Comb stabilizer for measuring the characteristics of an air flow in a turbomachine

Abstract

The present disclosure relates to a comb for measuring characteristics of an air flow circulating in a flow duct of a test turbomachine, the comb comprising a base intended to fix the comb to a support and a longitudinal arm extending from the base so as to extend in a test turbomachine duct along a radial axis of the test turbomachine and perpendicular to a flow direction of the flow. The arm comprises a measuring device extending from the arm parallel to the flow direction and in a direction opposite to the flow direction, the measuring device comprising a free end facing the flow. Still according to this first aspect, the comb is characterized in that it comprises a stabilizer fixed to the arm, the stabilizer being configured to deflect the flow and create lift on the comb along the radial axis. Figure for abstract: Fig. 2C

Description

Title of the invention: Comb stabilizer for measuring the characteristics of an air flow in a turbomachine Technical field

[0001] The present disclosure relates to the field of measuring devices in a turbomachine and more specifically to test turbomachines. More particularly, the present disclosure relates to a comb for measuring the characteristics of the air flow circulating in a vein of a test turbomachine. STATE OF THE ART

[0002] The design of a turbomachine requires the performance tests to be carried out on a test turbomachine.

[0003] Testing on the test turbomachine may involve subjecting the test turbomachine to many different physical conditions such as airflows having varying speed, varying pressure, varying temperature, etc.

[0004] In order to evaluate the performance of the test turbomachine it is necessary to carry out measurements at different points of the turbomachine during the tests.

[0005] In the case of air flow, it is possible to measure characteristics of the air flow such as pressure and speed, by positioning a measuring comb in a circulation vein of the air flow of the test turbomachine. The comb thus makes it possible to carry out so-called intrusive measurements, directly in the vein of the test turbomachine.

[0006] However, the measuring comb must be able to measure the characteristics of the air flow at different points in the vein, without disturbing the air flow. Indeed, such a disturbance could distort the measurements.

[0007] Thus, the comb must be sufficiently aerodynamic so as not to disturb the air flow in the vein while being sufficiently strong so as not to be subject to movement due to the air flow. Indeed, the air flow could mechanically constrain or vibrate the comb which could also distort the measurements. GENERAL DISCLOSURE

[0008] One aim of the disclosure is therefore to propose a comb that is more resistant to the mechanical stresses induced by the air flow without disturbing the flow of the air flow.

[0009] To this end, according to a first aspect of the present disclosure, a comb is proposed for measuring the characteristics of an air flow circulating in a flow path of a test turbomachine, the comb comprising a base intended to fix the comb to a support and a longitudinal arm extending from the base so as to extend in a flow path of the test turbomachine along a radial axis of the test turbomachine. and perpendicular to a flow direction of the flow. The arm comprises at least one measuring device extending from the arm parallel to the flow direction and in a direction opposite to the flow direction, the at least one measuring device comprising a free end facing the flow. Still according to this first aspect, the comb is characterized in that it comprises at least one stabilizer attached to the arm, the at least one stabilizer being configured to deflect the flow and create lift on the comb along the radial axis.

[0010] Advantageously, but optionally, the method described comprises at least one of the following characteristics, taken alone or in any combination:

[0011] - the at least one stabilizer comprises an aerodynamic profile, the profile aerodynamic being parallel to the flow direction and the radial axis;

[0012] - the leading edge is positioned downstream of the at least one measuring device according to the flow direction;

[0013] - the arm comprises a height from the base, the at least one stabilizer being positioned on the arm at more than one-third of the arm height;

[0014] - the at least one stabilizer comprises a fin at each of the ends, the fins are configured to reduce lift-induced drag created by the at least one stabilizer;

[0015] - the at least one stabilizer comprises a flexible profile portion configured to allow for low lift in the event of flow at too high a speed, the flexible profile portion causing the trailing edge to warp relative to the leading edge along the radial axis.

[0016] According to a second aspect, there is provided a test turbomachine comprising a flow vein of a flow and a comb according to the first aspect, the arm of the comb extending radially in the flow vein.

[0017] The test turbomachine may also comprise a fan and a rectifier, the comb being positioned upstream of the fan and / or downstream of the rectifier.

