Comb stabilizer for measuring the characteristics of an airflow in a turbomachine
The comb with stabilizers and aerodynamic features addresses mechanical stress and airflow disturbance issues, enabling precise airflow measurements in turbomachines.
Patent Information
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- SAFRAN AIRCRAFT ENGINES SAS
- Filing Date
- 2024-04-19
- Publication Date
- 2026-05-22
AI Technical Summary
Existing airflow measurement combs in turbomachines are susceptible to mechanical stress and airflow disturbance, leading to distorted measurements.
A comb with a base, longitudinal arm, and stabilizers configured to create lift along a radial axis, featuring aerodynamic profiles and winglets to minimize disturbance and stabilize the arm, reducing aerodynamic losses and preventing bending.
The comb effectively measures airflow characteristics without disturbing the flow, ensuring accurate and reliable data by minimizing mechanical stress and aerodynamic interference.
Smart Images
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Abstract
Description
Title of the invention: Comb stabilizer for measuring airflow characteristics in a turbomachine. Technical field
[0001] The present exposition relates to the field of measuring devices in a turbomachine, and more specifically to test turbomachines. More particularly, the present exposition concerns a comb for measuring the characteristics of the airflow circulating in a duct of a test turbomachine. STATE OF THE ART
[0002] The design of a turbomachine requires the performance of tests on a test turbomachine.
[0003] The tests on the test turbomachine may consist of subjecting the test turbomachine to many different physical conditions such as airflows with varying speed, pressure, 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 airflow, it is possible to measure airflow characteristics such as pressure and velocity by positioning a measuring comb in a circulation channel of the airflow in the test turbomachine. The comb thus allows for so-called intrusive measurements to be taken directly in the channel of the test turbomachine.
[0006] However, the measuring comb must be able to measure the characteristics of the airflow at different points in the vein, without disturbing the airflow. Indeed, such a disturbance could distort the measurements.
[0007] Thus, the comb must be sufficiently aerodynamic so as not to disturb the airflow in the vein, while also being sufficiently robust so as not to be subject to movement due to the airflow. Indeed, the airflow could mechanically constrain or cause the comb to vibrate, which could also distort the measurements. GENERAL STATEMENT
[0008] One aim of the presentation is therefore to propose a comb that is more resistant to the mechanical stresses induced by the airflow without disturbing the flow of the airflow.
[0009] To this end, according to a first aspect of the present description, a measuring comb for the characteristics of an airflow circulating in a flow channel of a test turbomachine is proposed, the comb comprising a base for fixing the comb to a support and a longitudinal arm extending from the base so as to extend into a flow channel of the test turbomachine along a radial axis of the test turbomachine. and perpendicular to a flow direction. The arm includes 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 having a free end facing the flow. Also according to this first aspect, the comb is characterized in that it includes at least one stabilizer fixed 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 described process includes at least one of the following features, taken alone or in any combination:
[0011] - at least one stabilizer comprises an aerodynamic profile, the profile aerodynamics being parallel to the flow direction and the radial axis;
[0012] - the leading edge is positioned downstream of at least one measuring device according to the direction of flow;
[0013] - the arm includes a height from the base, at least one stabilizer being positioned on the arm at more than one-third of the arm's height;
[0014] - at least one stabilizer comprises a fin at each end, the winglets are configured to reduce drag induced by the lift created by at least one stabilizer;
[0015] - at least one stabilizer comprises a portion of flexible profile configured for to allow hypo-lift in case of flow at too high speed, the portion of flexible profile inducing a warping of the trailing edge relative to the leading edge along the radial axis.
[0016] According to a second aspect, a test turbomachine is proposed comprising a flow channel of a flow and a comb according to the first aspect, the arm of the comb extending radially in the flow channel.
[0017] The test turbomachine may also include a blower and a rectifier, the comb being positioned upstream of the blower and / or downstream of the rectifier.
[0018] Moreover, the turbomachine according to this second aspect can include 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 THE FIGURES
[0019] Other features, purposes and advantages will become apparent from the following description, which is purely illustrative and not limiting, and which should be read in conjunction with the accompanying drawings on which:
[0020] Fig. 1 illustrates a schematic view of a partial cross-section of a turbomachine according to one possible embodiment of the present description;
[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] Figures [Fig. 3a] and [Fig. 3b] illustrate different views of a comb with several stabilizers according to embodiments of the present invention; and
[0023] Figure 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. 1], has a principal direction extending along a longitudinal axis X and comprises, from upstream to downstream in the direction of gas flow in the turbomachine 1 when it is in operation, a fan section 2 and a primary casing 3, often called a "gas generator", comprising a compressor section 4, a combustion chamber 5 and a turbine section 6. The turbomachine 1 is configured here for testing in order to characterize its performance. In other words, it is a test turbomachine 1.
