Aero-engine warm-up process turbine exhaust gas temperature adaptive control method

Abstract

The present application relates to a kind of turbine exhaust temperature self-adaptive control method of aero-engine warm-up process, and it is related to aero-engine control field.The online identification of warm-up condition is realized by the double criterion of parking time interval and compressor outlet temperature-intake temperature difference, to avoid misjudgment or missing judgment on warm-up process;By establishing the periodic recursive calculation model of rotor centrifugal deformation, blade and disc thermal deformation and casing thermal expansion, the synthesized amount of tip clearance is obtained in real time, and the clearance change difficult to measure in warm-up process is converted into calculable intermediate variable;The turbine efficiency is corrected with tip clearance deviation, and the proportional coefficient and integral coefficient of turbine exhaust temperature PI controller are scheduled online accordingly, so that control parameters are self-adaptive adjustment with engine characteristic time-varying, effectively inhibit the overshoot and oscillation of turbine exhaust temperature in warm-up stage;After warm-up, it is automatically switched back to design baseline parameter, to ensure that the control performance of turbine exhaust temperature in conventional condition is not affected.

Description

Technical Field

[0001] This invention relates to the field of aero-engine control technology, and in particular to an adaptive control method for turbine exhaust temperature during the warm-up process of an aero-engine. Background Technology

[0002] After an aero-engine starts, it needs to operate at low power for a period of time to allow the temperature of hot-end components such as the rotor and casing to gradually rise and fully expand thermally. This causes characteristic dimensions such as the blade tip clearance between the rotor and casing to converge to a specified range; this process is called warm-up. Warm-up is a crucial step in the engine's transition from the starting state to full-power operation, and its quality directly affects the safety margin of subsequent high-power conditions such as takeoff and climb. Currently, turbine exhaust temperature control in aero-engines is generally achieved by a Full Authority Digital Electronic Controller (FADEC), employing a fixed-parameter PI control law based on design point calibration. The deviation between the measured turbine exhaust temperature and the planned target value is used as input, and a fuel flow command is output to stabilize the turbine exhaust temperature within the planned envelope. This approach exhibits good control accuracy under engine hot, steady-state, and conventional transient operating conditions and has been widely adopted in current models.

[0003] However, the aforementioned control scheme has some shortcomings during the warm-up process. During warm-up, the engine is in a non-steady-state transition from a cold to a hot state. Influenced by the fluid-solid-thermal multi-field coupling effect, the combined effects of turbine rotor centrifugal deformation, blade and disk thermal deformation, and casing thermal expansion cause the blade tip clearance to continuously change with the warm-up progress. This leads to aerodynamic characteristic parameters such as turbine efficiency deviating from the design baseline and exhibiting time-varying characteristics. The existing FADEC control scheme has the following problems: it lacks a mechanism for identifying and judging the warm-up process, making it unable to distinguish between warm-up and normal operating conditions; it has not established a quantitative mapping relationship between rotor deformation, casing deformation, and blade tip clearance during warm-up, making it impossible to obtain real-time information on blade tip clearance changes; and it does not incorporate the impact of blade tip clearance changes on turbine efficiency into the control loop, keeping controller parameters fixed throughout the warm-up process and unable to adapt to the time-varying characteristics of the engine. These problems result in increased turbine exhaust temperature overshoot, prolonged settling time, and aggravated temperature fluctuations during warm-up. In severe cases, this may trigger over-temperature protection or cause unstable thrust output, affecting the safety and reliability of engine operation. Summary of the Invention