[0018] In addition, the turbomachine according to this second aspect may comprise a wheel of moving blades and a wheel of fixed blades, the comb being positioned upstream of the wheel of moving blades and / or downstream of the wheel of fixed blades. DESCRIPTION OF FIGURES

[0019] Other characteristics, aims and advantages will emerge from the following description, which is purely illustrative and non-limiting, and which must be read in conjunction with the appended drawings in which:

[0020] [Fig.l] illustrates a schematic view of a partial section of a turbomachine according to a possible embodiment of the present disclosure;

[0021] [Fig.2a], [Fig.2b] and [Fig.2c] illustrate different views of a comb with a stabilizer according to an embodiment of the present invention;

[0022] [Fig.3a] and [Fig.3b] illustrate different views of a comb with several stabilizers according to embodiments of the present invention; and

[0023] [Fig.4] illustrates a view of a comb with a stabilizer and fins according to an embodiment of the present invention.

[0024] Throughout the figures, similar elements bear identical references. DETAILED DESCRIPTION

[0025] Test turbomachine

[0026] A turbomachine 1, as illustrated for example in [Fig.l], has a main direction extending along a longitudinal axis X and comprises, from upstream to downstream in the direction of the flow of gases in the turbomachine 1 when it is in operation, a fan section 2 and a primary body 3, often called a “gas generator”, comprising a compressor section 4, a combustion chamber 5 and a turbine section 6. The turbomachine 1 is here configured to be tested in order to characterize its performance. In other words, it is a test turbomachine 1.

[0027] The compressor section 4 comprises a succession of stages each comprising a wheel of moving blades (rotor) 4a rotating in front of a wheel of fixed blades (stator) 4b. The turbine section 6 also comprises a succession of stages each comprising a wheel of fixed blades (stator) 6b behind which a wheel of moving blades (rotor) 6a rotates.

[0028] In the present disclosure, the axial direction, or flow direction, corresponds to the direction of the longitudinal axis X, in correspondence with the rotation of the shafts 7 of the primary body 3, and a radial direction is a direction perpendicular to this longitudinal axis X and passing through it. Furthermore, the circumferential (or lateral, or even tangential) direction corresponds to a direction perpendicular to the longitudinal axis X and not passing through it. Unless otherwise specified, internal (respectively, interior) and external (respectively, exterior), respectively, are used with reference to a radial direction so that the internal part or face of an element is closer to the longitudinal axis X than the external part or face of the same element.

[0029] During the tests, or trials, carried out on the turbomachine 1, an air flow F entering the turbomachine 1 is divided between a primary air flow F1 and a secondary air flow F2, which circulate from upstream to downstream in the turbomachine 1.

[0030] The secondary air flow F2, also called “bypass air flow”, flows around the primary body 3, in other words in a secondary vein 82 (in the case of an unducted fan section, the secondary vein 82 is fictitious and corresponds to the portion of the secondary air flow F2 flowing around the primary body 3 and passing through the fan section 2). The secondary air flow F2 allows the periphery of the primary body 3 to be cooled and is used to generate the majority of the thrust provided by the propulsion system 1.

[0031] The primary air flow F1 flows in a primary vein 81 inside the primary body 3, passing successively through the compressor section 4, the combustion chamber 5 where it is mixed with fuel to serve as an oxidant, and the turbine section 6. The passage of the primary air flow F1 through the turbine section 6 receiving energy from the combustion chamber 5 causes rotation of the rotor stages 6a of the turbine section 6 which in turn drives rotation of the rotor stages 4a of the compressor section 4 as well as a rotor 9 of the fan section 2.

[0032] The fan section 2 comprises at least the rotor 9 capable of being driven in rotation relative to a stator part 10 of the turbomachine 1 by at least one rotor part of the turbine section 6. Each rotor 9 of the fan section 2 comprises blades 11.

[0033] The fan section 2 may further comprise a stator 12, or rectifier, which comprises blades 13 mounted on a hub of the stator 12 and whose function is to straighten the secondary air flow F2 which flows out of the rotor 9.

[0034] The fan section 2 may be ducted or unducted.

