Cooling turbine characteristic identification method for extension residual error of aero-engine model

Abstract

The invention discloses a method for identifying cooling bleed air turbine characteristics of an aero-engine. The method comprises the following steps: analyzing an influence mechanism of the cooling bleed air turbine characteristics; based on the design points and the multi-steady-state-point test run data, establishing a high-precision component-level model of the aero-engine cooling air-entraining fully-open mode to ensure the accuracy of the component-level model in the basic mode and the reliability of the extension law; estimating response output parameters of a cooling bleed air turn-off mode by adopting model extension, and obtaining a complete machine performance change residual error caused by cooling bleed air change; according to the method, turbine characteristics are adjusted based on a residual error identification algorithm, various output parameter errors are reduced, accuracy verification is carried out in combination with multiple steady-state data of actual test run data, and the cooling bleed air turbine characteristics obtained through identification can meet engineering requirements.

Description

Technical Field

[0001] The present disclosure belongs to the field of aero-engine component characteristics, and particularly relates to a method for identifying the characteristics of a cooling turbine with extended residuals of an aero-engine model. Background Technique

[0002] During the past few decades, the compressor pressure ratio and turbine inlet temperature of gas turbine engines have been increased by designing turbine cooling air extraction systems, effectively improving the Brayton cycle efficiency. Currently, the commonly used turbine cooling forms include impingement cooling, convective cooling, film cooling, and transpiration cooling, etc. Among them, the combination mode of convective cooling and film cooling is the most effective in using cooling air. The turbine cooling air extraction volume of most traditional turbine engines cannot be actively adjusted and is determined according to the ablation risk in the maximum state, and there is a large margin in the full envelope range. Taking a military twin-rotor low-bypass ratio turbofan engine as an example, its turbine cooling air extraction flow accounts for 15-25% of the core flow. To balance the capabilities of low fuel consumption and high maneuverability, it is an important trend for variable cycle engines of the propulsion systems of new-generation fighter jets to actively and optimally adjust the turbine cooling air extraction volume in real time, adjust the turbine efficiency, optimize the overall engine performance, and reduce the fuel consumption rate in low operating states such as idle, cruise, and descent. For example, NASA conducted an active closed-loop cold air test on the N2A turbofan engine and found that a 12% cold air shut-off saved 3.6% fuel.

[0003] Accurate cooling air extraction turbine characteristics are an important basis for evaluating the overall engine performance and real-time optimization of the cold air volume. However, the current thermodynamic models used in the industry, such as GASCAN, TURBOMATCH, and IGCC, introduce a large number of undetermined unknown coefficients, which are mostly given by relying on the estimation method of empirical formulas, and their accuracy needs to be verified. On the other hand, regarding the characteristic acquisition methods such as component tests and CFD calculations, due to the differences in component test environments, the interference of sensors on the flow field, and the deviations in CFD calculations, the characteristics obtained often differ from the results of the overall engine test runs.

[0004] Identifying the characteristics of the cooling turbine component based on the overall engine test run data is a characteristic acquisition method that conforms to engineering practice. For the actual gas turbine engine overall test data, there are few sensor measurement points at the cross-sections near the front and rear of the turbine component. Generally, there are even no measurement points near the high-pressure turbine, which increases the difficulty of accurately extracting the cooling turbine characteristics. Even through the test run test method of artificially turning on / off the cooling air extraction, there will be a deviation in the operating state due to the re-matching of the overall engine components, and it is difficult to distinguish the part of the turbine characteristic change in the change of the output parameters.

[0005] Therefore, how to design a method for identifying the characteristics of a cooling turbine with extended residuals of an aero-engine model is an urgent problem to be solved in the industry.

[0006] The above information disclosed in the background section is only used to enhance the understanding of the background of the present invention, and thus may include information that does not constitute the prior art known to those of ordinary skill in the art. Summary of the Invention

[0007] In view of the deficiencies in the prior art, the purpose of the present disclosure is to provide a method for identifying the characteristics of a cooling turbine with extended residuals of an aero-engine model. By combining the steady-state points of the full-open mode of the high-pressure turbine bleed air in the test run data, a high-precision component-level model of the aero-engine in the full-open mode of the bleed air is established. For the high-pressure turbine bleed air cut-off mode in the test run data, the residuals of the calculated output parameters of the extended model are obtained, and an effective identification of the characteristics of the cooling turbine is carried out by combining the flow influence factor μ and the efficiency influence factor ζ identification algorithms.

[0008] To achieve the above purpose, the present disclosure provides the following technical solutions:

[0009] A method for identifying the characteristics of a cooling turbine with extended residuals of an aero-engine model, comprising the following steps:

[0010] Step S100: Analyze the influence mechanism of cooling bleed air on turbine characteristics;

[0011] Step S200: Based on the above analysis results and test run data, construct a high-precision component-level model of the aero-engine in the full-open mode of the bleed air;

[0012] Step S300: Extend the model to the stage of cooling bleed air cut-off, estimate the output parameters of the whole machine, and obtain the output parameter residuals;

[0013] Step S400: Based on the output parameter residuals, design a residual identification algorithm to adjust the turbine characteristics and eliminate various output parameter errors;

[0014] Step S500: Conduct accuracy verification by combining multiple steady-state data in the cooling bleed air cut-off mode.

[0015] Preferably, in step S100, the turbine characteristics include the turbine flow characteristics, i.e., the corrected flow rate through the turbine The formula for its definition is as follows:

[0016]

[0017] In the formula: Wa cor ——The corrected flow rate through the turbine; n cor ——The corrected speed of the turbine; ——The pressure drop ratio of the total pressure at the inlet and outlet of the turbine; Wa 41 ——The physical flow rate of the turbine / (kg / s); ——The total pressure at the critical section of the turbine guide vane / Pa; P std ——The sea-level pressure under standard conditions / Pa; —— Total temperature at the critical section of the turbine guide vane / K; T std —— Sea-level temperature on a standard day / K.

