General calculation model of mainstream parameters of turbofan engine and individual adaptive correction method

Abstract

This invention discloses a general calculation model for mainstream parameters of a turbofan engine and an individual adaptive correction method, comprising: based on an engine component-level model, combining some measured parameters and coupling analysis between parameters to perform dimensionality reduction on the common working equations to establish a general calculation model for mainstream parameters, and calculating the inter-stage parameters of rotating components; introducing individual differences and characteristic adjustment parameters representing performance degradation, estimating parameters using the residuals of the equilibrium equations and the deviation from the measured parameters, and designing an adaptive correction scheme based on the two-layer inverse Broyden iteration method for the general calculation model of mainstream parameters. The general calculation model for mainstream parameters of this invention effectively improves real-time performance under the condition that characteristic maps and design point parameters can be read from external sources; the adaptive correction scheme can effectively track the changes in mainstream parameters and inter-stage parameters of rotating components after degradation, reflecting the true operating state of the engine, and can provide accurate mainstream parameters before and after performance degradation within the entire envelope.

Description

Technical Field

[0001] This invention belongs to the field of aero-engine modeling and simulation, specifically involving a general calculation model for mainstream parameters of turbofan engines and an individual adaptive correction method. Background Technology

[0002] Aero engines have numerous components, many of which operate under harsh conditions, including prolonged exposure to high temperatures, high pressures, high speeds, and strong vibrations. This places high demands on the performance of each component. To ensure the aero engine operates safely and reliably without exceeding temperature, pressure, or speed limits, the availability of mainstream parameters—specifically, the total temperature and pressure parameters of the inlet and outlet sections of rotating components—is crucial. However, in actual engine manufacturing and applications, the total temperature and pressure parameters of some sections cannot be directly obtained from sensor parameters due to installation difficulties, sensor measurement ranges, and accuracy limitations. Therefore, calculating the parameters of each section using some measured parameters of the engine is highly applicable and can provide parameter support for engine performance calculations and over-limit protection. Furthermore, if the model built from the engine's design point is used for overall performance research and control to address performance degradation during engine operation, it will inevitably deviate from the engine's actual performance, leading to greater errors. Therefore, an adaptive model means that more accurate mainstream parameters can be provided based on experimental data and the engine's actual performance at that time, better reflecting the engine's true operating state. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to address the shortcomings of the prior art by providing a method based on engine partial measurement parameters (low-pressure speed measurement value n). Lr High-pressure speed measurement value n Hr , Total pressure measurement value P at the fan outlet 22r and the measured value of total pressure at the low-pressure turbine outlet P 5r This paper presents a general calculation model and adaptive correction method for the mainstream parameters of turbofan engine design.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0005] A general calculation model for mainstream parameters of a turbofan engine and an individual adaptive correction method are provided, including the following steps:

[0006] Step A) Based on the engine component-level model, using the measurement parameters and the physical relationships between the parameters, considering only the intake and core engine components, the common working equations are reduced in dimensionality. Based on the coupling analysis of the measurement parameters, a general calculation model of mainstream parameters that can be applied to different individual engines of the same type is established.

[0007] Step B) Design an adaptive correction architecture based on the two-layer inverse Broyden iteration method. The parameters are automatically adjusted according to individual differences and performance degradation correction characteristics to establish a mainstream parameter model that can be used for a long time, and the temperature and pressure parameters of key sections can be obtained.

[0008] Preferably, the general calculation model for the mainstream parameters in step A) includes selecting initial parameters and common working equations. Based on the provided measurement parameters, only the air intake and core components are considered. The number of selected initial parameters is reduced based on the coupling analysis of parameters, and the common working equations are reduced accordingly, reducing the 6 common working equations that need to be iteratively solved by the component-level model to 2.

[0009] Based on the measurement parameters, the high and low pressure speeds are directly derived from the measured value n of the low pressure speed. Lr High-pressure speed measurement value n Hr Since this is readily available, the selected initial parameter is the compressor pressure ratio π. comp and the high-pressure turbine pressure ratio π HTurb Fan pressure ratio π fan and low-pressure turbine pressure ratio π LTurb The measured value of the total temperature at the fan outlet, P, can be combined with the measured parameters. 22r and the measured value of total pressure at the low-pressure turbine outlet P 5r It can be represented in the following form:

[0010] π fan =P 22r / P2

[0011]

[0012] Among them, P2 and P6 are the total inlet temperature of the core engine and the total outlet temperature of the internal tunnel, respectively. P This represents the total pressure recovery coefficient from the low-pressure turbine outlet to the inner duct outlet.

