Shaft breakage protection method and system for low pressure rotor of turboshaft engine

Abstract

The application discloses a low-pressure rotor shaft breakage protection method and system of a turboshaft engine and belongs to the technical field of aero-engines. The method comprises the following steps: acquiring engine operation data, wherein the engine operation data comprises low-pressure rotor speed, high-pressure rotor speed, inlet pressure and fuel flow data supplied to the engine; performing low-pressure rotor shaft breakage judgment operation based on the engine operation data; and performing a shaft breakage protection operation after the low-pressure rotor shaft breakage is judged. The application can realize real-time detection of low-pressure rotor shaft breakage, ensure detection efficiency, avoid greater damage to the engine caused by shaft breakage and effectively ensure the operation safety of the engine by using the low-pressure rotor speed change rate, fuel feedback and inlet pressure and other parameters to judge the breakage of the low-pressure rotor shaft.

Description

Technical Field

[0001] This application belongs to the field of aero-engine technology, and specifically relates to a method and system for protecting the low-pressure rotor shaft of a turboshaft engine from shaft breakage. Background Technology

[0002] As a critical component connecting the turbine and compressor, the low-pressure rotor shaft of an aero-engine is prone to fracture due to fatigue, corrosion, material defects, manufacturing tolerances, bearing failure, and insufficient lubrication. Shaft fracture disrupts the mechanical connection between the turbine and compressor, causing drastic changes in engine parameters, potentially leading to engine damage and threatening operational safety. Therefore, a fault detection method for the low-pressure rotor shaft is necessary.

[0003] Existing technologies for detecting low-pressure rotor shaft fracture in turbofan engines are relatively mature, for example, referring to Figure 1 (In the figure, feature 1 represents the low-pressure rotor speed acceleration rate and the converted speed acceleration rate under different environmental pressures; feature 2 represents the slip characteristic of the converted high-low pressure speed; t0 represents the summation start time; and ΔT represents the summation time period.) Generally, online detection methods are constructed based on the relationship between the high-pressure and low-pressure physical speeds measured on-board. Combined with operational condition simulation, parameters are used to distinguish between normal acceleration / deceleration, surge, and shaft breakage processes. Judgment logic and thresholds are set to achieve fault detection. This method relies on a nonlinear performance model of a transitional turbofan engine based on component characteristics and is suitable for dual-shaft, high-bypass turbofan engines. It is only for turbofan engine shaft breakage detection. For the protection of the low-pressure rotor shaft of a turboshaft engine, it mainly relies on the overspeed protection module of the control system, achieving overspeed protection through speed thresholds. However, this method cannot achieve real-time identification during flight and has low fault identification accuracy, making it difficult to meet the fault detection requirements of the low-pressure rotor shaft of a turboshaft engine. Summary of the Invention

[0004] To address the aforementioned problems, this application provides a method and system for protecting the low-pressure rotor shaft of a turboshaft engine from shaft breakage, thereby resolving the issues raised in the background art.

[0005] A method for protecting the low-pressure rotor of a turboshaft engine from shaft breakage includes:

[0006] Acquire engine operating data, including low-pressure rotor speed, high-pressure rotor speed, inlet pressure, and fuel flow rate supplied to the engine;

[0007] A low-pressure rotor shaft breakage detection operation is performed based on engine operating data, and a breakage protection operation is performed after the low-pressure rotor shaft is determined to be broken. The breakage detection operation includes a third detection operation, which includes:

[0008] When the high-pressure rotor speed is greater than the idle speed and the low-pressure rotor speed decreases at a rate exceeding the set rate, the estimated value of the inlet pressure is calculated based on the fuel flow data supplied to the engine during the third set time of the low-pressure rotor speed decrease.

[0009] The judgment threshold is calculated based on the estimated value and the measured value of the inlet pressure. When the judgment threshold is greater than the set threshold, the low-pressure rotor shaft is judged to be broken.

