Method and system for determining over-speed oil cut-off speed, electronic equipment, and storage medium

Abstract

The present invention discloses a method and system for determining an over-speed fuel cut-off speed, an electronic device, and a storage medium. The method for determining the over-speed fuel cut-off speed of the present invention proposes for the first time an overall technical idea for determining the over-speed fuel cut-off speed. Compared with the manual experience setting method of the prior art, the over-speed fuel cut-off speed can be accurately determined for each engine, ensuring that the over-speed fuel cut-off speed is within the required speed margin range, and the problem of excessive or insufficient speed margin will not occur. Over-speed is effectively prevented, and the harmful consequences of turbine disc rupture due to broken shaft will not occur, thereby ensuring flight safety. In addition, it also takes into account that the turbine speed will continue to rise within the response time of the control system, further improving the accuracy of determining the over-speed fuel cut-off speed.

Description

Technical Field

[0001] The present invention relates to the technical field of aircraft engine over-speed protection, and in particular to a method and system for determining an over-speed fuel cut-off speed, electronic equipment, and a computer-readable storage medium. Background Art

[0002] If a shaft breaks during flight, the turbine components will lose load, causing the turbine speed to rapidly increase in a short period of time, resulting in overspeed. If the control system doesn't promptly cut off the fuel supply, the turbine disc will rupture. The high-speed turbine disc fragments have enormous kinetic energy, making it highly likely that the fragments will not be contained by the engine casing, seriously endangering the aircraft and flight safety. Therefore, during the aircraft engine design process, it is necessary to accurately determine the overspeed cutoff speed to ensure that the dangerous consequences of a shaft breakage causing a turbine disc rupture will not occur. Currently, the overspeed cutoff speed for aircraft engines is typically determined roughly based on engineering experience, which cannot guarantee accuracy and may result in excessive or insufficient speed margins. Summary of the Invention

[0003] The present invention provides a method and system for determining an over-revving fuel cut-off speed, an electronic device, and a computer-readable storage medium, which can accurately determine the over-revving fuel cut-off speed for each engine, effectively preventing over-revving and ensuring flight safety. It also takes into account that the turbine speed will continue to rise within the response time of the control system, further improving the accuracy of the over-revving fuel cut-off speed determination.

[0004] According to one aspect of the present invention, a method for determining an over-speed fuel cut-off speed is provided, comprising the following steps:

[0005] Determine the response time of the aircraft engine control system from the execution of the fuel cut command to the complete fuel cut;

[0006] The turbine speed variation curves at different moments after shaft breakage are obtained by fitting;

[0007] Assuming an over-speed cut-off speed, and combining the response time and turbine speed curve to determine the turbine speed corresponding to the fuel cut-off moment;

[0008] Determine the turbine disk rupture speed, compare the turbine speed corresponding to the oil cut-off moment with the turbine disk rupture speed, and if the difference between the two meets the preset speed margin requirement, use the assumed over-speed oil cut-off speed as the final over-speed oil cut-off speed.

[0009] Furthermore, the process of fitting and obtaining the turbine speed change curves at different times after the shaft breaks includes the following:

[0010] Obtain the turbine torque and turbine speed when the aircraft engine shaft is broken, and calculate the turbine torque at different turbine speeds after the shaft is broken;

[0011] The turbine torque at different turbine speeds after shaft breakage is fitted to obtain the functional relationship between the turbine torque and turbine speed after shaft breakage.

[0012] The iteration step size is set, and the turbine speed at different times after the shaft is broken is iteratively calculated based on the functional relationship between the turbine torque and the turbine speed after the shaft is broken. The turbine speed change curve at different times after the shaft is broken is obtained by data fitting.

[0013] Furthermore, the mapping relationship between turbine speed and turbine efficiency was obtained through turbine performance tests, and the turbine efficiency when the aircraft engine shaft was broken was obtained. The turbine torque at different turbine speeds after the shaft was broken was calculated based on the following formula:

[0014] TQ=(((TQ1×N1) / F1)×F) / N

[0015] Among them, TQ1, N1 and F1 represent the turbine torque, turbine speed and turbine efficiency when the shaft is broken, respectively. TQ and F represent the turbine torque and turbine efficiency corresponding to the turbine speed N after the shaft is broken, respectively.

