An aero-engine anti-fading capability evaluation method based on dissipative structure theory

Abstract

The application belongs to the technical field of aero-engines, and particularly relates to an aero-engine anti-degradation capability evaluation method based on a dissipative structure theory, the overall configuration of a newly designed engine to be evaluated is determined, and an overall configuration item for representing the anti-degradation capability is selected as a secondary index; for the overall configuration item, further decomposition is performed and a configuration item inside each component and system is selected as a tertiary index; based on statistical data of performance degradation of mature models, joint distribution of anti-degradation parameters of the overall configuration item, the configuration item inside the component and the configuration item inside the system is determined; based on an entropy value method and in comparison with the statistical data of the mature models, the secondary index weight of the overall configuration item and the tertiary index weight of the configuration item inside the component and the system are respectively determined; based on the weight, the joint distribution of the anti-degradation parameters and a preset anti-degradation capability calculation formula, an anti-degradation capability value of the newly designed engine relative to the mature models is calculated.

Description

Technical Field

[0001] This application belongs to the field of aero-engine technology, and specifically relates to a method for evaluating the anti-attenuation capability of aero-engines based on dissipative structure theory. Background Technology

[0002] In existing technical solutions, the performance degradation of aero-engines is generally analyzed from the evaluation criteria for performance degradation and the adjustment measures after performance degradation occurs. The above methods cannot be used to predict the subsequent performance degradation in the early stage of the forward design of a new engine. Therefore, they cannot guide the design of control measures for the performance degradation problem. A lot of work is done as a post-remedial measure. Therefore, there is an urgent need for a calculation method that can define and predict the degree of engine performance degradation in the initial design stage.

[0003] Furthermore, the characteristics of aero-engine performance degradation show that the overall performance degradation rate is not equal to the sum of the degradation rates of each component. This indicates that the system performance degradation is not a linear superposition of the performance degradation of each component, but has strong nonlinear characteristics and nonlinear coupling effects between components. Therefore, it is necessary to consider the performance degradation problem from an overall global perspective and urgently establish the correlation between overall performance degradation and overall configuration terms.

[0004] Existing technical solutions only provide evaluation criteria and conversion methods for the degree of performance degradation, but they have the following technical problems:

[0005] 1. Unable to guide the design of new engine performance degradation control measures;

[0006] 2. It is impossible to measure the overall performance degradation of a newly designed aircraft engine;

[0007] 3. It is impossible to numerically predict the rate of performance degradation of the newly designed engine during subsequent actual use;

[0008] 4. It cannot identify and analyze the differences in performance degradation between newly designed engines and mature engines, and lacks a positive decomposition method for performance degradation design indicators. Summary of the Invention

[0009] To address the aforementioned problems, this application provides a method for evaluating the anti-attenuation capability of aero-engines based on dissipative structure theory, comprising:

[0010] Step S100: Determine the overall configuration of the new engine design to be evaluated, and select the overall configuration item used to characterize the resistance to attenuation as a secondary indicator.

[0011] Step S200: For the overall configuration item, further decompose and select the configuration items of each component and system as third-level indicators;

[0012] Step S300: Based on the performance degradation statistics of mature models, determine the joint distribution of anti-degradation parameters of the overall configuration item, the internal configuration item of the component, and the internal configuration item of the system;

[0013] Step S400: Based on the entropy method and by referring to the statistical data of the mature models, determine the secondary index weights of the overall configuration item and the tertiary index weights of the component and system internal configuration items respectively;

[0014] Step S500: Based on the weights, the joint distribution of the anti-attenuation parameters, and the preset anti-attenuation capability calculation formula, calculate the anti-attenuation capability value of the newly designed engine relative to the mature engine model;

[0015] Step S600: Compare the calculated anti-attenuation capability value with the performance attenuation index required by the user, and determine whether the requirements are met based on the comparison results. If not, return to steps S100 to S400 to improve the configuration design and recalculate. If the requirements are met, the evaluation is completed.

[0016] Preferably, in step S500, the formula for calculating the anti-attenuation capability includes calculating the theoretical difference and the correlation difference;

[0017] The theoretical difference Calculated using the following formula:

[0018] ;

[0019] It is the dimensionless value of the j-th anti-attenuation index corresponding to the mature model. It is the dimensionless value of the j-th anti-fading index of the i-th parameter of the k-th component / system of the newly designed engine at time t. The weights are for the three-level indicators.

[0020] Preferably, in step S500, the correlation difference is calculated using grey relational analysis, where the correlation coefficient between the k-th component / system and the mature model at time t regarding the entropy value of the j-th anti-degradation index is... for:

[0021] ;

[0022] In the above formula, in the above formula, , It is the resolution coefficient, and its value range is set to... Within this range, the degree of difference between the same type of configuration item of a newly designed engine and a mature model can be used as a correction factor for the configuration item;

[0023] The correlation difference Calculated using the following formula:

[0024] .

[0025] Preferably, in step S500, the limit value H of the anti-fading capability of the newly designed engine is... 新机 Calculated using the following formula:

[0026]

[0027] in, This represents the performance degradation resistance value of mature models, which is based on statistical data on the performance degradation of mature models.

