Rotor system dynamics optimization method based on perturbation principle

Abstract

The invention belongs to the technical field of dynamics optimization. The invention provides a perturbation principle-based rotor system dynamics optimization method. According to the embodiment of the invention, the corresponding adjustable parameters can be determined according to the energy distribution condition of the birotor-supporting system substructure of the aero-engine under the condition that dynamic repeated iterative calculation is not needed, so that dynamic optimization is implemented, the energy of the system substructure is redistributed, and the optimization effect is achieved. The method is particularly used for optimizing a complex high-dimension aero-engine rotor system, time cost and labor cost needed by a traditional algorithm optimization method are greatly saved, and the method can play a certain role in dynamic related design of aero-engines or gas turbines and other rotating machines.

Description

Technical Field

[0001] The disclosed embodiments relate to the technical field of dynamics optimization, and in particular to a rotor system dynamics optimization method based on the perturbation principle. Background Art

[0002] Aircraft engines are core components of modern aviation engineering, and their performance and reliability are crucial to the safe operation of aircraft. With the continuous development of the aviation industry and the rapid growth of global air traffic, the demand for the optimization of aircraft engines is becoming increasingly urgent. The system structure of advanced aircraft engines / gas turbines is relatively complex, and there are many factors that cause the vibration of the entire engine. There is vibration coupling between rotors and between rotors and supporting structures. The structural state is difficult to predict, and dynamic analysis is difficult and troubleshooting is difficult. Therefore, in the design stage of aircraft engines, it is necessary to meet the requirements of vibration specifications, that is, to mainly evaluate the critical speed and energy distribution of the dual rotor-support system, minimize the sensitivity of the entire machine vibration and avoid harmful resonance.

[0003] The optimization design of rotor dynamic characteristics is mostly based on parameter optimization of mathematical algorithms, with unclear physical meanings, insufficient attention to the intrinsic relationship between optimization targets and optimization variables, and the use of pure algorithms for dynamic optimization, which is time-consuming and labor-intensive. Especially for high-dimensional rotor system models, the time from modeling to dynamic calculation is long. If traditional optimization algorithms are used for dynamic optimization iterative calculations, the cost is too high. Strain energy analysis in energy analysis has always been an indispensable part of the design and dynamics research of aircraft engine rotor systems. The energy-based optimization design of rotor dynamic characteristics is based on energy analysis, and gives the influence of optimization variables (structural parameters) on the optimization targets. The physical meaning is clear and easy to understand. In the gas turbine engine structural design criteria, the design requirements of the rotor system point out that in order to reduce the sensitivity of the unbalanced vibration response of the rotor system and avoid instability caused by self-excited vibration of the rotor system, strain energy analysis should be performed on the rotor-support-casing system.

[0004] In the related technologies, Ren Guangming et al. from Beihang University first used the strain energy analysis method to study the dynamics of complex rotor casing systems in “Strain Energy Analysis of Complex Rotor Casing Systems Using the Overall Transfer Matrix Method [J]. Journal of Aerospace Power, 1997, 12(1): 87-89+111.” Zhang Dayi et al. used the whole machine three-dimensional model to model the twin-rotor turbofan engine in “Establishment of Aeroengine Whole Machine Dynamics Model and Analysis of Vibration Characteristics [J]. Propulsion Technology, 2015, 36(5): 768-773.” and calculated and analyzed its vibration characteristics using the strain energy analysis method. Zheng Xudong et al. conducted a vibration study on the rotor-support-casing system in “Vibration Characteristics and Strain Energy Calculation and Analysis of Aeroengine Whole Machine [J]. Aeroengine, 2000, 26(2): 42-46.” They used the overall transfer matrix method to calculate the whole machine vibration characteristics and strain energy distribution of a certain type of counter-rotating engine. In “Vibration characteristic investigation of counter-rotating dual-rotor in aero-engine [J]. Transactions of Nanjing University of Aeronautics and Astronautics, 2012, 29(01): 33-39,” Feng Guoquan et al. from the China Aero Engine Corporation used the energy method to optimize the dynamics of a certain type of aircraft engine and conducted experimental verification.

[0005] Most aero-engines use strain energy analysis for dynamic analysis and optimization. This method can represent the modal characteristics of the rotor system to a certain extent and is a characterization of the stiffness characteristics of the rotor system. However, it lacks the characterization of the rotor inertia, and it is incomplete to use only strain energy for dynamic optimization. Therefore, kinetic energy and strain energy analysis methods should be used together as research methods for dynamic optimization.