[0016] Furthermore, the turbine speed at different times after the shaft breaks is iteratively calculated based on the following formula:

[0017] N=N1+((a×N 4 +b×N 3 +c×N 2 +d×N+e)×△T) / M

[0018] Among them, N represents the turbine speed at different times after the shaft breaks, N1 represents the turbine speed when the shaft breaks, △T represents the set iteration step size, M represents the moment of inertia of the turbine disk, and a, b, c, d, and e represent the fitting coefficients in the functional relationship between the turbine torque and the turbine speed after the shaft breaks.

[0019] Furthermore, the process of assuming the overrun fuel cut-off speed and determining the turbine speed corresponding to the fuel cut-off moment in combination with the response time and the turbine speed variation curve includes the following:

[0020] Assuming that the overspeed oil cut-off speed is N2, the overspeed moment T is found on the turbine speed change curve at different times after the shaft is broken based on the overspeed oil cut-off speed N2. The response time ΔT1 of the control system is added to the overspeed moment T as the oil cut-off time (T+ΔT1), and the turbine speed corresponding to the oil cut-off time (T+ΔT1) is found on the turbine speed change curve at different times after the shaft is broken.

[0021] Furthermore, the process of determining the turbine disk rupture rotation speed includes the following:

[0022] The turbine disk is mounted on a test bench and heated to simulate its actual temperature field distribution. During the heating process, the disk is rotated slowly to improve the uniformity of circumferential temperature rise. The disk is then accelerated at a preset acceleration until it ruptures, and the rotational speed at which the disk ruptures is measured.

[0023] Furthermore, if the difference between the turbine speed corresponding to the fuel cut-off moment and the turbine disc rupture speed does not meet the preset speed margin requirement, the assumed over-speed fuel cut-off speed is reduced and the above process is repeated until the difference between the two meets the preset speed margin requirement.

[0024] In addition, the present invention also provides a system for determining an over-speed fuel cut-off speed, comprising:

[0025] A control system response time determination module is used to determine the response time of the aircraft engine control system from executing the fuel cut-off instruction to completely cutting off the fuel;

[0026] The turbine speed change curve fitting module is used to fit the turbine speed change curve at different times after the shaft breaks;

[0027] The turbine speed determination module at the fuel cut-off moment is used to assume the over-speed fuel cut-off speed and determine the turbine speed corresponding to the fuel cut-off moment based on the response time and the turbine speed change curve;

[0028] The over-speed oil cut-off speed determination module is used to determine the turbine disk rupture speed. The turbine speed corresponding to the oil cut-off time is compared with the turbine disk rupture speed. If the difference between the two meets the preset speed margin requirement, the assumed over-speed oil cut-off speed is used as the final over-speed oil cut-off speed.

[0029] In addition, the present invention also provides an electronic device, including a processor and a memory, wherein the memory stores a computer program, and the processor is configured to execute the steps of the above method by calling the computer program stored in the memory.

[0030] In addition, the present invention also provides a computer-readable storage medium for storing a computer program for determining the over-speed fuel cut-off speed, wherein the computer program executes the steps of the above-mentioned method when running on a computer.

[0031] The present invention has the following beneficial effects:

[0032] The method for determining the over-speed fuel cut-off speed of the present invention proposes for the first time an overall technical idea for determining the over-speed fuel cut-off speed. Compared with the manual experience setting method of the prior art, the over-speed fuel cut-off speed can be accurately determined for each engine, ensuring that the over-speed fuel cut-off speed is within the required speed margin range, and there will be no problem of excessive or insufficient speed margin. Over-speed is effectively prevented, and the harmful consequences of turbine disc rupture due to broken shaft will not occur, thereby ensuring flight safety. It also takes into account that the turbine speed will continue to rise within the response time of the control system, further improving the accuracy of determining the over-speed fuel cut-off speed.

[0033] In addition, the system for determining the over-speed fuel cut-off speed of the present invention also has the above advantages.

