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

Abstract

The invention discloses a method and a system for determining an over-rotation fuel cut-off rotating speed, electronic equipment and a storage medium, and the method for determining the over-rotation fuel cut-off rotating speed proposes an overall technical thought for determining the over-rotation fuel cut-off rotating speed for the first time. According to the method, the over-rotation fuel cut-off rotating speed can be accurately determined for each type of engine, it is ensured that the over-rotation fuel cut-off rotating speed is within the required rotating speed margin range, the problem that the rotating speed margin is too large or too small cannot occur, over-rotation is effectively prevented, it is ensured that the harmful consequence that a turbine disc is broken due to shaft breakage cannot occur, flight safety is guaranteed, and the service life of the engine is prolonged. In addition, it is also considered that the rotating speed of the turbine continues to rise within the response time of the control system, and the accuracy of determining the over-rotation fuel cut-off rotating speed is further improved.

Description

Technical Field

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

[0002] During the installation and flight of an aero-engine, if a shaft break occurs, the turbine component will lose its load, and the turbine speed will rapidly increase within a short period of time, resulting in an over-speed phenomenon. If the control system does not cut off the fuel supply in time, the turbine disk will rupture. The kinetic energy of the turbine disk fragments at high speed is very large, and it is very likely that the turbine disk fragments cannot be contained by the engine casing, which will seriously endanger the aircraft body and flight safety. Therefore, during the design process of an aero-engine, it is necessary to accurately determine the over-speed fuel cut-off speed of the aero-engine to ensure that there will be no harmful consequences of turbine disk rupture caused by shaft break. At present, the determination of the over-speed fuel cut-off speed of an aero-engine usually relies on engineering experience for rough determination, which cannot guarantee accuracy, and there are problems of too large or too small speed margins. Summary of the Invention

[0003] The present invention provides a method and system for determining the over-speed fuel cut-off speed, an electronic device, and a computer-readable storage medium, which can accurately determine the over-speed fuel cut-off speed for each engine type, effectively prevent over-speed from occurring, ensure flight safety, and also consider that the turbine speed will continue to rise during the response time of the control system, further improving the accuracy of determining the over-speed fuel cut-off speed.

[0004] According to one aspect of the present invention, a method for determining the over-speed fuel cut-off speed is provided, including the following steps: Determine the response time of the aero-engine control system from executing the fuel cut-off instruction to complete fuel cut-off; Fit the turbine speed change curve at different times after shaft break; Assume the over-speed fuel cut-off speed, and combine the response time and the turbine speed change curve to determine the turbine speed corresponding to the fuel cut-off time; Determine the turbine disk rupture speed, compare the turbine speed corresponding to the fuel cut-off time with the turbine disk rupture speed, and if the difference between the two satisfies the preset speed margin requirement, then use the assumed over-speed fuel cut-off speed as the final over-speed fuel cut-off speed.

[0005] Further, the process of fitting the turbine speed change curve at different times after shaft break includes the following steps: Obtain the turbine torque and turbine speed at the time of shaft break of the aero-engine, and calculate the turbine torque at different turbine speeds after shaft break; Perform data fitting on the turbine torque at different turbine speeds after the shaft break to obtain the functional relationship between the turbine torque and the turbine speed after the shaft break; Set the iteration step size, and based on the functional relationship between the turbine torque and the turbine speed after the shaft break, iteratively calculate the turbine speed at different times after the shaft break, and perform data fitting to obtain the turbine speed change curve at different times after the shaft break.

[0006] Furthermore, the mapping relationship between the turbine speed and the turbine efficiency is also obtained through turbine performance tests, and the turbine efficiency at the time of the shaft break of the aero-engine is obtained. The turbine torque at different turbine speeds after the shaft break is calculated based on the following formula: TQ = (((TQ1 × N1) / F1) × F) / N where TQ1, N1, and F1 respectively represent the turbine torque, turbine speed, and turbine efficiency at the time of the shaft break, and TQ and F respectively represent the turbine torque and turbine efficiency corresponding to the turbine speed N after the shaft break.