[0006] Therefore, it is necessary to improve one or more problems existing in the above-mentioned related technical solutions.

[0007] It should be noted that this section is intended to provide background or context for the technical solutions of the present disclosure stated in the claims. The description herein is not admitted to be prior art by virtue of being included in this section. Summary of the invention

[0008] The purpose of the embodiments of the present disclosure is to provide a rotor system dynamics optimization method based on the perturbation principle, thereby overcoming one or more problems caused by the limitations and defects of the related art at least to a certain extent.

[0009] According to an embodiment of the present disclosure, a rotor system dynamics optimization method based on the perturbation principle is provided, the method comprising: Simplify and model the rotor-support system of an aircraft engine, and calculate the critical speeds of each order; According to the critical speeds of each order and the design speed, the critical speed to be optimized and the non-optimized critical speed are screened out; Dividing the rotor-support system of the aircraft engine into substructures, combining the critical speeds to be optimized and the non-optimized critical speeds of each order, so as to obtain the energy proportion of each substructure at the critical speeds to be optimized and the energy proportion of each substructure at the non-optimized critical speed; Determine the objective function of the optimization design based on the critical speed ratios to be optimized for each order and the corresponding energy proportion of the substructure, and determine the constraint function of the optimization design based on the non-optimized critical speed ratios for each order and the corresponding energy proportion of the substructure; Determine the optimization parameters and optimization range of the optimization parameters according to engineering design requirements; Based on the objective function, the constraint function, the optimization parameter and the optimization range of the optimization parameter, a dynamic optimization process is performed using an optimization algorithm to determine the change amount of the optimization parameter to form an initial optimization scheme; The initial optimization scheme is dynamically verified to determine whether the modal speed in the initial optimization scheme meets the preset vibration criterion requirements. If so, the initial optimization scheme is output as the target optimization scheme; otherwise, the optimization is continued.

[0010] Furthermore, the steps of simplifying the structure of the rotor-support system of the aircraft engine and calculating the critical speeds of each order thereof include: Simplifying the structure of the aircraft engine rotor-support system; Construct a Mechanical APDL finite element model based on the system's material characteristic data, structural characteristic data, support characteristic data, and speed characteristic data; Based on the Mechanical APDL finite element model, calculate the Campbell diagram, modal speed and modal formation; According to the Campbell diagram, determining the local monotonicity of the dynamic frequency line, and calculating the gyro kinetic energy at each modal speed according to the modal speed; The local monotonicity of the dynamic frequency line and the gyro kinetic energy of each modal speed are matched to obtain the critical speed of each order.

[0011] Furthermore, the step of dividing the aero-engine rotor-support system into substructures includes: The aircraft engine rotor-support system is divided into a plurality of substructures; wherein the substructures at least include blade disk components, shaft components and support components.

[0012] Furthermore, the energy calculation expression of the blade disk component is:

[0013] in, i Indicates the order, j Indicates the substructure number, is the kinetic energy of the blade disk, which includes mass kinetic energy, diameter moment of inertia kinetic energy and gyroscopic kinetic energy; For the i The quality of the blade disk components of the first stage, for x The speed of the direction, for y The speed of the direction, is the diameter moment of inertia, is the polar moment of inertia, for x Direction swing angle, for y Direction swing angle, is the axial angular velocity; The energy calculation expression of the rotating shaft components is:

[0014]

[0015] in, is the kinetic energy of the shaft, is the shaft material density, is the cross-sectional area of ​​the shaft, is the moment of inertia of the axial section, for x Direction swing angle, for y Direction swing angle; is the shaft strain energy, is the cross-sectional bending stiffness of the shaft, is Poisson's ratio, is the cross-sectional shear stiffness of the shaft, and The axes are x and y The partial derivative of the displacement in the axial direction; The energy calculation expression of the supporting components is:

[0016] in, is the total support strain energy of the system, For the i Pivot Points x The support stiffness in the direction, For the i Pivot Points y The support stiffness in the direction.

[0017] Furthermore, the method further comprises: According to the energy perturbation principle, the relationship between the substructure energy of the rotor-support system of the aircraft engine and the critical speed is obtained; Based on the relationship between the substructure energy and the critical speed of the aircraft engine rotor-support system, the critical speeds to be optimized and the non-optimized critical speeds of each order are combined to obtain a first energy proportion of each substructure at the critical speeds to be optimized of each order and a second energy proportion of each substructure at the non-optimized critical speed; The relationship between the substructure energy of the aero-engine rotor-support system and the critical speed is expressed as follows:

[0018] in, is the critical speed after structural change, is the critical speed before structural change, is the substructure code of the rotor-support system, and are the strain energy and kinetic energy of each substructure after the rotor-support structure changes, and They are the strain energy and equivalent kinetic energy of each substructure before the rotor-support structure changes.

