CN-121993297-A - Aviation steady start control method based on opposite-rotation turbine dynamic decoupling

CN121993297ACN 121993297 ACN121993297 ACN 121993297ACN-121993297-A

Abstract

The invention discloses an aviation steady start control method based on counter-rotating turbine dynamic decoupling, and relates to the technical field of turbine control. The method comprises the steps of extracting slip change rate of relative rotating speed in a starting acceleration section to determine whether a divergence trend of aerodynamic slip exists, if so, establishing a temperature rise characteristic sequence of exhaust temperature and performing cross-domain response analysis to identify whether a system cuts into an inter-stage aerodynamic dislocation period, if so, evaluating transient flow absorption capacity based on low-pressure rotor acceleration in the cut-in dislocation period, establishing temporary active feed-forward fuel oil saturation limiting, filtering a pseudo recovery section and determining an inter-stage reconstruction inflection point, and adjusting an energy accumulation coefficient analyzed in the dislocation period to calculate a dynamic fuel oil recovery slope so as to realize smooth handover from the saturation limiting to a conventional closed-loop control circuit. The invention is beneficial to eliminating the pseudo recovery state in the decoupling process of the pneumatic flow field, blocking the triggering condition of secondary pneumatic congestion and realizing the stable starting control.

Inventors

LIU YONG
LIU HAIJIE
SUN BING
You Daping
JIANG ZHONGFENG
LI HUA
WANG ZHIYONG

Assignees

太仓点石航空动力有限公司

Dates

Publication Date: 20260508
Application Date: 20260408

Claims (10)

