A method and system for robust control of an aeroengine in the presence of temperature distortions

Abstract

The application belongs to the field of aero-engine design, and is a method and system for stability expansion control of an aero-engine encountering temperature distortion. First, it is determined whether temperature distortion exists at the engine inlet section. If so, the temperature of the engine inlet section is collected in time sequence, the dynamic response error of the thermocouple is then corrected, and the corrected high-temperature zone inlet total temperature T1 of each temperature collection point is filtered with the adjacent temperature collection points. After filtering, the reconstructed high-temperature zone inlet total temperature T1 is used to calculate the control plan value of the engine state above the middle; finally, the reconstructed high-temperature zone inlet total temperature T1 is used to calculate the high-pressure compressor conversion speed n 2R , and the engine high-pressure adjustable guide vane angle α2 control plan value is obtained by using n 2R . The engine encountering temperature distortion can be more timely and accurately characterized, which not only improves the working stability of the engine, but also takes into account the exertion of engine thrust during take-off.

Description

Technical Field

[0001] This application belongs to the field of aero-engine design, and specifically relates to an extended stability control method and system for aero-engines when encountering temperature distortion. Background Technology

[0002] During takeoff, environmental wind or other factors may cause engine exhaust to backflow. When this backflow is drawn into the engine, the engine inlet temperature will rise rapidly, resulting in severe temperature distortion at the engine inlet. If the degree of distortion exceeds the engine's tolerance, it will induce engine surge.

[0003] Currently, the engine inlet total temperature sensor is only installed at one point. When the engine can detect a rise in inlet temperature, the engine's high-pressure equivalent speed decreases, and the control system adjusts the adjustable guide vane angle of the high-pressure compressor to decrease, improving the compressor surge margin. If a temperature distortion occurs at the engine inlet, due to the limited response rate of the inlet total temperature sensor, the engine may fail to detect the rise in inlet temperature in time and will not adjust the adjustable guide vane angle of the high-pressure compressor. Therefore, the engine may experience surge, which could affect takeoff safety. Summary of the Invention

[0004] The purpose of this application is to provide a method and system for extended stability control when an aero-engine encounters temperature distortion, so as to solve the problem in the prior art that it is difficult to identify the rise in engine inlet temperature in a timely manner, which affects the engine takeoff safety.

[0005] The technical solution of this application is: a method for extended stability control of an aero-engine when encountering temperature distortion, comprising: determining whether there is temperature distortion at the engine inlet section; if so, proceeding to the next step; collecting the temperature of the engine inlet section in chronological order to form several temperature collection points; obtaining the total temperature sensor time constant correction coefficient and recovery correction factor; correcting the dynamic response error of the thermocouple to form a reconstructed high-temperature zone inlet total temperature T1; filtering the corrected high-temperature zone inlet total temperature T1 of each temperature collection point with the adjacent temperature collection points; using the reconstructed high-temperature zone inlet total temperature T1 to calculate the control plan values ​​for the intermediate and higher states of the engine; and using the reconstructed high-temperature zone inlet total temperature T1 to calculate the high-pressure compressor converted speed n. 2R Using n 2R The planned control value of the engine high-pressure adjustable guide vane angle α2 is obtained.

[0006] Preferably, the formula for correcting the dynamic response error of the thermocouple is:

[0007]

[0008] In the formula, T(t) XThe corrected temperature is in K; T(t) is the indicated temperature measured by the thermocouple, in K; τ is the correction factor for the thermocouple thermal inertia time constant, in s; the data at times t and t-1 are the temperature data of two adjacent points before and after acquisition, respectively; Δt is the time difference between two adjacent temperature acquisition points; Kr is the recovery correction factor.

[0009] Preferably, the formula for filtering the temperature acquisition points is:

[0010]

[0011] Where n is an odd number, usually chosen as 5 or 7.