[0007] Furthermore, the turbine speed at different times after the shaft break is iteratively calculated based on the following formula: N = N1 + (((a × N 4 + b × N 3 + c × N 2 + d × N + e) × ΔT) / M where N represents the turbine speed at different times after the shaft break, N1 represents the turbine speed at the time of the shaft break, ΔT 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 break.

[0008] Furthermore, the process of assuming the over-speed fuel cut-off speed and determining the turbine speed corresponding to the fuel cut-off time in combination with the response time and the turbine speed change curve includes the following content: Assume that the over-speed fuel cut-off speed is N2. Based on the over-speed fuel cut-off speed N2, find the over-speed time T on the turbine speed change curve at different times after the shaft break. Add the response time ΔT1 of the control system to the over-speed time T as the fuel cut-off time (T + ΔT1), and find the turbine speed corresponding to the fuel cut-off time (T + ΔT1) on the turbine speed change curve at different times after the shaft break.

[0009] Furthermore, the process of determining the turbine disk rupture speed includes the following content: Install the turbine disk on the test bench, heat the turbine disk to simulate the actual temperature field distribution of the turbine disk, and make the turbine disk rotate slowly during the heating process to improve the circumferential temperature rise uniformity. Then accelerate the turbine disk according to the preset acceleration until the turbine disk ruptures, and measure the speed at which the turbine disk ruptures.

[0010] Further, if the difference between the turbine speed corresponding to the fuel cut-off moment and the turbine disk rupture speed does not meet the preset speed margin requirement, the assumed overspeed fuel cut-off speed is reduced and the above process is repeated until the difference between the two meets the preset speed margin requirement.

[0011] In addition, the present invention also provides a system for determining the overspeed fuel cut-off speed, including: A control system response time determination module, configured to determine the response time of the aero-engine control system from executing the fuel cut-off instruction to complete fuel cut-off; A turbine speed change curve fitting module, configured to fit the turbine speed change curves at different moments after shaft breakage; A turbine speed determination module at fuel cut-off moment, configured to assume the overspeed fuel cut-off speed, and determine the turbine speed corresponding to the fuel cut-off moment in combination with the response moment and the turbine speed change curve; An overspeed fuel cut-off speed determination module, configured to 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 overspeed fuel cut-off speed as the final overspeed fuel cut-off speed.

[0012] In addition, the present invention also provides an electronic device, including a processor and a memory, where a computer program is stored in the memory, and the processor is configured to execute the steps of the method described above by calling the computer program stored in the memory.

[0013] In addition, the present invention also provides a computer-readable storage medium, configured to store a computer program for determining the overspeed fuel cut-off speed, and the computer program executes the steps of the method described above when running on a computer.

[0014] The present invention has the following beneficial effects: The method for determining the overspeed fuel cut-off speed of the present invention first proposes an overall technical idea for determining the overspeed fuel cut-off speed. Compared with the manual experience setting method of the prior art, it can accurately determine the overspeed fuel cut-off speed for each engine, ensure that the overspeed 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, effectively preventing overspeed from occurring, ensuring that there will be no harmful consequences of turbine disk rupture caused by shaft breakage, guaranteeing flight safety, and also considering that the turbine speed will continue to rise within the response time of the control system, further improving the accuracy of determining the overspeed fuel cut-off speed.

[0015] In addition, the system for determining the overspeed fuel cut-off speed of the present invention also has the above advantages.