[0018] On the other hand, in a turbine without cooling bleed air, the following relationship exists between the flow characteristics of the turbine and the flow at the critical section of its guide vane:

[0019]

[0020] In the formula: Wa 41 —— Physical flow rate of the turbine / (kg / s); Wa 43 —— Air flow rate through the critical section of the turbine / (kg / s); n cor —— Corrected speed of the turbine; —— Pressure drop ratio of the total pressure at the inlet and outlet of the turbine; q—— Dimensionless mass flow; A 43 —— Area of the critical section of the guide vane / (m 2 ); —— Total pressure at the critical section of the turbine guide vane / Pa; —— Total temperature at the critical section of the turbine guide vane / K; K—— Constant, which can be calculated according to the following formula:

[0021]

[0022] In the formula: R—— Gas constant / (J / K / kg); k—— Adiabatic index.

[0023] Preferably, in step S100, the turbine characteristics further include the turbine efficiency characteristic, i.e., the turbine isentropic efficiency The formula for its definition is as follows:

[0024]

[0025] In the formula: η—— Turbine isentropic efficiency; n cor —— Corrected speed of the turbine; —— Pressure drop ratio of the total pressure at the inlet and outlet of the turbine; L T,r —— Rim work / J; L TS,r —— Ideal expansion work / J; cp—— Specific heat at constant pressure of the gas / (J / K / kg); —— Total temperature at the critical section of the turbine guide vane / K; —— Total temperature at the outlet of the turbine / K; R—— Gas constant / (J / K / kg); k—— Adiabatic index.

[0026] Analyze the existing high-pressure turbine cooling air bleeding technology of aeroengines, summarize different cooling schemes and cooling air bleeding injection methods. Considering that the defined range of turbine characteristics is from the critical section of the nozzle guide vane to the turbine outlet, taking the critical section of the turbine nozzle guide vane as the boundary, it is divided into pre-critical section cooling and post-critical section cooling. Analyze the influence of the latter on turbine characteristics through the principles of thermodynamics, and transform it into the flow rate influence factor μ and the efficiency influence factor ζ to complete the analysis of the influence mechanism.

[0027] Specifically, since the injection of cooling air bleeding after the critical section of the nozzle guide vane destroys the original flow rate characteristic law, in order to uniformly describe the flow rate characteristic laws of the uncooled turbine and the cooled turbine again, the equivalent critical area A of the nozzle guide vane is defined. Cr，eq . Among them, the injected cooling air bleeding bypasses the critical section, additionally increasing the turbine outlet flow rate, which can be equivalently considered that the dimensionless mass flow rate q characteristic law of the critical section of the nozzle guide vane remains unchanged, the critical area increases, and the flow capacity is improved. On the contrary, when the post-cooling air bleeding system of the turbine is shut off, it can be equivalently considered that the critical area of the nozzle guide vane decreases, and the turbine throttles.

[0028]

[0029] Where A Cr，eq ——Equivalent critical area of the nozzle guide vane / (m 2 ); Wa5——Flow rate at the outlet of the high-pressure turbine rotor / (kg / s); P 43 * ——Total pressure at the critical section of the high-pressure turbine nozzle guide vane / Pa; K——Constant of formula (9); q——Dimensionless mass flow rate; n [[ID=]1] cor ——Converted speed of the turbine; ——Pressure drop ratio of the total pressure at the inlet and outlet of the turbine; T 43 * ——Total temperature at the critical section of the high-pressure turbine nozzle guide vane / K; Wa 43 ——Flow rate at the critical section of the high-pressure turbine nozzle guide vane / (kg / s); Wa c2 ——Flow rate of the post-cooling air at the critical section of the high-pressure turbine nozzle guide vane / (kg / s).

[0030] According to the definition of the critical area A 43 in formula (8) and the connection between the equivalent critical area A Cr，eq in formula (11), the flow rate characteristic Wa cor,eq of the cooled turbine can be rewritten as:

[0031]

[0032] Where Wa cor,eq ——Equivalent equivalent converted flow rate; n cor ——Converted speed of the turbine; ——The pressure ratio of the total pressure at the inlet and outlet of the turbine; Wa 43 ——The flow rate of the critical section of the high-pressure turbine guide vane / (kg / s); Wa c2 ——The flow rate of the post-cooling air at the critical section of the high-pressure turbine guide vane / (kg / s);

[0033] P 43 * ——Is the total pressure at the critical section of the high-pressure turbine guide vane / Pa; K——The constant of formula (9); q——Dimensionless mass flow; A Cr，eq ——The equivalent critical area of the guide vane / (m 2 ); A 43 ——The critical section area of the guide vane / (m 2 ); μ——Flow influence factor.

[0034] The efficiency definition (10) of the traditional uncooled turbine ignores the influence of the cooling bleed air. Driven by the cooling bleed air, the turbine rim work L Tr Is updated as follows:

[0035]

[0036] Where L’ Tr ——The updated turbine rim work / J; L Tr ——The turbine rim work of the traditional uncooled turbine / J; ΔL——The additional rim work of the cooling bleed air impacting the turbine / J; Wa 43 ——The flow rate of the critical section of the high-pressure turbine guide vane / (kg / s); Wa c2 ——The flow rate of the post-cooling air at the critical section of the high-pressure turbine guide vane / (kg / s); T 43 * ——Is the total temperature at the critical section of the high-pressure turbine guide vane / K; T c2 * ——Is the total temperature of the cooling bleed air / K; ——The total temperature at the turbine outlet / K; cp——Specific heat capacity at constant pressure of the gas / (J / K / kg).

[0037] Therefore, there are also changes in the efficiency definition. Considering the isentropic ideal expansion work L TS，r Of the work capacity of multiple gases, the generalized turbine efficiency η T,eq Is defined as:

[0038]

[0039] Among them, η T,eq ——Generalized turbine efficiency; L T,r ——Rim work / J; L TS,r—— Ideal expansion work / J; i —— are 43 and various different airflows of c2 respectively; cp —— Specific heat capacity of gas at constant pressure / (J / K / kg); T i * —— Total temperature of the corresponding gas / K; —— Total temperature at the turbine outlet / K; Wa i —— Corresponding gas flow rate / (kg / s); k —— Adiabatic index; R —— Gas constant / (J / K / kg); P i * —— Total pressure of the corresponding gas / Pa; —— Total pressure at the turbine outlet / Pa.