[0013] Meanwhile, the six common working equations used in the iterative calculation of the component-level model were dimensionality-reduced, and the corresponding common working equation was selected as the high- and low-pressure turbine inlet and outlet flow balance:

[0014] e1=(W g43 -W cool ) / W g4 -1

[0015] e2=(W g5 -W cool ) / W g44 -1

[0016] Among them, W g4 W g43 W represents the inlet and outlet flow rates of the high-pressure turbine. g44 Wg5 For the inlet and outlet flow rates of the low-pressure turbine, W cool This refers to the induced air flow rate.

[0017] Preferably, the general calculation model for the mainstream parameters in step A) includes selecting an iterative solution method for the common working equations. The selected iterative solution method is the inverse Broyden rank-1 method.

[0018] Preferably, the general calculation model for the main parameters in step A) includes calculating the pressure ratio of each stage of the rotating component using empirical formulas, and then solving for the total temperature and pressure parameters of each stage. The calculation of the pressure ratio π of each stage of the rotating component is as follows: i Use the following formula:

[0019]

[0020] Where N is the number of component levels, π sum For the overall pressure ratio at the component design point, π opt-i For the design point pressure ratio of the i-th stage, π p This represents the total pressure ratio (pressure drop ratio) of the component obtained from performance calculations under different conditions.

[0021] Preferably, the general calculation model for mainstream parameters in step A) includes reading characteristic maps and design point parameters from an external source. By designing the characteristic maps and design point parameters as replaceable input interfaces, the general calculation model for mainstream parameters is not limited to a specific individual, but can be used for engines of the same type, thus improving its versatility.

[0022] Preferably, the adaptive correction scheme of the general calculation model for the mainstream parameters in step B) includes conducting a correlation analysis on the influence of health parameters on the equation residuals and selecting the estimated health parameters.

[0023] By analyzing the impact of health parameter degradation on the residuals of the equilibrium equation and the deviation from the measured parameters, the following equations are selected for the general calculation model of mainstream parameters, and their residuals are used as the basis for performance estimation.

[0024] e a1 =N LT η L / N F -1

[0025] e a2 =N HT η H / (N C +N ex )-1

[0026] e a3 =W g9 / W g7 -1

[0027] ea4 =P s16 / P s6 -1

[0028] e a5 =T 22 / T 22r -1

[0029] e a6 =T5 / T 5r -1

[0030] Where, N HT N LT The power outputs of the high-pressure and low-pressure turbines are respectively, N F N C and N ex η represents the power consumption of the fan, compressor, and related accessories. H η L For high and low pressure shaft mechanical efficiency; W g7 W g9 P represents the inlet and outlet flow rates of the tail nozzle; S16 P S6 The static pressure at the outlet sections of the outer duct and inner duct are respectively; T 22r T 5r These are the measured values ​​of the total temperature at the fan outlet and the total temperature at the low-pressure turbine outlet, respectively.

[0031] Based on the correlation analysis results of the influence of health parameters on the equation residuals, only the health parameter with the highest positive correlation is selected for each equation residual. If the parameters with the highest positive correlation in two or more equation residuals are the same, the parameter with the highest positive correlation is selected. For the other equation residual, the next health parameter with the highest positive correlation is selected sequentially. According to this health parameter selection rule, the estimated health parameters are selected as SE1, SW1, SW2, SE3, and SW4. Using e a1 e a2 e a3 e a5 e a6 The five residual equations shown are estimated and solved.

[0032] Preferably, the adaptive correction scheme for the general calculation model of the mainstream parameters in step B) includes designing an adaptive correction scheme for the general calculation model of the mainstream parameters. In this adaptive scheme, the inner layer iteration still selects the compressor pressure ratio π. comp and the high-pressure turbine pressure ratio π HTurb As initial guesses, the flow balance equations of the high and low pressure turbines are used for solving. The outer iteration uses the health parameters SE1, SW1, SW2, SE3, and SW4 as initial guesses and iterates based on the five selected residual equations. Both iterations use the inverse Broyden rank-1 method for solving.