[0016] In addition to the purposes, features and advantages described above, the present invention has other purposes, features and advantages. The present invention will be further described in detail below with reference to the drawings. Description of the Drawings

[0017] The drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings: Figure 1 is a schematic flowchart of a method for determining the over-speed fuel cut-off speed of a preferred embodiment of this application; Figure 2 is Figure 1 a sub-flowchart of step S2 in Figure 3 is a schematic diagram showing the relationship between the turbine speed and the turbine efficiency of a certain type of aero-engine obtained by fitting in a preferred embodiment of this application; Figure 4 is a schematic diagram showing the relationship between the turbine speed and the turbine torque after the shaft breakage of a certain type of aero-engine obtained by fitting in a preferred embodiment of this application; Figure 5 is a schematic diagram of a curve showing the change of the turbine speed at different times after the shaft breakage of a certain type of aero-engine obtained by fitting in a preferred embodiment of this application; Figure 6 is a schematic diagram of the module structure of a system for determining the over-speed fuel cut-off speed in another embodiment of this application. Detailed Embodiments

[0018] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0019] Referring to Figure 1 , a preferred embodiment of this application provides a method for determining the over-speed fuel cut-off speed, including the following: Step S1: Determine the response time of the aero-engine control system from executing the fuel cut-off instruction to the complete cut-off of the fuel; Step S2: Fit the curve of the turbine speed change at different times after the shaft breakage; Step S3: Assume the over-speed fuel cut-off speed, and combine the response time and the turbine speed change curve to determine the turbine speed corresponding to the fuel cut-off time; Step S4: Determine the turbine disk rupture speed, compare the turbine speed corresponding to the fuel cut-off time with the turbine disk rupture speed. If the difference between the two satisfies the preset speed margin requirement, the assumed over-speed fuel cut-off speed is used as the final over-speed fuel cut-off speed.

[0020] It can be understood that for the method of determining the over-speed fuel cut-off speed in this embodiment, first, the response time of the control system from executing the fuel cut-off instruction to complete fuel cut-off is determined. After fitting the turbine speed change curves at different times after the shaft break, 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 requirements, and the assumed over-speed fuel cut-off speed is used as the final over-speed fuel cut-off speed. Therefore, the method of determining the over-speed fuel cut-off speed of the present invention first proposes the overall technical idea of determining the over-speed fuel cut-off speed. Compared with the manual experience setting method of the prior art, it can accurately determine the over-speed fuel cut-off speed for each engine type, ensure that the over-speed fuel cut-off speed is within the required speed margin range, avoid problems such as too large or too small speed margin, effectively prevent over-speed from occurring, ensure that no harmful consequences of turbine disk rupture due to shaft break will occur, guarantee flight safety, and also consider that the turbine speed will continue to rise during the response time of the control system, further improving the accuracy of determining the over-speed fuel cut-off speed.

[0021] During flight, the aero-engine control system monitors the turbine speed in real time. After the shaft break, when the monitored turbine speed reaches the set over-speed fuel cut-off speed, the control system executes the fuel cut-off instruction to reduce the engine speed and prevent over-speed or even turbine disk rupture. The present invention takes into account that there is a process from the control system executing the fuel cut-off instruction to the actual complete fuel cut-off, that is, there is a response time, and during this response time, the turbine speed will continue to rise, and the turbine speed at the actual complete fuel cut-off has exceeded the turbine speed when the fuel cut-off instruction is executed (i.e., the over-speed fuel cut-off speed). Therefore, in step S1, in order to accurately determine the over-speed fuel cut-off speed and ensure that it meets the speed margin requirement, the present invention considers the speed increase problem during the response time of the control system, and obtains the response time of the aero-engine control system from executing the fuel cut-off instruction to complete fuel cut-off through a fuel cut-off semi-physical simulation test of the control system, so as to facilitate the subsequent determination of the turbine speed at the actual complete fuel cut-off.