[0010] Furthermore, the estimated import pressure calculated based on fuel flow data supplied to the engine includes:

[0011] Calculate the rate of change of fuel flow rate supplied to the engine within the fourth set time period, and calculate the estimated value of the inlet pressure based on the rate of change of fuel flow rate.

[0012] The threshold for judgment is the ratio of the difference between the estimated value of import pressure and the measured value of import pressure to the maximum value of the measured value of import pressure within a third set time period.

[0013] Furthermore, the broken axle protection operation includes parking protection.

[0014] Furthermore, the broken shaft determination process also includes a first determination process, which includes:

[0015] When the high-pressure rotor speed is greater than the idle speed and the low-pressure rotor speed is less than the first set speed, and this continues for a first set time, the low-pressure rotor shaft is determined to be broken.

[0016] Furthermore, the first set speed is 30% of the rated speed of the low-pressure rotor.

[0017] Furthermore, the protection method is executed based on the electronic controller, and the first set time is equal to the operating cycle of the electronic controller.

[0018] Furthermore, the broken shaft determination process also includes a second determination process, which includes:

[0019] During startup, if the low-pressure rotor speed signal fails or the low-pressure rotor speed is less than the second set speed within the second set time before the high-pressure rotor speed rises to the idle speed, the low-pressure rotor shaft is determined to be broken.

[0020] Furthermore, the first set time is equal to the second set time, and the first set speed is equal to the second set speed.

[0021] Another aspect of this application discloses a low-pressure rotor shaft breakage protection system for a turboshaft engine, comprising:

[0022] The acquisition module is configured to acquire engine operating data, which includes low-pressure rotor speed, high-pressure rotor speed, inlet pressure, and fuel flow rate to the engine.

[0023] The judgment execution model is configured to perform a low-pressure rotor shaft breakage judgment operation based on engine operating data, and to perform a breakage protection operation after determining that the low-pressure rotor shaft is broken. The breakage judgment operation includes a third judgment operation, which includes:

[0024] When the high-pressure rotor speed is greater than the idle speed and the low-pressure rotor speed decreases at a rate exceeding the set rate, the estimated value of the inlet pressure is calculated based on the fuel flow data supplied to the engine during the third set time of the low-pressure rotor speed decrease.

[0025] The judgment threshold is calculated based on the estimated value and the measured value of the inlet pressure. When the judgment threshold is greater than the set threshold, the low-pressure rotor shaft is judged to be broken.

[0026] Furthermore, the estimated import pressure calculated based on fuel flow data supplied to the engine includes:

[0027] Calculate the rate of change of fuel flow rate supplied to the engine within the fourth set time period, and calculate the estimated value of the inlet pressure based on the rate of change of fuel flow rate.

[0028] The threshold for judgment is the ratio of the difference between the estimated value of import pressure and the measured value of import pressure to the maximum value of the measured value of import pressure within a third set time period.

[0029] Compared with the prior art, this application has the following advantages:

[0030] This application uses parameters such as the low-pressure rotor speed change rate, fuel feedback, and inlet pressure to determine the fracture of the low-pressure rotor shaft. Compared with the existing technology that determines shaft fracture based on a single speed threshold, this method not only improves the accuracy of shaft fracture determination but also enables real-time detection of low-pressure rotor shaft fracture while ensuring detection efficiency. This avoids further damage to the engine caused by shaft fracture and effectively ensures the safe operation of the engine.

[0031] Other features and advantages of this application will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the application. The objectives and other advantages of this application may be realized and obtained by means of the structures pointed out in the description, claims and drawings. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 A schematic diagram of a prior art method for detecting low-pressure rotor shaft fracture in turbofan engines is shown.

