A control method and device for preventing overspeed of low-pressure rotation of an aero-engine

Abstract

This application belongs to the field of engine control technology, and particularly relates to a control method and device for preventing the low-pressure speed of an aeroengine from overspeeding. The method includes step S1 of obtaining the measured value of the low-pressure speed in real time; and step S2 of, if the measured value of the low-pressure speed exceeds the set value, performing a main fuel flow correction. The set value is formed by increasing a specified value on the basis of the given value in the control plan. The main fuel flow correction includes: a first correction for reducing the main fuel flow based on the degree of closing of the stator vane angle relative to the given value, and a second correction for reducing the main fuel flow based on the degree of opening of the engine nozzle relative to the given value. This application can ensure that the low-pressure rotor speed of the engine does not overspeed under abnormal conditions, improve the mission completion rate of the engine, reduce the occurrence probability of accident symptoms, and improve the user experience.

Description

Technical Field

[0001] This application belongs to the technical field of engine control, and particularly relates to a control method and device for preventing low-pressure speed overrun of an aeroengine. Background Art

[0002] During the use of a certain type of aeroengine, there are occasional abnormal situations where the engine experiences low-pressure speed overrun due to reasons such as abnormal nozzle control (instantaneously opening the nozzle to the mechanical maximum) and abnormal control of the fan variable stator vane angle (instantaneously switching from fully open to fully closed).

[0003] Generally, in order to ensure that the control parameters can be applied within the full envelope of the aeroengine, the control system parameters are set conservatively to prevent excessive overshoot and the risk of unstable engine operation. However, when the engine operates in an abnormal situation at a higher state (instantaneous nozzle enlargement, instantaneous deviation of the fan variable stator vane angle), due to the overly conservative handling of the control system, it is unable to promptly reduce the main fuel flow of the engine, easily leading to low-pressure speed overrun of the engine. Summary of the Invention

[0004] To solve one of the above problems, this application provides a control method and device for preventing low-pressure speed overrun of an aeroengine, which can not only ensure the stable operation of the engine within the full envelope without excessive overshoot, but also ensure that when an abnormal situation occurs, the main fuel flow can be quickly reduced to prevent the engine from overspeeding.

[0005] The first aspect of this application provides a control method for preventing low-pressure speed overrun of an aeroengine, mainly including:

[0006] Step S1: Real-time obtain the measured value of the low-pressure speed;

[0007] Step S2: If the measured value of the low-pressure speed exceeds the set value, perform main fuel flow correction. The set value is formed by increasing a specified value on the basis of the control plan given value. The main fuel flow correction includes:

[0008] Perform a first correction to reduce the main fuel flow based on the degree of deviation of the stator vane angle from the given value, and perform a second correction to reduce the main fuel flow based on the degree of deviation of the engine nozzle from the given value.

[0009] Preferably, in step S2, performing the first correction to reduce the main fuel flow includes:

[0010] Step S21: Determine the first angle difference between the stator vane angle measured at the current moment and the stator vane angle set value, and calculate the first fuel reduction percentage corresponding to the first angle difference according to the fuel reduction percentage corresponding to each degree of angle difference.

[0011] Step S22: Determine the fuel supply amount at the current moment calculated by the control system.

[0012] Step S23: On the basis of the fuel supply amount at the current moment, calculate the corrected fuel supply amount at the current moment according to the first fuel reduction percentage.

[0013] Preferably, in step S22, the fuel supply amount at the current moment calculated by the control system is formed by subtracting the set fuel amount from the fuel supply amount at the previous moment, and the set fuel amount is the main fuel reduction amount at the current moment calculated based on the difference between the actual rotational speed and the set rotational speed.

[0014] Preferably, in step S2, the second correction for reducing the main fuel flow rate includes:

[0015] Step S24: Determine the nozzle control mode of the engine, and the nozzle control mode includes control by area or control by turbine pressure ratio drop.

[0016] Step S25: When the nozzle control mode is control by area, determine the second magnification percentage of the nozzle area at the current moment compared to the nozzle area set value, and calculate the second fuel reduction percentage corresponding to the second magnification percentage according to the fuel reduction percentage corresponding to each magnification percentage. When the nozzle control mode is control by pressure ratio drop, determine the third magnification percentage of the turbine pressure ratio drop at the current moment compared to the turbine pressure ratio drop set value, and calculate the third fuel reduction percentage corresponding to the third magnification percentage according to the fuel reduction percentage corresponding to each magnification percentage.

[0017] Step S26: Based on the second fuel reduction percentage or the third fuel reduction percentage, correct the fuel supply amount on the basis of the fuel supply amount at the current moment.