[0034] In addition to the above-described objects, features and advantages, the present invention has other objects, features and advantages. The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0036] Figure 1 1 is a flow chart of a method for determining an over-speed fuel cut-off speed according to a preferred embodiment of the present application;

[0037] Figure 2 yes Figure 1 Schematic diagram of the sub-process of step S2;

[0038] Figure 3 This is a schematic diagram of the relationship between the turbine speed and turbine efficiency of a certain type of aircraft engine obtained by fitting in a preferred embodiment of the present application;

[0039] Figure 4 This is a schematic diagram showing the relationship between the turbine speed and turbine torque of a certain type of aircraft engine after shaft breakage obtained by fitting in a preferred embodiment of the present application;

[0040] Figure 5 This is a schematic diagram of a turbine speed change curve at different times after a shaft breakage of a certain type of aircraft engine obtained by fitting in a preferred embodiment of the present application;

[0041] Figure 6 It is a schematic diagram of the module structure of a system for determining an over-speed fuel cut-off speed according to another embodiment of the present application. DETAILED DESCRIPTION

[0042] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0043] Reference Figure 1 The preferred embodiment of the present application provides a method for determining an over-speed fuel cut-off speed, comprising the following contents:

[0044] Step S1: determining the response time of the aircraft engine control system from executing the fuel cut-off instruction to completely cutting off the fuel;

[0045] Step S2: fitting to obtain the turbine speed change curve at different times after the shaft breaks;

[0046] Step S3: Assuming an over-speed fuel cut-off speed, and combining the response time and the turbine speed variation curve to determine the turbine speed corresponding to the fuel cut-off moment;

[0047] Step S4: Determine the turbine disk rupture speed, compare the turbine speed corresponding to the oil cut-off moment with the turbine disk rupture speed, and if the difference between the two meets the preset speed margin requirement, use the assumed over-speed oil cut-off speed as the final over-speed oil cut-off speed.

[0048] It can be understood that the method for determining the over-speed fuel cut-off speed in this embodiment first determines the response time of the control system from executing the fuel cut-off command to completely cutting off the fuel. After fitting the turbine speed change curves at different times after the shaft is broken, an over-speed fuel cut-off speed is assumed and combined with the response time and the turbine speed change curve to determine the turbine speed corresponding to the fuel cut-off moment. Then, the turbine disk rupture speed is determined, and the turbine speed corresponding to the fuel cut-off moment is compared with the turbine disk rupture speed. If the difference between the two meets the preset speed margin requirement, it is considered that the assumed over-speed fuel cut-off speed meets the requirement, and the assumed over-speed fuel cut-off speed is used as the final over-speed fuel cut-off speed. Therefore, the method for determining the over-speed fuel cut-off speed of the present invention proposes for the first time an overall technical idea for determining the over-speed fuel cut-off speed. Compared with the manual experience setting method of the prior art, the over-speed fuel cut-off speed can be accurately determined for each engine, ensuring that the over-speed fuel cut-off speed is within the required speed margin range, and there will be no problem of too large or too small speed margin. Over-speed is effectively prevented, and the harmful consequences of turbine disc rupture due to broken shaft will not occur, thereby ensuring flight safety. In addition, it also takes into account that the turbine speed will continue to rise within the response time of the control system, further improving the accuracy of the over-speed fuel cut-off speed determination.

[0049] During flight, the aircraft engine control system monitors the turbine speed in real time. After the shaft breaks, when the turbine speed reaches the set over-speed cut-off speed, the control system executes the fuel cut-off command, causing the engine to reduce speed to prevent overspeed and even turbine disc rupture. The present invention takes into account that it takes a process for the aircraft engine control system to execute the fuel cut-off command to actually completely cut off the fuel, that is, there is a response time. During this response time, the turbine speed will continue to rise. The turbine speed when the fuel is actually completely cut off has exceeded the turbine speed when the fuel cut-off command is executed (i.e., the over-speed cut-off speed). Therefore, in step S1, in order to accurately determine the over-speed cut-off speed and ensure that it meets the speed margin requirement, the present invention considers the speed increase problem within the control system response time. The response time of the aircraft engine control system from executing the fuel cut-off command to completely cutting off the fuel is obtained through a semi-physical simulation test of the control system cutting off the fuel, so as to facilitate the subsequent determination of the turbine speed when the fuel is actually completely cut off.