1. The aviation steady start control method based on the decoupling of the counter-rotating turbine dynamics is characterized by comprising the following steps of: Synchronous sampling is carried out on the real-time rotating speeds of the high-pressure rotor and the low-pressure rotor in the starting accelerating section, and the slip change rate of the relative rotating speeds of the high-pressure rotor and the low-pressure rotor is extracted; if a divergence trend exists, establishing a temperature rise characteristic sequence of the exhaust temperature, and carrying out cross-domain response analysis for inducing a thermal hysteresis effect based on a slip change rate to obtain cross-domain response homology; If the interstage pneumatic dislocation period is entered, the transient flow absorption capacity is estimated based on the current acceleration of the low-pressure rotor to obtain a critical oil supply upper limit; And eliminating a pseudo recovery interval caused by thermal hysteresis based on the hysteresis deviation feature, and determining an interstage reconstruction inflection point.
2. The method for aeronautical smooth start control based on decoupling of contra-rotating turbine dynamics according to claim 1, wherein the way to extract the slip rate of change is: Acquiring real-time rotating speeds of a high-pressure rotor and a low-pressure rotor in a starting acceleration section, and performing low-pass filtering on the real-time rotating speeds of the two rotors to establish a high-pressure rotating speed sequence and a low-pressure rotating speed sequence; Calculating the ratio of the low-pressure rotating speed to the high-pressure rotating speed in the same sampling period based on the high-pressure rotating speed sequence and the low-pressure rotating speed sequence to obtain a relative rotating speed ratio; and establishing a sliding window with a fixed time length, performing linear fitting on the relative rotation speed ratio in the continuous N sampling periods by adopting a least square method, and taking the slope of a straight line obtained by the linear fitting as the slip change rate.
3. The method for aeronautical smooth start control based on the decoupling of the counter-rotating turbine dynamics according to claim 1, wherein the cross-domain response analysis is performed by the following steps: extracting a divergence origin of the slip change rate; Collecting a real-time temperature signal, performing analog-to-digital conversion and low-pass filtering on the real-time temperature signal, then performing backward differential derivation, and establishing a temperature rise slope sequence of the exhaust temperature; establishing a time observation window by taking a divergence origin of the slip change rate as a starting point, and optimizing and extracting extreme values and corresponding moments of a transient temperature rise slope sequence in the time observation window to serve as a heat pulse shock increasing point; Calculating a hysteresis time difference from a slip change rate divergence origin to a heat pulse shock increase point; Synchronously extracting the rotating speed of the high-pressure rotor corresponding to the slip change rate divergence origin, calling a preset flow delay mapping table, and calculating the reference heat transmission time under the current working condition; performing energy accumulation analysis based on the reference heat transfer time to obtain an energy accumulation coefficient; and carrying out product processing on the time sequence deviation coefficient and the energy accumulation coefficient to obtain the cross-domain response homology.
4. The method for aeronautical soft start control based on counter-rotating turbine kinetic decoupling of claim 3, wherein the energy accumulation analysis is performed in the following manner: Performing normalized deviation calculation processing on the actual hysteresis time difference based on the reference heat transmission time to obtain a time sequence deviation coefficient; and performing a quotient processing on the temperature rise slope average value of the reference background in the time observation window by using the extremum to obtain an energy accumulation coefficient.
5. The method for aeronautical soft start control based on counter-rotating turbine kinetic decoupling of claim 1, wherein the process of assessing the transient flow absorption capacity is: Acquiring real-time acceleration of a low-pressure rotor and physical conversion rotating speed of a low-pressure turbine in a circulation working state; Taking the real-time acceleration and the physical conversion rotating speed of the low-voltage rotor as double independent variable index items, and calling a preset turbine inter-stage throughput mapping table; inputting the double independent variable index items into an output turbine interstage throughput mapping table, and matching to obtain the current transient flow absorption index of the low-pressure turbine; acquiring the real-time rotating speed of the high-pressure rotor at the current moment, and acquiring the conventional maximum allowable fuel quantity corresponding to the high-pressure rotating speed by looking up a table; and (3) multiplying the transient flow absorption index by the conventional maximum allowable fuel quantity to obtain the critical oil supply upper limit.
6. The method for aeronautical soft start control based on counter-rotating turbine kinetic decoupling of claim 1, wherein the manner of determining the interstage reconstruction inflection point is: Continuously monitoring a numerical evolution track of the hysteresis deviation feature; extracting an inherent heat capacity time constant of a turbine metal piece under the current working condition of the engine, and setting a thermodynamic residual tolerance base line representing a safe heat extraction boundary based on the inherent heat capacity time constant; and establishing heat comparison logic based on the thermal residual tolerance base line, and obtaining the result of whether the timestamp is an interstage reconstruction inflection point based on the comparison result.
7. The method for aeronautical smooth start control based on counter-rotating turbine kinetic decoupling of claim 6, wherein the hysteresis departure feature is obtained by: Acquiring a transient flow absorption index minimum value in a pneumatic dislocation period, calling a normal target reference value preset in an acceleration reference model in the digital electronic controller, dividing the difference value of the transient flow absorption index at the current moment from the minimum value by the difference value of the normal target reference value and the minimum value, and obtaining real-time pneumatic recovery degree; Synchronously reading a time sequence of the exhaust temperature, acquiring an exhaust temperature maximum value in a dislocation period, calling a normal target temperature synchronously output by an acceleration reference model, dividing the difference value between the exhaust temperature maximum value and the current exhaust temperature by the difference value between the exhaust temperature maximum value and the normal target temperature, and obtaining real-time thermodynamic emptying degree; and subtracting the real-time thermodynamic emptying degree from the real-time aerodynamic recovery degree, extracting the numerical value difference of the real-time aerodynamic recovery degree and the thermodynamic emptying degree at the same moment, and taking the numerical value difference as a hysteresis deviation feature.
8. The aeronautical smooth start control method based on the decoupling of the dynamics of the counter-rotating turbine according to claim 1, characterized in that: And after the interstage reconstruction inflection point is crossed, extracting the energy accumulation coefficient analyzed in the dislocation period, calculating the dynamic fuel supply recovery slope, and constructing a saturated amplitude limiting normal closed-loop control circuit based on the dynamic fuel supply recovery slope to control the feed-forward fuel release.
9. The method for aeronautical smooth start control based on counter-rotating turbine kinetic decoupling of claim 8, wherein the closed loop control circuit is constructed in the following manner: The critical oil supply upper limit at the moment of the inflection point of the interstage reconstruction is used as a starting point, the dynamic oil supply recovery slope is used as a climbing derivative, a feedforward fuel release track is generated, and a physical oil supply limit is set for the feedforward fuel release track to be used as a safety constraint top plate; synchronously monitoring a closed-loop demand oil supply instruction output by a conventional acceleration closed-loop control loop; subtracting a feedforward fuel instruction generated by a feedforward fuel release track from the closed-loop demand fuel supply instruction to obtain an instruction fuel difference; And injecting the command fuel difference as negative feedback compensation into an integral term of a conventional closed-loop control circuit to perform desaturation reduction.
10. The method for aeronautical smooth start control based on counter-rotating turbine kinetic decoupling of claim 8, wherein the method for obtaining the dynamic oil supply recovery slope is as follows: and obtaining a calibration reference oil supply slope of the engine under the current environmental condition, and dividing the calibration reference oil supply slope by the energy accumulation coefficient to obtain a dynamic oil supply recovery slope.