[0004] The purpose of this invention is to provide an adaptive control method for turbine exhaust temperature during the warm-up process of an aero-engine, so as to solve the problems existing in the prior art.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: An adaptive control method for turbine exhaust temperature during the warm-up process of an aero-engine, the method comprising the following steps: S10, by using the time interval between the current start time and the last shutdown time of the aero-engine, and the difference between the current compressor outlet temperature and the engine inlet temperature, determine whether the current process is a warm-up process; if it is determined to be a warm-up process, set the warm-up determination flag to be valid and set the initial value of the warm-up process progress counter to zero; otherwise, set the warm-up determination flag to be invalid. S20, if the warm-up judgment flag is invalid, then execute S110; otherwise, execute S30; S30, the warm-up process progress counter is incremented. When the product of the incremented count value and the control step size reaches the warm-up time threshold, the warm-up process end judgment flag is set to valid, and the warm-up process progress counter is cleared to zero. S40: If the warm-up process end judgment flag is invalid, then execute S50, S60, S70, S80, S90, and S100 in sequence and return to S30 for repeated execution; otherwise, execute S110. S50, calculate the centrifugal deformation of the turbine rotor based on the current engine speed, calculate the thermal deformation of the turbine blades and the thermal deformation of the turbine disk based on the difference between the turbine exhaust temperature and the compressor outlet temperature at the start of warm-up and the heat transfer time constant, and sum the centrifugal deformation of the turbine rotor, the thermal deformation of the turbine blades and the thermal deformation of the turbine disk to obtain the combined deformation of the rotor. S60, calculate the radial thermal deformation of the computer casing based on the difference between the turbine exhaust temperature and the casing temperature and the casing heat transfer time constant; S70, add the radial thermal deformation of the casing to the cold clearance, and then subtract the rotor composite deformation to obtain the blade tip clearance composite amount; S80, based on the deviation between the combined tip clearance and the design tip clearance, the average height of the turbine blades, and the loss coefficient, the turbine efficiency design value is corrected to obtain the turbine efficiency during the warm-up process. S90, based on the deviation between the turbine efficiency during the warm-up process and the turbine efficiency design value, the proportional parameter design baseline value and the integral constant design baseline value are respectively scheduled to obtain the proportional coefficient and integral coefficient of the current cycle; S100 uses the proportional and integral coefficients adjusted by S90 to calculate the fuel flow command for the turbine exhaust temperature circuit through an incremental PI control law. S110 uses the proportional and integral parameters of the design baseline state to calculate the fuel flow command for the turbine exhaust temperature circuit through an incremental PI control law.

[0006] In some implementations, step S10 specifically includes: When the ground start command changes from invalid to valid, if the following two conditions are met simultaneously, it is determined to be a warm-up process, and the warm-up judgment flag is set. Cold engine flag Set the warm-up process progress counter to 1. Engine warm-up temperature If the value is 0, it is determined to be a non-warm-up process, and the warm-up judgment flag is set. Cold engine flag =0; The two judgment conditions are: Condition 1: ; Condition 2: And this condition is satisfied for t1 seconds; in, The time is current Beijing time, obtained from aircraft communications; The Beijing time recorded when the engine last stopped is retrieved from the controller's internal memory; The parking interval threshold is measured in seconds (s) and ranges from 1800s to 10800s. The current compressor outlet temperature of the engine, in K; The current engine inlet temperature, in Kelvin; The temperature difference threshold is measured in K and ranges from 5K to 30K.

[0007] In some implementations, step S30 specifically includes: In each control cycle, the warm-up process progress counter Engine warm-up temperature Perform an accumulation operation; when At that time, the warm-up process is completed. The value is set to 1, and the warm-up process progress counter is simultaneously set to 1. Engine warm-up temperature Reset to zero; in, To control the step size, the dimension is s, and the value range is 0.02s to 0.05s; The warm-up time threshold, measured in seconds, ranges from 180s to 600s; the end-of-warm-up process determination flag. It is a Boolean value, initially set to 0.

[0008] In some implementations, step S50 specifically includes: Calculate the centrifugal deformation of the turbine rotor: Centrifugal deformation of the turbine rotor in period t. Where t is the number of discrete cycles, which is a positive integer, and increases by 1 for each execution of S50; The centrifugal deformation coefficient is obtained through simulation or experimentation. The engine speed value collected at time t; Calculate the thermal deformation of the turbine blade: Thermal deformation of the turbine blade in period t. ;in, The blade thermal deformation coefficient is obtained through simulation or experimentation; The compressor outlet temperature recorded at the moment when the warm-up judgment flag changes from invalid to valid; the blade temperature in period t. ;in, The blade time constant is obtained through simulation or experimentation; The turbine exhaust temperature is the value collected at time t. Calculate the thermal deformation of the turbine disk: Thermal deformation of the turbine disk in period t. ;in, The coefficient of thermal deformation of the wheel is obtained through simulation or experiment; the wheel temperature at time t is... ;in, The time constant of the roulette wheel is obtained through simulation or experimentation. The deviation between the gas temperature and the average temperature of the wheel is obtained through simulation or experiment. Calculate the rotor's combined deformation: In period t, the rotor's combined deformation... .

[0009] In some implementations, step S60 specifically includes: Radial thermal deformation of the casing during period t ;in, The thermal deformation coefficient of the casing is obtained through simulation or experimentation; During period t, the casing temperature ;in, The time constant of the casing is obtained through simulation or experimentation.

[0010] In some implementations, step S70 specifically includes: In period t, the synthesis amount of tip gap ;in, The gap is a cold gap, obtained through calibration.