[0027] The compressor section 4 comprises a series of stages, each including a rotating blade wheel (rotor) 4a in front of a stationary blade wheel (stator) 4b. The turbine section 6 also comprises a series of stages, each including a stationary blade wheel (stator) 6b behind which a rotating blade wheel (rotor) 6a rotates.
[0028] In the present description, the axial direction, or flow direction, corresponds to the direction of the longitudinal axis X, corresponding to the rotation of the shafts 7 of the primary body 3, and a radial direction is a direction perpendicular to and passing through this longitudinal axis X. Furthermore, the circumferential (or lateral, or tangential) direction corresponds to a direction perpendicular to and not passing through the longitudinal axis X. Unless otherwise specified, internal (respectively, inner) and external (respectively, outer), respectively, are used with reference to a radial direction such that the inner part or face of an element is closer to the longitudinal axis X than the outer part or face of the same element.
[0029] During the tests, or trials, carried out on the turbomachine 1, an airflow F entering the turbomachine 1 is divided between a primary airflow Fl and a secondary airflow F2, which flow from upstream to downstream in the turbomachine 1.
[0030] The secondary airflow F2, also called the "bypass airflow", flows around the primary body 3, in other words in a secondary vein 82 (in the case of an unfaired blower section, the secondary vein 82 is fictitious and corresponds to the portion of the secondary airflow F2 flowing around the primary body 3 and passing through the blower section 2). The secondary airflow F2 cools the periphery of the primary body 3 and is used to generate most of the thrust provided by the propulsion system 1.
[0031] The primary airflow Fl flows in a primary channel 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 oxidizer, and the turbine section 6. The passage of the primary airflow Fl through the turbine section 6 receiving energy from the combustion chamber 5 causes a rotation of the rotor stages 6a of the turbine section 6 which in turn drives the rotation of the rotor stages 4a of the compressor section 4 as well as a rotor 9 of the blower section 2.
[0032] The blower section 2 includes at least the rotor 9 suitable for 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 blower section 2 includes blades 11.
[0033] The blower section 2 may further include a stator 12, or rectifier, which includes blades 13 mounted on a hub of the stator 12 and whose function is to rectify the secondary airflow F2 which flows out of the rotor 9.
[0034] The blower section 2 can be shrouded or unshrouded.
[0035] In the case of a shrouded blower section 2, the blower section 2 comprises a blower housing and the rotor 9 is housed within the blower housing. A shrouded blower section 2 comprises a rotor 9 extending upstream of a stator 12. The blades 13 of the stator 12 are then generally referred to as "outlet blades" (or "OGV", for "Outlet Guide Vane" in Anglo-Saxon terminology) and have a fixed position relative to the hub of the stator 12.
[0036] In an unfaired fan section 2, the fan section 2, which may also be referred to as the "propeller," is not enclosed by a fan casing. Propulsion systems comprising at least one unfaired rotor 9 are known, in Anglo-Saxon terminology, as "open rotor" or "unducted fan." The propulsion system 1 may comprise two unfaired, counter-rotating rotors 9. Such a propulsion system 1 is known, in Anglo-Saxon terminology, by 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 unfaired rotor 9 and an unfaired stator 16. streamlined (straightener). 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, the combs 14 are positioned in, on or around the turbomachine 1.
[0038] Comb
[0039] The comb 14 can be used to measure aerodynamic quantities, such as pressure, temperature, or velocity, 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 simplicity, we will subsequently refer simply to the flow 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 perform measurements on the flow F, Fl, F2, at various desired locations in the primary vein 81 and / or in the secondary vein 82. The comb 14 thus makes it possible to perform so-called intrusive measurements, that is to say, directly in the flow F, Fl, F2. Intrusive measurements make it possible to minimize 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 In the case of a comb 14 positioned in the secondary duct 82 to perform aerodynamic measurements on the secondary flow F2, the support 140 is fixed to the fan casing (in the case of a shrouded fan section) or to an external support (in the case of an unshrouded fan section). In the case of a comb 14 positioned in the primary duct 81 to perform aerodynamic measurements on the primary flow Fl, 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 the radial axis Y, in the primary channel 81 or in the secondary channel 82 of the turbomachine 1. The arm 16 thus extends perpendicularly to the longitudinal axis X and therefore to the flow direction 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, Fl, F2.
[0045] The arm 16 comprises at least one, and preferably several, measuring device 19. The measuring device 19 is configured to perform 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 F, Fl, F2 stream, and includes a free end facing the flow F, Fl, F2 stream. In other words, the measuring device 19 extends upstream of the arm 16 to which it is attached. This arrangement allows the measuring device 19 to perform measurements on the F, Fl, F2 stream 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 perform a measurement on the flow F, Fl, 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 duct 81 or secondary duct 82.