[0012] Preferably, when reconstructing the temperature acquisition points, the first temperature acquisition point is not corrected, and the correction starts from the second temperature acquisition point. If n=5, after the fifth temperature acquisition point is corrected, the third temperature acquisition point is filtered.

[0013] As one specific implementation, an extended stability control system for an aero-engine encountering temperature distortion includes:

[0014] The imported total temperature reconstruction module is used to collect the temperature of the engine inlet section in chronological order to form several temperature collection points, obtain the time constant correction coefficient and recovery correction factor of the total temperature sensor, correct the dynamic response error of the thermocouple, and form the reconstructed high-temperature zone inlet total temperature T1.

[0015] The filtering module is used to filter the corrected total inlet temperature T1 of the high-temperature zone at each temperature acquisition point and the adjacent temperature acquisition points.

[0016] The engine control plan value calculation module is used to calculate the control plan values ​​of the engine in intermediate and higher states using the reconstructed high-temperature zone inlet total temperature T1.

[0017] The adjustable guide vane angle of the engine high pressure is used to calculate the converted speed n of the high-pressure compressor using the reconfigured high-temperature zone inlet total temperature T1. 2R Using n 2R The control plan value of the adjustable guide vane angle α2 of the engine is obtained.

[0018] This application discloses a method and system for extended stability control of an aero-engine encountering temperature distortion. First, it determines whether temperature distortion exists at the engine inlet cross-section. If so, the temperature at the engine inlet cross-section is collected sequentially over time. Then, the dynamic response error of the thermocouples is corrected, and the corrected high-temperature zone inlet total temperature T1 at each temperature collection point is filtered against adjacent temperature collection points. After filtering, the reconstructed high-temperature zone inlet total temperature T1 is used to calculate the control plan values ​​for the engine's intermediate and higher states. Finally, the reconstructed high-temperature zone inlet total temperature T1 is used to calculate the high-pressure compressor's converted speed n. 2R Using n 2R The planned control value for the adjustable guide vane angle α2 of the engine high-pressure zone was obtained. This reconstructed high-temperature zone inlet total temperature T1 is compared to the high-temperature zone inlet total temperature T1 and T2 obtained directly from the inlet total temperature sensor. 25 It can more timely and accurately characterize the timing and intensity of engine temperature distortion, and the control angle can more realistically represent the engine's needs. It can not only improve the engine's working stability, but also take into account the engine's thrust during takeoff. Attached Figure Description

[0019] To more clearly illustrate the technical solutions provided in this application, the accompanying drawings will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application.

[0020] Figure 1 This is a schematic diagram of the overall process of this application;

[0021] Figure 2 This is a schematic diagram of the correction results for the imported total temperature sensor thermocouple in this application. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages 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.

[0023] A method for extended stability control of an aero-engine encountering temperature distortion. When the engine inhales high-temperature exhaust gas, it encounters temperature distortion, resulting in a high-temperature zone on the engine inlet cross-section. The circumferential range and location of this high-temperature zone are related to the characteristics of the encountered temperature distortion. Since the inlet total temperature sensor used in the engine control system is in a fixed position, it may not detect the increase in inlet temperature. Therefore, the controller will adjust the temperature according to the temperature T collected by the inlet total temperature sensor. 1D The high-pressure converted speed n is calculated using the engine's high-pressure physical speed n2. 2r Using the calculated n 2r The interpolation calculation yields the engine's high-pressure adjustable guide vane angle α2, as follows:

[0024] a) Temperature T is collected using an imported total temperature sensor. 1D Calculate the compressor speed n from the engine speed n2. 2R See formula (1) for details:

[0025] n 2R = n × SQRT(288.15 / T) 1D (1)

[0026] b) Calculate the rotational speed n using a high-pressure compressor. 2R The angle α2 of the high-pressure adjustable guide vane of the engine is obtained by interpolation.

[0027] Assuming that the actual inlet total temperature T1 of the high-temperature zone is different from T at this time 1D If the value is high, then n is calculated using Formula 1. 2R To be low, if the high-pressure adjustable guide vane angle is still set to T. 1D The calculated α2 will deviate, making the engine prone to surge.