[0011] In some implementations, step S80 specifically includes: Turbine efficiency in period t ;in, The design value for turbine efficiency under this operating condition is obtained by interpolation of engine speed, compressor outlet pressure and turbine outlet pressure. The loss coefficient is obtained through simulation or experimentation; This is the design value for the blade tip clearance, in mm. The average height of the turbine blade is expressed in mm.

[0012] In some implementations, step S90 specifically includes: Period t, proportionality coefficient ;in, This is the proportional scheduling coefficient, with a value ranging from 0.1 to 0.4. A baseline value for the proportional parameter under normal conditions is designed and obtained through simulation. In the t-th period, the integral coefficient ;in, The integral scheduling coefficient ranges from 0.1 to 0.4. A baseline value for the integral constant under normal conditions was designed and obtained through simulation.

[0013] In some implementations, step S100 specifically includes: In cycle t, the fuel flow command for the turbine exhaust temperature circuit. ;in, This refers to the fuel flow command from the previous cycle; The turbine exhaust temperature control deviation in cycle t. ; The target value for limiting the turbine exhaust temperature at time t is obtained from the control plan; The turbine exhaust temperature is the value collected at time t. This is the deviation in turbine exhaust temperature control from the previous cycle.

[0014] In some implementations, step S110 specifically includes: In cycle t, the fuel flow command for the turbine exhaust temperature circuit. .

[0015] The beneficial effects of the technical solution provided by this invention include at least the following: This technical solution achieves online identification of the warm-up condition through dual criteria of the shutdown time interval and the difference between the compressor outlet temperature and the inlet temperature, avoiding misjudgment or omission of the warm-up process. By establishing a cycle-by-cycle recursive calculation model of rotor centrifugal deformation, blade and disk thermal deformation, and casing thermal expansion, the composite amount of blade tip clearance is obtained in real time, transforming the clearance change that is difficult to measure directly during the warm-up process into a calculable intermediate variable. Based on this, the turbine efficiency is corrected with the blade tip clearance deviation, and the proportional and integral coefficients of the turbine exhaust temperature PI controller are scheduled online accordingly, so that the control parameters are adaptively adjusted according to the time-varying engine characteristics, effectively suppressing the overshoot and oscillation of turbine exhaust temperature during the warm-up stage. After the warm-up is completed, the system automatically switches back to the design baseline parameters to ensure that the turbine exhaust temperature control performance under normal operating conditions is not affected. Attached Figure Description

[0016] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0017] Figure 1 The diagram shows a flowchart illustrating an adaptive control method for turbine exhaust temperature during the warm-up process of an aero-engine, provided by an exemplary embodiment of the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0020] Figure 1 The diagram illustrates a flowchart of an adaptive control method for turbine exhaust temperature during the warm-up process of an aero-engine, provided by an exemplary embodiment of the present invention. This adaptive control method for turbine exhaust temperature during the warm-up process of an aero-engine is repeatedly executed in a periodic operation mode within the full authority digital electronic controller (FADEC) of the aero-engine. The method includes the following steps: Step S10: Determine whether the current process is a warm-up process by using the time interval between the current start time and the previous shutdown time of the aero-engine, and the difference between the current compressor outlet temperature and the engine inlet temperature. If the process is determined to be a warm-up process, set the warm-up determination flag to be valid and set the initial value of the warm-up process progress counter to zero. Otherwise, set the warm-up determination flag to be invalid.

[0021] In some embodiments, step S10 specifically includes: When the ground start command changes from invalid to valid, if the following two conditions are met simultaneously, it is determined to be a warm-up process, and the warm-up judgment flag is set. Cold engine flag Set the warm-up process progress counter to 1. Engine warm-up temperature If the value is 0, it is determined to be a non-warm-up process, and the warm-up judgment flag is set. Cold engine flag =0 ( Cold engine flag and Engine warm-up temperature (The initial values ​​are all 0). The two judgment conditions are: Condition 1: ; Condition 2: And this condition is satisfied for t1 seconds; in, The time is current Beijing time, obtained from aircraft communications; The Beijing time recorded when the engine last stopped is retrieved from the controller's internal memory; The parking interval threshold is measured in seconds (s) and ranges from 1800s to 10800s. The current compressor outlet temperature of the engine, in K; The current engine inlet temperature, in Kelvin; The temperature difference threshold is measured in K and ranges from 5K to 30K.