[0019] Furthermore, the expression of the critical speed ratio to be optimized for each order is:

[0020] in, is the critical speed ratio, , represents the strain energy ratio of the substructure, represents the substructure kinetic energy ratio, represents the proportion of substructure strain energy, represents the proportion of substructure kinetic energy, represents the structural optimization proportional coefficient, , , .

[0021] Furthermore, the objective function is expressed as:

[0022] in, is the substructure strain energy ratio, is the strain energy corresponding to each substructure at the critical speed to be optimized, To optimize the ratio of front and rear critical speeds, is the substructure kinetic energy ratio, is the kinetic energy corresponding to each substructure at the critical speed to be optimized, For the i The critical speed to be optimized is For the i The target critical speed of the stage is based on the critical speed requirements of aircraft engines. ≥ 1.2 , The design speed includes the slow speed, the design point speed and the maximum speed; The expression of the constraint function is:

[0023] in, To optimize the i The ratio of the critical speeds of the order not to be optimized, is the strain energy proportion of each substructure under the non-critical speed to be optimized, It is the kinetic energy proportion of each substructure under the non-critical speed to be optimized.

[0024] Further, based on the objective function, the constraint function, the optimization parameter and the optimization range of the optimization parameter, the step of performing a dynamic optimization process using an optimization algorithm to determine the change amount of the optimization parameter to form an optimization scheme includes: When each parameter changes, the energy proportion coefficient of each substructure is determined according to the optimization parameter and the optimization range of the optimization parameter; The energy proportion coefficient of the substructure is substituted into the objective function and continuously iterated and screened until the constraint function is satisfied to obtain an optimization solution.

[0025] Furthermore, the substructure kinetic energy ratio coefficient corresponding to the mass kinetic energy is:

[0026] in, represents the critical speed, and The mass kinetic energy expressed before and after optimization, represents the substructure mass, represents the change in the mass of the substructure; The substructure kinetic energy ratio corresponding to the kinetic energy of the diameter moment of inertia is:

[0027] in, and Respectively represent the kinetic energy of the diameter moment of inertia before and after optimization, represents the moment of inertia of the substructure diameter, Indicates the change in the moment of inertia of the substructure diameter; The substructure kinetic energy proportion coefficient corresponding to the gyro kinetic energy is:

[0028] in, and Respectively represent the polar moment of inertia kinetic energy before and after optimization, represents the polar moment of inertia of the substructure, Represents the change in the polar moment of inertia of the substructure; The substructure kinetic energy ratio corresponding to the shaft kinetic energy is:

[0029] in, and Respectively represent the optimization of the kinetic energy of the front and rear axles, d , D , Δ d , Δ D Indicates the outer diameter of the shaft and its change, and Indicates the length of the axis and its change; The substructure strain energy ratio corresponding to the rotation axis strain energy is:

[0030] in, and Respectively represent the strain energy of the optimized front and rear axles, represents the elastic modulus, 、 represents the interface inertia moment of the axis and its change, and Indicates the length of the axis and its change; The substructure strain energy ratio corresponding to the support strain energy is:

[0031] in, and denote the strain energy of the support before and after optimization, 、 Indicates the support stiffness of the shaft and its change.

[0032] The technical solution provided by the embodiments of the present disclosure may have the following beneficial effects: In the embodiments of the present disclosure, through the above-mentioned rotor system dynamics optimization method based on the perturbation principle, on the one hand, the method can determine the corresponding adjustable parameters for dynamics optimization and redistribute the system substructure energy distribution for the dual rotor-support system of the aircraft engine without repeated dynamics iterative calculations, and then achieve optimization results. On the other hand, the method is particularly optimized for complex and high-dimensional aircraft engine rotor systems, saving the time and labor costs required by traditional optimization methods, and can play a certain role in the dynamics-related design of rotating machinery such as aircraft engines or gas turbines. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings herein are incorporated into the specification and constitute a part of the specification, illustrate embodiments consistent with the present disclosure, and together with the specification are used to explain the principles of the present disclosure. Obviously, the accompanying drawings described below are only some embodiments of the present disclosure, and for ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without creative work.