[0028] Therefore, it is necessary to modify the engine inlet T1, specifically including the following steps:

[0029] In step S100, during takeoff, if there is temperature distortion at the engine inlet section, the "engine encounters temperature distortion" flag is set, and then proceed to the next step.

[0030] When it is determined that no high-temperature combustion gases are being inhaled, the "engine encountering temperature distortion" warning is invalid. The compressor adjustable blades can be opened to a suitable state according to normal design requirements to ensure the thrust required for aircraft takeoff.

[0031] Step S200, Method for reconstructing the total inlet temperature T1 of the high-temperature zone

[0032] The temperature of the engine inlet section is collected in chronological order to form several temperature collection points. The time interval between adjacent temperature collection points is the same. The time constant correction coefficient and recovery correction factor of the total temperature sensor are obtained to correct the dynamic response error of the thermocouple and form the reconstructed high-temperature zone inlet total temperature T1.

[0033] The correction formula for rapidly changing temperatures measured by imported total temperature sensor thermocouples is as follows:

[0034] T(t) X = [T(t) + Time Constant Correction + Radiation Correction] * [Recovery Correction]

[0035] T(t) X The total inlet temperature T1 of the reconstructed high-temperature zone is obtained because the temperature gradient between the engine intake wall temperature and the thermocouple thermistor is very small, and the radiation error is not a major error. Therefore, the influence of radiation heat conduction can be ignored, resulting in:

[0036] T(t) X = [T(t) + Time Constant Correction] * [Recovery Correction]

[0037] The formula for correcting the dynamic response error of a thermocouple is as follows:

[0038]

[0039] In the formula, T(t) X The corrected temperature is in K; T(t) is the indicated temperature measured by the thermocouple, in K; τ is the correction factor for the thermocouple thermal inertia time constant, in s; the data at times t and t-1 are the temperature data of two adjacent points before and after the acquisition, respectively; Δt is the time difference between two adjacent temperature acquisition points.

[0040] Kr is the recovery correction factor, defined by formula (3):

[0041]

[0042] In the formula, γ is the specific heat ratio of the fuel gas, which is 1.4 for air;

[0043] M—Mach number;

[0044] r — the thermocouple's coefficient of restitution.

[0045] Step S300: The corrected total inlet temperature T1 of the high-temperature zone at each temperature acquisition point is filtered together with the temperature acquisition points adjacent to it.

[0046] According to the book "Measurement of Aerodynamic Parameters of Aircraft Engines" (compiled by Northwestern Polytechnical University), the coefficient of restitution of a thermocouple with a stagnation chamber structure at Mach number 0.5 is approximately 0.95. Domestically designed thermocouples with stagnation chamber structures, even those with poor stagnation performance, still have a coefficient of restitution above 0.9. If r = 0.9, then Kr = 0.005.

[0047] Each temperature acquisition point is filtered in conjunction with its adjacent temperature acquisition points to further correct the reconstructed total inlet temperature T1 of the high-temperature zone, which is also known as T(t). X The processing method is shown in formula (4), where n is an odd number, usually 5 or 7.

[0048]

[0049] When reconstructing the temperature acquisition points, the first temperature acquisition point is not corrected. Correction begins from the second temperature acquisition point. If n=5, filtering is applied to the third temperature acquisition point after the fifth temperature acquisition point is corrected. This process continues, and the first two temperature acquisition points are not averaged after correction.

[0050] Using the above method, the engine inlet temperature before and after encountering temperature distortion surge is corrected, such as... Figure 2 , where 1 is the curve of the total inlet temperature T1 in the high-temperature zone without correction over time, and 2 is the curve of T(t) when the thermocouple restoration system is set to 1. X The curves change over time; curve 3 represents T(t) when the thermocouple system returns to zero. X The curves show how the surge signal changes over time; curve 4 shows how the surge signal changes over time.