[0022] In this embodiment, a dual criterion is established using the shutdown time interval and the compressor outlet temperature-inlet temperature difference. The former eliminates false triggering of hot restarts after short-term shutdowns from a time perspective, while the latter confirms that the engine is indeed in a cold or near-cold state from a thermodynamic perspective. This effectively avoids the risk of misjudgment under boundary conditions using a single criterion. Condition 2 introduces a constraint that must be met continuously for time t1 to filter out false temperature signals caused by sensor transient noise or airflow disturbances, improving the criterion's anti-interference capability. Warm-up judgment flag. Cold engine flag As a Boolean state variable, it provides a clear basis for switching subsequent S20 logic branches; the warm-up process progress counter Engine warm-up temperature The system is simultaneously reset to zero when determining the warm-up time, ensuring that the warm-up progress measurement in S30 accumulates from a unified starting point and avoiding deviations in the calculation of warm-up time due to residual values ​​in the counter.

[0023] In step S20, if the warm-up judgment flag is invalid, proceed to step S110; otherwise, proceed to step S30.

[0024] In this embodiment of the application, this step is based on the warm-up judgment flag output in step S10. Cold engine flag The control channel can be switched online, decoupling the warm-up adaptive control loop from the conventional design baseline control loop into two independent paths.

[0025] Step S30: Accumulate the warm-up process progress counter. When the product of the accumulated count value and the control step size reaches the warm-up time threshold, set the warm-up process end judgment flag to valid and clear the warm-up process progress counter to zero.

[0026] In some embodiments, step S30 specifically includes: Warm-up process progress counter for each control cycle Engine warm-up temperature Perform an accumulation operation; when At that time, the warm-up process is completed. The value is set to 1, and the warm-up process progress counter is simultaneously set to 1. Engine warm-up temperature Reset to zero; in, To control the step size, the dimension is s, and the value range is 0.02s to 0.05s; The warm-up time threshold, measured in seconds, ranges from 180s to 600s; the indicator for determining the end of the warm-up process. It is a Boolean value, initially set to 0.

[0027] In this embodiment of the application, a cycle-by-cycle accumulator counter is used. Engine warm-up temperature and control step size Multiplication transforms discrete period counts into physically meaningful cumulative time quantities, thus characterizing the warm-up process in terms of time. When the cumulative time reaches a warm-up time threshold... This indicates that the engine's hot-end components have fully completed thermal expansion, and the blade tip clearance has reached a steady state. At this point, [the engine is placed in a position where...]. To ensure effectiveness, a back-switch operation of subsequent control parameters to the design baseline is triggered, avoiding unnecessary parameter offsets introduced by the adaptive scheduling strategy's continuous intervention under hot and steady-state conditions. The design of synchronously resetting the counter has a dual significance: first, it eliminates the potential interference of residual counts on the next warm-up determination, ensuring the independence and consistency of warm-up duration measurement in multiple start-stop cycles; second, it provides... The flag reset provides a corresponding state reset to prevent logical asynchrony between the flag bit and the counter.

[0028] In step S40, if the warm-up process end judgment flag is invalid, then execute steps S50, S60, S70, S80, S90, and S100 in sequence and return to step S30 for repeated execution; otherwise, execute step S110.

[0029] In the embodiments of this application, when When invalid, the gap calculation-efficiency correction-parameter scheduling closed loop consisting of steps S50 to S100 is executed iteratively cycle by cycle, and then jumps back to step S30 to continuously accumulate the warm-up progress, forming a complete adaptive control cycle; when Once the setting is effective, immediately exit the loop and switch to the normal control channel in step S110 to achieve a seamless switch from the warm-up-specific strategy to the design baseline control law, avoiding parameter conflicts caused by the parallel operation of two sets of control logic.

[0030] Step S50: Calculate the centrifugal deformation of the turbine rotor based on the current engine speed; calculate the thermal deformation of the turbine blades and the thermal deformation of the turbine disk based on the difference between the turbine exhaust temperature and the compressor outlet temperature at the start of warm-up and the heat transfer time constant; and sum the centrifugal deformation of the turbine rotor, the thermal deformation of the turbine blades, and the thermal deformation of the turbine disk to obtain the composite deformation of the rotor.