[0018] The second aspect of the present application provides a control device for preventing over - rotation of the low - pressure rotational speed of an aero - engine, mainly including:

[0019] A low - pressure rotational speed acquisition module for real - time acquisition of the low - pressure rotational speed measurement value.

[0020] A main fuel flow rate correction module for performing main fuel flow rate correction when the low - pressure rotational speed measurement value exceeds the set value. The set value is formed by floating a specified value on the basis of the control plan set value. The main fuel flow rate correction module includes:

[0021] A first correction unit for performing a first correction to reduce the main fuel flow based on the deviation degree of the stator vane angle relative to a given value, and a second correction unit for performing a second correction to reduce the main fuel flow based on the deviation degree of the engine nozzle relative to a given value.

[0022] Preferably, the first correction unit includes:

[0023] A first fuel reduction percentage calculation sub-unit for determining a first angle difference between the stator vane angle measured at the current moment and the given value of the stator vane angle, and calculating a first fuel reduction percentage corresponding to the first angle difference according to the fuel reduction percentage corresponding to each degree of angle difference;

[0024] A control system given fuel acquisition sub-unit for determining the fuel supply amount at the current moment calculated by the control system;

[0025] A first correction sub-unit for calculating the corrected fuel supply amount at the current moment based on the fuel supply amount at the current moment according to the first fuel reduction percentage.

[0026] Preferably, in the control system given fuel acquisition sub-unit, the fuel supply amount at the current moment calculated by the control system is formed by subtracting the set fuel amount from the fuel supply amount at the previous moment, and the set fuel amount is the main fuel reduction amount at the current moment calculated based on the difference between the actual speed and the given speed.

[0027] Preferably, the second correction unit includes:

[0028] A nozzle control mode determination sub-unit for determining the nozzle control mode of the engine, and the nozzle control mode includes area control or turbine pressure ratio control;

[0029] A second and third fuel reduction percentage calculation sub-unit for determining a second magnification percentage of the nozzle area at the current moment compared to the given value of the nozzle area when the nozzle control mode is area control, and calculating a second fuel reduction percentage corresponding to the second magnification percentage according to the fuel reduction percentage corresponding to each magnification percentage, and determining a third magnification percentage of the turbine pressure ratio at the current moment compared to the given value of the turbine pressure ratio when the nozzle control mode is pressure ratio control, and calculating a third fuel reduction percentage corresponding to the third magnification percentage according to the fuel reduction percentage corresponding to each magnification percentage;

[0030] A second correction sub-unit for correcting the fuel supply amount based on the second fuel reduction percentage or the third fuel reduction percentage on the basis of the fuel supply amount at the current moment.

[0031] The key point of this application lies in reasonably setting the value of gradually reducing the main fuel quantity to prevent engine parameter fluctuations caused by excessive reduction of the main fuel flow or unstable situations such as over - speed due to insufficient reduction.

[0032] This application can gradually increase the reduction value of the main fuel quantity according to the deviation degree of the measured adjustable stator vane angle and nozzle area from the given values (the greater the deviation degree, the more the main fuel flow is reduced), ensuring that the low - pressure rotor speed of the engine will not over - speed under abnormal conditions, improving the mission completion rate of the engine, reducing the occurrence probability of accident symptoms, and enhancing the user experience. Brief Description of the Drawings

[0033] Figure 1 It is a flowchart of a preferred embodiment of the control method for preventing low - pressure speed over - speed of the aero - engine in this application. Detailed Embodiments

[0034] To make the purpose, technical solutions, and advantages of the implementation of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings in the embodiments of this application. In the drawings, the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions from beginning to end. The described embodiments are part of the embodiments of this application, not all of them. The embodiments described below with reference to the drawings are exemplary and are intended to explain this application, and should not be construed as limiting this application. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the drawings.

[0035] The first aspect of this application provides a control method for preventing low - pressure speed over - speed of an aero - engine, as Figure 1 shown, mainly including:

[0036] Step S1: Obtain the measured value of the low - pressure speed in real - time;

[0037] Step S2: If the measured value of the low - pressure speed exceeds the set value, perform main fuel flow correction. The set value is formed by floating a specified value on the basis of the given value in the control plan. The main fuel flow correction includes:

[0038] Perform the first correction to reduce the main fuel flow based on the deviation degree of the stator vane angle from the given value, and perform the second correction to reduce the main fuel flow based on the deviation degree of the engine nozzle from the given value.