[0034] Figure 1 A step diagram showing a rotor system dynamics optimization method based on the perturbation principle in an exemplary embodiment of the present disclosure; Figure 2 A specific flow chart of a rotor system dynamics optimization method based on the perturbation principle in an exemplary embodiment of the present disclosure is shown; Figure 3 A schematic diagram showing the substructure division of an aircraft engine rotor system in an exemplary embodiment of the present disclosure is shown; Figure 4 The strain energy distribution of each substructure in different modes under low-pressure rotor excitation in an exemplary embodiment of the present disclosure is shown; Figure 5 The kinetic energy distribution of each substructure in different modes under low-pressure rotor excitation in an exemplary embodiment of the present disclosure is shown; Figure 6 The strain energy distribution of each substructure in different modes under high-pressure rotor excitation in an exemplary embodiment of the present disclosure is shown; Figure 7 The kinetic energy distribution of each substructure in different modes under high-pressure rotor excitation in an exemplary embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0035] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that the disclosure will be more comprehensive and complete and to fully convey the concepts of the example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0036] In addition, the accompanying drawings are only schematic illustrations of the embodiments of the present disclosure and are not necessarily drawn to scale. The same reference numerals in the figures represent the same or similar parts, and their repeated descriptions will be omitted. Some of the block diagrams shown in the accompanying drawings are functional entities and do not necessarily correspond to physically or logically independent entities.

[0037] In this example implementation, a rotor system dynamics optimization method based on the perturbation principle is provided. Figure 1 As shown in , the rotor system dynamics optimization method based on the perturbation principle may include: steps S101 to S107.

[0038] Step S101: simplifying the structure of the rotor-support system of the aircraft engine and modeling it, and calculating the critical speeds of each order; Step S102: screening out the critical speed to be optimized and the non-optimized critical speed according to the critical speeds of each order and the design speed; Step S103: dividing the aircraft engine rotor-support system into substructures, combining the critical speeds to be optimized and the non-optimized critical speeds of each order, so as to obtain the energy proportion of each substructure at the critical speeds to be optimized and the energy proportion of each substructure at the non-optimized critical speed; Step S104: determining an objective function of the optimization design based on the critical speed ratios to be optimized for each order and the corresponding energy proportion of the substructure, and determining a constraint function of the optimization design based on the non-optimized critical speed ratios for each order and the corresponding energy proportion of the substructure; Step S105: Determine optimization parameters and optimization ranges of optimization parameters according to engineering design requirements; Step S106: Based on the objective function, the constraint function, the optimization parameters and the optimization range of the optimization parameters, an optimization algorithm is used to perform a dynamic optimization process, and a change amount of the optimization parameters is determined to form an initial optimization scheme; Step S107: Performing dynamic verification on the initial optimization scheme to determine whether the modal speed in the initial optimization scheme meets the preset vibration criterion requirement. If so, outputting the initial optimization scheme as the target optimization scheme.

[0039] Through the above-mentioned rotor system dynamics optimization method based on the perturbation principle, on the one hand, this method can determine the corresponding adjustable parameters for dynamics optimization and redistribute the system substructure energy distribution for the dual rotor-support system of the aircraft engine without repeated dynamics iteration calculations, and then achieve optimization results. On the other hand, this method is particularly effective in optimizing complex and high-dimensional aircraft engine rotor systems, saving the time and labor costs required by traditional optimization methods, and can play a certain role in the dynamics-related design of rotating machinery such as aircraft engines or gas turbines.

[0040] Next, we will refer to Figures 1 to 7 Each step of the rotor system dynamics optimization method based on the perturbation principle in this example implementation is described in more detail.

[0041] In step S101, Figure 2 The figure shows a specific flow chart of the rotor system dynamics optimization method based on the perturbation principle. The rotor-support system of an aero-engine is structurally simplified, and its critical speeds of each order are calculated.

[0042] Specifically, first, simplify the structure of the aircraft engine rotor-support system, and model the rotor-support system based on the engine material characteristic data, structural characteristic data and support characteristic data; generate a data file based on the material characteristic data, structural characteristic data, support characteristic data and speed characteristic data, and then use MATLAB to convert the data file to generate a parameterized command file. Generate a Mechanical APDL finite element model based on the parameterized command file, and perform modal calculation on the Mechanical APDL finite element model to obtain the Campbell diagram, modal speed and modal formation. Determine the local monotonicity of the dynamic frequency line based on the Campbell diagram, and calculate the corresponding gyro kinetic energy based on the modal speed; correspond the local monotonicity of the dynamic frequency line and the gyro kinetic energy at each modal speed to obtain the critical speed of each order.