[0050] The process of the semi-physical simulation test for a control system fuel cutoff is as follows: first, the engine fuel and control system are physically installed on a test platform; then, a mathematical engine model is used to replace the actual engine, and the test platform's measurement and control system is used to input parameters of the actual engine components to generate parameters such as the rotor speed and gas temperature corresponding to the engine under actual operating conditions; then, the relevant parameters are converted into analog and digital signals through a signal conversion module. The control system then controls the engine fuel pump regulator, fuel cutoff valve, and other mechanisms based on the corresponding signals to achieve fuel supply and cutoff to the engine; finally, the total response time ΔT1 of the control system from executing the fuel cutoff command to the actual complete fuel cutoff is measured. In other embodiments of the present invention, actual fuel cutoff tests of the control system can also be used to obtain this response time, but this will increase the test time and cost.

[0051] In addition, during flight, after the shaft breaks, the turbine components will lose load, and the turbine speed will rise rapidly in a short period of time. In order to accurately determine the turbine speed when the fuel is actually completely cut off, it is necessary to first fit the turbine speed change curve at different times after the shaft breaks. Figure 2 As shown, the process of fitting the turbine speed change curves at different times after the shaft breaks includes the following:

[0052] Step S21: obtaining the turbine torque and turbine speed when the aero-engine shaft is broken, and calculating the turbine torque at different turbine speeds after the shaft is broken;

[0053] Step S22: performing data fitting on the turbine torque at different turbine speeds after the shaft is broken to obtain a functional relationship between the turbine torque and the turbine speed after the shaft is broken;

[0054] Step S23: Set the iteration step size, and iteratively calculate the turbine speed at different times after the shaft is broken based on the functional relationship between the turbine torque and the turbine speed after the shaft is broken, and perform data fitting to obtain the turbine speed change curve at different times after the shaft is broken.

[0055] Specifically, first obtain the turbine torque TQ1 and turbine speed N1 when the aircraft engine breaks its shaft under a certain working state, and then assume that the turbine efficiency is constant and does not change with the speed. Since the engine power is constant during the period, the turbine torque at different turbine speeds after the shaft is broken can be calculated based on the following formula: TQ = (TQ1×N1) / N. For example, on the basis of the turbine speed N1, assume a higher turbine speed N, and then calculate the turbine torque TQ corresponding to the turbine speed N. Repeat this process continuously to obtain the turbine torque corresponding to different turbine speeds after the shaft is broken.

[0056] As a preferred embodiment, the present invention takes into account that the turbine inlet and outlet boundary conditions at different turbine speeds are inconsistent. Therefore, there are certain differences in turbine efficiency at different turbine speeds. Therefore, the present invention also obtains the mapping relationship between turbine speed and turbine efficiency through turbine performance testing. For example, the mapping relationship between turbine speed and turbine efficiency of a certain type of aircraft engine is as follows: Figure 3 As shown, the turbine performance test belongs to the existing conventional engine test, and the specific principles and processes are not repeated here. The turbine efficiency F1 of the aircraft engine when the shaft is broken is obtained, and the turbine torque at different turbine speeds after the shaft is broken is corrected using the turbine efficiency. That is, the turbine torque at different turbine speeds after the shaft is broken is calculated based on the following formula:

[0057] TQ=(((TQ1×N1) / F1)×F) / N

[0058] Among them, TQ1, N1 and F1 represent the turbine torque, turbine speed and turbine efficiency when the shaft is broken, respectively, and TQ and F represent the turbine torque and turbine efficiency corresponding to the turbine speed N after the shaft is broken, respectively. It can be understood that the present invention introduces the turbine efficiency for correction when calculating the turbine torque at different turbine speeds after the shaft is broken, which improves the accuracy of the calculation and is conducive to improving the fitting accuracy of the turbine speed change curve at different times after the shaft is broken, thereby improving the accuracy of the over-speed oil cut-off speed. In addition, as a preference, the turbine torque, turbine speed and turbine efficiency when the shaft is broken at the maximum working state of the aircraft engine are preferentially selected for calculation, because the shaft breaking at the maximum working state is the most dangerous working condition. If the over-speed oil cut-off speed set under the most dangerous working condition meets the speed margin requirements, then the over-speed oil cut-off speed under other working conditions will definitely meet the requirements.

[0059] After calculating the turbine torque at different turbine speeds after shaft breakage, a polynomial curve fitting is performed on the two to obtain the functional relationship between the turbine torque and turbine speed after shaft breakage, which can be expressed as: TQ = a × N 4 +b×N 3 +c×N 2 +d×N+e, where a, b, c, d, and e represent fitting coefficients. For example, the relationship between turbine speed and turbine torque after shaft breakage obtained by fitting a certain type of aircraft engine based on consideration of turbine efficiency correction is as follows: Figure 4 shown.