[0028] Preferably, in step S400, the process of determining the index weights using the entropy method includes:

[0029] Calculate the joint distribution value of the j-th index at time t. :

[0030] ;

[0031] Calculate the entropy flow value of the index and its coefficient of difference ;

[0032] ;

[0033] The difference coefficients are normalized to obtain the indicator weights. ;

[0034] .

[0035] Preferably, in step S200, the anti-attenuation parameter of the configuration term is dimensionless using the mean method, and the calculation formula is as follows: ;

[0036] in, This represents the original value of the j-th anti-attenuation index of the i-th parameter in the k-th component / system. This represents the average value of the indicator.

[0037] Preferably, in step S100, the overall configuration items include one or more of rotor support stiffness, rotor system damping, sealing clearance, and hot end component wall temperature.

[0038] Preferably, in step S200, the internal configuration items of the component include one or more of blade consistency, blade aspect ratio, stage load factor, flow factor, compressor rotor tip speed, and turbine rotor tip speed; the internal configuration items of the system include one or more of lubricating oil supply pressure, lubricating oil supply flow rate, and bearing cavity return oil volume.

[0039] Compared with existing technologies, it has the following advantages and beneficial effects:

[0040] 1. Based on the overall structure, in the initial design stage of a newly designed engine, the anti-attenuation capability of the newly designed engine can be numerically evaluated by calculation methods based on dissipative structure theory. By comparing the actual performance attenuation with that of mature models, the numerical evaluation and iteration of the performance attenuation indicators proposed by the user can be achieved with greater accuracy, which can meet the requirements of demand compliance analysis in the design stage.

[0041] 2. By forward-calculating the degree of performance degradation and analyzing the configuration items of the whole system, the key configurations for achieving the performance degradation index can be identified, and the contribution of the configuration items in each component / system to the anti-degradation capability can be determined.

[0042] Achieving a positive decomposition of performance degradation indicators on the user side can satisfy the performance evaluation criteria for the anti-degradation capabilities of each component / system. Attached Figure Description

[0043] Figure 1 This is a flowchart for evaluating the anti-attenuation capability of aero-engines based on dissipative structure theory. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are only some embodiments of this application, not all embodiments. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without creative effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings. This invention proposes a method for calculating the anti-attenuation of aero-engines based on dissipative structure theory. The calculation process is as follows: Figure 1As shown, the anti-agement capability of an aero-engine is defined as its resistance to performance degradation. It reflects the engine's overall resistance to disturbances and also the rate of change of the joint entropy of multiple parameters within the engine's dissipative structure. The steps of the engine anti-agement capability assessment process proposed based on dissipative structure theory are as follows:

[0045] Step 1: Based on the user's requirements for the newly designed engine, identify the overall engine performance degradation index requirements as the primary indicator for overall engine anti-degradation.

[0046] Step 2: Identify the overall configuration items that affect the overall aircraft's anti-age characteristics, such as the overall aircraft's inlet characteristics, flight envelope, rotor's limiting physical speed, and pivot point layout, as secondary indicators of the overall aircraft's anti-age characteristics.

[0047] Step 3: Determine the internal configuration items of each component that affect the anti-attenuation characteristics of each component, such as the number of fan stages, average stage load factor, maximum tangential velocity at the blade tip, disk connection structure, material selection, etc., as the three-level indicators of the overall anti-attenuation of the machine.

[0048] Step 4: Identify the internal configuration items of each system that affect the anti-fading characteristics of each system, such as the fuel pump architecture of the control system and the oil return volume of the bearing cavity of the mechanical system, as the third-level indicators of the overall machine's anti-fading characteristics.

[0049] Step 5: Determine the joint distribution of the anti-attenuation parameters of each configuration item of the whole machine by referring to the statistical data of mature models;

[0050] Step 6: Determine the joint distribution of the anti-attenuation parameters of each component's internal configuration items by comparing with statistical data from mature models;

[0051] Step 7: Determine the joint distribution of the anti-attenuation parameters of each internal configuration item in each system by comparing with the statistical data of mature models;

[0052] Step 8: Determine the secondary index weights of the anti-attenuation parameters of each configuration item of the whole machine based on the entropy method and by referring to the statistical data of mature models;

[0053] Step 9: Determine the weights of the three-level indicators for the anti-attenuation parameters of each component's internal configuration items based on the entropy method and by referring to statistical data from mature models;

[0054] Step 10: Determine the weights of the three-level indicators for the anti-attenuation parameters of each internal configuration item in each system based on the entropy method and by referring to the statistical data of mature models;

[0055] Step 11: Calculate the theoretical difference between each configuration item of the whole machine and the mature model according to the following anti-attenuation capability calculation formula;

[0056] Step 12: Calculate the correlation difference between each configuration item of the whole machine and the mature model according to the following anti-attenuation capability calculation formula;

[0057] Step 13: Based on the statistical data of performance degradation of mature models, calculate the limit value of the anti-degradation capability of the newly designed engine;

[0058] Step 14: Compare with the user's performance degradation index. If it is not met, return to Steps 2 to 4 to improve the overall structure and review the performance of each component / system in terms of degradation resistance.