[0034] Figure 2 A schematic diagram of the detection method in an embodiment of this application is shown. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0036] A method for protecting the low-pressure rotor of a turboshaft engine (hereinafter referred to as the protection method) is disclosed. This protection method is executed based on an electronic control unit (EECU). The EECU has built-in control software, and the engine is equipped with multiple sensing units to acquire data during engine operation. The EECU executes the protection method steps based on the data collected during operation. In some embodiments, the engine is equipped with a speed sensing unit, a fuel feedback unit, an inlet pressure sensing unit, and an environmental and operating condition sensing unit. Specifically, the speed sensing unit is a speed sensor used to collect data on the high-pressure rotor speed (N2) and the low-pressure rotor speed (N1). For example, the speed sensor can be installed... At the rotor shaft end gear ring; the fuel feedback unit is used to obtain the fuel supply status. For example, the main body of the fuel feedback unit consists of a fuel flow sensor and a fuel pressure sensor; the inlet pressure sensing unit is used to obtain inlet pressure data. In some examples, the inlet pressure sensing unit includes a piezoelectric pressure sensor installed at the combustion chamber inlet; the environment and operating condition sensing unit is used to obtain environmental and operating condition data to provide a basis for setting the values ​​of various parameters in the protection method (such as the subsequent first set speed and second set speed, etc.). In some embodiments, the environment and operating condition sensing unit includes an atmospheric pressure sensor, an ambient temperature sensor, and an altitude sensor.

[0037] In some embodiments, refer to Figure 2 The above protection methods include:

[0038] S100: Acquire engine operating data, including low-pressure rotor speed, high-pressure rotor speed, inlet pressure, and fuel flow rate supplied to the engine;

[0039] S200: Performs a low-pressure rotor shaft breakage determination operation based on engine operating data, and performs a breakage protection operation after determining that the low-pressure rotor shaft is broken.

[0040] In some embodiments, the above-mentioned shaft breakage determination operation includes multiple parallel determination operations, which are independent of each other. After any determination operation determines that the rotor shaft is broken, a corresponding shaft breakage protection operation can be performed. Specifically, the above-mentioned shaft breakage determination operation includes a first determination operation, a second determination operation, and a third determination operation in parallel, wherein the first determination operation includes:

[0041] When the high-pressure rotor speed is greater than the idle speed and the low-pressure rotor speed is less than the first set speed, and this continues for a first set time, the low-pressure rotor shaft is determined to be broken.

[0042] Specifically, the first set speed can be adaptively adjusted based on engine characteristics. For example, the first set speed is 30% of the rated speed of the low-pressure rotor. Correspondingly, the first set time can also be adjusted based on engine characteristics, for example, it can be one operating cycle of the electronic controller (e.g., 0.2s).

[0043] In some embodiments, the second determination operation described above includes:

[0044] During startup, if the low-pressure rotor speed signal fails or the low-pressure rotor speed is less than the second set speed within the second set time before the high-pressure rotor speed rises to the idle speed, the low-pressure rotor shaft is determined to be broken.

[0045] The starting process refers to the process in which the electronic controller receives the starting command and controls the starter motor to drive the engine rotor to rotate. Correspondingly, whether the low-pressure rotor speed fails is determined by the electronic controller, that is, based on whether the electronic controller receives the low-pressure rotor speed signal.

[0046] Specifically, the setting of the second setting time is the same as that of the first setting time, for example, it can be 0.2s. Correspondingly, the second setting speed is equal to the first setting speed, for example, it can also be 30% of the rated speed of the low-pressure rotor.

[0047] In some examples, the third decision task mentioned above includes:

[0048] When the high-pressure rotor speed is greater than the idle speed and the low-pressure rotor speed decreases at a rate exceeding the set rate, the estimated value of the inlet pressure is calculated based on the fuel flow data supplied to the engine during the third set time of the low-pressure rotor speed decrease.

[0049] The judgment threshold is calculated based on the estimated value and the measured value of the inlet pressure. When the judgment threshold is greater than the set threshold, the low-pressure rotor shaft is judged to be broken.