[0060] Then, set the iteration step △T = 0.5ms, and immediately iteratively calculate the turbine speed at different times after the shaft breaks based on the following formula: N = N1 + (TQ × △T)) / M, and then substitute the functional relationship between the turbine torque and turbine speed after the shaft breaks into the formula to obtain N = N1 + ((a × N 4 +b×N 3 +c×N 2 +d×N+e)×△T) / M, where M represents the moment of inertia of the turbine disk. Finally, the turbine speed at different times after the shaft is broken is fitted to obtain the turbine speed change curve at different times after the shaft is broken. For example, the turbine speed change curve at different times after the shaft of a certain type of aircraft engine is as follows: Figure 5 shown.

[0061] It can be understood that the present invention can obtain the turbine speed change curve at different times after the shaft is broken through simple formula conversion and data fitting, and can quickly and accurately obtain the turbine speed at different times after the shaft is broken, so as to accurately determine the turbine speed corresponding to the moment when the fuel is actually completely cut off. In addition, the turbine efficiency is also introduced for correction calculation, which improves the calculation accuracy and is conducive to improving the accuracy of determining the over-speed fuel cut-off speed.

[0062] In addition, in other embodiments of the present invention, after a shaft breaks, data fitting can be performed on the real-time monitoring results of the turbine speed sensor to obtain a turbine speed change curve at different times after the shaft breaks, but the moment of shaft breakage needs to be accurately determined to ensure the accuracy of the data fitting.

[0063] In addition, in step S3, the process of assuming the overrunning fuel cut-off speed and determining the turbine speed corresponding to the fuel cut-off moment in combination with the response time and the turbine speed change curve includes the following:

[0064] Assuming that the over-speed fuel cut-off speed is N2, the over-speed moment T is found on the turbine speed change curve at different times after the shaft is broken based on the over-speed fuel cut-off speed N2. The response time ΔT1 of the control system is added to the over-speed moment T as the fuel cut-off time (T+ΔT1), that is, the time when the fuel is actually completely cut off. The turbine speed N3 corresponding to the fuel cut-off time (T+ΔT1) is found on the turbine speed change curve at different times after the shaft is broken. The subsequent speed margin is judged based on the turbine speed N3, which can improve the accuracy of the over-speed fuel cut-off speed determination.

[0065] In addition, in step S4, the process of determining the turbine disk rupture rotation speed includes the following:

[0066] The turbine disk is mounted on a test bench and heated to simulate the actual temperature field distribution of the turbine disk. During the heating process, the turbine disk is rotated slowly to improve the uniformity of the circumferential temperature rise. The turbine disk is then accelerated according to a preset acceleration until it ruptures. The speed N4 at which the turbine disk ruptures is measured, i.e., the turbine disk rupture speed.

[0067] It can be understood that the present invention can accurately obtain the turbine disk rupture speed through the turbine disk rupture speed test, and by controlling the turbine disk to rotate slowly while heating the turbine disk, the uniformity of circumferential temperature rise can be improved, thereby more accurately simulating the actual temperature field distribution of the turbine disk, more closely fitting the actual working conditions of the turbine disk, and thus more accurately obtaining the turbine disk rupture speed.

[0068] Then, the turbine speed N3 corresponding to the fuel cutoff moment obtained in step S3 is compared with the turbine disk rupture speed N4. If the difference between the two meets a preset speed margin requirement, for example, N4-N3 ≥ 30%, the assumed over-speed fuel cutoff speed N2 is deemed to meet the requirement and the assumed over-speed fuel cutoff speed N2 is used as the final over-speed fuel cutoff speed. If the difference N4 between the turbine speed N3 corresponding to the fuel cutoff moment and the turbine disk rupture speed N4 does not meet the preset speed margin requirement, for example, N4-N3 is less than 30%, the assumed over-speed fuel cutoff speed N2 is reduced and the above process is repeated until the difference between the two meets the preset speed margin requirement, that is, N4-N3 ≥ 30%. Of course, in other embodiments of the present invention, the speed margin requirement may also be 10%, 20%, 25%, etc., and can be set according to actual needs. In addition, when the preset speed margin requirement is not met, you can also choose to increase the turbine disk rupture speed N4, for example, by increasing the strength and quality of the turbine disk. However, this improvement method will increase the weight of the turbine disk and may cause problems such as engine vibration exceeding the limit and overweight.