[0040] Combined with the definition of the non-cooled turbine efficiency in formula (10), η T,eq Can be equivalent to:

[0041]

[0042] Among them, η T,eq —— Generalized turbine efficiency; n cor —— Turbine conversion speed; —— Pressure drop ratio of the total pressure at the inlet and outlet of the turbine; ζ —— Efficiency influence factor; Wa c2 —— Cooling air flow rate after the critical section of the high-pressure turbine guide vane / (kg / s); Wa 43 —— Flow rate at the critical section of the high-pressure turbine guide vane / (kg / s).

[0043] Preferably, in step S200, the process of establishing the high-precision component-level model of the aero-engine includes:

[0044] By collecting the ground test bench test data of the actual aero-engine, combining with the adjustment law of the cooling system of the actual engine, selecting the steady-state data points in the full-open mode of the high-pressure turbine bleed air as the reference data for modeling, selecting the intermediate state of the steady-state point test data as the model design point, and combining with the thermodynamic calculation method, generating the characteristics of each component to form a high-precision whole-engine model in the full-open mode of the high-pressure turbine bleed air.

[0045] Preferably, in step S300, the steps of extending the model to the bleed air cut-off stage include:

[0046] According to the high-precision whole-engine model in the full-open mode of the high-pressure turbine bleed air and the steady-state point test data in the bleed air cut-off mode of the high-pressure turbine, extend the estimated output parameters of the model, as shown in the following formula:

[0047]

[0048] In the formula: Γ A (.) —— High-precision whole-engine model in the full-open mode of the high-pressure turbine bleed air; ——The output parameter vector of the engine in the full-open high-pressure turbine bleed mode at time t; ——The input parameter vector; ——The state parameter vector.

[0049] According to the high-precision overall engine model Γ A (.) of the full-open high-pressure turbine bleed mode, and the steady-state point test run data of the high-pressure turbine bleed cut-off mode, the extended model calculation residual is as expressed by the following formula:

[0050]

[0051] In the formula: τ—the extended model calculation residual; ——The steady-state point test run data of the engine in the high-pressure turbine bleed cut-off mode at time t, including the input parameters state parameters output parameters μ—the flow rate influence factor; ζ—the efficiency influence factor; ——The output parameter vector of the engine in the high-pressure turbine bleed cut-off mode at time t; Γ A (.)—The high-precision overall engine model of the full-open high-pressure turbine bleed mode; ——The input parameter vector; ——The state parameter vector.

[0052] Preferably, in step S400, the residual identification algorithm for adjusting the turbine characteristics includes:

[0053] The adjustment optimization objective is to minimize the extended model calculation residual τ, the adjustable parameters are the flow rate influence factor μ and the efficiency influence factor ζ, and the optimization constraint range is and is the steady-state data set of the engine in the high-pressure turbine bleed cut-off mode at time t. Among them, considering the degree of influence of the actual cooling bleed system on the turbine, ζ min = 0.8, ζ max = 1.2, μ min = 0.8, μ max = 1.2:

[0054]

[0055] In the formula: τ—the extended model calculation residual; ——The steady-state point test run data of the engine in the high-pressure turbine bleed cut-off mode at time t, including the input parameters state parameters output parameters μ—the flow rate influence factor; ζ—the efficiency influence factor; ——The output parameter vector of the engine in the high-pressure turbine bleed cut-off mode at time t; ΓA (.)——High-precision overall engine model in the full-open high-pressure turbine bleed air mode; ——Input parameter vector; ——State parameter vector; μ min ——Minimum value of the flow rate influence factor; μ max ——Maximum value of the flow rate influence factor; ζ min ——Minimum value of the efficiency influence factor; ζ max ——Maximum value of the efficiency influence factor.

[0056] Preferably, in step S400, the residual identification algorithm is iterated by the following method:

[0057] Step S401 initializes the residual identification algorithm: Initialize the initial values of 1.0 for the flow rate influence factor μ and the efficiency influence factor ζ respectively;

[0058] Step S402 calculates the initial residual: Compare the output of the extended calculation of the model with the actual output parameters of the engine to calculate the residual

[0059] Step S403 calculates the gradient: According to the current residual at the nth step The gradient of the adjustment coefficient Optimize to determine the value of the adjustment coefficient for the next iteration Gradient calculation formula:

[0060] The adjustment optimization objective is to minimize the residual τ of the extended calculation of the model. The adjustable parameters are the flow rate influence factor μ and the efficiency influence factor ζ, and the optimization constraint range is And Is the steady-state data set of the engine in the high-pressure turbine bleed air cut-off mode at time t. Among them, considering the influence degree of the actual cooling bleed air system on the turbine, ζ min = 0.8, ζ max = 1.2, μ min = 0.8, μ max = 1.2:

[0061]

[0062] In the formula: τ——Residual of the extended calculation of the model; ——Steady-state point test run data of the engine in the high-pressure turbine bleed air cut-off mode at time t, including input parameters State parameters Output parameters ——Flow rate influence factor; ζ——Efficiency influence factor; ——Output parameter vector of the engine in the high-pressure turbine bleed air cut-off mode at time t; Γ A (.)——High-precision overall engine model in the full-open high-pressure turbine bleed air mode; —— Input parameter vector; —— State parameter vector; μ min —— Minimum value of flow influence factor; μ max —— Maximum value of flow influence factor; ζ min —— Minimum value of efficiency influence factor; ζ max —— Maximum value of efficiency influence factor.

[0063] Step S404 Update adjustment coefficient: Based on the residual gradient obtained in the above steps, design an adjustment coefficient to update the damping step size, update the adjustment coefficient, and the update formula:

[0064]

[0065] In the formula: —— Flow influence factor and efficiency influence factor obtained by the (n + 1)-th iteration of the steady-state point commissioning data at time t; —— Flow influence factor and efficiency influence factor obtained by the n-th iteration of the steady-state point commissioning data at time t; λ step —— Adjustment coefficient update damping step size, taking a value in the interval [0, 1]; Represents the inverse of the gradient matrix calculated in step S403; —— Residual of the n-th iteration of the model extension calculation at time t.