[0031] In some embodiments, step S50 specifically includes: Calculate the centrifugal deformation of the turbine rotor: Centrifugal deformation of the turbine rotor in period t. Where t is the number of discrete cycles, which is a positive integer, and increases by 1 for each execution of S50; The centrifugal deformation coefficient is obtained through simulation or experimentation. The engine speed value collected at time t; Calculate the thermal deformation of the turbine blade: Thermal deformation of the turbine blade in period t. ;in, The blade thermal deformation coefficient is obtained through simulation or experimentation; The compressor outlet temperature recorded at the moment when the warm-up judgment flag changes from invalid to valid; the blade temperature in period t. ;in, The blade time constant is obtained through simulation or experimentation; The turbine exhaust temperature is the value collected at time t. Calculate the thermal deformation of the turbine disk: Thermal deformation of the turbine disk in period t. ;in, The coefficient of thermal deformation of the wheel is obtained through simulation or experiment; the wheel temperature at time t is... ;in, The time constant of the roulette wheel is obtained through simulation or experimentation. The deviation between the gas temperature and the average temperature of the wheel is obtained through simulation or experiment. Calculate the rotor's combined deformation: In period t, the rotor's combined deformation... .

[0032] In this embodiment, the rotor radial deformation is decomposed into three independent components based on physical mechanisms: centrifugal deformation, blade thermal deformation, and disk thermal deformation. These components are modeled separately and then linearly superimposed. In this case, the centrifugal deformation component is characterized by a square relationship with the rotational speed, which can instantly track the elastic expansion caused by changes in rotational speed. The blade and disk thermal deformation components are both described by a first-order exponential approach model to describe the transient heat transfer process, using their respective independent time constants. and By distinguishing the differences in thermal inertia between the blades and the impeller, their thermal response rates are decoupled, avoiding estimation errors caused by equating components with different heat capacities to a single time constant. The compressor outlet temperature at the start of warm-up is used as the reference. As a reference for thermal deformation, the influence of initial temperature offset on the calculation of deformation increment is eliminated. Various deformation coefficients... , , All results were obtained through offline simulation or experimental calibration, reducing the complex three-dimensional thermal-structural coupling problem to a low-order analytical model suitable for embedded controllers, thus ensuring estimation accuracy while meeting real-time constraints.

[0033] Step S60: Calculate the radial thermal deformation of the computer casing based on the difference between the turbine exhaust temperature and the casing temperature and the casing heat transfer time constant.

[0034] In some embodiments, step S60 specifically includes: Radial thermal deformation of the casing during period t ;in, The thermal deformation coefficient of the casing is obtained through simulation or experimentation; During period t, the casing temperature ;in, The time constant of the casing is obtained through simulation or experimentation.

[0035] In this embodiment, the casing, as a stator component, has a significantly different thermal inertia from that of the rotor-side blades and the wheel disk; therefore, a separate time constant is set for the casing. It can accurately characterize the transient response of the casing wall temperature lagging behind the gas temperature, avoiding the bias in clearance estimation introduced by sharing the same time constant between the casing and rotor components. Casing temperature Also using a first-order exponential approach model, Reference temperature, As the driving source, maintaining consistency with the rotor-side modeling method facilitates the alignment of dimensions and correspondence of physical meanings for each component in subsequent clearance difference calculations. Casing thermal deformation coefficient. Through offline calibration, the complex multi-layer wall heat transfer problem of the casing is simplified into a first-order analytical expression suitable for real-time control.

[0036] Step S70: Add the radial thermal deformation of the casing to the cold clearance, and then subtract the rotor composite deformation to obtain the blade tip clearance composite amount.

[0037] In some embodiments, step S70 specifically includes: In period t, the synthesis amount of tip gap ;in, The gap is a cold gap, obtained through calibration.

[0038] In this embodiment of the application, a cold gap is used. Using the geometric reference, the radial thermal deformation of the casing is algebraically superimposed as the clearance increase term and the combined rotor deformation as the clearance decrease term. The physical meaning is that during warm-up, the casing expands outward due to heat, increasing the clearance, while the rotor's centrifugal and thermal expansion causes the blade tips to extend outward, decreasing the clearance. The two effects on the clearance are opposite in direction. This difference calculation structure allows the clearance estimation model to reflect transient clearance fluctuations caused by the mismatch in thermal response rates between the rotor and casing. and , Depending on the value, during the initial warm-up phase, the casing temperature rises later than the rotor, and the clearance exhibits a dynamic process of first contracting and then recovering. This model can accurately capture this characteristic. Cold-state clearance. Obtained through offline calibration, the effects of assembly tolerances and manufacturing deviations are encapsulated as fixed offsets, avoiding the introduction of unobservable geometric parameters in online calculations.

[0039] Step S80: Based on the deviation between the combined tip clearance and the design tip clearance, the average height of the turbine blades, and the loss coefficient, the turbine efficiency design value is corrected to obtain the turbine efficiency during the warm-up process.