[0069] In addition, if Figure 6As shown, another embodiment of the present invention further provides a system for determining an over-speed fuel cut-off speed, preferably using the above-mentioned method for determining an over-speed fuel cut-off speed, including:

[0070] A control system response time determination module is used to determine the response time of the aircraft engine control system from executing the fuel cut-off instruction to completely cutting off the fuel;

[0071] The turbine speed change curve fitting module is used to fit the turbine speed change curve at different times after the shaft breaks;

[0072] The turbine speed determination module at the fuel cut-off moment is used to assume the over-speed fuel cut-off speed and determine the turbine speed corresponding to the fuel cut-off moment based on the response time and the turbine speed change curve;

[0073] The over-speed oil cut-off speed determination module is used to determine the turbine disk rupture speed. The turbine speed corresponding to the oil cut-off time is compared with the turbine disk rupture speed. If the difference between the two meets the preset speed margin requirement, the assumed over-speed oil cut-off speed is used as the final over-speed oil cut-off speed.

[0074] It can be understood that the system for determining the over-speed fuel cut-off speed of the present embodiment first determines the response time of the control system from executing the fuel cut-off command to completely cutting off the fuel. After fitting the turbine speed change curves at different times after the shaft is broken, an over-speed fuel cut-off speed is assumed and combined with the response time and the turbine speed change curve to determine the turbine speed corresponding to the fuel cut-off time. Then, the turbine disk rupture speed is determined, and the turbine speed corresponding to the fuel cut-off time is compared with the turbine disk rupture speed. If the difference between the two meets the preset speed margin requirement, it is considered that the assumed over-speed fuel cut-off speed meets the requirement, and the assumed over-speed fuel cut-off speed is used as the final over-speed fuel cut-off speed. Therefore, the over-speed fuel cut-off speed determination system of the present invention proposes for the first time an overall technical idea for determining the over-speed fuel cut-off speed. Compared with the manual experience setting method of the prior art, the over-speed fuel cut-off speed can be accurately determined for each engine, ensuring that the over-speed fuel cut-off speed is within the required speed margin range, and there will be no problem of excessive or insufficient speed margin. Over-speed is effectively prevented, and the harmful consequences of turbine disc rupture due to broken shaft will not occur, thereby ensuring flight safety. In addition, the fact that the turbine speed will continue to rise within the response time of the control system is taken into consideration, thereby further improving the accuracy of the over-speed fuel cut-off speed determination.

[0075] In addition, another embodiment of the present invention further provides an electronic device, including a processor and a memory, wherein the memory stores a computer program, and the processor is configured to execute the steps of the above method by calling the computer program stored in the memory.

[0076] In addition, another embodiment of the present invention further provides a computer-readable storage medium for storing a computer program for determining the over-speed fuel cut-off speed, wherein the computer program executes the steps of the above-described method when running on a computer.

[0077] Common computer-readable storage media include: floppy disks, flexible disks, hard disks, magnetic tape, any other magnetic media, CD-ROMs, any other optical media, punch cards, paper tape, any other physical medium with a pattern of holes, random access memory (RAM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), flash-erasable programmable read-only memory (FLASH-EPROM), any other memory chip or cartridge, or any other medium that can be read by a computer. Instructions can further be transmitted or received via a transmission medium. The term transmission medium may include any tangible or intangible medium that can be used to store, encode, or carry instructions for execution by a machine, and includes digital or analog communication signals or other intangible media that facilitate communication of such instructions. Transmission media include coaxial cables, copper wire, and fiber optics, including the wires of a bus used to transmit a computer data signal.

[0078] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code. The scheme in the embodiment of the present application can be implemented in various computer languages, for example, object-oriented programming language Java and literal translation scripting language JavaScript, etc.

[0079] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1A device that provides the functions specified in a block or multiple blocks.

[0080] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0081] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0082] Although the preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present application.