[0033] Compared with the prior art, the present invention, employing the above technical solution, has the following technical effects:

[0034] (1) The general calculation model of the mainstream parameters involved in this invention is based on the analysis of the measurement parameters of the engine and the coupling between the parameters. Compared with the component-level model, the solution of the nonlinear common working equation system is changed from 6-dimensional to 2-dimensional, and the inverse Broyden rank-1 method with less time consumption is used to replace the original Newton-Raphson method, which ensures a certain level of accuracy and real-time performance.

[0035] (2) The present invention designs an adaptive correction scheme based on the double-layer inverse Broyden method for the established general calculation model of mainstream parameters, which can still provide relatively accurate mainstream parameter values ​​when engine performance degrades. Attached Figure Description

[0036] Figure 1 This is a flowchart of the general calculation model for mainstream parameters and the adaptive correction scheme;

[0037] Figure 2 This is a structural diagram of a certain type of twin-rotor turbofan engine;

[0038] Figure 3 The results are simulation results of the general calculation model with H=0km and Ma=0. (a) is the actual input parameters, (b) is the fan outlet section, (c) is the compressor outlet section, (d) is the combustion chamber outlet section, (e) is the high-pressure turbine outlet section, and (f) is the low-pressure turbine outlet section.

[0039] Figure 4 The results are simulation results of the general calculation model with mainstream parameters H=11km and Ma=1.5. (a) is the actual input parameters, (b) is the fan outlet section, (c) is the compressor outlet section, (d) is the combustion chamber outlet section, (e) is the high-pressure turbine outlet section, and (f) is the low-pressure turbine outlet section.

[0040] Figure 5 This is a correlation analysis of health parameters on the equation residuals. (a) represents the equation residuals e. a1 (b) represents the residual e of the equation. a2 (c) represents the residual e of the equation a3 , (d) is the residual e of the equation a4 (e) represents the residual e of the equation. a5 , (f) is the residual e of the equation a6 ;

[0041] Figure 6The following are the health parameter estimation and mainstream parameter tracking results when H=0km, Ma=0 and performance degradation occurs: (a) is the gas path performance parameter estimation, (b) is the fan outlet section, (c) is the compressor outlet section, (d) is the combustion chamber outlet section, (e) is the high-pressure turbine outlet section, and (f) is the low-pressure turbine outlet section.

[0042] Figure 7 The following are the health parameter estimation and mainstream parameter tracking results when performance degradation occurs at H=3km and Ma=0.3: (a) is the gas path performance parameter estimation, (b) is the fan outlet section, (c) is the compressor outlet section, (d) is the combustion chamber outlet section, (e) is the high-pressure turbine outlet section, and (f) is the low-pressure turbine outlet section.

[0043] Figure 8 The simulation results of the total temperature and total pressure of each stage of the rotating component after adding an adaptive correction scheme with H=3km and Ma=0.3 are as follows: (a) is the total temperature of each stage of the fan, (b) is the total pressure of each stage of the fan, (c) is the total temperature of each stage of the compressor, (d) is the total pressure of each stage of the compressor, (e) is the total temperature of each stage of the high-pressure turbine, (f) is the total pressure of each stage of the high-pressure turbine, (g) is the total temperature of each stage of the low-pressure turbine, and (h) is the total pressure of each stage of the low-pressure turbine. Detailed Implementation

[0044] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings.

[0045] The present invention first uses a component-level model of the engine to reduce the dimensionality of the common working equations through measured parameters and the physical relationships between them. Then, during the iterative calculation process, the inverse Broyden rank-1 method is used to replace the Newton-Raphson method, thereby establishing a general calculation model for the mainstream parameters. Next, health parameters are used as the initial guesses for the outer iteration, and iterative calculations are performed using unused equilibrium equations and deviations from the measured parameters, thus designing a two-layer inverse Broyden method adaptive correction scheme. The flowcharts of the general calculation model for the mainstream parameters and the adaptive correction scheme are shown below. Figure 1 .