[0040] In some embodiments, step S80 specifically includes: Turbine efficiency in period t ;in, The design value for turbine efficiency under this operating condition is obtained by interpolation of engine speed, compressor outlet pressure and turbine outlet pressure. The loss coefficient is obtained through simulation or experimentation; This is the design value for the blade tip clearance, in mm. The average height of the turbine blade is expressed in mm.

[0041] In the embodiments of this application, gap deviation is used. With average blade height The ratio of these values ​​is used as a normalized clearance offset, eliminating the influence of blade geometry on loss sensitivity and making the loss coefficient... It has a universal physical meaning across different engine models. Turbine efficiency design value. The correction reference is obtained through three-dimensional interpolation of speed, compressor outlet pressure, and turbine outlet pressure, ensuring a strict correspondence between the correction benchmark and the current operating point, thus avoiding insufficient adaptability to operating conditions caused by correction based on a fixed design point efficiency. Loss coefficient Through offline calibration, the complex three-dimensional flow loss of the tip leakage vortex is condensed into a single scaling factor, so that online calculation only requires one multiplication and division operation to complete the efficiency correction, which meets the computing power constraints of the embedded controller.

[0042] Step S90: Based on the deviation between the turbine efficiency during the warm-up process and the turbine efficiency design value, the design baseline values ​​of the proportional parameter and the integral constant are scheduled to obtain the proportional coefficient and integral coefficient for the current cycle.

[0043] In some embodiments, step S90 specifically includes: Period t, proportionality coefficient ;in, This is the proportional scheduling coefficient, with a value ranging from 0.1 to 0.4. A baseline value for the proportional parameter under normal conditions is designed and obtained through simulation. In the t-th period, the integral coefficient ;in, The integral scheduling coefficient ranges from 0.1 to 0.4. A baseline value for the integral constant under normal conditions was designed and obtained through simulation.

[0044] In the embodiments of this application, the scaling factor In terms of efficiency As a scheduling factor, when turbine efficiency decreases due to excessive clearance, the proportional gain decreases accordingly, suppressing speed overshoot and oscillation caused by insufficient actuator response. Integral coefficient The reciprocal of the efficiency ratio As a scheduling factor, the more severe the efficiency degradation, the stronger the integral effect, compensating for the steady-state speed deviation caused by the decline in work capacity and shortening the settling time. Proportional scheduling coefficient With integral scheduling coefficient The value range is limited to 0.1 to 0.4, setting upper and lower bound constraints for the scheduling amplitude to prevent excessive gain offset under extreme operating conditions, which could compromise closed-loop stability. This scheduling strategy ensures that the PI controller maintains a control bandwidth that matches the actual work capacity of the turbine throughout the warm-up process, avoiding speed fluctuations and overshoot problems caused by insufficient execution capability during the initial warm-up phase when using a fixed-gain design.

[0045] In step S100, the fuel flow command for the turbine exhaust temperature circuit is calculated using the proportional coefficient and integral coefficient adjusted in step S90 through an incremental PI control law.

[0046] In some embodiments, step S100 specifically includes: In cycle t, the fuel flow command for the turbine exhaust temperature circuit. ;in, This refers to the fuel flow command from the previous cycle; The turbine exhaust temperature control deviation in cycle t. ; The target value for limiting the turbine exhaust temperature at time t is obtained from the control plan; The turbine exhaust temperature is the value collected at time t. This is the deviation in turbine exhaust temperature control from the previous cycle.

[0047] In this embodiment, an incremental PI structure is used instead of a positional one, and its output is the cycle-by-cycle increment of the fuel flow command superimposed on the previous cycle command. Above all, it possesses a naturally seamless switching characteristic. When switching between warm-up compensation and normal control modes, because the output is incremental rather than absolute, it does not produce a step change in command, thus avoiding turbocharger exhaust temperature shocks caused by sudden changes in fuel flow. Control deviation Turbine exhaust temperature limiting target value With collected values The difference constitutes, Obtained from the control plan, ensure that the temperature protection boundary is consistent with the engine's full envelope safety constraints. After scheduling in step S90... and By embedding this incremental calculation, the temperature response lag caused by the turbine efficiency degradation during the warm-up phase is offset by gain compensation.

[0048] Step S110: Using the proportional and integral parameters of the design baseline state, calculate the fuel flow command for the turbine exhaust temperature circuit through an incremental PI control law.

[0049] In some embodiments, step S110 specifically includes: In cycle t, the fuel flow command for the turbine exhaust temperature circuit. .