Description

Aviation steady start control method based on opposite-rotation turbine dynamic decoupling Technical Field The invention relates to the technical field of turbine control, in particular to an aviation steady starting control method based on counter-rotating turbine dynamics decoupling. Background In the development of modern aero gas turbines, counter-rotating turbine architectures are widely used in high performance aero engine designs. In a counter-rotating turbine, however, there is no mechanical physical connection between the high-pressure rotor and the low-pressure rotor, and the energy transfer between the two is entirely dependent on aerodynamic coupling inside the flow path. In the engine start acceleration section (especially the critical area of the transition to the slow vehicle self-sustaining state), the combustion chamber establishes an initial thermodynamic cycle, and the high pressure rotor is rapidly accelerated under the action of combustion. Because the low-pressure rotor has large self-rotation inertia and is only passively towed by aerodynamic force, the transient acceleration of the low-pressure rotor is significantly delayed from that of the high-pressure rotor. The dynamic asymmetric evolution results in severe deflection of the absolute airflow velocity and swirl angle at the high pressure turbine outlet, which can induce transient aerodynamic choking (i.e., inter-stage aerodynamic misalignment) between counter-rotating stages when the deflected airflow impacts the low pressure turbine blades with a rotational speed lag at a very large false angle of attack. The pneumatic choking directly blocks the normal circulation of the flow channel of the core machine, so that the heat released by combustion is accumulated in a large amount between stages and cannot be dissipated to the downstream exhaust flow channel in time. For this reason, the invention provides an aeronautical stationary start control method based on the dynamic decoupling of a counter-rotating turbine. Disclosure of Invention The invention aims to provide an aviation steady start control method based on decoupling of counter-rotating turbine dynamics, which aims to solve the problems that when deflection airflow impacts a low-pressure turbine blade with a delayed rotating speed at a very large error attack angle, transient pneumatic congestion is induced between counter-rotating stages, the pneumatic congestion directly blocks the normal circulation of a core machine runner, so that a large amount of heat released by combustion is accumulated between the stages and cannot be dissipated in a downstream exhaust runner in time. The aim of the invention can be achieved by the following technical scheme: An aviation steady start control method based on the decoupling of the dynamics of a counter-rotating turbine comprises the following steps: Synchronous sampling is carried out on the real-time rotating speeds of the high-pressure rotor and the low-pressure rotor in the starting accelerating section, and the slip change rate of the relative rotating speeds of the high-pressure rotor and the low-pressure rotor is extracted; if a divergence trend exists, establishing a temperature rise characteristic sequence of the exhaust temperature, and carrying out cross-domain response analysis for inducing a thermal hysteresis effect based on a slip change rate to obtain cross-domain response homology; If the interstage pneumatic dislocation period is entered, the transient flow absorption capacity is estimated based on the current acceleration of the low-pressure rotor to obtain a critical oil supply upper limit; And eliminating a pseudo recovery interval caused by thermal hysteresis based on the hysteresis deviation feature, and determining an interstage reconstruction inflection point. Further, the way to extract the slip change rate is: Acquiring real-time rotating speeds of a high-pressure rotor and a low-pressure rotor in a starting acceleration section, and performing low-pass filtering on the real-time rotating speeds of the two rotors to establish a high-pressure rotating speed sequence and a low-pressure rotating speed sequence; Calculating the ratio of the low-pressure rotating speed to the high-pressure rotating speed in the same sampling period based on the high-pressure rotating speed sequence and the low-pressure rotating speed sequence to obtain a relative rotating speed ratio; and establishing a sliding window with a fixed time length, performing linear fitting on the relative rotation speed ratio in the continuous N sampling periods by adopting a least square method, and taking the slope of a straight line obtained by the linear fitting as the slip change rate. Further, the cross-domain response analysis is performed by: extracting a divergence origin of the slip change rate; Collecting a real-time temperature signal, performing analog-to-digital conversion and low-pass filtering on the real-time temperature signal, th