[0050] The aforementioned inlet pressure refers to the combustion chamber inlet pressure. The aforementioned set rate is determined based on Table 1 below. In Table 1, the low-pressure converted speed is obtained by processing and converting the measured speed obtained from the sensor. The specific conversion formula is as follows:

[0051]

[0052] Table 1 is a linear interpolation table of the set values ​​(i.e., set rates) of the low-pressure converted speed and the low-pressure speed change rate. Specifically, Table 1 shows the set values ​​(i.e., set rates) of the low-pressure speed change rate corresponding to the low-pressure converted speeds of 0%, 35%, 55%, 70%, 80%, 90%, and 100%. At the same time, the set values ​​(i.e., set rates) of the low-pressure speed change rate corresponding to adjacent low-pressure converted speeds in Table 1 are obtained by linear interpolation. For example, taking the low-pressure rotor speed converted to 35% in Table 1 as an example, the set rate is 30%. If the rate of decrease of the low-pressure rotor speed exceeds 30% at this time, it means that the rate of decrease of the low-pressure rotor speed exceeds the set rate.

[0053] Table 1

[0054]

[0055] The third setting time mentioned above is the same as the first and second setting times, for example, it can be 0.2s.

[0056] In some embodiments, the estimated inlet pressure is calculated based on fuel flow data supplied to the engine, including:

[0057] Calculate the rate of change of fuel flow rate supplied to the engine within the fourth set time period, and calculate the estimated value of the inlet pressure based on the rate of change of fuel flow rate.

[0058] The threshold for judgment is the ratio of the difference between the estimated value of import pressure and the measured value of import pressure to the maximum value of the measured value of import pressure within a third set time period.

[0059] For example, the fourth setting time is 0.12s.

[0060] In some examples, the estimated inlet pressure is calculated from the fuel flow data supplied to the engine, which is a mature and existing technology (for example, the estimated inlet pressure can be calculated by importing the engine model into engine performance software and inputting parameters such as engine speed and flow rate at the engine state point), which will not be elaborated here.

[0061] The formula for calculating the above-mentioned threshold is as follows:

[0062] K = (Estimated import pressure - Measured import pressure) / Maximum measured import pressure within the third set time period.

[0063] In some embodiments, the axle breakage protection operation includes a shutdown protection mechanism, specifically, a shutdown protection mechanism that can be implemented by controlling the closure of a valve to cut off the fuel supply.

[0064] This application also discloses a low-pressure rotor shaft breakage protection system for a turboshaft engine, comprising:

[0065] The acquisition module is configured to acquire engine operating data, which includes low-pressure rotor speed, high-pressure rotor speed, inlet pressure, and fuel flow rate to the engine.

[0066] The judgment execution model is configured to perform a low-pressure rotor shaft breakage judgment operation based on engine operating data, and to perform a breakage protection operation after determining that the low-pressure rotor shaft is broken. The breakage judgment operation includes a third judgment operation, which includes:

[0067] When the high-pressure rotor speed is greater than the idle speed and the low-pressure rotor speed decreases at a rate exceeding the set rate, the estimated value of the inlet pressure is calculated based on the fuel flow data supplied to the engine during the third set time of the low-pressure rotor speed decrease.

[0068] The judgment threshold is calculated based on the estimated value and the measured value of the inlet pressure. When the judgment threshold is greater than the set threshold, the low-pressure rotor shaft is judged to be broken.

[0069] Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A method for protecting the low-pressure rotor shaft of a turboshaft engine from breakage, characterized in that, include: Acquire engine operating data, including low-pressure rotor speed, high-pressure rotor speed, inlet pressure, and fuel flow rate supplied to the engine, wherein the inlet pressure is the combustion chamber inlet pressure; A low-pressure rotor shaft breakage detection operation is performed based on engine operating data, and a breakage protection operation is performed after the low-pressure rotor shaft is determined to be broken. The breakage detection operation includes a third detection operation, which includes: When the high-pressure rotor speed is greater than the idle speed and the low-pressure rotor speed decreases at a rate exceeding the set rate, the estimated value of the inlet pressure is calculated based on the fuel flow data supplied to the engine during the third set time of the low-pressure rotor speed decrease. The judgment threshold is calculated based on the estimated value and the measured value of the inlet pressure. When the judgment threshold is greater than the set threshold, the low-pressure rotor shaft is judged to be broken.