[0022] Among them, the process of the control system cutting off fuel in the semi-physical simulation test is specifically as follows: First, install the engine fuel and the control system on the test platform in the form of physical objects; then, replace the real engine with the engine mathematical model, and then use the measurement and control system of the test platform to input the parameters of the real engine components to generate parameters such as the rotor speed and gas temperature of the engine under real working conditions; next, convert the relevant parameters into analog signals and digital signals through the signal conversion module, and the control system controls mechanisms such as the engine fuel pump regulator and fuel cut-off valve according to the corresponding signals to achieve the fuel supply and cut-off of the engine; finally, obtain the total response time △T1 from the control system executing the fuel cut-off command to the actual complete fuel cut-off through test measurement. In addition, in other embodiments of the present invention, the control system can also cut off the actual fuel test to obtain this response time, but it will increase the test time and test cost.

[0023] In addition, during flight, after the shaft breaks, the turbine component will lose the load, and the turbine speed will rise rapidly in a short 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 break. Among them, as Figure 2 shown, the process of fitting the turbine speed change curve at different times after the shaft break includes the following contents: Step S21: Obtain the turbine torque and turbine speed when the aero-engine shaft breaks, and calculate the turbine torque at different turbine speeds after the shaft break; Step S22: Perform data fitting on the turbine torque at different turbine speeds after the shaft break to obtain the functional relationship between the turbine torque and turbine speed after the shaft break; Step S23: Set the iteration step size, and iteratively calculate the turbine speed at different times after the shaft break based on the functional relationship between the turbine torque and turbine speed after the shaft break, and perform data fitting to obtain the turbine speed change curve at different times after the shaft break.

[0024] Specifically, first obtain the turbine torque TQ1 and turbine speed N1 when the aero-engine shaft breaks in 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 this period, the turbine torque at different turbine speeds after the shaft break can be calculated based on the following formula: TQ = (TQ1 × N1) / N. For example, assuming a higher turbine speed N based on the turbine speed N1, the turbine torque TQ corresponding to the turbine speed N can be calculated, and by repeating continuously, the turbine torques corresponding to different turbine speeds after the shaft break can be obtained.

[0025] Preferably, considering that the boundary conditions at the inlet and outlet of the turbine are inconsistent at different turbine speeds in the present invention, there are certain differences in the turbine efficiency at different turbine speeds. Therefore, the present invention also obtains the mapping relationship between the turbine speed and the turbine efficiency through turbine performance tests. For example, the mapping relationship between the turbine speed and the turbine efficiency of a certain type of aero-engine is as Figure 3 shown. Among them, the turbine performance test belongs to the existing conventional engine test, and the specific principle and process will not be elaborated here. And the turbine efficiency F1 at the time of the shaft break of the aero-engine is obtained, and the turbine torque at different turbine speeds after the shaft break is corrected by using the turbine efficiency, that is, the turbine torque at different turbine speeds after the shaft break is calculated based on the following formula: TQ = (((TQ1 × N1) / F1) × F) / N wherein, TQ1, N1, and F1 respectively represent the turbine torque, turbine speed, and turbine efficiency at the time of the shaft break, and TQ and F respectively represent the turbine torque and turbine efficiency corresponding to the turbine speed N after the shaft break. 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 break, improving the calculation accuracy, which is beneficial to improving the fitting accuracy of the turbine speed change curve at different times after the shaft break, thereby improving the accuracy of the over-speed fuel cut-off speed. In addition, preferably, the turbine torque, turbine speed, and turbine efficiency at the time of the shaft break in the maximum working state of the aero-engine are preferentially selected for calculation, because the shaft break in the maximum working state is the most dangerous working condition. If the over-speed fuel cut-off speed set under the most dangerous working condition meets the speed margin requirements, then the over-speed fuel cut-off speed under other working conditions will surely meet the requirements.

[0026] After calculating the turbine torque at different turbine speeds after the shaft break, a polynomial curve fitting is performed on the two to obtain the functional relationship between the turbine torque and the turbine speed after the shaft break, 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 the turbine speed and the turbine torque after the shaft break of a certain type of aero-engine obtained by fitting on the basis of considering turbine efficiency correction is as Figure 4 shown.

