machine comprising a flow distortion device (8) arranged upstream of the bladed wheel movable along the direction of the air flow, said flow distortion device (8) being rotatably mounted around the longitudinal axis (X).

2. Testing machine (100) according to claim 1, comprising actuating means (108) of the flow distortion device (8) and means for transmitting rotation of the actuating means to said flow distortion device (8).

3. Testing machine (100) according to one of the preceding claims, wherein the flow distortion device (8) comprises a grid (9) mounted on a grid support, said grid support comprising an inner annular portion (11) and an outer annular portion (12) connected by reinforcing arms (10, 13), said outer annular portion (12) being coaxial with and surrounding said inner annular portion (11), said reinforcing arms extending radially and being distributed circumferentially around an axis of said inner and outer annular portions.

4. Testing machine (100) according to one of the preceding claims, comprising a casing (3) defining the air flow vein (2) and in which the movable impeller (7) and the flow distortion device (8) are arranged.

5. Testing machine (100) according to claim 4 in combination with claim 2, wherein the actuating means (108) of the flow distortion device (8) and the rotation transmission means are arranged in a housing of the casing (3) arranged upstream of the movable impeller (7).

6. Testing machine (100) according to the preceding claim, in which sealing means (126, 124) are arranged at the outlet of the housing into the air flow vein (2).

7. Testing machine (100) according to one of the preceding claims taken in combination with claims 2 and 3, wherein the rotation transmission means comprise a rotating support (112), the radially external part of the flow distortion device (8) being removably mounted on said rotating support.

8. Testing machine (100) according to one of the preceding claims taken in combination with claims 2 and 3, comprising a guide bearing (116,118) for rotation of the flow distortion device (8), said radially external part being removably mounted on the guide bearing (116,118).

9. Testing machine (100) according to one of the preceding claims, comprising at least one sensor arranged at the air flow vein (2), said sensor being configured to detect a characteristic of the flow circulating in the air flow vein.

10. Method for characterizing the flow circulating in a testing machine (100) according to one of the preceding claims, comprising the steps of: - mounting the flow distortion device (8) in the air flow vein (2), - orienting the flow distortion device (8) around the longitudinal axis (X) in a given orientation, and - carrying out measurements of the characteristics of the flow circulating in the air flow vein (2).

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