[0035] In the case of a shrouded fan section 2, the fan section 2 comprises a fan casing and the rotor 9 is housed in the fan casing. A shrouded fan section 2 comprises a rotor 9 extending upstream of a stator 12. The vanes 13 of the stator 12 are then generally called “outlet vanes” (or “OGV”, for “Outlet Guide Vane” in English terminology) and have a fixed setting relative to the hub of the stator 12.

[0036] In an unducted fan section 2, the fan section 2, which may also be referred to as a “propeller,” is not surrounded by a fan casing. Propulsion systems comprising at least one unducted rotor 9 are known, in English terminology, as “open rotor” or “unducted fan.” The propulsion system 1 may comprise two unducted, counter-rotating rotors 9. Such a propulsion system 1 is known, in English terminology, as the acronym “CROR” for “Contra-Rotating Open Rotor” or “UDF” for “Unducted Double Fan.” The rotors 9 can be placed at the rear of the primary body 3 so as to be of the pusher type or at the front of the primary body 3 so as to be of the tractor type.Alternatively, the propulsion system 1 may comprise a single unducted rotor 9 and a non-ducted stator 16. ducted (rectifier). Such a propulsion system 1 is known, in Anglo-Saxon terminology, by the acronym “USF” for “Unducted Single Fan”.

[0037] In order to carry out the tests, combs 14 are positioned in, on or around the turbomachine 1.

[0038] Comb

[0039] The comb 14 can make it possible to carry out measurements of aerodynamic quantities, such as pressure or temperature or speed, of a gas flow such as the air flow F entering the turbomachine 1, the primary air flow Fl and / or the secondary air flow F2. For greater simplicity, we will hereinafter simply refer to flows F, Fl, F2, to refer to the air flow F entering the turbomachine 1, the primary air flow Fl and the secondary air flow F2 in which the comb 14 is positioned.

[0040] The comb 14 is placed in the primary vein 81 and / or in the secondary vein 82 in order to carry out the measurements on the flow F, Fl, F2, at different desired locations of the primary vein 81 and / or in the secondary vein 82. The comb 14 thus makes it possible to carry out so-called intrusive measurements, i.e. directly in the flow F, Fl, F2. The intrusive measurements make it possible to minimize the measurement uncertainties.

[0041] The comb 14 comprises a base 15 and an arm 16.

[0042] The base 15 of the comb 14 is intended to fix the comb 14 to a support 140. In the case of a comb 14 positioned in the secondary vein 82 to carry out measurements of aerodynamic quantities on the secondary flow F2, the support 140 is fixed to the fan casing (in the case of a ducted fan section) or to an external support (in the case of a non-ducted fan section). In the case of a comb 14 positioned in the primary vein 81 to carry out measurements of aerodynamic quantities on the primary flow F1, the support 140 is fixed to a casing of the primary body 3.

[0043] The arm 16 of the comb 14 extends from the base 15. The arm 16 is longitudinal and is configured to extend radially in the turbomachine 1. In other words, once the base 15 of the comb 14 is fixed to the support 140, the arm 16 extends along a radial axis of the turbomachine 1, called radial axis Y, in the primary vein 81 or in the secondary vein 82 of the turbomachine 1. The arm 16 thus extends perpendicular to the longitudinal axis X and therefore to the direction of flow of the flow.

[0044] The arm 16 comprises a first end 17 and a second end 18. The first end 17 is fixed to the base 15 while the second end 18 is free and positioned in the primary vein 81 or in the secondary vein 82 and subjected to the flow F, F1, F2.

[0045] The arm 16 comprises at least one, and preferably several, measuring devices 19. The measuring device 19 is configured to carry out measurements of aerodynamic quantities. The measuring device 19 is fixed to the arm 16 and extends parallel to the longitudinal axis. The measuring device 19 extends from the arm 16 in a direction opposite to the flow of the stream F, Fl, F2, and comprises a free end facing the stream F, Fl, F2. In other words, the measuring device 19 extends upstream of the arm 16 to which it is attached. Such an arrangement allows the measuring device 19 to carry out measurements on the stream F, Fl, F2, before the arm 16 disturbs it.

[0046] The measuring device 19 can be of different types such as for example a tube / nozzle extending along the longitudinal axis X.

[0047] In the case of an arm 16 with several measuring devices, each measuring device 19 can thus carry out a measurement on the flow F, F1, F2, at a different radius. In other words, several measurements of the same aerodynamic characteristic or of different aerodynamic characteristics can be carried out at different radial positions in the primary vein 81 or secondary vein 82.