[0046] This invention takes a certain type of turbofan engine as an example to provide mainstream parameters that are crucial for engine performance calculation and over-limit protection. The total temperature and total pressure parameters of the inlet and outlet sections of rotating components are defined as mainstream engine parameters, denoted by V. main Indicated. Wherein, V main =[T 22 P 22 T3 P3 T4 P4 T 43 P 43[T5 P5], in order, represent the total temperature at the fan outlet, the total pressure at the fan outlet, the total temperature at the compressor outlet, the total pressure at the compressor outlet, the total temperature at the combustion chamber outlet, the total pressure at the combustion chamber outlet, the total temperature at the high-pressure turbine outlet, the total pressure at the high-pressure turbine outlet, the total temperature at the low-pressure turbine outlet, and the total pressure at the low-pressure turbine outlet. Figure 2 This is a structural diagram of a certain type of dual-rotor turbofan engine. The general calculation model and individual adaptive correction method for the mainstream parameters of this turbofan engine include the following steps:

[0047] Step A) Based on the engine component-level model, using the measurement parameters and the physical relationships between the parameters, considering only the intake and core engine components, the common working equations are reduced in dimensionality. Based on the coupling analysis of the measurement parameters, a general calculation model of mainstream parameters that can be applied to different individual engines of the same type is established.

[0048] Step B) Design an adaptive correction architecture based on the two-layer inverse Broyden iteration method. The parameters are automatically adjusted according to individual differences and performance degradation correction characteristics to establish a mainstream parameter model that can be used for a long time, and the temperature and pressure parameters of key sections can be obtained.

[0049] The detailed steps of step A) are as follows:

[0050] Step A1), select initial parameters and common working equations.

[0051] The modeling approach for the nonlinear component-level model of the engine is as follows: first, establish individual component models using the aerodynamic and thermodynamic principles followed by the components during operation; then, combine these models into a complete engine model based on the common working equations of each component. For engines of the same type but different models, the thermodynamic models of their components are not significantly different; the model can be established simply by reading design point parameters and characteristic diagrams from external sources, demonstrating strong versatility. Compared to conventional component-level models, this mainstream parameter universal calculation model follows the modeling concept of component-level models, retaining the common working equations and iterative calculation process. However, it incorporates measured parameters to reduce the dimensionality of the common working equations, thereby improving the real-time performance of this mainstream parameter universal calculation model.

[0052] The steady-state model of a certain type of dual-rotor turbofan engine needs to solve for the pressure ratio and high and low pressure rotor speeds of four rotating components, so six common working equations need to be selected.

[0053] Static pressure balance equation:

[0054] e1 = P s16 / P s6 -1

[0055] Among them, P S16 P S6 These are the static pressures at the outlet sections of the outer duct and the inner duct, respectively.

[0056] Flow balance equation:

[0057] e2=(W g43 -W cool ) / W g4 -1

[0058] e3=(W g5 -W cool ) / W g44 -1

[0059] e4 = W g9 / W g7 -1

[0060] Among them, W g4 W g43 W represents the inlet and outlet flow rates of the high-pressure turbine. g44 W g5 For the inlet and outlet flow rates of the low-pressure turbine, W cool For induced draft air flow rate, W g7 W g9 This refers to the inlet and outlet flow rates of the tail nozzle.

[0061] Power balance equation:

[0062] e5 = N LT η L / N F -1

[0063] e6 = N HT η H / (N C +N ex )-1

[0064] Where, N HT N LT The power outputs of the high-pressure and low-pressure turbines are respectively, N F N C and N ex η represents the power consumption of the fan, compressor, and related accessories. H η L To improve the mechanical efficiency of high and low pressure shafts.

[0065] By iteratively solving the above common working equations, the output parameters of the engine nonlinear component-level model can be obtained.

[0066] Due to the presence of low-pressure speed measurement value n Lr High-pressure speed measurement value n Hr Total temperature measurement P at the fan outlet 22r and the measured value of total pressure at the low-pressure turbine outlet P 5r With the support of [the relevant authority], the initial parameter selected is only the compressor pressure ratio π. comp and the high-pressure turbine pressure ratio πHTurb That is, the fan pressure ratio π fan and low-pressure turbine pressure ratio π LTurb It can be expressed in the following form by combining the measurement parameters:

[0067] π fan =P 22r / P2

[0068]

[0069] Among them, P2 and P6 are the total inlet temperature of the core engine and the total outlet temperature of the internal tunnel, respectively. P This represents the total pressure recovery coefficient from the low-pressure turbine outlet to the inner duct outlet.

