Method and system for estimating airflow through an aircraft air intake

Abstract

The invention relates to a method for estimating the airflow through an aircraft air outlet (100), having at least two pressure sensors (103) positioned along a pressure measurement extraction line (104) on or near a lip (102) of the outlet, comprising calibration and correlation steps. The calibration step includes generating a database associating, for each of at least two airflows applied to the outlet, the values ​​of at least two airflow characteristics and the pressure distribution measurements along the measurement extraction line. The correlation step includes measuring a pressure distribution along the line (104) while the aircraft is in flight and correlating the measured pressure distribution, associated with the values ​​of the two characteristics, with the database data to estimate the airflow while the aircraft is in flight. Abstract figure: Figure 1b

Description

Title of the invention: Method and system for estimating airflow through an aircraft air intake Domain

[0001] The present invention relates to the estimation of the airflow through an aircraft air vent, and more particularly to a method and a system for estimating this airflow using sensors positioned on or near a lip of the air vent. Context

[0002] The drag of an aircraft is generally determined by evaluating engine thrust. Engine thrust cannot be measured in flight and is estimated using a model that uses the airflow through an engine air intake as a key parameter. This is particularly relevant during flight tests, where, to evaluate aircraft performance, the engine airflow must be calculated in flight to accurately assess engine thrust.

[0003] For other applications, such as cooling or ventilation systems, accurately knowing the airflow rate is essential for system validation, troubleshooting, certification and predicting the impact on aircraft drag.

[0004] On turbojet engines, the secondary flow airflow is generally evaluated to determine a total average fan nozzle pressure. The airflow is generally deduced from this ratio of fan nozzle pressure combined with the fan nozzle coefficients determined by wind tunnel or ground tests.

[0005] The limitations of these techniques include the installation and maintenance time, which is often extended.

[0006] The techniques mentioned in this section should not be presumed to belong to the prior art simply by virtue of their mention. Similarly, a problem mentioned in this same section should not be presumed to have been previously identified in the prior art simply by virtue of its mention. Summary

[0007] Embodiments of the present invention have been developed based on the developers' understanding of the shortcomings associated with the prior art. The present invention thus comprises, in various embodiments, a method for estimating the airflow through an aircraft air intake, at least two pressure sensors being positioned along a pressure measurement extraction line on or near an air vent lip, the method comprising:

[0008] a calibration step comprising

[0009] apply to the air vent successively at least two airflows, each airflow having at least two characteristics, one of velocity, and one of incidence of the airflow relative to the air vent, the values ​​of the at least two characteristics of each airflow being known;

[0010] for each of the at least two airflows applied to the air outlet, measure a corresponding pressure distribution along the measurement extraction line; and

[0011] generate a reference database associating, respectively for each of the at least two airflows applied to the air outlet, the values ​​of the at least two characteristics and the pressure distribution measurements along the measurement extraction line; and

[0012] a correlation step, comprising: measuring a pressure distribution along the measurement extraction line when the aircraft is in flight; and correlating the measured pressure distribution, associated with the values ​​of at least two characteristics of the airflow through the air outlet in flight, with the data from the reference database, to estimate the airflow through the air outlet when the aircraft is in flight.

[0013] In an implementation of the process, at least one of the at least two airflows of the calibration step is applied by an actual physical test on the air outlet.

[0014] In another implementation of the method, at least one of the at least two airflows from the calibration step is applied to the air outlet by computer simulation.

[0015] In another implementation of the method, correlating the measured pressure distribution with the data from the reference database includes an extrapolation.

[0016] In another implementation of the method, the calibration step includes: using all or part of the information from the reference database to feed a neural network, and training it by machine learning; and the correlation step includes: feeding the trained neural network with the measured pressure distribution, associated with the values ​​of at least two characteristics of the airflow through the air outlet in flight, the trained model inferring the estimate of the airflow through the air outlet when the aircraft is in flight.

[0017] The present invention also includes, in different embodiments, a processor-readable medium comprising instructions for executing the above process.