[0027] Then, the iteration step size △T = 0.5 ms is set, and immediately the turbine speed at different times after the shaft break is iteratively calculated based on the following formula: N = N1 + (TQ × △T) / M, and then substituting the functional relationship formula between the turbine torque and the turbine speed after the shaft break, we can get N = N1 + ((a × N 4 + b × N 3 + c × N 2((d × N + e) × ΔT) / M, where M represents the moment of inertia of the turbine disk. Finally, by performing data fitting on the turbine speeds at different times after the shaft break, the change curve of the turbine speed at different times after the shaft break can be obtained. For example, the change curve of the turbine speed at different times after the shaft break of a certain type of aero-engine is as Figure 5 shown.

[0028] It can be understood that in the present invention, the change curve of the turbine speed at different times after the shaft break can be obtained through simple formula conversion and data fitting, and the turbine speed at different times after the shaft break can be quickly and accurately obtained, so as to accurately determine the turbine speed corresponding to the actual complete fuel cut-off moment. Moreover, the turbine efficiency is introduced for correction calculation, which improves the calculation accuracy and is beneficial to improving the accuracy of determining the over-speed fuel cut-off speed.

[0029] In addition, in other embodiments of the present invention, after the shaft break occurs, the change curve of the turbine speed at different times after the shaft break can also be obtained by performing data fitting on the real-time monitoring results of the turbine speed sensor, but it is necessary to accurately determine the shaft break moment to ensure the accuracy of data fitting.

[0030] In addition, in the step S3, 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 content: Assume the over-speed fuel cut-off speed is N2. Based on the over-speed fuel cut-off speed N2, find the over-speed moment T on the change curve of the turbine speed at different times after the shaft break. Add the response time ΔT1 of the control system to the over-speed moment T as the fuel cut-off moment (T + ΔT1), that is, the actual complete fuel cut-off moment. Then find the turbine speed N3 corresponding to the fuel cut-off moment (T + ΔT1) on the change curve of the turbine speed at different times after the shaft break. Then, using this turbine speed N3 as a reference for subsequent judgment of the speed margin can improve the accuracy of determining the over-speed fuel cut-off speed.

[0031] In addition, in the step S4, the process of determining the turbine disk rupture speed includes the following content: Install the turbine disk on the test bench, heat the turbine disk to simulate the actual temperature field distribution of the turbine disk, and make the turbine disk rotate slowly during the heating process to improve the circumferential temperature rise uniformity. Then accelerate the turbine disk according to a preset acceleration until the turbine disk ruptures, and measure the speed N4 when the turbine disk ruptures, that is, the turbine disk rupture speed.

[0032] It can be understood that through the turbine disk rupture speed test of the present invention, the rupture speed of the turbine disk can be accurately obtained. By controlling the slow rotation of the turbine disk while heating it, the circumferential temperature rise uniformity can be improved, thus more accurately simulating the actual temperature field distribution of the turbine disk, better conforming to the actual working conditions of the turbine disk, and thus more accurately obtaining the rupture speed of the turbine disk.

[0033] Then, compare the turbine speed N3 corresponding to the fuel cut-off moment obtained in step S3 with the turbine disk rupture speed N4. If the difference between the two satisfies the preset speed margin requirement, for example, N4 - N3 ≥ 30%, it is considered that the assumed overspeed fuel cut-off speed N2 meets the requirement, and the assumed overspeed fuel cut-off speed N2 is taken as the final overspeed fuel cut-off speed; if the difference N4 between the turbine speed N3 corresponding to the fuel cut-off moment and the turbine disk rupture speed does not satisfy the preset speed margin requirement, for example, N4 - N3 is less than 30%, then reduce the assumed overspeed fuel cut-off speed N2 and repeat the above process until the difference between the two satisfies the preset speed margin requirement, that is, N4 - N3 ≥ 30%. Of course, in other embodiments of the present invention, the speed margin requirement can also be 10%, 20%, 25%, etc., which can be specifically set according to actual needs. In addition, when the preset speed margin requirement is not satisfied, it is also possible to choose to increase the turbine disk rupture speed N4, for example, by improving the strength and quality of the turbine disk to increase the turbine disk rupture speed, but this improvement method will increase the weight of the turbine disk and may cause problems such as engine vibration exceeding the limit and overweight.