[0066] Step S405 Residual update: Based on the new adjustment coefficient of the iteration, calculate the residual of the (n + 1)-th iteration, and the update formula:

[0067]

[0068] In the formula: —— Residual of the (n + 1)-th step of the model extension calculation at time t; τ(.) —— Model extension calculation residual function; Γ A (.) —— High-precision whole-engine model in the full-open mode of high-pressure turbine bleed air; —— Steady-state point commissioning data of the engine in the high-pressure turbine bleed air cut-off mode at time t, including input parameters State parameters Output parameters —— Flow influence factor and efficiency influence factor obtained by the (n + 1)-th iteration of the steady-state point commissioning data at time t.

[0069] Repeat steps S403 to S405: Repeat the steps of calculating the gradient, updating the adjustment coefficient, and residual update until the predetermined number of iterations is reached or the residual function converges.

[0070] The present invention also discloses a cooling turbine characteristic identification system for an aero-engine model extended residual, including:

[0071] An analysis module for analyzing the influence mechanism of cooling bleed air on turbine characteristics;

[0072] A construction module for constructing a high-precision component-level model of an aero-engine in the full-open bleed air mode according to the above analysis results and test run data;

[0073] An acquisition module for obtaining output parameter residuals through the output parameters of the whole machine;

[0074] An elimination module for designing a residual identification algorithm according to the output parameter residuals to adjust turbine characteristics and eliminate various output parameter errors;

[0075] A verification module for performing accuracy verification by combining multiple steady-state data in the cooling bleed air off mode.

[0076] The present invention also discloses a computer storage medium, wherein the storage medium includes computer instructions, which when run on a computer, cause the computer to execute the method described in any one of the foregoing.

[0077] The present invention also discloses an electronic device, wherein the electronic device includes: a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein when the processor executes the program, it implements the method described in any one of the foregoing.

[0078] Compared with the prior art, the beneficial effects brought by the present invention are as follows: The present disclosure can carry out turbine characteristic identification only based on test run data without adding additional sensor measurement points. For the component rematching phenomenon near the full-open / closed state of the high-pressure turbine cooling bleed air, the output parameter changes in the actual test run data are isolated through model extension calculation, and combined with the residual identification algorithm, so as to effectively identify the cooling turbine characteristics. Description of the Drawings

[0079] Figure 1 is a flowchart of a method for identifying the cooling turbine characteristics of an aero-engine model extended residual provided by an embodiment of the present disclosure;

[0080] Figure 2 is a definition diagram of the cooling high-pressure turbine station of an engine provided by an embodiment of the present disclosure;

[0081] Figure 3 is a schematic diagram of the turbine cooling bleed air cut-off logic of a twin-spool turbofan engine provided by an embodiment of the present disclosure;

[0082] Figure 4 is a schematic diagram of the influence of the engine output parameter response change provided by an embodiment of the present disclosure;

[0083] Figure 5 It is a schematic diagram of the principle of the method for identifying the extended residual of an aero-engine model provided by an embodiment of the present disclosure;

[0084] Figure 6 It is a structural diagram of an aero-engine model provided by an embodiment of the present disclosure;

[0085] Figure 7 It is a diagram of specific test run data and parameters provided by an embodiment of the present disclosure;

[0086] Figure 8 It is a test chart of the identification result provided by an embodiment of the present disclosure. Specific embodiments

[0087] Next, specific embodiments of the present disclosure will be described in detail with reference to the appended Figures 1 to 8 Although specific embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure can be more thoroughly understood and the scope of the present disclosure can be fully conveyed to those skilled in the art.

[0088] It should be noted that certain terms are used in the description and claims to refer to specific components. Those skilled in the art should understand that different terms may be used to refer to the same component. The description and claims of this specification do not use the difference in terms as a way to distinguish components, but use the difference in the functions of components as the criterion for distinction. As mentioned throughout the description and claims, the term "comprising" or "including" is an open-ended term, and should be interpreted as "including but not limited to". The subsequent description of the specification is for the purpose of implementing the preferred embodiments of the present disclosure, but the description is for the general principle of the specification and is not used to limit the scope of the present disclosure. The scope of protection of the present disclosure shall be subject to what is defined by the appended claims.

[0089] For the convenience of understanding the embodiments of the present disclosure, the following will further explain with specific embodiments as examples in conjunction with the drawings, and each drawing does not constitute a limitation on the embodiments of the present disclosure.

[0090] In one embodiment, as Figure 1 shown, the present disclosure provides a method for identifying the cooling turbine characteristics of the extended residual of an aero-engine model, including the following steps:

[0091] Step S100: Analyze the influence mechanism of the cooling bleed air on the turbine characteristics;

[0092] Step S200: Establish a high-precision component-level model of the aero-engine in the full-open bleed air mode based on the test run data at the design point and multiple steady-state points;

[0093] Step S300: Extend the model to the cooling bleed air cut-off stage, estimate the overall engine output parameters, and obtain the output parameter residuals;

[0094] Step S400: Design a residual identification algorithm to adjust the turbine characteristics and eliminate the errors of multiple output parameters such as the low-pressure rotational speed N1, the high-pressure rotational speed N2, the pressure P after the compressor, 31 and the temperature T6 after the low-pressure turbine;

[0095] Step S500: Combine the steady-state data at multiple points in the cooling bleed air cut-off mode for accuracy verification.

[0096] In one embodiment, as Figure 2 shown, the present disclosure provides a structure of an engine turbine object, a definition of the gas path cross-section station, and a thermodynamic characteristic process, including the following details: The high-pressure turbine includes two components, namely the stator and the rotor. The gas path cross-section at the stator inlet is section 4, the stator outlet, which is the rotor inlet, is section 45, and the rotor outlet is section 5. During the thermodynamic process of the gas flowing through the 4-45-5 cross-sections, the enthalpy h of the gas decreases and the entropy S increases.

[0097] In one embodiment, as Figure 3 shown, the present disclosure provides a schematic diagram of the cooling bleed air cut-off logic for a twin-spool turbofan engine turbine. At the design point state where the throttle lever PLA is 65, the corrected rotational speed N of the high-pressure rotor of the engine 2cor is relatively high, the temperature in front of the turbine is relatively large, and the turbine cooling bleed air is in the fully open state A; as the input throttle lever command PLA gradually decreases and the engine state gradually drops, the corrected rotational speed N of the high-pressure rotor 2cor gradually decreases. When it exceeds the switching point, the turbine cooling bleed air of the engine changes from the fully open state A to the cut-off state B.