[0018] The present invention also includes, in various embodiments, an aircraft air vent, at least two pressure sensors being positioned along a pressure measurement extraction line on or near a lip of the air vent, the air vent being equipped with a reference database obtained by a calibration step comprising:

[0019] apply to the air vent successively at least two airflows, each airflow having at least two characteristics, one of velocity, and one of incidence of the airflow relative to the air vent, the at least two airflow characteristics being known;

[0020] for each of the at least two airflows applied to the air outlet, measure a corresponding pressure distribution along the measurement extraction line; and

[0021] generate a reference database associating respectively for each of the at least two airflows applied to the air outlet, the values ​​of the at least two characteristics and the pressure distribution measurements along the measurement extraction line.

[0022] In an implementation of the air vent, the at least two pressure sensors have a minimal protrusion relative to the lip of the air vent.

[0023] In an implementation of the air vent, the at least two pressure sensors are ultra-thin pressure sensors embedded in the perforated lip of the air vent.

[0024] In an implementation of the air vent, the at least two pressure sensors are pneumatic type pressure sensors.

[0025] The present invention also includes, in different embodiments, a system comprising a processor configured to execute the above process.

[0026] The present invention finally comprises, in various embodiments, an aircraft comprising an air intake as above, to which a correlation step is applied, comprising: measure a pressure distribution along the measurement extraction line when the aircraft is in flight; correlate the measured pressure distribution, associated with the values ​​of at least two characteristics of the airflow through the air outlet in flight, with the data from the reference database, to estimate the airflow through the air outlet when the aircraft is in flight. Brief description of the drawings

[0027] For a better understanding of the present invention, reference is made to the following description, which should be used in conjunction with the accompanying drawings, where: Fig. the

[0028] [Fig.la] represents a perspective view of an air inlet on an aircraft engine. Fig. 1b

[0029] [Fig. 1b] represents a detailed perspective view of an air vent equipped with pressure sensors. Fig. the

[0030] [Fig. 1] represents pressure sensors positioned along a line of pressure measurement according to a specific embodiment. Fig. 2

[0031] [Fig.2] represents the pressure values ​​measured at each of the sensors from the pressure measurement line, for four flight cases and airflows with known characteristics. Fig. 3

[0032] [Fig.3] illustrates the steps of a process according to the invention. Fig. 4a

[0033] [Fig.4a] shows a cross-sectional view of a pressure sensor with a projection minimal in relation to a lip of the air vent. Fig. 4b

[0034] [Fig.4b] shows a cross-sectional view of an ultra-thin pressure sensor embedded in the perforated lip of the air vent. Fig. 4c

[0035] [Fig. 4c] shows a cross-sectional view of a pneumatic pressure sensor classic. Fig. 5

[0036] [Fig. 5] illustrates a computer system that can be used in the present invention. Fig. 6

[0037] [Fig.6] represents a perspective view of an aircraft equipped with an air intake for to which the present invention can be applied.

[0038] It should be noted that, unless explicitly stated otherwise herein, the drawings are not to scale. Finally, identical elements from one drawing to another bear the same numerical reference. Description of the implementation methods

[0039] In what follows, measurement data emitted by a sensor is to be understood as a set of a plurality of measurement data emitted by said sensor.

[0040] For the purposes of this description, unless expressly stated otherwise, a "processor" may refer to, but is not limited to, any type of "computer system", "electronic device", "computerized system", "control unit", "monitoring device", "server" and / or any combination thereof. appropriate to the task in question, in relation to the receipt, storage, processing and / or transmission of data.

[0041] In the context of this description, the term "FPGA" is intended to include Field Programmable Gate Array (FPGA) type systems available on the market at the time of filing of this patent application, such as the Xilinx VU9P or Intel Stratix V, and all subsequent equivalent inventions that have become available, regardless of their name, consisting of computer system hardware programmable with software.

[0042] For the purposes of this description, a "processor" may include a single dedicated processor, a single shared processor, or a plurality of individual processors, some of which may be shared. A "processor" may be a general-purpose processor, such as a central processing unit (CPU), a processor dedicated to a specific purpose, or a processor implemented in an FPGA. Other conventional and / or custom hardware and software may also be included in a "processor."

[0043] For the purposes of this description, unless expressly stated otherwise, the term "memory" includes random access storage systems available on the market at the time of filing of this patent application, and all subsequent equivalent inventions that become available, regardless of their designation, consisting of computer system media for storing digital information. An example of such memory is static random access memory (SRAM).

[0044] Within the framework of this description, the functional steps represented in the figures can be ensured through the use of dedicated hardware, as well as hardware capable of running appropriate software.