[0043] In step S102 and step S103, if Figure 2 As shown, according to the critical speed and design speed of each order, the critical speed to be optimized and the non-optimized critical speed of each order are screened out; the aircraft engine rotor-support system is divided into substructures, and combined with the critical speeds to be optimized of each order, the energy proportion of each substructure under the critical speed to be optimized of each order is obtained.

[0044] Specifically, the critical speed within 20% of the design speed is screened out, and the safe speed outside the margin is used as the optimization target.

[0045] like Figure 3As shown, the aircraft engine rotor-support system is divided into several substructures; wherein the substructures include at least blade disk components, shaft components and support components; blade disk components include fans, compressors, high-pressure turbines and low-pressure turbines; shaft components include high-pressure turbine shafts, low-pressure turbine shafts, fans and compressor drums; support components include bearings and support structures connected to the bearings.

[0046] The energy of each substructure is calculated using energy analysis; 1) The four major components of the fan, compressor, high-pressure turbine and low-pressure turbine are mainly blade disks, and their energy expression is: (1) Kinetic energy of blade and its mass Diameter moment of inertia and polar moment of inertia There is a positive correlation.

[0047] 2) The high-pressure turbine shaft, low-pressure turbine shaft, and the drums of the fan and compressor are all rotating shaft components, and their energy expressions are: a. Kinetic energy: (2) When the speed and vibration mode remain unchanged, the kinetic energy of the shaft is proportional to the mass and moment of inertia of the shaft.

[0048] b. Strain energy: (3) The strain energy of the shaft is positively correlated with the bending stiffness of the shaft.

[0049] 3) The supporting components are mainly bearings and supporting structures connected to the bearings, and their strain energy expression is: (4) The strain energy of a support is proportional to its support stiffness ki .

[0050] The problem of small changes in structural parameters causing changes in structural vibration characteristics is of great significance to the optimal design of engineering structures. The perturbation principle can be used to obtain the relative variation expression of the natural frequency of the rotor system: (5) The natural frequency relationship before and after the rotor-support system structure change can be further obtained: (6) (7) Where: ω is the natural frequency after the structural change, ω0 is the natural frequency before the structural change, j It is the substructure code of the rotor-support system. and are the strain energy and kinetic energy of each substructure after the rotor-support structure changes, and are the strain energy and kinetic energy of each substructure before the rotor-support structure changes.

[0051] Substituting the kinetic energy into the formula, we get: (8) in: Optimize the scale factor for the structure, that is: .make , , According to the perturbation principle, we have: (9) Express each absolute energy as a relative quantity, that is: (10) in: is the speed ratio between the new structure and the original structure; represents the coefficient of strain energy proportion of the substructure; represents the coefficient of substructure kinetic energy share; represents the relative strain energy of the substructure; It indicates the relative kinetic energy of the substructure. From the above formula, it can be seen that when the speed ratio and the proportion of strain energy and kinetic energy of each substructure are known, the corresponding proportion coefficients of strain energy and kinetic energy can be deduced, thereby guiding the relative optimization amount of the substructure.

[0052] In step S104 and step S105, the objective function of the optimization design is determined based on the critical speed to be optimized and the energy proportion of the rotor system substructure, and the constraint function of the optimization design is determined based on the non-optimized critical speed and the energy proportion of the rotor system substructure; the optimization parameters and the optimization range of the optimization parameters are determined according to the engineering design requirements.

[0053] Specifically, the expression of the objective function is: (11) in: Indicates the first i Critical speed. is the target critical speed of the i-th order. According to the critical speed requirements of aircraft engines, ≥ 1.2 ( Indicates the design speed, including: slow speed, design point speed and maximum speed).

[0054] This function represents the dynamic optimization objective function under high-pressure rotor excitation or low-pressure rotor excitation. The number of objectives is determined according to the number of critical speeds to be adjusted: when the critical speed to be adjusted is one, the optimization problem is a single-objective optimization problem; when the critical speed to be adjusted is multiple, the optimization problem becomes a multi-objective optimization problem. When the target critical speed is determined, the function value ≥ 0, it is considered that the first i The critical speed meets the vibration requirements of aircraft engines.

[0055] Constraint function. The critical speeds not involved in the optimization all meet the dynamic design requirements, that is, the critical speeds of each order are within the safe range of the design speed.

[0056] (12) in: , They represent the relative strain energy and kinetic energy of each substructure without participating in the optimization critical speed. It is the engine design speed, including: idle speed, design point speed and maximum speed.