[0039] It should be noted that this application corrects the main fuel flow in real time, obtains a low-pressure speed measurement value in each calculation cycle, corrects the main fuel flow in this cycle when the condition is met, and stops the correction process when the measured value of the low-pressure rotor speed is less than or equal to the set value. In step S2, the specified value can be given according to the swing amount of the low-pressure speed.

[0040] In addition, the adjustment principle of this application will be described.

[0041] 1. Correction principle of the main fuel flow for the adjustable stator vane angle α1 of the fan

[0042] According to the characteristics of the fan component, when the adjustable stator vane angle α1 of the fan is closed, both the air flow W2 of the fan and the fan pressure ratio π fan will decrease, resulting in a decrease in the work L required by the fan fan as shown in formula (1). At this time, the power of the low-pressure turbine remains unchanged, causing the low-pressure speed to increase. The control system ensures that the low-pressure speed remains constant by reducing the main fuel flow. Therefore, when the adjustable stator vane angle α1 of the fan shows an abnormal closing, the main fuel flow can be reduced in advance to avoid over-speed of the low-pressure speed.

[0043]

[0044] Where: W2 is the air flow at the fan inlet; π fan is the fan pressure ratio.

[0045] 2. Correction principle of the main fuel flow for nozzle control

[0046] When the engine nozzle area changes, it will cause a change in the power distribution relationship between the high / low-pressure shafts of the twin-spool engine, thereby causing a change in the high / low-pressure speeds. For example, when the areas of the high / low-pressure turbine guides remain unchanged, when the nozzle area is enlarged, the high-pressure shaft power will decrease and the low-pressure shaft power will increase, resulting in a decrease in the high-pressure speed and an increase in the low-pressure speed of the engine. Therefore, when the nozzle area is abnormally enlarged, the main fuel flow can be reduced to ensure that the low-pressure speed does not over-speed.

[0047] In some alternative embodiments, in step S2, the first correction for reducing the main fuel flow includes:

[0048] Step S21: Determine the first angle difference between the stator vane angle measured at the current moment and the given value of the stator vane angle, and calculate the first fuel reduction percentage corresponding to the first angle difference according to the fuel reduction percentage corresponding to each degree of angle difference;

[0049] Step S22: Determine the fuel supply amount at the current moment calculated by the control system;

[0050] Step S23. On the basis of the fuel supply amount at the current moment, calculate the corrected fuel supply amount at the current moment according to the first fuel reduction percentage.

[0051] In this embodiment, the measured value of the adjustable stator vane angle α1 of the fan is detected in real time. For every 1° decrease of the measured value of α1 at the current moment relative to the given value of α1, the control system reduces the fuel supply amount w at the calculated current moment by an additional Δw f_Dem前一时刻 -Δw f_dec on the basis of, that is f_α1 %, that is

[0052] w f_α1当前时刻 =(w f_Dem前一时刻 -Δw f_dec )×k_α1 (2)

[0053] Where:

[0054] w f_Dem前一时刻 is the main fuel given value at the previous moment; Δw f_dec is the main fuel reduction amount value at the current moment calculated according to the difference between the actual speed and the given speed; Δw f_α1 is the percentage value of the reduction of the main fuel flow of the engine required to ensure that the low-pressure speed remains unchanged for every 1° decrease of the adjustable stator vane angle α1 of the fan.

[0055] In some alternative embodiments, in step S2, the second correction for reducing the main fuel flow includes:

[0056] Step S24. Determine the nozzle control mode of the engine, where the nozzle control mode includes area control or control according to the turbine pressure ratio;

[0057] Step S25. When the nozzle control mode is area control, determine the second magnification percentage of the nozzle area at the current moment compared with the given value of the nozzle area, and calculate the second fuel reduction percentage corresponding to the second magnification percentage according to the fuel reduction percentage corresponding to each magnification percentage. When the nozzle control mode is control according to the pressure ratio, determine the third magnification percentage of the turbine pressure ratio at the current moment compared with the given value of the turbine pressure ratio, and calculate the third fuel reduction percentage corresponding to the third magnification percentage according to the fuel reduction percentage corresponding to each magnification percentage;

[0058] Step S26. Based on the second fuel reduction percentage or the third fuel reduction percentage, correct the fuel supply amount on the basis of the fuel supply amount at the current moment.