[0051] It can be seen that the engine experiences a significant temperature surge before and after surge, therefore this calculation method is relatively accurate.

[0052] By correcting the temperature in real time, it can be ensured that the engine controls the relevant laws according to the actual inlet temperature.

[0053] Step S400: Calculate the control plan values ​​for the engine's intermediate and higher states using the reconstructed high-temperature zone inlet total temperature T1.

[0054] Control plan values ​​for engine intermediate and higher states include high and low pressure speeds, exhaust temperature, afterburner fuel quantity, and nozzle (π) values. T Or EPR, etc. In this way, the engine can be accurately controlled according to the existing control rate in the intermediate and normal states.

[0055] Step S500: Calculate the converted speed n of the high-pressure compressor using the reconstructed total inlet temperature T1 of the high-temperature zone. 2R Using n 2R The planned control value of the engine high-pressure adjustable guide vane angle α2 is obtained.

[0056] After reconstructing the total inlet temperature T1 in the high-temperature zone, the angle of the high-pressure adjustable blades can be adaptively reduced, thereby improving the stability of the engine.

[0057] In other words, when a temperature distortion is detected, the control law for the adjustable guide vane angle of the high-pressure compressor is directly converted to calculate the α2 control plan value using the reconstructed high-temperature zone inlet total temperature T1. When no temperature distortion is detected, the control law is converted back to calculate the α2 control plan value using the original high-temperature zone inlet total temperature T1. The above conversion process is limited to |α2 plan change rate| ≤ 3° / s (adjustable range, 0.1° / s~5° / s).

[0058] This application first determines whether there is temperature distortion at the engine inlet section. If so, the temperature at the engine inlet section is collected sequentially over time. Then, the dynamic response error of the thermocouple is corrected, and the corrected high-temperature zone inlet total temperature T1 at each temperature collection point is filtered with the adjacent temperature collection points. After filtering, the reconstructed high-temperature zone inlet total temperature T1 is used to calculate the control plan values ​​for the engine's intermediate and higher states. Finally, the reconstructed high-temperature zone inlet total temperature T1 is used to calculate the converted speed n of the high-pressure compressor. 2R Using n 2R The planned control value for the adjustable guide vane angle α2 of the engine high-pressure zone was obtained. This reconstructed high-temperature zone inlet total temperature T1 is compared to the high-temperature zone inlet total temperature T1 and T2 obtained directly from the inlet total temperature sensor. 25 It can more timely and accurately characterize the timing and intensity of engine temperature distortion, and the control angle can more realistically represent the engine's needs. It can not only improve the engine's working stability, but also take into account the engine's thrust during takeoff.

[0059] As one specific implementation, an extended stability control system for an aero-engine encountering temperature distortion includes:

[0060] The temperature distortion detection module is used to determine whether there is temperature distortion at the engine inlet section;

[0061] The imported total temperature reconstruction module is used to collect the temperature of the engine inlet section in chronological order to form several temperature collection points, obtain the time constant correction coefficient and recovery correction factor of the total temperature sensor, correct the dynamic response error of the thermocouple, and form the reconstructed high-temperature zone inlet total temperature T1.

[0062] The filtering module is used to filter the corrected total inlet temperature T1 of the high-temperature zone at each temperature acquisition point and the adjacent temperature acquisition points.

[0063] The engine control plan value calculation module is used to calculate the control plan values ​​of the engine in intermediate and higher states using the reconstructed high-temperature zone inlet total temperature T1.

[0064] The guide vane angle calculation module is used to calculate the converted speed n of the high-pressure compressor using the reconstructed high-temperature zone inlet total temperature T1. 2R Using n 2R The planned control value of the engine high-pressure adjustable guide vane angle α2 is obtained.