[0057] Optimizing design parameters 1) Parameters corresponding to strain energy terms: a) The strain energy of a support is proportional to its support stiffness k ; b) The strain energy of the shaft is proportional to the stiffness of the shaft ; 2) The parameters corresponding to the kinetic energy term mainly include three items, namely, the mass kinetic energy term, the diameter moment of inertia kinetic energy term and the polar moment of inertia kinetic energy term: a) The mass kinetic energy of a blade is proportional to its mass , the kinetic energy of the diameter moment of inertia is proportional to its diameter moment of inertia , the polar moment of inertia kinetic energy is proportional to its polar moment of inertia ; b) The mass kinetic energy of the shaft is proportional to the mass of the shaft , the kinetic energy of the diameter moment of inertia is proportional to its diameter moment of inertia , the polar moment of inertia kinetic energy is proportional to its polar moment of inertia .

[0058] In step S106 and step S107, based on the objective function, constraint function, optimization parameters and optimization range of the optimization parameters, the optimization algorithm is used to perform a dynamic optimization process to determine the change in the optimization parameters to form an initial optimization scheme; the initial optimization scheme is dynamically verified to determine whether the modal speed in the initial optimization scheme meets the preset vibration criterion requirements. If so, the initial optimization scheme is output as the target optimization scheme.

[0059] Specifically, when each parameter changes, the energy proportion coefficient of each substructure is determined according to the optimization parameter and the optimization range of the optimization parameter; 1) The strain energy of the support. The strain energy of the support is proportional to its support stiffness. , then the substructure strain energy ratio corresponding to the support strain energy term is: (13) 2) The strain energy of the shaft segment is proportional to the stiffness of the shaft , then the substructure strain energy ratio corresponding to the axis strain energy term is: (14) 3) The kinetic energy of the blade disk consists of three parts: mass kinetic energy, diameter moment of inertia kinetic energy and gyroscopic kinetic energy.

[0060] The mass kinetic energy of the blade is proportional to its mass , then the substructure kinetic energy ratio corresponding to the mass kinetic energy term of the blade disk is: (15) The kinetic energy of the blade's diameter moment of inertia is proportional to its diameter moment of inertia , then the substructure kinetic energy ratio corresponding to the inertia kinetic energy term of the blade disk is: (16) The gyroscopic kinetic energy of the blade is proportional to its extreme moment of inertia , then the substructure kinetic energy ratio corresponding to the gyroscopic kinetic energy term of the blade disk is: (17) 4) Kinetic energy of the shaft segment The kinetic energy of the shaft is proportional to the mass of the shaft , then the substructure kinetic energy ratio corresponding to the kinetic energy term of the axis is: (18) The energy proportion of each substructure of the model and the critical speed of each order are known, and the optimized critical speed, optimization design target and optimization design objective function are determined. When each parameter changes, the substructure energy proportion coefficient is determined, brought into the objective function, and iterated screening is continuously carried out until the optimization constraints are met and the optimization result is obtained.

[0061] At this point, the dynamic optimization method of the aircraft engine rotor system based on the energy perturbation principle has been established. The kinetic energy and strain energy of each substructure are parameterized. The dynamic optimization of the rotor-support system is based on the energy method, with the support stiffness, shaft stiffness, disk mass and shaft mass as optimization parameters. The parameters are adjusted within the allowable range of engineering design to achieve the optimal design of vibration characteristics.

[0062] In a specific embodiment, in order to make the technical solution and advantages of the present invention more clear, the specific implementation mode of the present invention is given below and further described in detail with reference to the accompanying drawings.

[0063] The rotor-support system of an aircraft engine is structurally simplified and its critical speeds of each order are calculated. The critical speeds within 20% of the design speed are selected, and the safe speed outside the margin is used as the optimization target. Determine the optimization parameters and parameter optimization range according to engineering design requirements; Divide the aircraft engine rotor-support system into substructures, such as Figure 3 As shown, the strain energy and kinetic energy distribution of each substructure at each critical speed are calculated, as shown in Figures 4 to 7 As shown. Among them, Figure 4 The strain energy distribution of each substructure under different modes of low-pressure rotor excitation; Figure 5 The kinetic energy distribution of each substructure in different modes under low-pressure rotor excitation; Figure 6 The strain energy distribution of each substructure in different modes under high-pressure rotor excitation; Figure 7 This is the kinetic energy distribution of each substructure in different modes under high-pressure rotor excitation.

[0064] Establish the engine objective function and constraint function according to the optimization target and optimization parameters; Use optimization algorithms (such as genetic algorithms, etc.) to perform dynamic optimization, determine the changes in structural optimization parameters, and form an optimization plan; Perform dynamic calculations for the optimization scheme to verify whether the speed of each modal order meets the vibration criteria requirements of the aircraft engine rotor system; The vibration of the optimized solution meets the standard and the optimization process ends.