[0050] In this embodiment, step S110 serves as the baseline control branch of the turbine exhaust temperature loop under normal conditions, forming a complementary dual-mode control architecture with the warm-up gap compensation branch of step S100. Step S110 directly employs a fixed gain calibrated through offline simulation. and Without introducing clearance scheduling correction, this method is applicable when the warm-up process is complete and the tip clearance has returned to a steady-state or quasi-steady-state condition near the design value. Within this operating range, the turbine efficiency deviation from the design value is negligible, and the fixed gain has been fully verified to ensure that the phase margin and amplitude margin of the temperature loop meet the stability index, requiring no additional scheduling intervention. This branch also adopts an incremental PI structure, with the output being a cycle-by-cycle increment of the fuel flow command, maintaining the same command recursion form as step S100. This ensures that the outputs of the two branches are continuous at the switching time, without generating a step in fuel flow, achieving a smooth transition from the warm-up compensation mode to the normal mode.

[0051] It is understood that the specific examples in this document are only intended to help those skilled in the art better understand this disclosure, and are not intended to limit the scope of the invention.

[0052] It is understood that in the various embodiments of this specification, the sequence number of each process does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of this disclosure.

[0053] It is understood that the various implementation methods described in this specification can be implemented individually or in combination, and this disclosure does not limit them.

[0054] Unless otherwise stated, all technical and scientific terms used in this disclosure have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of this specification. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items. The singular forms "a," "the," and "the" as used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0055] The above description is merely a specific embodiment of this specification, but the scope of protection of this invention 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 specification should be included within the scope of protection of this specification. Therefore, the scope of protection of this invention should be determined by the scope of the claims.

Claims

1. A method for adaptive control of turbine exhaust temperature during the warm-up process of an aero-engine, characterized in that, The method includes the following steps: S10, by using the time interval between the current start time and the last shutdown time of the aircraft engine, and the difference between the current compressor outlet temperature and the engine inlet temperature, determine whether the current process is a warm-up process; if it is determined to be a warm-up process, set the warm-up determination flag to be valid and set the initial value of the warm-up process progress counter to zero; otherwise, set the warm-up determination flag to be invalid. S20, if the warm-up judgment flag is invalid, then execute S110; otherwise, execute S30; S30, the warm-up process progress counter is incremented. When the product of the incremented count value and the control step size reaches the warm-up time threshold, the warm-up process end judgment flag is set to valid, and the warm-up process progress counter is cleared to zero. S40: If the warm-up process end judgment flag is invalid, then execute S50, S60, S70, S80, S90, and S100 in sequence and return to S30 for repeated execution; otherwise, execute S110. S50, calculate the centrifugal deformation of the turbine rotor based on the current engine speed, calculate the thermal deformation of the turbine blades and the thermal deformation of the turbine disk based on the difference between the turbine exhaust temperature and the compressor outlet temperature at the start of warm-up and the heat transfer time constant, and sum the centrifugal deformation of the turbine rotor, the thermal deformation of the turbine blades and the thermal deformation of the turbine disk to obtain the combined deformation of the rotor. S60, based on the difference between the turbine exhaust temperature and the casing temperature and the casing heat transfer time constant, calculate the radial thermal deformation of the computer casing. S70, add the radial thermal deformation of the casing to the cold clearance, and then subtract the rotor composite deformation to obtain the blade tip clearance composite amount; S80, based on the deviation between the combined tip clearance and the design tip clearance, the average height of the turbine blades, and the loss coefficient, the turbine efficiency design value is corrected to obtain the turbine efficiency during the warm-up process. S90, based on the deviation between the turbine efficiency during the warm-up process and the turbine efficiency design value, the proportional parameter design baseline value and the integral constant design baseline value are respectively scheduled to obtain the proportional coefficient and integral coefficient of the current cycle; S100 uses the proportional and integral coefficients adjusted by S90 to calculate the fuel flow command for the turbine exhaust temperature circuit through an incremental PI control law. S110 uses the proportional and integral parameters of the design baseline state to calculate the fuel flow command for the turbine exhaust temperature circuit through an incremental PI control law.

2. The adaptive control method for turbine exhaust temperature during the warm-up process of an aero-engine according to claim 1, characterized in that, Step S10 specifically includes: When the ground start command changes from invalid to valid, if the following two conditions are met simultaneously, it is determined to be a warm-up process, and the warm-up judgment flag is set. bColdEngine Set the warm-up process progress counter to 1. T_EngineWarm If the value is 0, it is determined to be a non-warm-up process, and the warm-up judgment flag is set. bColdEngine =0; The two judgment conditions are: Condition 1: ; Condition 2: And this condition is satisfied for t1 seconds; in, The time is current Beijing time, obtained from aircraft communications; The Beijing time recorded when the engine last stopped is retrieved from the controller's internal memory; The parking interval threshold is measured in seconds (s) and ranges from 1800s to 10800s. The current compressor outlet temperature of the engine, in K; The current engine inlet temperature, in Kelvin; The temperature difference threshold is measured in K and ranges from 5K to 30K.