[0070] After determining the initial parameters, the six common working equations selected in the component-level model are reduced in dimensionality, and only the following two flow balance equations are selected:

[0071] High-pressure turbine inlet and outlet flow balance:

[0072] e1=(W g43 -W cool ) / W g4 -1

[0073] Low-pressure turbine inlet and outlet flow balance:

[0074] e2=(W g5 -W cool ) / W g44 -1

[0075] At this point, the initial parameters and common working equations have been selected.

[0076] Step A2) Select an iterative solution method for the common working equation system.

[0077] Traditional nonlinear component-level models are solved iteratively using the Newton-Raphson method, which exhibits second-order convergence. However, each iteration requires solving the Jacobian matrix through perturbation, and the number of flow path calculations in each iteration is the same as the number of initial variables, leading to a large computational load. The main advantage of the inverse Broyden rank-1 method is that it only calculates the Jacobian matrix once, resulting in high computational efficiency and superlinear convergence; however, it is sensitive to initial values. Therefore, the inverse Broyden rank-1 method is chosen for the iterative solution of the common working equations, and its iterative formula is as follows:

[0078]

[0079] Among them, s k =x k+1 -x k y k =F(x)k+1 )-F(x k ).

[0080] After solving the common working equations using the inverse Broyden rank-1 method, the main parameters can be obtained. At this point, the general calculation model for the main parameters has been established, and its characteristic diagrams and design point parameters can be read from external sources, no longer limited to a specific engine model, thus exhibiting strong versatility; however, the drawback is that there is still an iterative calculation process, which limits its real-time performance to some extent.

[0081] Since the operating conditions of the blades at each stage of the rotating components are not consistent, providing the total outlet temperature and pressure of each stage of the engine's rotating components is of practical significance for calculating the performance and lifespan of each stage blade. Based on experience, the pressure ratio π of each stage under any operating condition can be calculated. i The method is as follows:

[0082]

[0083] Where N is the number of component levels, π sum For the overall pressure ratio at the component design point, π opt-i For the design point pressure ratio of the i-th stage, π p This represents the total pressure ratio (pressure drop ratio) of the component obtained from performance calculations under different conditions.

[0084] Based on this empirical formula, the pressure ratio of each stage under a certain state can be calculated by combining the pressure ratio at a certain state with the design point pressure ratio. Then, the total temperature and total pressure performance parameters of each stage outlet can be obtained, providing a reference for performance calculation and other related processes.

[0085] Step A3) Read in the characteristic diagram and design point parameters from the outside, and perform simulation verification on the tracking of the established mainstream parameter general calculation model and component-level model.

[0086] Select the following different test points 1, 2, and 3 to check the time consumption and accuracy of the established general calculation model for mainstream parameters.

[0087] (1) H=0km, Ma=0, W fb =0.4kg / s, A8=0.54m 2 ;

[0088] (2) H=0km, Ma=1.06, W fb =0.5kg / s, A8=0.54m 2 ;

[0089] (3) H = 11 km, Ma = 0.8, W fb =1.0 kg / s, A8 = 0.27 m 2 ;

[0090] Where H is the flight altitude, Ma is the flight Mach number, and W... fb A is the main fuel flow rate, and A8 is the throat area.

[0091] For each selected steady-state point, the time consumption and error of the mainstream parameters obtained by the component-level model and the general calculation model of mainstream parameters are compared and summarized, as shown in Table 1 and Table 2.

[0092] Table 1 Comparison of steady-state point simulation time for mainstream parameter general calculation models

[0093]

[0094] Table 2 Summary of Steady-State Point Simulation Errors of Mainstream Parameter General Calculation Model

[0095]

[0096] As shown in Table 1, the time consumption comparison reveals that the general calculation model for mainstream parameters reduces the number of common working equations by utilizing some measured parameters, saving approximately 75% of the time. Table 2, summarizing the simulation errors at steady-state points, indicates that the general calculation model for mainstream parameters has good accuracy at steady-state points, with the maximum error for each mainstream parameter not exceeding 0.5%. Therefore, the established general calculation model for mainstream parameters demonstrates better real-time performance and accuracy compared to the component-level model.

[0097] The dynamic simulation results at the ground point (H=0km, Ma=0) are as follows Figure 3 As shown. The actual input parameter changes are as follows. Figure 3 As shown in (a), the simulation results of each mainstream parameter are as follows: Figure 3 As shown in (b) to (f), the maximum errors of each mainstream parameter compared with the nonlinear component-level model during the dynamic process are summarized in Table 3.