[0065] Through the above-mentioned rotor system dynamics optimization method based on the perturbation principle, on the one hand, this method can determine the corresponding adjustable parameters for dynamics optimization and redistribute the system substructure energy distribution for the dual rotor-support system of the aircraft engine without repeated dynamics iteration calculations, and then achieve optimization results. On the other hand, this method is particularly effective in optimizing complex and high-dimensional aircraft engine rotor systems, saving the time and labor costs required by traditional optimization methods, and can play a certain role in the dynamics-related design of rotating machinery such as aircraft engines or gas turbines.

[0066] It should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc. in the above description indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present disclosure and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present disclosure.

[0067] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present disclosure, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0068] In the embodiments of the present disclosure, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present disclosure can be understood according to specific circumstances.

[0069] In the embodiments of the present disclosure, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features not being in direct contact but being in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes the first feature being directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0070] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification.

[0071] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the invention disclosed herein. This application is intended to cover any modification, use or adaptation of the present disclosure, which follows the general principles of the present disclosure and includes common knowledge or customary techniques in the art that are not disclosed in the present disclosure. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present disclosure are indicated by the appended claims.

Claims

1. A rotor system dynamics optimization method based on perturbation principle, characterized in that: The method includes: Simplify and model the rotor-support system of an aircraft engine, and calculate the critical speeds of each order; According to the critical speeds of each order and the design speed, the critical speed to be optimized and the non-optimized critical speed are screened out; Dividing the aircraft engine rotor-support system into substructures, combining the critical speeds to be optimized and the non-optimized critical speeds of each order, so as to obtain the energy proportion of each substructure at the critical speeds to be optimized and the energy proportion of each substructure at the non-optimized critical speed; Based on the critical speed ratios to be optimized for each order and the energy proportion of the engine substructure, an objective function of the optimization design is determined, and based on the non-optimized critical speed ratios for each order and the non-optimized critical speed, a constraint function of the optimization design is determined; Determine the optimization parameters and optimization range of the optimization parameters according to engineering design requirements; Based on the objective function, the constraint function, the optimization parameter and the optimization range of the optimization parameter, a dynamic optimization process is performed using an optimization algorithm to determine the change amount of the optimization parameter to form an initial optimization scheme; The initial optimization scheme is dynamically verified to determine whether the modal speed in the initial optimization scheme meets the preset vibration criterion requirements. If so, the initial optimization scheme is output as the target optimization scheme; otherwise, the optimization is continued.

2. The rotor system dynamics optimization method based on the perturbation principle according to claim 1 is characterized in that: The steps of simplifying the structure of the rotor-support system of an aircraft engine and calculating the critical speeds of each order thereof include: Simplifying the structure of the aircraft engine rotor-support system; Construct a Mechanical APDL finite element model based on the system's material characteristic data, structural characteristic data, support characteristic data, and speed characteristic data; Based on the Mechanical APDL finite element model, calculate the Campbell diagram, modal speed and modal formation; According to the Campbell diagram, determining the local monotonicity of the dynamic frequency line, and calculating the gyro kinetic energy at each modal speed according to the modal speed; The local monotonicity of the dynamic frequency line and the gyro kinetic energy of each modal speed are matched to obtain the critical speed of each order.

3. The rotor system dynamics optimization method based on the perturbation principle according to claim 2 is characterized in that: The step of dividing the aero-engine rotor-support system into substructures comprises: The aircraft engine rotor-support system is divided into a plurality of substructures; wherein the substructures at least include blade disk components, shaft components and support components.

4. The rotor system dynamics optimization method based on the perturbation principle according to claim 3 is characterized in that: The energy calculation expression of the blade disk component is: in, i Indicates the order, j Indicates the substructure number, is the kinetic energy of the blade disk, which includes mass kinetic energy, diameter moment of inertia kinetic energy and gyroscopic kinetic energy; For the i The quality of the blade disk components of the first stage, for x The speed of the direction, for y The speed of the direction, is the diameter moment of inertia, is the polar moment of inertia, for x Direction swing angle, for y Direction swing angle, is the axial angular velocity; The energy calculation expression of the rotating shaft components is: in, is the kinetic energy of the shaft, is the shaft material density, is the cross-sectional area of ​​the shaft, is the moment of inertia of the axial section, for x Direction swing angle, for y Direction swing angle; is the shaft strain energy, is the cross-sectional bending stiffness of the shaft, is Poisson's ratio, is the cross-sectional shear stiffness of the shaft, and The axes are x and y The partial derivative of the displacement in the axial direction; The energy calculation expression of the supporting components is: in, is the total support strain energy of the system, For the i Pivot Points x The support stiffness in the direction For the i Pivot Points y The support stiffness in the direction.