[0059] In this step, when the engine is controlled according to the measured nozzle area A8, for every 1% increase of the measured value of A8 at the current moment relative to the given value of A8, the control system reduces the fuel supply amount w calculated f_α1当前时刻On this basis, further reduce Δw f_A8 ;

[0060] When the engine nozzle is controlled according to the measured π t For control, according to the π at the current moment t The measured value is relative to π t For each 1% increase in the given value, on the basis of the fuel supply amount w f_α1当前时刻 calculated by the control system, further reduce Δw f_πt ;

[0061]

[0062] Where:

[0063]

[0064] Among them, Δw f_πt is the percentage value by which the main fuel flow of the engine needs to be reduced to ensure that the low-pressure rotational speed remains unchanged when the turbine pressure ratio π t is increased by 1%; Δw f_A8 is the percentage value by which the main fuel flow of the engine needs to be reduced to ensure that the low-pressure rotational speed remains unchanged when the nozzle area A8 is increased by 1%.

[0065] The second aspect of the present application provides a control device for preventing over-speed of the low-pressure rotational speed of an aero-engine corresponding to the above method, mainly including:

[0066] A low-pressure rotational speed acquisition module for acquiring the measured value of the low-pressure rotational speed in real time;

[0067] A main fuel flow correction module for correcting the main fuel flow when the measured value of the low-pressure rotational speed exceeds a set value, and the set value is formed by floating a specified value on the basis of the given value of the control plan. The main fuel flow correction module includes:

[0068] A first correction unit for performing a first correction to reduce the main fuel flow based on the degree of deviation of the stator vane angle from the given value, and a second correction unit for performing a second correction to reduce the main fuel flow based on the degree of deviation of the engine nozzle from the given value.

[0069] In some alternative embodiments, the first correction unit includes:

[0070] A first fuel reduction percentage calculation sub-unit for determining a first angle difference between the stator vane angle measured at the current moment and the given value of the stator vane angle, and calculating a first fuel reduction percentage corresponding to the first angle difference according to the fuel reduction percentage corresponding to each degree of angle difference;

[0071] The control system's given fuel acquisition subunit is used to determine the fuel supply amount at the current moment calculated by the control system;

[0072] The first correction subunit is used to calculate the corrected fuel supply amount at the current moment based on the fuel supply amount at the current moment according to the first fuel reduction percentage.

[0073] In some alternative embodiments, in the control system's given fuel acquisition subunit, the fuel supply amount at the current moment calculated by the control system is formed by subtracting the set fuel amount from the fuel supply amount at the previous moment, and the set fuel amount is the main fuel reduction amount at the current moment calculated based on the difference between the actual rotational speed and the given rotational speed.

[0074] In some alternative embodiments, the second correction unit includes:

[0075] The nozzle control mode determination subunit is used to determine the nozzle control mode of the engine, and the nozzle control mode includes area control or control according to the turbine outlet pressure ratio;

[0076] The second and third fuel reduction percentage calculation subunit is used to, when the nozzle control mode is area control, determine the second magnification percentage of the nozzle area at the current moment compared to the given value of the nozzle area, and calculate the second fuel reduction percentage corresponding to the second magnification percentage according to the fuel reduction percentage corresponding to each magnification percentage. When the nozzle control mode is control according to the pressure ratio, determine the third magnification percentage of the turbine outlet pressure ratio at the current moment compared to the given value of the turbine outlet pressure ratio, and calculate the third fuel reduction percentage corresponding to the third magnification percentage according to the fuel reduction percentage corresponding to each magnification percentage;

[0077] The second correction subunit is used to correct the fuel supply amount based on the second fuel reduction percentage or the third fuel reduction percentage on the basis of the fuel supply amount at the current moment.

[0078] This application can gradually increase the value of reducing the main fuel amount according to the measured adjustable stator vane angle and the deviation degree of the nozzle area from the given value (the greater the deviation degree, the more the main fuel flow is reduced), ensure that the low-pressure rotor speed of the engine does not overspeed under abnormal conditions, improve the mission completion rate of the engine, reduce the occurrence probability of accident symptoms, and improve the user experience.

[0079] Although the present application has been described in detail above with general descriptions and specific implementation examples, based on the present application, some modifications or improvements can be made, which are obvious to those skilled in the art. Therefore, these modifications or improvements made without departing from the spirit of the present application all fall within the scope of protection required by the present application.