[0048] The presence of the arm 16 in the primary vein 81 or in the secondary vein 82 induces aerodynamic losses which can distort measurements. Thus, the arm 16 may have a biconvex profiled shape in an axial plane in order to reduce aerodynamic losses. The profile of the arm 16 from the first end 17 to the second end 18 may be a NACA type aerodynamic profile. Thus, the arm 16 comprises an upstream portion forming a leading edge 20 and a downstream portion forming a trailing edge 21. The measuring device(s) 19 is(are) positioned on the leading edge 20 of the arm 16.

[0049] For reasons of flow resistance but also of limitation of disturbances of the flow F, F1, F2, the first end 17 of the arm 16 may comprise a chord line of greater length than the chord line of the second end 18 of the arm 16.

[0050] Stabilizer

[0051] The comb 14 comprises one or more stabilizers 22 attached to the arm 16. The stabilizer 22 is configured to create lift on the comb 14 in the direction of the radial axis Y and thus prevent bending of the arm 16 of the comb 14 perpendicular to the radial axis Y.

[0052] Indeed, the comb 14 is positioned in the flow F, Fl, F2, to carry out measurements at different points of the flow F, Fl, F2, while avoiding as much as possible disturbing the flow of the flow F, Fl, F2, so as not to distort the measurements. The arm 16 of the comb 14 is therefore subject to forces transverse to the radial axis Y and can enter into resonance and / or bending, which can generate fatigue and damage to the comb 14.

[0053] The stabilizer 22 has an aerodynamic profile configured to deflect the flow F, F1, F2, and create lift on the comb 14. The aerodynamic profile of the stabilizer 22 extends in an axial plane of the turbomachine 1, in other words, the profile aerodynamic is parallel to the flow direction X and to the radial axis Y. Thus, the stabilizer 22 creates lift on the comb 14 along the radial axis Y so that the comb 14 is constrained along the radial axis Y to avoid flexions of the comb 14 perpendicular to the radial axis Y.

[0054] The aerodynamic profile comprises a leading edge 23 and a trailing edge 24. The leading edge 23 and / or the trailing edge 24 may extend respectively in a radial plane, in other words in a plane normal to the direction of flow. The leading edge 23 and the trailing edge 24 may, furthermore, be perpendicular to the arm 16 to which the stabilizer 22 is attached or else be an arc of circumference centered on the longitudinal axis X, in other words be concentric with the flow F, F1, F2.

[0055] Advantageously, the stabilizer 22 comprises a lower surface 25 on the side of the first end 17 and an upper surface 26 on the side of the second end 18. In other words, the stabilizer 22 comprises a camber line having a concave curvature towards the first end 17. Thus, the lift force induced by the presence of the stabilizer 22 constrains the arm 16 along the radial axis Y and towards the second end 18.

[0056] The comb 14 with stabilizer 22 is positioned in the primary vein 81 or in the secondary vein 82 in order to carry out measurements on the flows F, Fl, F2. For example, the comb 14 can be positioned: - in the secondary vein 82, upstream of the blower 9 and / or downstream of the rectifier 12; and / or - in the primary vein 81, upstream of a moving blade wheel 4a, 6a and / or downstream of a fixed blade wheel 4b, 6b.

[0057] The leading edge 23 of the stabilizer 22 is fixed to the arm 16 downstream of the measuring device 19 in the direction of flow. In other words, the flow F, F1, F2 is deflected by the stabilizer 22 downstream of the measuring device 19. Thus, the measurement by the measuring device 19 is not disturbed by the presence of the stabilizer 22.

[0058] The stabilizer 22 may, in addition, comprise a flexible profile portion 27. In other words, the stabilizer 22 may comprise a low-lift device, or inverted high-lift device (or inverted flap according to the usual English terminology). The flexible profile portion 27 is configured to allow low-lift in the event of flow F, F1, F2, at too high a speed. Indeed, the flow F, F1, F2, whose speed would be too high, could create a lift on the stabilizer 22 which could damage the comb 14. The flexible profile portion 27 induces a warping of the trailing edge 24 relative to the leading edge 23 along the radial axis Y in the direction of the second end 18 of the arm 16, in other words the flexible profile portion 27 makes it possible to reduce, or cancel, the concavity of the camber line. of the profile of the arm 16. The flexible profile portion 27 thus makes it possible to reduce the lift force induced on the arm 16.