[0098] As Figure 4 shown, commissioning data D is collected for the fully open state A of the engine turbine cooling bleed air A , and commissioning data D is collected for the cut-off state B of the engine turbine cooling bleed air B . The commissioning data includes input parameters I E , output parameters O E , and state parameters x. Among them, the engine model Γ A established based on the commissioning data D of the fully open state A A , when entering the cut-off state B, according to the engine input parameters I B in the engine commissioning data D E，B (main fuel flow rate wf, fan guide vane angle a1, high-pressure compressor guide vane angle a2, nozzle throat area A8) and state parameters x BEngine model output parameter Γ calculated by extrapolating (low-pressure speed N1, high-pressure speed N2) A (I E，B , x B )(including low-pressure speed N1, high-pressure speed N2, compressor outlet pressure P 31 , and low-pressure turbine outlet temperature T6), based on test run data D B of output parameter O E,B Calculation error. Since the component flow characteristics and efficiency characteristics change suddenly before and after the high-pressure turbine cooling air bleed is cut off, this part of the error reflects the magnitude of the change in turbine characteristics caused by the cut-off of the cooling air bleed, and is the key to identifying the influence of the cooling air bleed on the high-pressure turbine characteristics.

[0099] In this embodiment, by analyzing the influence mechanism of the cooling air bleed on the turbine characteristics, based on the test run data at the design point and multi-stable points, a high-precision component-level model of the aero-engine in the full-open air bleed mode is established; the model is extended to the stage of cooling air bleed cut-off, the output parameters of the whole engine are estimated, and the output parameter residuals are obtained; according to the output parameter residuals and the designed residual identification algorithm, the turbine characteristics are adjusted to eliminate various output parameter errors; it can overcome the problem that it is difficult to identify the cooling turbine characteristics due to the small number of sensor measurement points near the front and rear sections of the turbine components and the re-matching of the engine components before and after the cooling air bleed is shut off, and can accurately describe the influence of the aero-engine cooling air bleed on the turbine characteristics and the ability of behavior prediction.

[0100] In another embodiment, in step S100, the analysis steps of the influence principle of the cooling air bleed on the turbine characteristics are as follows:

[0101] Turbine characteristics include turbine flow characteristics (i.e., the corrected flow rate Wa cor ) through the turbine and turbine efficiency characteristics (i.e., turbine isentropic efficiency η), and their defined formulas are as follows:

[0102]

[0103] In the formula: Wa cor ——Corrected flow rate through the turbine; n cor ——Turbine corrected speed; ——Pressure drop ratio of the total pressure at the inlet and outlet of the turbine; Wa 41 ——Turbine physical flow rate / (kg / s); ——Total pressure at the critical section of the turbine guide vane / Pa; P std ——Sea level pressure on a standard day / Pa; ——Total temperature at the critical section of the turbine guide vane / K; T std ——Sea level temperature on a standard day / K.

[0104] On the other hand, in a turbine without cooling bleed air, the following relationship exists between the flow characteristics of the turbine and the flow in its nozzle critical section:

[0105]

[0106] In the formula: Wa 41 ——Physical flow rate of the turbine / (kg / s); Wa 43 ——Air flow rate passing through the turbine critical section / (kg / s); n cor ——Corrected speed of the turbine; ——Pressure drop ratio of the total pressure at the inlet and outlet of the turbine; q——Dimensionless mass flow density; A 43 ——Area of the nozzle critical section / (m 2 ); ——Total pressure of the turbine nozzle critical section / Pa; ——Total temperature of the turbine nozzle critical section / K; K——Constant, which can be calculated according to the following formula:

[0107]

[0108] In the formula: R——Gas constant / (J / K / kg); k——Adiabatic index.

[0109]

[0110] In the formula: η——Isentropic efficiency of the turbine; n cor ——Corrected speed of the turbine; ——Pressure drop ratio of the total pressure at the inlet and outlet of the turbine; L T,r ——Work done at the rim / J; L TS,r ——Ideal expansion work / J; cp——Specific heat capacity at constant pressure of the gas / (J / K / kg); ——Total temperature of the turbine nozzle critical section / K; ——Total temperature at the outlet of the turbine / K; R——Gas constant / (J / K / kg); k——Adiabatic index.

[0111] Analyze the existing high-pressure turbine cooling bleed air technology of aero-engines, summarize different cooling schemes and cooling bleed air injection methods. Considering that the definition range of turbine characteristics is from the nozzle critical section to the turbine outlet, taking the turbine nozzle critical section as the boundary, it is divided into pre-critical section cooling and post-critical section cooling. Analyze the influence of the latter on turbine characteristics through thermodynamic principles, transform it into a flow influence factor μ and an efficiency influence factor ζ, and complete the analysis of the influence mechanism.

[0112] Specifically as follows: Since the injection of cooling bleed air after the nozzle critical section destroys the original flow characteristic law, in order to uniformly describe the flow characteristic law forms of turbines without cooling and cooled turbines again, define the equivalent critical area A of the nozzleCr，eq Among them, the injected cooling bleed air bypasses the critical section, additionally increasing the turbine outlet flow rate, which can be equivalent to the dimensionless density flow rate q characteristic law of the stator vane critical section remaining unchanged, the critical area increasing, and the flow capacity improving. On the contrary, when the post-turbine cooling bleed air system is shut off, it can be equivalent to the reduction of the stator vane critical area and turbine throttling.

[0113]

[0114] Where A Cr，eq —— Equivalent critical area of the stator vane / (m 2 ); Wa5 —— Outlet flow rate of the high-pressure turbine rotor / (kg / s); P 43 * —— Total pressure at the critical section of the high-pressure turbine stator vane / Pa; K —— Constant of formula (25); q —— Dimensionless density flow rate; n cor —— Turbine corrected speed; —— Pressure drop ratio of the total pressure at the inlet and outlet of the turbine; T 43 * —— Total temperature at the critical section of the high-pressure turbine stator vane / K; Wa 43 —— Flow rate at the critical section of the high-pressure turbine stator vane / (kg / s); Wa c2 —— Post-cooling air flow rate at the critical section of the high-pressure turbine stator vane / (kg / s).