[0098] Table 3 Summary of Maximum Errors in Dynamic Processes of Mainstream Parameter General Calculation Models when H=0km and Ma=0

[0099]

[0100] Depend on Figure 3 As shown in Table 3, during the change of input parameters at the ground points, all mainstream parameters can track the output of the nonlinear component-level model well. The maximum error of each parameter during the entire dynamic process is 3.38%, indicating good accuracy. During the entire dynamic process, the nonlinear component-level model takes 0.4682 seconds, while the general calculation model for the mainstream parameters takes 0.0631 seconds, saving approximately 86.52% of the time and demonstrating good real-time performance.

[0101] The dynamic simulation results at the high-altitude point (H = 11 km, Ma = 1.5) are as follows: Figure 4 As shown. The actual input parameter changes are as follows. Figure 4 As shown in (a), the simulation results of each mainstream parameter are as follows: Figure 4 As shown in (b) to (f), the maximum errors of each mainstream parameter compared with the nonlinear component-level model during the dynamic process are summarized in Table 4.

[0102] Table 4 Summary of the maximum error in the dynamic process of the general calculation model for mainstream parameters H=11km, Ma=1.5

[0103]

[0104] Depend on Figure 4 As shown in Table 4, the tracking performance of the main parameters is good during the input parameter changes, with a maximum error of only 1.58% compared to the component-level model. The nonlinear component-level model takes 0.2220s in the entire dynamic process, while the general calculation model for the main parameters takes 0.0569s, saving about 74% of the time and demonstrating good real-time performance.

[0105] In summary, the established general calculation model for mainstream parameters has good performance in terms of accuracy and real-time performance. Moreover, it can load characteristic diagrams and design point parameters from external sources, is not limited to a specific engine model, and has strong versatility.

[0106] The detailed steps of step B) are as follows:

[0107] Step B1) Perform correlation analysis on the impact of health parameters on the equation residuals and select the estimated health parameters.

[0108] Step B1.1) involves a correlation analysis of the impact of health parameters on the residuals of the equation.

[0109] The nonlinear model of an engine is based on the characteristics of its components under design conditions. However, due to individual differences in engine manufacturing and inevitable performance degradation during service, the rated engine model may fail to reflect the actual operating state of the engine. To more accurately reflect the current engine state during flight and provide more precise mainstream parameters, adaptive correction of the established general calculation model for mainstream parameters is essential. Aero engines have complex structures and operate in harsh environments, inevitably experiencing performance degradation during service. This means that the flow and efficiency of engine components deviate from their ideal state. This deviation leads to changes in engine performance parameters, which can be used to evaluate the health status or degree of failure of the engine's airflow performance. To accurately describe the degradation of engine component performance, the component health parameter characterizing engine performance degradation is defined as the efficiency coefficient SE of rotating components. i and flow coefficient SW i as follows:

[0110]

[0111] Where, η i and W i These are the actual values ​​for component efficiency and flow rate. and W i * The values ​​represent the rated efficiency and flow rate of the component. The design values ​​are used in this paper. The subscript i represents the number of the rotating component.

[0112] The general calculation model for the mainstream parameters established in the previous step only used the balance equations of the inlet and outlet flow of the high and low pressure turbines. The following four unused balance equations and the deviation equations from the two measured parameters will change accordingly when the health parameters degrade.

[0113] e a1 =N LT η L / N F -1

[0114] e a2 =N HT η H / (N C +N ex )-1

[0115] e a3 =W g9 / W g7 -1

[0116] e a4 =P s16 / P s6 -1

[0117] e a5 =T 22 / T 22r -1

[0118] e a6 =T5 / T 5r -1

[0119] Among them, T 22r T 5r These are the measured values ​​of the total temperature at the fan outlet and the total temperature at the low-pressure turbine outlet, respectively.

[0120] At the ground point, when each of the engine's eight health parameters degraded by 3%, the changes in the residuals of the balance equation and the deviations from the measured parameters are shown in Table 3. This indicates that when engine health parameters degrade, the actual measured parameters also change. When input into the general calculation model for mainstream parameters, the system assumes a healthy state at this point. The mainstream parameters calculated using this model lead to changes in the residuals of the balance equation and the deviations from the measured parameters, with the overall trend of the residuals increasing. Therefore, using these changes in residuals for health parameter estimation is feasible.