3. The adaptive control method for turbine exhaust temperature during the warm-up process of an aero-engine according to claim 1, characterized in that, Step S30 specifically includes: In each control cycle, the warm-up process progress counter T_EngineWarm Perform an accumulation operation; when At that time, the warm-up process is completed. The value is set to 1, and the warm-up process progress counter is simultaneously set to 1. T_EngineWarm Reset to zero; in, To control the step size, the dimension is s, and the value range is 0.02s to 0.05s; The warm-up time threshold, measured in seconds, ranges from 180s to 600s; the end-of-warm-up process determination flag. It is a Boolean value, initially set to 0.

4. The adaptive control method for turbine exhaust temperature during the warm-up process of an aero-engine according to claim 1, characterized in that, Step S50 specifically includes: Calculate the centrifugal deformation of the turbine rotor: Centrifugal deformation of the turbine rotor in period t. Where t is the number of discrete cycles, which is a positive integer, and increases by 1 for each execution of S50; The centrifugal deformation coefficient is obtained through simulation or experimentation. The engine speed value collected at time t; Calculate the thermal deformation of the turbine blade: Thermal deformation of the turbine blade in period t. ;in, The blade thermal deformation coefficient is obtained through simulation or experimentation; The compressor outlet temperature recorded at the moment when the warm-up judgment flag changes from invalid to valid; the blade temperature in period t. ;in, The blade time constant is obtained through simulation or experimentation; The turbine exhaust temperature is the value collected at time t. Calculate the thermal deformation of the turbine disk: Thermal deformation of the turbine disk in period t. ;in, The coefficient of thermal deformation of the wheel is obtained through simulation or experiment; the wheel temperature at time t is... ;in, The time constant of the roulette wheel is obtained through simulation or experimentation. The deviation between the gas temperature and the average temperature of the wheel is obtained through simulation or experiment. Calculate the rotor's combined deformation: In period t, the rotor's combined deformation... .

5. The adaptive control method for turbine exhaust temperature during the warm-up process of an aero-engine according to claim 1, characterized in that, Step S60 specifically includes: Radial thermal deformation of the casing during period t ;in, The thermal deformation coefficient of the casing is obtained through simulation or experimentation; During period t, the casing temperature ;in, The time constant of the casing is obtained through simulation or experimentation.

6. The adaptive control method for turbine exhaust temperature during the warm-up process of an aero-engine according to claim 1, characterized in that, Step S70 specifically includes: In period t, the synthesis amount of tip gap ;in, The gap is a cold gap, obtained through calibration.

7. The adaptive control method for turbine exhaust temperature during the warm-up process of an aero-engine according to claim 1, characterized in that, Step S80 specifically includes: Turbine efficiency in period t ;in, The design value for turbine efficiency under this operating condition is obtained by interpolation of engine speed, compressor outlet pressure and turbine outlet pressure. The loss coefficient is obtained through simulation or experimentation; This is the design value for the blade tip clearance, in mm. The average height of the turbine blade is expressed in mm.

8. The adaptive control method for turbine exhaust temperature during the warm-up process of an aero-engine according to claim 1, characterized in that, Step S90 specifically includes: Period t, proportionality coefficient ;in, This is the proportional scheduling coefficient, with a value ranging from 0.1 to 0.

4. A baseline value for the proportional parameter under normal conditions is designed and obtained through simulation. In the t-th period, the integral coefficient ;in, The integral scheduling coefficient ranges from 0.1 to 0.

4. A baseline value for the integral constant under normal conditions was designed and obtained through simulation.

9. The adaptive control method for turbine exhaust temperature during the warm-up process of an aero-engine according to claim 1, characterized in that, Step S100 specifically includes: In cycle t, the fuel flow command for the turbine exhaust temperature circuit. ;in, This refers to the fuel flow command from the previous cycle; The turbine exhaust temperature control deviation in cycle t. ; The target value for limiting the turbine exhaust temperature at time t is obtained from the control plan; The turbine exhaust temperature is the value collected at time t. This is the deviation in turbine exhaust temperature control from the previous cycle.

10. The adaptive control method for turbine exhaust temperature during the warm-up process of an aero-engine according to claim 1, characterized in that, Step S110 specifically includes: In cycle t, the fuel flow command for the turbine exhaust temperature circuit. .

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