[0045] In the context of this description, unless expressly stated otherwise, the words "first", "second", "third", etc. have been used as adjectives only for the purpose of distinguishing the nouns they accompany from one another, and not for the purpose of describing a particular relationship between these nouns.

[0046] The implementations of the present invention each have at least one of the objects and / or aspects mentioned above, but do not necessarily have all of them.

[0047] Additional and / or alternative features, aspects and advantages of implementations of the present invention will become apparent from the following description, the accompanying drawings and the attached claims.

[0048] The examples and associated conditions detailed herein are primarily intended to help the reader understand the principles of the present invention and not to limit its scope to these specific examples and conditions. It will be understood that a person skilled in the art can conceive of various arrangements which, although not explicitly described or represented herein, nevertheless embody the principles of the present invention and are included in its spirit and scope.

[0049] Furthermore, to facilitate understanding, the following description may describe relatively simplified implementations of the present invention. As a person skilled in the art will understand, other implementations of the present invention may be of greater complexity.

[0050] In some cases, examples of modifications to the present invention may also be shown. This is done simply to aid understanding and, again, not to define the scope or establish the limits of the present invention. These modifications are not an exhaustive list, and a person skilled in the art may make other modifications while remaining within the scope of the present invention.

[0051] Furthermore, all the following statements relating to the principles, aspects, and implementations of the present invention, as well as the specific examples thereof, are intended to encompass both the structural and functional equivalents thereof, whether currently known or developed in the future. Thus, for example, it will be understood by those skilled in the art that all the functional diagrams represent conceptual views of example circuits incorporating the principles of the present invention. Similarly, it will be clearly understood that all the flowcharts, state transition diagrams, pseudocode, and the like, represent various processes that can be implemented on computer-readable media and thus executed by a computer or processor, whether such a computer or processor is shown in the figures or not.

[0052] The functions of the various elements shown in the figures, including any functional block, can be performed using dedicated hardware as well as hardware capable of running appropriate software. They can also be performed by a processor. Other hardware, conventional and / or customized, can also be used.

[0053] Software modules, or modules assumed to be software, may be represented herein as a combination of flowchart elements, or other elements indicating the execution of steps in a process, and / or as a textual description. Such modules may be executed by hardware that is expressly shown or not. Furthermore, it should be understood that "module" may include, for example, but not limited to, computer program logic, computer program instructions, software, a software stack, firmware, a hardware circuit, or a combination of these different elements that provides the required capabilities.

[0054] Having established this, we will now consider some non-limiting examples to illustrate various implementations of the present invention.

[0055] In one example, and in accordance with [Fig. 1a], 1b and 1a, the invention is applied to the air inlet 100 of the cooling system of an aircraft engine 101. On or near the lip 102 of the air inlet 100, at least two pressure sensors 103 are positioned along a pressure measurement extraction line 104.

[0056] The invention can generally be applied to any air inlet fitted to an aircraft, whether for propulsion systems with a compressor, such as auxiliary power units (APUs), or more passive systems using the energy of the external airflow to cool or ventilate an area / component of the aircraft. The invention can also be applied to any air outlet fitted to an aircraft. All such aircraft air inlets and outlets are collectively referred to as "air vents."

[0057] The invention proposes a non-intrusive solution for estimating the airflow through an air vent, equipped with at least two pressure sensors 103 positioned along a pressure measurement extraction line 104, on or near the lip 102 of the air vent, for example the air inlet 100. The solution consists of exploiting the pressure measurement distribution information from the pressure sensors 103 along the pressure measurement extraction line 104, and comprises:

[0058] - a calibration step: two airflows with known characteristics (including (including velocity and angle of attack), are applied to the air outlet by actual physical tests (e.g., wind tunnel tests, ground tests, etc.), or by computer simulation (e.g., numerical simulation of fluid flows, etc.); for each airflow, the pressure measurement value from the pressure sensors 103 along the pressure measurement extraction line 104 is recorded, allowing the establishment of a reference database; and

[0059] - an in-flight correlation step (understood throughout this application as an in-flight (Real or wind tunnel) of the aircraft: an airflow with known characteristics (including speed and angle of attack) then passes through the air outlet; the pressure measurement value from the pressure sensors 103 along the pressure measurement extraction line 104 is recorded and correlated with information from the reference database to deduce an estimate of the airflow actually passing through the air outlet. The correlation step can be performed, for example, by extrapolation, machine learning, etc.