[0115] According to the relationship between the definition of the critical area A 43 in formula (24) and the equivalent critical area A Cr，eq in formula (27), the cooling turbine flow rate characteristic Wa cor,eq can be rewritten as:

[0116]

[0117] Where Wa cor,eq —— Equivalent equivalent corrected flow rate; n cor —— Turbine corrected speed; —— Pressure drop ratio of the total pressure at the inlet and outlet of the turbine; Wa 43 —— Flow rate at the critical section of the high-pressure turbine stator vane / (kg / s); Wa c2 —— Post-cooling air flow rate at the critical section of the high-pressure turbine stator vane / (kg / s);

[0118] P 43 * —— Total pressure at the critical section of the high-pressure turbine stator vane / Pa; K —— Constant of formula (25); q —— Dimensionless density flow rate; A Cr，eq —— Equivalent critical area of the stator vane / (m 2 ); A 43 —— Area of the critical section of the stator vane / (m2 ); μ - flow influence factor.

[0119] The efficiency definition of the traditional uncooled turbine (26) ignores the influence of the cooling bleed air. Driven by the cooling bleed air, the turbine rim work L Tr is updated as follows:

[0120]

[0121] where L’ Tr - updated turbine rim work / J; L Tr - traditional uncooled turbine rim work / J; ΔL - additional rim work added to the turbine by the cooling bleed air impact / J; Wa 43 - high-pressure turbine nozzle critical section flow rate / (kg / s); Wa c2 - cooling air flow rate after the high-pressure turbine nozzle critical section / (kg / s); T 43 * - is the total temperature at the high-pressure turbine nozzle critical section / K; T c2 * - is the total temperature of the cooling bleed air / K; - total temperature at the turbine outlet / K; cp - specific heat capacity at constant pressure of the gas / (J / K / kg).

[0122] Therefore, there are also changes in the efficiency definition. Considering the isentropic ideal expansion work L TS，r of the work capacity of multiple gas streams, the generalized turbine efficiency η T,eq is defined as:

[0123]

[0124] where, η T,eq - generalized turbine efficiency; L T,r - rim work / J; L TS,r - ideal expansion work / J; i - are 43, c2 for various different gas flows; cp - specific heat capacity at constant pressure of the gas / (J / K / kg); T i * - corresponding gas total temperature / K; - total temperature at the turbine outlet / K; Wa i - corresponding gas flow rate / (kg / s); k - adiabatic index; R - gas constant / (J / K / kg); P i * - corresponding gas total pressure / Pa; - total pressure at the turbine outlet / Pa.

[0125] Combined with the efficiency definition of the uncooled turbine in formula (26), η T,eq can be equivalently expressed as:

[0126]

[0127] Among them, η T,eq —— Generalized turbine efficiency; n cor —— Turbine corrected speed; —— Pressure drop ratio of total pressure at the inlet and outlet of the turbine; ζ —— Efficiency influence factor; Wa c2 —— Cooling air flow rate after the critical section of the high-pressure turbine guide vane / (kg / s); Wa 43 —— Flow rate of the critical section of the high-pressure turbine guide vane / (kg / s).

[0128] In another embodiment, in step S200, the steps for establishing the high-precision component-level model of the aeroengine are as follows:

[0129] By collecting the ground bench test data of the actual aeroengine, as Figure 7 shown, the test run duration is about 6000s, specifically including the throttle lever angle PLA Figure 7 in (a) during the test run; input parameters Figure 7 in (b) the fan guide vane a1, the compressor guide vane a2, and the main fuel wf; output parameters Figure 7 in (c) the low-pressure speed N1, the high-pressure speed N2, the pressure P 31 after the compressor; the low-pressure turbine outlet temperature T6; and Figure 7 in (d) an obvious cooling bleed air cut-off process between 2100 - 2200s. Combining with the adjustment law of the cooling system of the actual engine, select the steady-state data points in the full-open mode of the high-pressure turbine bleed air as the reference data for modeling. As shown in Table 1, select the intermediate state of the steady-state point test run data as the model design point to establish a high-precision overall engine model in the full-open mode of the high-pressure turbine bleed air.

[0130] Table 1

[0131]

[0132] The modeling accuracy for the steady-state data points in the full-open mode of the bleed air is shown in Table 2. The relative errors of N1 are {-0.04%, -0.03%, -0.05%, -0.73%, -0.75%, -0.17%} respectively, not exceeding 1.0%. The relative errors of N2 are {-0.07%, -0.08%, -0.09%, -0.57%, -1.14%, -0.66%} respectively, approximately around 1.0%. sP 31 The relative errors of are {-0.02%, 0.34%, 0.03%, -0.83%, -1.03%, -1.26%} respectively, approximately around 1.0%. T t6The relative errors are {0.10%, -0.17%, -0.63%, -0.13%, -0.05%, 0.63%} respectively, T t6 The absolute error does not exceed 6.0K, indicating that in the basic stage A, the model and the actual test run data have a good degree of agreement.

[0133]

[0134] In the formula: Γ A (.)——High-precision whole-engine model in the full-open mode of high-pressure turbine bleed air; ——Output parameter vector of the engine in the full-open mode of high-pressure turbine bleed air at time t; ——Input parameter vector; ——State parameter vector.

[0135] Table 2

[0136]

[0137] In another embodiment, in step S300, the steps of extending the model to the bleed air cut-off stage are as follows:

[0138] According to the high-precision whole-engine model Γ A (.) of the full-open mode of high-pressure turbine bleed air, and the steady-state point test run data of the high-pressure turbine bleed air cut-off mode, the extended model calculates the residual error, which is expressed as the following formula

[0139]

[0140] In the formula: τ——Model extension calculation residual error; ——Steady-state point test run data of the engine in the high-pressure turbine bleed air cut-off mode at time t, including input parameters State parameters Output parameters μ——Flow influence factor; ζ——Efficiency influence factor; ——Output parameter vector of the engine in the high-pressure turbine bleed air cut-off mode at time t; Γ A (.)——High-precision whole-engine model in the full-open mode of high-pressure turbine bleed air; ——Input parameter vector; ——State parameter vector.