Claims

1. A control method for preventing over - speed of low - pressure rotation of an aero - engine, characterized in that, Including: Step S1, obtaining the low-pressure rotational speed measurement value in real time; Step S2, if the low-pressure rotational speed measurement value exceeds the low-pressure rotational speed set value, perform main fuel flow correction. The low-pressure rotational speed set value is formed by floating a specified value on the basis of the low-pressure rotational speed given value in the control plan. The main fuel flow correction includes: Performing a first correction to reduce the main fuel flow based on the deviation degree of the stator vane angle relative to the stator vane angle given value, and performing a second correction to reduce the main fuel flow based on the deviation degree of the engine nozzle relative to the engine nozzle given value; Among them, in step S2, performing the first correction to reduce the main fuel flow includes: Step S21, determining the first angle difference between the stator vane angle measured at the current moment and the stator vane angle given value, and calculating the first fuel reduction percentage corresponding to the first angle difference according to the fuel reduction percentage corresponding to each degree of angle difference; Step S22, determining the fuel supply amount at the current moment calculated by the control system; Step S23, on the basis of the fuel supply amount at the current moment, calculating the corrected fuel supply amount at the current moment according to the first fuel reduction percentage; In step S22, the fuel supply amount at the current moment calculated by the control system is formed by subtracting the set fuel amount from the fuel supply amount at the previous moment. The set fuel amount is the main fuel reduction amount at the current moment calculated based on the difference between the actual rotational speed and the given rotational speed; In step S2, performing the second correction to reduce the main fuel flow includes: Step S24, determining the nozzle control mode of the engine. The nozzle control mode includes area control or control according to the turbine pressure ratio; Step S25, when the nozzle control mode is area control, determining the second magnification percentage of the nozzle area at the current moment compared to the nozzle area given value, and calculating the second fuel reduction percentage corresponding to the second magnification percentage according to the fuel reduction percentage corresponding to each magnification percentage. When the nozzle control mode is control according to the pressure ratio, determining the third magnification percentage of the turbine pressure ratio at the current moment compared to the turbine pressure ratio given value, and calculating the third fuel reduction percentage corresponding to the third magnification percentage according to the fuel reduction percentage corresponding to each magnification percentage; Step S26, correcting the fuel supply amount on the basis of the second fuel reduction percentage or the third fuel reduction percentage at the current moment of the fuel supply amount; 2. A control device for preventing over - speed of low - pressure rotation of an aero - engine, characterized in that, Using the control method for preventing over-speed of the low-pressure rotational speed of an aero-engine as described in claim 1, the device includes: A low-pressure rotational speed acquisition module for obtaining the low-pressure rotational speed measurement value in real time; A main fuel flow correction module for performing main fuel flow correction when the low-pressure rotational speed measurement value exceeds the low-pressure rotational speed set value. The low-pressure rotational speed set value is formed by floating a specified value on the basis of the low-pressure rotational speed given value in the control plan. The main fuel flow correction module includes: A first correction unit for performing a first correction to reduce the main fuel flow based on the deviation degree of the stator vane angle relative to the given value of the stator vane angle, and a second correction unit for performing a second correction to reduce the main fuel flow based on the deviation degree of the engine nozzle relative to the given value of the engine nozzle.

3. The control device for preventing over - speed of low - pressure rotation of an aero - engine according to claim 2, characterized in that, The first correction unit includes: A first fuel reduction percentage calculation sub-unit for determining a first angle difference between the stator vane angle measured at the current moment and the given value of the stator vane angle, and calculating a first fuel reduction percentage corresponding to the first angle difference according to the fuel reduction percentage corresponding to each degree of angle difference; A control system given fuel acquisition sub-unit for determining the fuel supply amount at the current moment calculated by the control system; A first correction sub-unit for calculating the corrected fuel supply amount at the current moment based on the fuel supply amount at the current moment according to the first fuel reduction percentage.

4. The control device for preventing over - speed of low - pressure rotation of an aero - engine according to claim 3, characterized in that, In the control system given fuel acquisition sub-unit, the fuel supply amount at the current moment calculated by the control system is formed by subtracting the set fuel amount from the fuel supply amount at the previous moment, and the set fuel amount is the main fuel reduction amount at the current moment calculated based on the difference between the actual speed and the given speed.

5. The control device for preventing over - speed of low - pressure rotation of an aero - engine according to claim 2, characterized in that, The second correction unit includes: A nozzle control mode determination sub-unit for determining the nozzle control mode of the engine, and the nozzle control mode includes area control or turbine pressure ratio control; A second and third fuel reduction percentage calculation sub-unit for, when the nozzle control mode is area control, determining a second magnification percentage of the nozzle area at the current moment compared to the given value of the nozzle area, and calculating a second fuel reduction percentage corresponding to the second magnification percentage according to the fuel reduction percentage corresponding to each magnification percentage, and when the nozzle control mode is pressure ratio control, determining a third magnification percentage of the turbine pressure ratio at the current moment compared to the given value of the turbine pressure ratio, and calculating a third fuel reduction percentage corresponding to the third magnification percentage according to the fuel reduction percentage corresponding to each magnification percentage; A second correction sub-unit for correcting the fuel supply amount based on the second fuel reduction percentage or the third fuel reduction percentage on the basis of the fuel supply amount at the current moment.

Images