[0060] In one example, the invention comprises only the calibration step, when implemented by a manufacturer of a system comprising an air outlet, who sells, as a supplier, this system to an aircraft manufacturer. In this case, the supplier book with the system sold the information from the calibration stage (i.e.: the reference database), allowing the aircraft manufacturer to proceed with the in-flight correlation stage of the aircraft.

[0061] When an aircraft is in flight, a number of measurements (Alpha, Beta, Mach, Pitch, RPM, etc.) are available and known. These measurements characterize the airflow passing through an air intake on the aircraft, the air intake being positioned at a certain angle relative to the flight path. These same characteristics can be emulated during the calibration step, through the characteristics of at least two airflows applied to the air intake.

[0062] Thus, during the calibration step, at least two "flight cases" are defined, each flight case being associated with at least two characteristics of the airflow applied to the air outlet, and which emulate the same two characteristics of an actual flight. For each flight case in calibration, the pressure measurements provided by the pressure sensors 103 are recorded along the pressure measurement extraction line 104.

[0063] Thus, at the end of the calibration step, a table 1 (as an example of the implementation of a reference database) below can be established, in a simplified example where:

[0064] four Ci-C4 flight cases are emulated;

[0065] six pressure sensors equip the pressure measurement extraction line, positioned respectively at an abscissa XrX6 along this line;

[0066] each flight case Q corresponding to four respective ValCarÿ values ​​of four flight characteristics Car;;

[0067] for each flight case Q, the pressure values ​​at six respective abscissa values ​​Xk are measured and recorded: ValPresjk.

[0068] [Tables 1] Case of vo 1 Flight characteristics Curvilinear abscissa along the extraction line of pressure measurements 104 Cari Car2 Car3 Car4 X! x2 x3 x4 X5 X6 Cj Val Carn Val Car12 Val Car13 Val Car14 Valpj-e sll Valpj-e sl2 Valpj-e sl3 Valpj-e sl4 Valpj-e sl5 V alpre sl6 c2 Val Car21 Val Car22 Val Car23 Val Car24 Val^ s21 Valpj- s22 Val Carn Val^ s Val^ s22 s25 V alPre s 26 c3 Val Car31 Val Car32 Val Car33 Val Car34 Valpj-e s31 Valpj-e s32 Valpj-e s35 V alpre s36 c4 Val Car41 Val Car42 Val Car43 Val Car^ Val Car^ Val Car^ s414 s Valj^4 s Val^4 s45 V alPre s46

[0069] Figure 2 shows a graph corresponding to the information in Table 1. The horizontal axis corresponds to the curvilinear abscissa along the air outlet, with six respective values ​​XrX6. The vertical axis corresponds to the respective pressure measurement for each of the six sensors located at abscissas XrX6. The values ​​are indicated for each of the four flight cases CrC4. Furthermore, each flight case corresponds to a ValCar value for each of the four Cari-Car4 characteristics. The information is thus associated between the flight characteristic values ​​ValCarÿ and the pressure values ​​ValPresjk along the pressure measurement extraction line 104.

[0070] Each of the C1-C4 flight cases can correspond to an actual physical test, or a computer simulation.

[0071] In one example, the calibration step includes using all or part of the information from Table 1 to feed a model, for example a neural network, and training it by machine learning.

[0072] The correlation step includes, in particular, measuring a pressure distribution along the measurement extraction line while the aircraft is in flight, in association with known flight characteristics (Alpha, Beta, Mach, Pitch, RPM, etc.), and then correlating the pressure distribution measured while the aircraft is in flight, associated with these known flight characteristics, with the data and values ​​in Table 1, in order to estimate the airflow through the air intake while the aircraft is in flight. Those skilled in the art know how to perform this correlation step, for example by extrapolation, etc., or by using the aforementioned trained model for inference.

[0073] [Fig. 3] illustrates the steps of a process according to the invention. In step 301, the process includes applying successively to an aircraft air outlet (100) at least two airflows, each airflow having at least two known characteristics, including one of velocity and one of the angle of incidence of the airflow relative to the outlet of air, at least two pressure sensors (103) being positioned along a pressure measurement extraction line (104) on or near a lip (102) of the air outlet.