[0048] The presence of the arm 16 in the primary vein 81 or in the secondary vein 82 induces aerodynamic losses that can distort measurements. Thus, the arm 16 may have a biconvex streamlined 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 resistance to the flow but also of limiting the disturbances of the flow F, Fl, F2, the first end 17 of the arm 16 may include a line of rope of greater length than the line of rope of the second end 18 of the arm 16.
[0050] Stabilizer
[0051] The comb 14 includes one, or more, stabilizer 22 fixed 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 perform measurements at different points within the flow F, Fl, F2, while minimizing disturbance to the flow of the flow F, Fl, F2, so as not to distort the measurements. The arm 16 of the comb 14 is therefore subjected 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, Fl, 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 aerodynamics 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 bending 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, that is to say, in a plane normal to the flow direction. The leading edge 23 and the trailing edge 24 may, moreover, be perpendicular to the arm 16 to which the stabilizer 22 is attached or be an arc of circumference centered on the longitudinal axis X, that is to say, be concentric with the flow F, Fl, F2.
[0055] Advantageously, the stabilizer 22 comprises an intrados 25 on the side of the first end 17 and an extrados 26 on the side of the second end 18. In other words, the stabilizer 22 comprises a line of camber 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 perform measurements on the F, Fl, F2 flows. For example, the comb 14 can be positioned: - in the secondary vein 82, upstream of the blower 9 and / or downstream of the straightener 12; and / or - in the primary vein 81, upstream of a rotating 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, Fl, 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, include a flexible airfoil portion 27. In other words, the stabilizer 22 may include a low-lift device, or an inverted high-lift device (or inverted "flap" according to common Anglo-Saxon terminology). The flexible airfoil portion 27 is configured to allow for low lift in the event of excessively high-speed F, Fl, F2 flow. Indeed, an excessively high-speed F, Fl, F2 flow could create lift on the stabilizer 22 that could damage the comb 14. The flexible airfoil portion 27 induces a warping of the trailing edge 24 relative to the leading edge 23 along the radial axis Y towards the second end 18 of the arm 16; in other words, the flexible airfoil portion 27 reduces, or eliminates, the concavity of the camber line. of the profile of arm 16. The flexible profile portion 27 thus makes it possible to reduce the lift force induced on arm 16.
[0059] The stabilizer 22 can be fixed to 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 the resistance of the arm 16 to bending induced by the flow F, Fl, F2. As illustrated in [Fig. 3a], it is possible to fix several stabilizers 22, of identical or different sizes, on the same arm 16, as illustrated for example in [Fig. 3b].
[0060] The stabilizer 22 may include a winglet 28 at each of its circumferential ends, as illustrated in [Fig. 4]. The winglets 28 are configured to reduce drag induced by the lift generated by the stabilizer 22. The winglets 28 help to reduce the perturbation of the flow F, Fl, F2, induced by the presence of the comb 14 and the stabilizer 22. The winglets 28 may be of different shapes and sizes depending on the requirements and the comb 14 considered.
Claims
Demands
1. Comb (14) for measuring the characteristics of a flow (F,F1,F2) of air circulating in a flow channel (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 into a channel (81,82) of 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. Comb (14) according to claim 1, wherein at least one stabilizer (22) comprises an aerodynamic profile including a leading edge (23), the aerodynamic profile being parallel to the flow direction (X) and to the radial axis (Y).
3. Comb (14) according to claim 2, wherein the leading edge (23) is positioned downstream of at least one measuring device (19) along the flow direction (X).
4. Comb (14) according to any one of claims 1 to 3, wherein the arm (16) comprises a height from the base (15), at least one stabilizer (22) being positioned on the arm (16) at more than one third of the height of the arm (16).
5. Comb (14) according to any one of claims 1 to 4, wherein at least one stabilizer (22) comprises a fin (28) at each of the circumferential ends, the fins (28) are configured to reduce lift-induced drag created by at least one stabilizer (22).
6. Comb (14) according to any one of claims 1 to 5, wherein at least one stabilizer (22) comprises a portion of flexible profile (27) configured to permit hypo-lift in the event of flow (F,F1,F2) at too high speed, the portion of flexible profile (27) inducing a warping of the trailing edge (21) with respect to the leading edge (20) along the radial axis (Y).
7. Test turbomachine (1) comprising a flow duct (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 duct (81,82).
8. Test turbomachine (1) according to claim 7, comprising a blower (9) and a straightener (12), the comb (14) being positioned upstream of the blower (9) and / or downstream of the straightener (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).