[0034] In addition, as Figure 6 shown, another embodiment of the present invention also provides a system for determining the overspeed fuel cut-off speed, preferably adopting the method for determining the overspeed fuel cut-off speed as described above, including: A control system response time determination module, which is used to determine the response time of the aero-engine control system from executing the fuel cut-off instruction to complete fuel cut-off; A turbine speed change curve fitting module, which is used to fit the turbine speed change curves at different times after the shaft break; A turbine speed determination module at the fuel cut-off moment, which is used to assume the overspeed fuel cut-off speed and determine the turbine speed corresponding to the fuel cut-off moment in combination with the response moment and the turbine speed change curve; An overspeed fuel cut-off speed determination module, which is used to 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 satisfies the preset speed margin requirement, take the assumed overspeed fuel cut-off speed as the final overspeed fuel cut-off speed.

[0035] It can be understood that for the overspeed fuel cut-off speed determination system of this embodiment, first, the response time of the control system from executing the fuel cut-off instruction to complete fuel cut-off is determined. After fitting the turbine speed change curves at different times after the shaft breakage, an overspeed fuel cut-off speed is assumed and combined with the response time and the turbine speed change curves 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 satisfies the preset speed margin requirement, it is considered that the assumed overspeed fuel cut-off speed meets the requirements, and the assumed overspeed fuel cut-off speed is used as the final overspeed fuel cut-off speed. Therefore, the overspeed fuel cut-off speed determination system of the present invention first proposes the overall technical idea for determining the overspeed fuel cut-off speed. Compared with the manual experience setting method of the prior art, it can accurately determine the overspeed fuel cut-off speed for each engine type, ensure that the overspeed fuel cut-off speed is within the required speed margin range, and avoid problems such as too large or too small speed margins, effectively preventing overspeed from occurring, ensuring that there will be no harmful consequences of turbine disk rupture caused by shaft breakage, guaranteeing flight safety, and also considering that the turbine speed will continue to rise during the response time of the control system, further improving the accuracy of overspeed fuel cut-off speed determination.

[0036] In addition, another embodiment of the present invention further provides an electronic device, including a processor and a memory. A computer program is stored in the memory, and the processor is configured to execute the steps of the method as described above by calling the computer program stored in the memory.

[0037] In addition, another embodiment of the present invention further provides a computer-readable storage medium for storing a computer program for determining the overspeed fuel cut-off speed. The computer program executes the steps of the method as described above when running on a computer.

[0038] The forms of computer-readable storage media generally include: floppy disks, flexible disks, hard disks, magnetic tapes, any other magnetic media, CD-ROMs, any other optical media, punch cards, paper tapes, any other physical media with a pattern of holes, random access memories (RAMs), programmable read-only memories (PROMs), erasable programmable read-only memories (EPROMs), flash erasable programmable read-only memories (FLASH-EPROMs), any other memory chips or cartridges, or any other media readable by a computer. Instructions can further be transmitted or received by a transmission medium. The term transmission medium can 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 the intangible medium that facilitates the communication of the above instructions. Transmission media include coaxial cables, copper wires, and optical fibers, which include the wires of a bus used to transmit a computer data signal.

[0039] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memories, CD-ROMs, optical memories, etc.) containing computer-usable program code. The solutions in the embodiments of the present application can be implemented in various computer languages. For example, object-oriented programming languages such as Java and interpreted scripting languages such as JavaScript.

[0040] The present application is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of flows and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate means for implementing the functions specified in Figure 1 one or more of the flows or multiple flows and / or blocks Figure 1 one or more of the blocks or multiple blocks.