[0074] In step 302, the method also includes, for each of the at least two airflows applied to the air outlet, measuring a corresponding pressure distribution along the measurement extraction line.

[0075] In step 303, the method also includes generating a database associating respectively with the known characteristics of each of the at least two airflows applied to the air outlet, a pressure distribution along the measurement extraction line.

[0076] In step 304, the method also includes measuring a pressure distribution along the measurement extraction line when the aircraft is in flight.

[0077] In step 305, the method also includes correlating the pressure distribution measured when the aircraft is in flight, associated with known flight characteristics, with data from the database, to estimate the airflow through the air outlet when the aircraft is in flight.

[0078] In one example, the correlation step includes feeding a machine learning trained model during the calibration step with the pressure distribution data measured when the aircraft is in flight, associated with the known flight characteristics, the trained model inferring the estimate of the airflow through the air outlet when the aircraft is in flight.

[0079] In one example, the calibration step was performed with a measurement extraction line 104 comprising 400 points, i.e., 400 pressure sensors 103, and 24 Ci-C24 flight cases, each combining 4 Cari-Car4 characteristics. This data was used to train a neural network. In the in-flight correlation step, the trained neural network estimated the airflow through the air outlet 100 with an accuracy of 0.5%.

[0080] The invention implements, for example, one or the other of the pressure sensors 103 referred to in [Fig. 4a], 4b, and 4c. The pressure sensors 103 must be capable of evaluating the local static pressure along the pressure measurement extraction line 104 when positioned on or near the lip 102. [Fig. 4a] illustrates the case of a pressure sensor 103 with minimal protrusion from the lip 102, for example, through an ultra-thin pressure sensor, for example, of the MEMS (Microelectromechanical Systems) type. [Fig. 4b] illustrates the case of an ultra-thin pressure sensor 103 embedded in the perforated lip 102. [Fig. 4c] illustrates the case of a conventional pneumatic pressure sensor 103. Thus, the sensors 103 adapted for the invention can be more or less flush with the surface of lip 102; the person skilled in the art knows how to adapt the calibration step accordingly.

[0081] Figure 5 illustrates a computer system that can be used in the present invention, for example, to perform the calibration or correlation steps described above. As will be understood by those skilled in the art, such a computer system can be implemented in any other suitable hardware, software, and / or firmware, or a combination thereof, and can be a single physical entity or several separate physical entities with distributed functionality.

[0082] The computer system 500 may comprise various hardware components, including one or more single-core or multi-core processors collectively represented by a processor 501, a memory 503, and an input / output interface 504. In this context, the processor 501 may or may not be included in an FPGA. The computer system 500 may be a generic, "off-the-shelf" computer system. The computer system 500 may also be distributed among several systems. The computer system 500 may also be specifically dedicated to the implementation of the present invention. As a person skilled in the art of the present invention can understand, multiple variations in the way the computer system 500 is implemented can be envisaged.

[0083] Communication between the different components of the computer system 500 can be enabled by one or more internal and / or external buses 505 (for example a PCI bus, a universal serial bus, an IEEE 1394 "Firewire" bus, a SCSI bus, a Serial-ATA bus, ARINC bus, etc.), to which the different hardware components are electronically coupled.

[0084] The 504 input / output interface can enable networking capabilities such as wired or wireless access. By way of example, the 504 input / output interface can include a network interface such as, but not limited to, a network port, a network jack, a network interface controller, and the like. Numerous examples of how the networking interface can be implemented will become apparent to those skilled in the art of the present invention.

[0085] Memory 503 can store code instructions 508, such as those forming part of, for example, a library, an application, etc., which can be loaded into memory 503 and executed by the processor 501 to, for example, implement the calibration or correlation steps according to the present invention. Memory 503 can also store a database 509, for example, the database generated in the calibration step above. Those skilled in the art will understand that the database 509, the code instructions 508, and generally memory 503 can also reside physically outside the computer system 500, still within the scope of the present invention.

[0086] The input / output interface 504 can enable the computer system 500 to communicate with other processors via a connection 510. This can be the case, for example, if the calibration step above is implemented in the computer system 500, while the correlation step above is implemented in a processor outside the computer system 500, for example on the aircraft.