[0141] In another embodiment, in step S400, the residual error identification algorithm for adjusting the turbine characteristics includes:

[0142] The adjustment optimization objective is to minimize the model extension calculation residual error τ, the adjustable parameters are the flow influence factor μ and the efficiency influence factor ζ, and the optimization constraint range is And It is the steady-state data set of the engine in the high-pressure turbine bleed-off mode at time t. Among them, considering the influence degree of the actual cooling bleed system on the turbine, ζ min = 0.8, ζ max = 1.2, μ min = 0.8, μ max = 1.2:

[0143]

[0144] In the formula: τ—the residual of the model extension calculation; —The steady-state point test run data of the engine in the high-pressure turbine bleed-off mode at time t, including input parameters state parameters output parameters μ—the flow influence factor; ζ—the efficiency influence factor; —The output parameter vector of the engine in the high-pressure turbine bleed-off mode at time t; Γ A (.)—The high-precision overall engine model in the full-open high-pressure turbine bleed mode; —The input parameter vector; —The state parameter vector; μ min —The minimum value of the flow influence factor; μ max —The maximum value of the flow influence factor; ζ min —The minimum value of the efficiency influence factor; ζ max —The maximum value of the efficiency influence factor.

[0145] In another embodiment, in step S400, the residual identification algorithm is iterated by the following method:

[0146] Step S401 initializes the residual identification algorithm: Initialize the initial values of 1.0 for the flow influence factor μ and the efficiency influence factor ζ respectively;

[0147] Step S402 calculates the initial residual: According to the residual calculation formula in step S300, compare the output of the model extension calculation with the actual output parameters of the engine to calculate the residual As shown in Table 3, the initial residuals in three groups of cooling bleed-off states are shown;

[0148] Table 3

[0149]

[0150] Step S403 calculates the gradient: According to the current residual at the nth step The gradient of the adjustment coefficient Optimize to determine the value of the adjustment coefficient for the next iteration Gradient calculation formula:

[0151]

[0152] Wherein: —— The residual gradient of the model extension calculation at time t; —— The partial derivative function; τ(.)—— The residual function of the model extension calculation; Γ A (.)—— The high-precision whole-machine model in the full-open mode of high-pressure turbine bleed air; —— The steady-state point test run data of the engine in the high-pressure turbine bleed air cut-off mode at time t, including input parameters State parameters Output parameters μ—— Flow influence factor; ζ—— Efficiency influence factor;

[0153] Step S404 Update adjustment coefficient: Based on the residual gradient obtained in the above steps, design an adjustment coefficient to update the damping step size, update the adjustment coefficient, and the update formula:

[0154]

[0155] Wherein: —— The flow influence factor and efficiency influence factor obtained by the (n + 1)-th iteration according to the steady-state point test run data at time t; —— The flow influence factor and efficiency influence factor obtained by the n-th iteration according to the steady-state point test run data at time t; λ step —— The adjustment coefficient updates the damping step size to take a number in the range of [0, 1]; Represents the inverse of the gradient matrix calculated in step S403; —— The n-th iteration residual of the model extension calculation at time t.

[0156] Step S405 Residual update: Based on the new adjustment coefficient of the iteration, calculate the residual of the (n + th iteration, and the update formula:

[0157]

[0158] Wherein: —— The (n + 1)-th residual of the model extension calculation at time t; τ(.)—— The residual function of the model extension calculation; Γ A (.)—— The high-precision whole-machine model in the full-open mode of high-pressure turbine bleed air; —— The steady-state point test run data of the engine in the high-pressure turbine bleed air cut-off mode at time t, including input parameters State parameters Output parameters —— The flow influence factor and efficiency influence factor obtained by the (n + 1)-th iteration according to the steady-state point test run data at time t.

[0159] Repeat steps S403 to S405: Repeatedly execute the steps of calculating the gradient, updating the adjustment coefficient, and residual updating until a predetermined number of iterations is reached or the residual function converges. The convergence results are shown in Table 4.

[0160] Table 4

[0161]

[0162] Step S500: Embed the flow rate influence factor μ and the efficiency influence factor ζ described in step S400 into the engine model, and verify it using the remaining steady-state point data of the cooling bleed air cut-off mode in the test run data. The fan speed N1, high-pressure compressor speed N2, and high-pressure compressor outlet pressure sP output by the model 31 , and the low-pressure turbine outlet temperature T t6 The error between the parameters and the test run data is effectively reduced. As Figure 8 shown, it is proved that the model residual extension identification method is feasible, and the identified cooling turbine characteristics have good accuracy.

[0163] Next, the effectiveness of the method described in the present disclosure is verified through simulation experiments.

[0164] First, based on the relationship between the cooling bleed air system and component characteristics of an aeroengine high-pressure turbine, establish a high-precision component-level model of the aeroengine in the full-open bleed air mode based on the design point and multi-steady-state point test run data; secondly, extend the model to the cooling bleed air cut-off stage, estimate the output parameters of the whole machine, and obtain the output parameter residuals; then, design a residual identification algorithm to adjust the turbine characteristics and eliminate various output parameter errors; finally, embed the identified cooling bleed air high-pressure turbine characteristics into the engine whole-machine model for test and comparison. The test data and results are respectively as Figure 7 and Figure 8 shown. It can be seen from the figure that the results of the identified cooling bleed air high-pressure turbine characteristics are basically consistent with the expectations, indicating that the cooling turbine characteristics identification method based on model extension residuals in the present disclosure is effective.

[0165] The above has introduced the present disclosure in detail. Specific examples are used in this article to elaborate on the principle and implementation manner of the present disclosure. The description of the above embodiments is only used to help understand the method and its core idea of the present disclosure; at the same time, for those skilled in the art, according to the idea of the present disclosure, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present disclosure.

Claims

1. A method for identifying the characteristics of a cooling turbine with extended residuals of an aero-engine model, characterized in that, It includes the following steps: Step S100: Analyze the influence mechanism of cooling bleed air on turbine characteristics; Step S200: Based on the above analysis results and test run data, construct a high-precision component-level model of an aero-engine in the full-open bleed air mode; Step S300: Extend the model to the cooling bleed air cut-off stage, estimate the output parameters of the whole engine, and obtain the output parameter residuals; Step S400: Based on the output parameter residuals, design a residual identification algorithm to adjust the turbine characteristics and eliminate various output parameter errors; Step S500: Conduct accuracy verification by combining multiple steady-state data in the cooling bleed air shut-off mode.