[0121] Table 3. Changes in residuals of equilibrium equations when health parameters deteriorate.

[0122]

[0123] The effects of eight health parameters on the residuals of the six equations above were considered separately, and correlation analysis was performed. The results are as follows: Figure 5 As shown.

[0124] Step B1.2) Select the estimated health parameters based on the results of the correlation analysis.

[0125] The selection rule for health parameters is as follows: for each equation residual, only the health parameter with the highest positive correlation is selected. If the parameters with the highest positive correlation of two or more equation residuals are the same, then the parameter with the highest positive correlation is selected. For the other equation residual, the next health parameter with the highest positive correlation is selected in sequence.

[0126] Depend on Figure 5 Based on the correlation analysis results and the selection rules for health parameters, the estimated health parameters were selected as SE1, SW1, SW2, SE3, and SW4. Using e a1 e a2 e a3 e a5 e a6 The five residual equations shown are estimated and solved.

[0127] Step B2) Design an adaptive correction scheme for the general calculation model of mainstream parameters.

[0128] Based on the selected health parameters and residual equations, an adaptive scheme based on two-layer iteration is designed. In this adaptive scheme, the inner iteration still selects the compressor pressure ratio π. comp and the high-pressure turbine pressure ratio π HTurb As initial guesses, the flow balance equations of the high and low pressure turbines are used for solving. The outer iteration uses the health parameters SE1, SW1, SW2, SE3, and SW4 as initial guesses and iterates based on the five selected residual equations. Both iterations use the inverse Broyden rank-1 method for solving.

[0129] Step B3) After establishing the general calculation model for the mainstream parameters and designing an adaptive correction scheme for it, the performance parameter estimation and the mainstream parameters before and after adding the adaptive correction scheme are simulated and verified.

[0130] Ground point (H=0km, Ma=0, W) fb =2.892kg / s), a simulation analysis was conducted on the performance degradation of the general calculation model of the mainstream parameters before and after the addition of the adaptive module. The simulation time was 25s, the engine sampling step size was 0.025s, and the health parameters were all 1 at the beginning of the simulation. At 2.5s, a performance degradation simulation of 3% degradation of the engine compressor flow was added. The gas path performance estimation results are as follows. Figure 6 As shown in (a), the simulation results before and after adding the adaptive module are as follows: Figure 6 As shown in (b) to (f).

[0131] At a high altitude (H = 3 km, Ma = 0.3, W... fb Simulation analysis was performed using an engine sampling step size of 2.0 kg / s. The simulation time remained constant with the engine sampling step size. At 2.5 seconds, a performance degradation simulation was introduced, with fan flow rate decreasing by 2% and efficiency decreasing by 3%. The estimated gas path performance results are as follows: Figure 7 As shown in (a), the simulation results before and after adding the adaptive module are as follows: Figure 7 As shown in (b) to (f).

[0132] Depend on Figure 6 and 7 It can be seen that, at both ground and high-altitude points, the designed adaptive module rapidly responds to and characterizes the engine's performance degradation after component performance deteriorates. Furthermore, after health parameters deteriorate, compared to the mainstream parameters without the adaptive module, the general calculation model for mainstream parameters with the adaptive module more accurately tracks the changes in mainstream parameters after the fault, proving that the designed adaptive module can reflect the actual operating state of the engine. In addition, Figure 8 The variation trends of total temperature and total pressure at each stage of the rotating component after adding an adaptive correction scheme during the performance degradation process are presented. These trends conform to the principles of aerodynamic thermodynamics and can be used as a reference for the total temperature and total pressure at the outlet of each stage of the rotating component.