[0087] The aircraft 600 shown in [Fig. 6] has an air intake 100, to which the present invention is applied to estimate the airflow through it in flight. The aircraft 600 also includes an onboard computer system 500 in which, for example, the correlation step described above can be implemented.

[0088] Although the implementations described above have been described and illustrated with reference to particular steps performed in a particular order, it will be understood that these steps may be combined, subdivided, or reordered without departing from the teachings of this disclosure. At least some of the steps may be performed in parallel or sequentially. Therefore, the order and grouping of the steps do not constitute a limitation of the present invention.

[0089] Modifications and improvements to the above-described implementations of the present invention may be apparent to a person skilled in the art. The above description is illustrative by way of examples rather than exhaustive. The scope of the present invention is therefore limited only by the scope of the claims below.

[0090] .

Claims

1.

2.

3. Demands A method for estimating the airflow through an aircraft air vent (100), where at least two pressure sensors (103) are positioned along a line (104) on or near a lip (102) of the air vent, the method comprising: - a calibration step including: i. apply (301) to the air vent successively at least two airflows, each airflow having at least two characteristics, one of velocity, and one of incidence of the airflow relative to the air vent, the values ​​of the at least two characteristics of each airflow being known; ii. For each of the at least two airflows applied to the air outlet, measure (302) a corresponding local static pressure distribution along the line; and iii. generate (303) a reference database associating, respectively, for each of the at least two airflows applied to the air outlet, the values ​​of the at least two characteristics and the local static pressure distribution measurements along the line; and - a correlation step, comprising: i. measure (304) a local static pressure distribution along the line when the aircraft is in flight; and ii. correlate (305) the measured local static pressure distribution, associated with the values ​​of at least two characteristics of the airflow through the air outlet in flight, with the data in the reference database, to estimate the airflow through the air outlet when the aircraft is in flight. Method according to claim 1, wherein at least one of the at least two airflows of the calibration step is applied by an actual physical test on the air outlet (100). Method according to claim 1 or 2, wherein at least one of the at least two airflows of the calibration step is applied to the air outlet (100) by computer simulation.

4. A method according to any one of claims 1 to 3, wherein correlating (305) the measured local static pressure distribution with the data from the reference database includes an extrapolation.

5. A method according to any one of claims 1 to 3, wherein the calibration step comprises: - using all or part of the information from the reference database to feed a neural network, and training it by machine learning; and the correlation step comprises: - feeding the trained neural network with the measured local static pressure distribution, associated with the values ​​of at least two characteristics of the airflow through the air outlet in flight, the trained model inferring the estimate of the airflow through the air outlet when the aircraft is in flight.

6. Processor-readable medium containing instructions for executing the method according to any one of claims 1 to 5.

7. Aircraft air vent (100), at least two pressure sensors (103) being positioned along a line (104) on or near a lip (102) of the air vent, the air vent being equipped with a reference database obtained by a calibration step comprising: - applying (301) to the air vent successively at least two airflows, each airflow having at least two characteristics, one of velocity, and one of incidence of the airflow relative to the air vent, the at least two airflow characteristics being known; - for each of the at least two airflows applied to the air vent, measuring (302) a corresponding local static pressure distribution along the line;and - generate (303) a reference database associating respectively, for each of the at least two airflows applied to the air outlet, the values ​​of the at least two characteristics and the local static pressure distribution measurements along the line; the air outlet being configured for a correlation step, comprising: - measuring (304) a local static pressure distribution along the line when the aircraft is in flight; and;

8.

9.

10.

11.

12. - correlate (305) the measured local static pressure distribution, associated with the values ​​of at least two characteristics of the airflow through the air outlet in flight, with the data from the reference database, to estimate the airflow through the air outlet when the aircraft is in flight. Air vent according to claim 7, wherein the at least two pressure sensors (103) have a minimal protrusion relative to the lip (102) of the air vent. Air vent according to claim 7, wherein the at least two pressure sensors (103) are ultra-thin pressure sensors embedded in the perforated lip (102) of the air vent. Air vent according to claim 7, wherein the at least two pressure sensors (103) are pneumatic type pressure sensors. System comprising a processor configured to execute the process according to any one of claims 1 to 5. Aircraft (600) comprising an air outlet (100) according to any one of claims 7 to 10.

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