2. The method for protecting the low-pressure rotor of a turboshaft engine from shaft breakage according to claim 1, characterized in that, The estimated inlet pressure, calculated based on fuel flow data supplied to the engine, includes: Calculate the rate of change of fuel flow rate supplied to the engine within the fourth set time period, and calculate the estimated value of the inlet pressure based on the rate of change of fuel flow rate. The threshold for judgment is the ratio of the difference between the estimated value of import pressure and the measured value of import pressure to the maximum value of the measured value of import pressure within a third set time period.

3. The method for protecting the low-pressure rotor of a turboshaft engine from shaft breakage according to claim 1, characterized in that, The broken axle protection operation includes stop protection.

4. The method for protecting the low-pressure rotor of a turboshaft engine from shaft breakage according to claim 1, characterized in that, The broken shaft determination process further includes a first determination process, which includes: When the high-pressure rotor speed is greater than the idle speed and the low-pressure rotor speed is less than the first set speed, and this continues for a first set time, the low-pressure rotor shaft is determined to be broken.

5. A method for protecting the low-pressure rotor shaft of a turboshaft engine according to claim 4, characterized in that, The first set speed is 30% of the rated speed of the low-pressure rotor.

6. The method for protecting the low-pressure rotor of a turboshaft engine from shaft breakage according to claim 4, characterized in that, The protection method is executed based on an electronic controller, and the first set time is equal to the operating cycle of the electronic controller.

7. A method for protecting a low-pressure rotor of a turboshaft engine from shaft breakage according to claim 4, characterized in that, The broken shaft determination process further includes a second determination process, which includes: During startup, if the low-pressure rotor speed signal fails or the low-pressure rotor speed is less than the second set speed within the second set time before the high-pressure rotor speed rises to the idle speed, the low-pressure rotor shaft is determined to be broken.

8. A method for protecting the low-pressure rotor of a turboshaft engine from shaft breakage according to claim 7, characterized in that, The first set time is equal to the second set time, and the first set speed is equal to the second set speed.

9. A low-pressure rotor shaft breakage protection system for a turboshaft engine, characterized in that, include: The acquisition module is configured to acquire engine operating data, which includes low-pressure rotor speed, high-pressure rotor speed, inlet pressure, and fuel flow rate to the engine. The judgment execution model is configured to perform a low-pressure rotor shaft breakage judgment operation based on engine operating data, and to perform a breakage protection operation after determining that the low-pressure rotor shaft is broken. The breakage judgment operation includes a third judgment operation, which includes: When the high-pressure rotor speed is greater than the idle speed and the low-pressure rotor speed decreases at a rate exceeding the set rate, the estimated value of the inlet pressure is calculated based on the fuel flow data supplied to the engine during the third set time of the low-pressure rotor speed decrease. The judgment threshold is calculated based on the estimated value and the measured value of the inlet pressure. When the judgment threshold is greater than the set threshold, the low-pressure rotor shaft is judged to be broken.

10. A low-pressure rotor shaft breakage protection system for a turboshaft engine according to claim 9, characterized in that, The estimated inlet pressure, calculated based on fuel flow data supplied to the engine, includes: Calculate the rate of change of fuel flow rate supplied to the engine within the fourth set time period, and calculate the estimated value of the inlet pressure based on the rate of change of fuel flow rate. The threshold for judgment is the ratio of the difference between the estimated value of import pressure and the measured value of import pressure to the maximum value of the measured value of import pressure within a third set time period.

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