[0059] The stabilizer 22 can be fixed on the arm 16 at different levels along the radial axis Y. Advantageously, the stabilizer 22 is positioned on the arm 16 at more than one third of the height of the arm 16 from the base 15. The stabilizer 22 can be positioned at the second end 18 of the arm 16. The position of the stabilizer 22 on the arm 16 along the radial axis Y is a function of the force induced by the flow F, Fl, F2, and of the resistance of the arm 16 to the bending induced by the flow F, Fl, F2. As illustrated by [Fig.3a], it is possible to fix several stabilizers 22, of identical or different sizes, on the same arm 16, as illustrated for example by [Fig.3b].

[0060] The stabilizer 22 may comprise a fin 28 (or "winglet" according to the usual Anglo-Saxon terminology) at each of its circumferential ends, as illustrated by [Fig. 4]. The fins 28 are configured to reduce drag induced by the lift created by the stabilizer 22. The fins 28 make it possible to reduce the disturbance of the flow F, Fl, F2, induced by the presence of the comb 14 and the stabilizer 22. The fins 28 may be of different shapes and different sizes depending on the needs and the comb 14 considered.

Claims

Claims

1. Comb (14) for measuring characteristics of a flow (F, F1, F2) of air circulating in a flow vein (81, 82) of a test turbomachine (1), the comb (14) comprising: - a base (15) intended to fix the comb (14) to a support (140); and - a longitudinal arm (16) extending from the base (15) so as to extend in a vein (81, 82) of the test turbomachine (1) along a radial axis (Y) of the test turbomachine (1) and, perpendicular to a flow direction (X) of the flow (F, F1, F2), the arm (16) comprising at least one measuring device (19) extending from the arm (16) parallel to the flow direction (X) and in a direction opposite to the flow direction (X), the at least one measuring device (19) comprising a free end facing the flow (F, F1, F2);the comb (14) being characterized in that it comprises at least one stabilizer (22) fixed to the arm (16), the at least one stabilizer (22) being configured to deflect the flow (F, F1, F2) and create lift on the comb (14) along the radial axis (Y) so that the comb (14) is constrained along the radial axis (Y).;

2. The comb (14) of claim 1, wherein the at least one stabilizer (22) comprises an airfoil comprising a leading edge (23), the airfoil being parallel to the flow direction (X) and the radial axis (Y).

3. Comb (14) according to claim 2, wherein the leading edge (23) is positioned downstream of the at least one measuring device (19) in the flow direction (X).

4. A comb (14) according to any one of claims 1 to 3, wherein the arm (16) comprises a height from the base (15), the at least one stabilizer (22) being positioned on the arm (16) at more than one third of the height of the arm (16).

5. The comb (14) of any one of claims 1 to 4, wherein the at least one stabilizer (22) comprises a fin (28) at each of the circumferential ends, the fins (28) are configured to reduce drag induced by lift created by the at least one stabilizer (22).

6. Comb (14) according to any one of claims 1 to 5, in which the at least one stabilizer (22) comprises a flexible profile portion (27) configured to allow hypo-lift in the event of flow (F, F1, F2) at too high a speed, the flexible profile portion (27) inducing a warping of the trailing edge (21) relative to the leading edge (20) along the radial axis (Y).

7. Test turbomachine (1) comprising a flow vein (81, 82) of a flow (F, Fl, F2) and a comb (14) according to any one of claims 1 to 6, the arm (16) of the comb (14) extending radially in the flow vein (81, 82).

8. A test turbomachine (1) according to claim 7, comprising a fan (9) and a rectifier (12), the comb (14) being positioned upstream of the fan (9) and / or downstream of the rectifier (12).

9. Test turbomachine (1) according to claim 7, comprising a moving blade wheel (4a, 6a) and a fixed blade wheel (4b, 6b), the comb (14) being positioned upstream of the moving blade wheel (4a, 6a) and / or downstream of the fixed blade wheel (4b, 6b).

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