[0133] It should be noted that the above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations and substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for constructing a general calculation model for the mainstream parameters of a turbofan engine, wherein the mainstream parameters include the inlet and outlet cross sections of the rotating component and the total temperature and total pressure parameters of each stage of the rotating component, characterized in that, Includes the following steps: The initial parameters of the general calculation model with compressor pressure ratio and high-pressure turbine pressure ratio as the main parameters; A common set of working equations is established, which includes the high-pressure turbine inlet and outlet flow balance equations and the low-pressure turbine inlet and outlet flow balance equations. The common working equations are solved iteratively using the inverse Broyden rank-1 method to obtain a general calculation model for the mainstream parameters. Among them, the fan pressure ratio π fan and low-pressure turbine pressure ratio π LTurb Combined with the measured parameters, the total temperature P at the fan outlet 22r and the measured value of total pressure at the low-pressure turbine outlet P 5r It can be represented in the following form: π fan =P 22r / P2 Among them, P2 and P6 are the total inlet temperature of the core engine and the total outlet temperature of the internal tunnel, respectively. P This represents the total pressure recovery coefficient from the low-pressure turbine outlet to the inner duct outlet; Choose the following equilibrium equation: High-pressure turbine inlet and outlet flow balance equations: e1=(W g43 -IN cool ) / IN g4 -1 Low-pressure turbine inlet and outlet flow balance equation: e2=(W g5 -W cool ) / W g44 -1 Among them, W g4 W g43 W represents the inlet and outlet flow rates of the high-pressure turbine. g44 W g5 For the inlet and outlet flow rates of the low-pressure turbine, W cool This refers to the induced air flow rate.

2. The method for constructing a general calculation model for mainstream parameters of a turbofan engine according to claim 1, characterized in that, The characteristic diagram and design point parameters of the general calculation model of the mainstream parameters can be read from outside the general calculation model of the mainstream parameters.

3. The method for constructing a general calculation model for mainstream parameters of a turbofan engine according to claim 1, characterized in that, The pressure ratio of each stage of the rotating component is calculated using empirical formulas, and then the total temperature and pressure parameters of each stage are solved to calculate the pressure ratio π of each stage of the rotating component. i Use the following formula: Where N is the number of component levels, π sum For the overall pressure ratio at the component design point, π opt-i For the design point pressure ratio of the i-th stage, π p This represents the total pressure ratio of the component obtained from performance calculations under different conditions.

4. An individual adaptive correction method for turbofan engines based on a general calculation model of mainstream parameters, characterized in that, Includes the following steps: Construct the residual equations for a general calculation model of mainstream parameters; Based on the correlation between health parameters and residual equations, health parameters are selected; The mainstream parameters of the general calculation model are adaptively corrected for individual turbofan engines, including: the inner iteration selects the compressor pressure ratio and the high-pressure turbine pressure ratio as initial guesses, and iterates and solves them using the high-low pressure turbine flow balance equation; the outer iteration uses the selected health parameters as initial guesses, and iterates and solves them according to the selected residual equation; the corrected mainstream parameters are obtained. Both the inner and outer iterations are solved using the inverse Broyden rank-1 method; The component health parameter characterizing engine performance degradation is the efficiency coefficient (SE) of rotating components. i and flow coefficient SW i as follows: Where, η i and W i These are the actual values ​​for component efficiency and flow rate. and W i * The rated values ​​are the component efficiency and flow rate. The design values ​​are used for these rated values, and the subscript i is the number of the rotating component. By analyzing the impact of health parameter degradation on the residuals of the equilibrium equations and the deviations from the measured parameters, the following equations are selected for the general calculation model of mainstream parameters, and their residuals are used as the basis for performance estimation: e a1 =N LT or L / N F -1 e a2 =N HT or H / (N C +N ex )-1 have been a3 =W g9 / W g7 -1 e a4 =P s16 / P s6 -1 e a5 =T 22 / T 22r -1 and a6 =T5 / T 5r -1 Where, N HT N LT The power outputs of the high-pressure and low-pressure turbines are respectively, N F N C and N ex η represents the power consumption of the fan, compressor, and related accessories. H η L For high and low pressure shaft mechanical efficiency; W g7 W g9 P represents the inlet and outlet flow rates of the tail nozzle; S16 P S6 The static pressure at the outlet sections of the outer duct and inner duct are respectively; T 22r T 5r These are the measured values ​​of the total temperature at the fan outlet and the total temperature at the low-pressure turbine outlet, respectively.

5. The individual adaptive correction method for turbofan engines according to claim 4, characterized in that, The health parameter selection rules are as follows: for each equation residual, only the health parameter with the highest positive correlation is selected. If the parameters with the highest positive correlation of two or more equation residuals are the same, then the parameter with the highest positive correlation is selected. For the other equation residual, the next health parameter with the highest positive correlation is selected in sequence. Based on the correlation analysis results and the health parameter selection rules, the selected health parameters are SE1, SW1, SW2, SE3, and SW4.

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