2. The method according to claim 1, wherein Preferably, in step S100, the turbine characteristics include the turbine flow characteristics, that is, the converted flow rate Wa through the turbine cor , and its defined formula is as follows: Where: Wa cor —— The corrected flow rate through the turbine; n cor —— The corrected speed of the turbine; —— The pressure ratio of the total pressure at the inlet and outlet of the turbine; Wa 41 —— The physical flow rate of the turbine / (kg / s); —— The total pressure of the critical section of the turbine nozzle / Pa; P std —— The sea-level pressure on a standard day / Pa; —— The total temperature of the critical section of the turbine nozzle / K; T std —— The sea-level temperature on a standard day / K; On the other hand, in a turbine without cooling bleed air, there is the following relationship between the flow characteristics of the turbine and the flow at the critical section of its guide vane: Where: Wa 41 —— Physical flow rate of the turbine / (kg / s); Wa 43 —— Air flow rate through the critical section of the turbine / (kg / s); n cor —— Corrected speed of the turbine; —— Pressure drop ratio of the total pressure at the inlet and outlet of the turbine; q—— Dimensionless mass flow; A 43 —— Area of the critical section of the nozzle guide vane / (m 2 ); —— Total pressure of the critical section of the turbine nozzle guide vane / Pa; —— Total temperature of the critical section of the turbine nozzle guide vane / K; K—— Constant, which can be calculated according to the following formula: In the formula: R - gas constant / (J / K / kg); k - adiabatic index.

3. The method according to claim 1, characterized in that, In Step S100, the turbine characteristics also include the turbine efficiency characteristics, that is, the turbine isentropic efficiency η, and its defined formula is as follows: Where: η——isentropic efficiency of the turbine; n cor ——converted speed of the turbine; ——pressure drop ratio of the total pressure at the inlet and outlet of the turbine; L T,r ——work done on the rim / J; L TS , r——ideal expansion work / J; cp——specific heat capacity at constant pressure of the gas / (J / K / kg); ——total temperature at the critical section of the turbine guide vane / K; ——total temperature at the outlet of the turbine / K; R——gas constant / (J / K / kg); k——adiabatic index.

4. The method according to claim 1, wherein In step S100, the existing high-pressure turbine cooling air extraction technology of aeroengines is analyzed, different cooling schemes and cooling air extraction injection methods are summarized. Starting from the principle of the influence of cooling air extraction on turbine characteristics, considering that the definition range of turbine characteristics is from the critical section of the nozzle guide vane to the turbine outlet, with the critical section of the nozzle guide vane as the boundary, it is divided into pre-critical section cooling and post-critical section cooling, and the equivalent critical area A of the nozzle guide vane is defined. Cr，eq and the generalized turbine efficiency η T,eq , the relationship between the traditional turbine characteristics definitions without cooling is compared, and it is transformed into the flow rate influence factor μ and the efficiency influence factor ζ to complete the analysis of the influence mechanism.

5. The method according to claim 1, wherein In Step S200, the establishment process of the high-precision component-level model of the aero-engine includes: By collecting the ground test stand test run data of the actual aero-engine, combining the adjustment rules of the cooling system of the actual engine, selecting the steady-state data points in the full-open high-pressure turbine bleed air mode as the reference data for modeling, selecting the intermediate state of the steady-state point test run data as the model design point, and combining the thermodynamic calculation method to generate the characteristics of each component to form a high-precision whole-engine model in the full-open high-pressure turbine bleed air mode.

6. The method according to claim 1, characterized in that In Step S300, the steps of extending the model to the bleed air cut-off stage include: According to the high-precision whole-engine model in the full-open high-pressure turbine bleed air mode and the steady-state point test run data in the high-pressure turbine bleed air cut-off mode, extend the model to calculate the residuals, as shown in the following formula: Where: Γ A (.)——High-precision whole-engine model in the full-open high-pressure turbine bleed air mode; ——Output parameter vector of the engine in the full-open high-pressure turbine bleed air mode at time t; ——Input parameter vector; ——State parameter vector.

7. The method according to claim 1, characterized in that, In Step S400, the adjustment of the turbine characteristics by the residual identification algorithm includes: The adjustment and optimization objective is to minimize the model extension calculation residual τ, the adjustable parameters are the flow rate influence factor μ and the efficiency influence factor ζ, and the optimization constraint range is and Steady-state data set of the high-pressure turbine bleed-off mode engine: where: τ——residual of model extension calculation; ——steady-state point test data of the engine in the high-pressure turbine bleed-off mode at time t, including input parameters state parameters output parameters μ——flow influence factor; ζ——efficiency influence factor; ——output parameter vector of the engine in the high-pressure turbine bleed-off mode at time t; Γ A (.)——high-precision whole-engine model in the high-pressure turbine fully open mode; ——input parameter vector; ——state parameter vector; μ min ——minimum value of flow influence factor; μ max ——maximum value of flow influence factor; ζ min ——minimum value of efficiency influence factor; ζ max ——maximum value of efficiency influence factor.

8. A cooling turbine characteristic identification system for the extension residuals of an aero-engine model, comprising: An analysis module, used to analyze the influence mechanism of cooling bleed air on turbine characteristics; A construction module, used to construct a high-precision component-level model of an aero-engine in the full-open bleed air mode according to the above analysis results and test run data; An acquisition module, used to obtain the output parameter residuals through the output parameters of the whole engine; An elimination module, used to design a residual identification algorithm according to the output parameter residuals to adjust the turbine characteristics and eliminate various output parameter errors; A verification module, used to conduct accuracy verification by combining multiple steady-state data in the cooling bleed air shut-off mode.

9. A computer storage medium, wherein, The storage medium includes computer instructions, which when running on a computer, cause the computer to execute the method according to any one of claims 1 to 7.

10. An electronic device, wherein, The electronic device includes: a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein when the processor executes the program, it implements the method according to any one of claims 1 to 7.

Images