[0041] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to operate in a particular manner, such that the instructions stored in the computer-readable memory produce a manufacture including an instruction device that implements the functions specified in one or more of the processes and / or blocks Figure 1 in one or more of the processes and / or blocks Figure 1 specified in one or more of the blocks or blocks.

[0042] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus, such that a series of operational steps are performed on the computer or other programmable apparatus to produce a computer-implemented process, whereby the instructions executed on the computer or other programmable apparatus provide steps for implementing the functions specified in one or more of the processes and / or blocks Figure 1 in one or more of the processes and / or blocks Figure 1 specified in one or more of the blocks or blocks.

[0043] Although the preferred embodiments of the present application have been described, those skilled in the art can make additional changes and modifications once they learn the basic creative concept. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications that fall within the scope of the present application.

[0044] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application is also intended to include these modifications and variations.

[0045] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for determining an over-speed oil cut-off speed, characterized in that: Includes the following: Determine the response time of the aircraft engine control system from executing the fuel cut command to the complete fuel cut; The turbine speed variation curve at different times after the shaft is broken is obtained by fitting; Assuming the overrun fuel cut-off speed, and combining the response time and the turbine speed change curve to determine the turbine speed corresponding to the fuel cut-off time; 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, take the assumed over-speed oil cut-off speed as the final over-speed oil cut-off speed.

2. The method for determining the over-speed fuel cut-off speed according to claim 1, characterized in that: The process of fitting and obtaining the turbine speed change curve at different times after the shaft is broken includes the following contents: 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 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.

3. The method for determining the over-speed fuel cut-off speed according to claim 2, characterized in that: The mapping relationship between turbine speed and turbine efficiency is also obtained through turbine performance tests, and the turbine efficiency of the aircraft engine when the shaft is broken is obtained. The turbine torque at different turbine speeds after the shaft is broken is 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, and TQ and F represent the turbine torque and turbine efficiency corresponding to the turbine speed N after the shaft is broken, respectively.

4. The method for determining the over-speed fuel cut-off speed according to claim 3, characterized in that: The turbine speed at different times after the shaft is broken is iteratively calculated based on the following formula: N= N1+((a×N 4 + b×N 3 + c×N 2 +d×N+e)×△T) / M Among them, N represents the turbine speed at different times after the shaft is broken, N1 represents the turbine speed when the shaft is broken, △T represents the set iteration step, 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 is broken.

5. The method for determining the over-speed fuel cut-off speed according to claim 1, characterized in that: The process of assuming the overrun fuel cut-off speed and determining the turbine speed corresponding to the fuel cut-off time in combination with the response time and the turbine speed change curve includes the following: Assuming that the over-speed oil 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 oil cut-off speed N2, and the control system response time ΔT1 is added to the over-speed 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.

6. The method for determining the over-speed fuel cut-off speed according to claim 1, characterized in that: The process of determining the turbine disk rupture speed includes the following: The turbine disk is installed on the 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 circumferential temperature rise. The turbine disk is then accelerated according to a preset acceleration until the turbine disk breaks, and the rotational speed when the turbine disk breaks is measured.

7. The method for determining the over-speed fuel cut-off speed according to claim 1, characterized in that: 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 overspeed oil cut-off speed is reduced and the above process is repeated until the difference between the two meets the preset speed margin requirement.

8. A system for determining an over-speed fuel cut-off speed, characterized in that: include: A control system response time determination module, used to determine the response time of the aircraft engine control system from executing a 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 is broken; A turbine speed determination module at the fuel cut-off time, used to assume an over-speed fuel cut-off speed and determine the turbine speed corresponding to the fuel cut-off time in combination with 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 moment 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.

9. 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 used to execute the steps of the method according to any one of claims 1 to 7 by calling the computer program stored in the memory.

10. 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 7 are executed.

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