[0083] Obviously, those skilled in the art may make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

[0084] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for determining an over-speed fuel cut-off speed, characterized in that: Includes the following: Determine the response time of the aircraft engine control system from the execution of the fuel cut command to the complete fuel cut; The turbine speed variation curves at different moments after shaft breakage are obtained by fitting; Assuming an over-speed cut-off speed, and combining the response time and turbine speed curve to determine the turbine speed corresponding to the fuel cut-off moment; Determine the turbine disk rupture speed, compare the turbine speed corresponding to the fuel cut-off moment with the turbine disk rupture speed, and if the difference between the two meets the preset speed margin requirement, use the assumed over-speed fuel cut-off speed as the final over-speed fuel cut-off speed; The process of fitting the turbine speed change curves at different times after the shaft breaks includes the following: Obtain the turbine torque and turbine speed when the aircraft engine shaft is broken, and calculate the turbine torque at different turbine speeds after the shaft is broken; The turbine torque at different turbine speeds after shaft breakage is fitted to obtain the functional relationship between the turbine torque and turbine speed after shaft breakage. The iteration step size is set, and the turbine speed at different times after the shaft break is iteratively calculated based on the functional relationship between the turbine torque and the turbine speed after the shaft break. The turbine speed change curve at different times after the shaft break is obtained by data fitting; The process of assuming the over-speed fuel cut-off speed and determining the turbine speed corresponding to the fuel cut-off moment in combination with the response time and the turbine speed change curve includes the following: Assuming that the overspeed oil cut-off speed is N2, the overspeed moment T is found on the turbine speed change curve at different times after the shaft is broken based on the overspeed oil cut-off speed N2. The response time ΔT1 of the control system is added to the overspeed moment T as the oil cut-off time (T+ΔT1), and the turbine speed corresponding to the oil cut-off time (T+ΔT1) is found on the turbine speed change curve at different times after the shaft is broken.

2. The method for determining the over-speed fuel cut-off speed according to claim 1, wherein: The mapping relationship between turbine speed and turbine efficiency was also obtained through turbine performance tests, and the turbine efficiency when the aircraft engine shaft was broken was obtained. The turbine torque at different turbine speeds after the shaft was broken was calculated based on the following formula: TQ=(((TQ1×N1) / F1)×F) / N Among them, TQ1, N1 and F1 represent the turbine torque, turbine speed and turbine efficiency when the shaft is broken, respectively. TQ and F represent the turbine torque and turbine efficiency corresponding to the turbine speed N after the shaft is broken, respectively.

3. The method for determining the over-speed fuel cut-off speed according to claim 1, wherein: The process of determining the turbine disk rupture speed includes the following: The turbine disk is mounted on a test bench and heated to simulate its actual temperature field distribution. During the heating process, the disk is rotated slowly to improve the uniformity of circumferential temperature rise. The disk is then accelerated at a preset acceleration until it ruptures, and the rotational speed at which the disk ruptures is measured.

4. The method for determining the over-speed fuel cut-off speed according to claim 1, wherein: If the difference between the turbine speed corresponding to the oil cut-off moment and the turbine disc rupture speed does not meet the preset speed margin requirement, the assumed over-speed oil cut-off speed is reduced and the above process is repeated until the difference between the two meets the preset speed margin requirement.

5. A system for determining an over-speed fuel cut-off speed, using the method for determining an over-speed fuel cut-off speed according to any one of claims 1 to 4, characterized in that: include: A control system response time determination module is used to determine the response time of the aircraft engine control system from executing the fuel cut-off instruction to completely cutting off the fuel; The turbine speed change curve fitting module is used to fit the turbine speed change curve at different times after the shaft breaks; The turbine speed determination module at the fuel cut-off moment is used to assume the over-speed fuel cut-off speed and determine the turbine speed corresponding to the fuel cut-off moment based on the response time and the turbine speed change curve; The over-speed oil cut-off speed determination module is used to determine the turbine disk rupture speed. The turbine speed corresponding to the oil cut-off time is compared with the turbine disk rupture speed. If the difference between the two meets the preset speed margin requirement, the assumed over-speed oil cut-off speed is used as the final over-speed oil cut-off speed.

6. An electronic device, characterized in that: The method comprises a processor and a memory, wherein a computer program is stored in the memory, and the processor is configured to execute the steps of the method according to any one of claims 1 to 4 by calling the computer program stored in the memory.

7. A computer-readable storage medium for storing a computer program for determining an over-speed fuel cut-off speed, characterized in that: When the computer program is run on a computer, the steps of the method according to any one of claims 1 to 4 are executed.

Images