[0065] Through the coordinated operation of the temperature distortion judgment module, the inlet total temperature reconstruction module, the filtering module, the engine control plan value calculation module, and the guide vane angle calculation module, temperature distortion can be judged in a timely manner, the inlet total temperature T1 in the high-temperature zone can be effectively reconstructed, and the various states of the engine and compressor can be stably controlled.

[0066] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for extended stability control of an aero-engine when encountering temperature distortion, characterized in that, include: During takeoff, if there is temperature distortion at the engine inlet section, the "engine encounters temperature distortion" flag is activated, and the next step is executed. The temperature of the engine inlet section is collected in chronological order to form several temperature collection points. The time constant correction coefficient and recovery correction factor of the total temperature sensor are obtained, and the dynamic response error of the thermocouple is corrected to form the reconstructed high-temperature zone inlet total temperature T1. The corrected total inlet temperature T1 of the high-temperature zone at each temperature acquisition point is filtered against the adjacent temperature acquisition points. The control plan values ​​for the engine's intermediate and higher states are calculated by interpolating the reconstructed high-temperature zone inlet total temperature T1. The converted speed n of the high-pressure compressor is calculated using the reconstructed high-temperature zone inlet total temperature T1. 2R Using n 2R The planned control value of the engine high-pressure adjustable guide vane angle α2 is obtained; The formula for correcting the dynamic response error of the thermocouple is as follows: ； In the formula, The corrected temperature is in K. The indicated temperature measured by the thermocouple, in K; This is the correction factor for the thermocouple thermal inertia time constant, in seconds; The data at time t and t-1 are the temperature data of two adjacent points before and after the acquisition, respectively; Kr is the time difference between two adjacent temperature acquisition points; Kr is the recovery correction factor. The formula for calculating the recovery correction factor is: ； In the formula, —Specific heat ratio of fuel gas, air is 1.4; M—Mach number; r — the thermocouple's coefficient of restitution.

2. The extended stability control method for an aero-engine encountering temperature distortion as described in claim 1, characterized in that, The formula for filtering the temperature acquisition points is: ； Where n is an odd number, and is chosen to be 5 or 7.

3. The extended stability control method for an aero-engine encountering temperature distortion as described in claim 2, characterized in that: When reconstructing the temperature acquisition points, the first temperature acquisition point is not corrected, and the correction starts from the second temperature acquisition point. If n=5, after the fifth temperature acquisition point is corrected, the third temperature acquisition point is filtered.

4. A stability enhancement control system for an aero-engine encountering temperature distortion, characterized in that, include: The imported total temperature reconstruction module is used to collect the temperature of the engine inlet section in chronological order to form several temperature collection points, obtain the time constant correction coefficient and recovery correction factor of the total temperature sensor, correct the dynamic response error of the thermocouple, and form the reconstructed high-temperature zone inlet total temperature T1. The formula for correcting the dynamic response error of the thermocouple is as follows: ； In the formula, The corrected temperature is in K. The indicated temperature measured by the thermocouple, in K; This is the correction factor for the thermocouple thermal inertia time constant, in seconds; The data at time t and t-1 are the temperature data of two adjacent points before and after the acquisition, respectively; Kr is the time difference between two adjacent temperature acquisition points; Kr is the recovery correction factor. The formula for calculating the recovery correction factor is: ； In the formula, —Specific heat ratio of fuel gas, air is 1.4; M—Mach number; r—the thermocouple's coefficient of restitution; The filtering module is used to filter the corrected total inlet temperature T1 of the high-temperature zone at each temperature acquisition point and the adjacent temperature acquisition points. The engine control plan value calculation module uses the reconstructed high-temperature zone inlet total temperature T1 to calculate the control plan values ​​for the engine in intermediate and higher states. The engine high-pressure adjustable guide vane angle calculation module uses the reconstructed high-temperature zone inlet total temperature T1 to calculate the high-pressure compressor equivalent speed n. 2R Using n 2R The control plan value of the engine high-pressure adjustable guide vane angle α2 was obtained by interpolation calculation.

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