5. The rotor system dynamics optimization method based on the perturbation principle according to claim 4 is characterized in that: The method further includes: According to the energy perturbation principle, the relationship between the substructure energy of the rotor-support system of the aircraft engine and the critical speed is obtained; Based on the relationship between the substructure energy and the critical speed of the aircraft engine rotor-support system, the energy proportion of each substructure at the critical speed to be optimized and the energy proportion of each substructure at the non-optimized critical speed are obtained by combining the critical speeds to be optimized and the non-optimized critical speeds of each order; The relationship between the substructure energy of the aero-engine rotor-support system and the critical speed is expressed as follows: in, is the critical speed after structural change, is the critical speed before structural change, is the substructure code of the rotor-support system, and are the strain energy and kinetic energy of each substructure after the rotor-support structure changes, and They are the strain energy and equivalent kinetic energy of each substructure before the rotor-support structure changes.

6. The rotor system dynamics optimization method based on the perturbation principle according to claim 5 is characterized in that: The expression of the critical speed ratio to be optimized for each order is: in, is the critical speed ratio, , represents the strain energy ratio of the substructure, represents the substructure kinetic energy ratio, represents the proportion of substructure strain energy, represents the proportion of substructure kinetic energy, represents the structural optimization proportional coefficient, , , .

7. The rotor system dynamics optimization method based on the perturbation principle according to claim 6 is characterized in that: The expression of the objective function is: in, is the substructure strain energy ratio, is the strain energy corresponding to each substructure at the critical speed to be optimized, To optimize the ratio of front and rear critical speeds, is the substructure kinetic energy ratio, is the kinetic energy corresponding to each substructure at the critical speed to be optimized, For the i The critical speed to be optimized is For the i The target critical speed of the stage is based on the critical speed requirements of aircraft engines. ≥ 1.2 , The design speed includes the slow speed, the design point speed and the maximum speed; The expression of the constraint function is: in, To optimize the i The ratio of the critical speeds of the order not to be optimized, is the strain energy proportion of each substructure under the non-critical speed to be optimized, It is the kinetic energy proportion of each substructure under the non-critical speed to be optimized.

8. The rotor system dynamics optimization method based on the perturbation principle according to claim 7 is characterized in that: Based on the objective function, the constraint function, the optimization parameter and the optimization range of the optimization parameter, the step of performing a dynamic optimization process using an optimization algorithm to determine the change amount of the optimization parameter to form an optimization scheme includes: When each parameter changes, the energy proportion coefficient of each substructure is determined according to the optimization parameter and the optimization range of the optimization parameter; The energy proportion coefficient of the substructure is substituted into the objective function and continuously iterated and screened until the constraint function is satisfied to obtain an optimization solution.

9. The rotor system dynamics optimization method based on the perturbation principle according to claim 8 is characterized in that: The substructure kinetic energy ratio coefficient corresponding to the mass kinetic energy is: in, represents the critical speed, and The mass kinetic energy expressed before and after optimization, represents the substructure mass, represents the change in the mass of the substructure; The substructure kinetic energy ratio corresponding to the kinetic energy of the diameter moment of inertia is: in, and Respectively represent the kinetic energy of the diameter moment of inertia before and after optimization, represents the moment of inertia of the substructure diameter, Indicates the change in the moment of inertia of the substructure diameter; The substructure kinetic energy proportion coefficient corresponding to the gyro kinetic energy is: in, and Respectively represent the polar moment of inertia kinetic energy before and after optimization, represents the polar moment of inertia of the substructure, Represents the change in the polar moment of inertia of the substructure; The substructure kinetic energy ratio corresponding to the shaft kinetic energy is: in, and Respectively represent the optimization of the kinetic energy of the front and rear axles, d , D , Δ d , Δ D Indicates the outer diameter of the shaft and its change, and Indicates the length of the axis and its change; The substructure strain energy ratio corresponding to the axis strain energy is: in, and Respectively represent the strain energy of the optimized front and rear axles, represents the elastic modulus, 、 represents the interface inertia moment of the axis and its change, and Indicates the length of the axis and its change; The substructure strain energy ratio corresponding to the support strain energy is: in, and denote the strain energy of the support before and after optimization, 、 Indicates the support stiffness of the shaft and its change.

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