[0059] Step 15: If Step 14 meets the user's performance degradation index requirements, then the overall anti-degradation capability assessment is complete.

[0060] Based on the above workflow, the specific calculation formulas proposed by this invention for each step are as follows:

[0061] Assume that the j-th anti-age index of the i-th anti-age parameter in the internal configuration term of the k-th component / system in the engine is... And taking into account the joint distribution of parameters within the component / system. Therefore, the total anti-attenuation sum of the k-th component / system at time t is defined as:

[0062] ...(1)

[0063] ...(2)

[0064] In the above formula, The weights of the secondary indicators (integral structure items). The weights are for the third-level indicators (component / system internal configuration items).

[0065] The weights of the above indicators are calculated using the entropy method and by referring to the statistical data of mature models to eliminate the influence of the dimensions of the configuration parameters. The difference coefficient of the entropy value of the j-th anti-attenuation index of the i-th anti-attenuation parameter of the internal configuration is calculated by the following formula (3):

[0066] ………………………(3)

[0067] In the above formula, The entropy flow value is the indicator. Let be the joint distribution value of the j-th index at time t:

[0068] ………………………………………(4)

[0069] After normalization, the indicator weights are obtained as follows:

[0070] ………………………………………(5)

[0071] To unify the original data dimensions for each configuration item, the mean method is used to perform dimensionless processing of the data. This method can eliminate the influence of dimensions and orders of magnitude while preserving the degree of difference between each parameter. Dimensionless processing is performed according to the following formula:

[0072] ………………………………………(6)

[0073] This allows us to obtain the theoretical difference in anti-fading characteristics between a newly designed engine and a mature engine model. It is the j-th anti-attenuation index of the i-th anti-attenuation parameter corresponding to mature models:

[0074] ………………………………(7)

[0075] Then, based on the grey relational analysis method, the correlation coefficient between the k-th component / system and the mature model at time t with respect to the entropy value of the j-th anti-degradation index is:

[0076] ………………………………(8)

[0077] In the above formula, , It is the resolution coefficient, and its value range is set to... Within this range, the degree of difference between a newly designed engine of the same type and a mature engine is represented, and it can be used as a correction factor for the configuration item.

[0078] Therefore, the correlation difference between each configuration term can be expressed as:

[0079] …………(9)

[0080] Based on the calculation results of equations (7) and (9), and combined with the statistical data of performance degradation of mature models, the limit value of the anti-degradation capability of the newly designed engine can be obtained, as shown in equation (10) below:

[0081] ………………………(10)

[0082] In the formula This indicates the resistance to degradation of the newly designed engine. This represents the performance degradation resistance value of mature models (statistical data on performance degradation). By comparing this value, a more accurate performance degradation assessment result is obtained. This result is then compared with the performance degradation index given by the user. If the result does not meet the requirements, the system will check which component / system has a significantly lower performance degradation resistance index than the mature model. Targeted design improvements and enhancements to improve performance degradation resistance will then be carried out. This process will be iterated repeatedly until the user's requirements are met.

[0083] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for evaluating the anti-attenuation capability of aero-engines based on dissipative structure theory, characterized in that, include: Step S100: Determine the overall configuration of the new engine design to be evaluated, and select the overall configuration item used to characterize the resistance to attenuation as a secondary indicator. Step S200: For the overall configuration item, further decompose and select the configuration items of each component and system as third-level indicators; Step S300: Based on the performance degradation statistics of mature models, determine the joint distribution of anti-degradation parameters of the overall configuration item, the internal configuration item of the component, and the internal configuration item of the system; Step S400: Based on the entropy method and by referring to the statistical data of the mature models, determine the secondary index weights of the overall configuration item and the tertiary index weights of the component and system internal configuration items respectively; Step S500: Based on the weights, the joint distribution of the anti-attenuation parameters, and the preset anti-attenuation capability calculation formula, calculate the anti-attenuation capability value of the newly designed engine relative to the mature engine model; Step S600: Compare the calculated anti-attenuation capability value with the performance attenuation index required by the user, and determine whether the requirements are met based on the comparison results. If not, return to steps S100 to S400 to improve the configuration design and recalculate. If the requirements are met, the evaluation is completed.

2. The method for evaluating the anti-attenuation capability of aero-engines based on dissipative structure theory as described in claim 1, characterized in that, In step S500, the formula for calculating the anti-attenuation capability includes calculating the theoretical difference and the correlation difference; The theoretical difference Calculated using the following formula: ； It is the dimensionless value of the j-th anti-attenuation index corresponding to the mature model. It is the dimensionless value of the j-th anti-fading index of the i-th parameter of the k-th component / system of the newly designed engine at time t. The weights are for the three-level indicators.

3. The method for evaluating the anti-attenuation capability of aero-engines based on dissipative structure theory as described in claim 1, characterized in that, In step S500, the correlation difference is calculated using grey relational analysis, which is the correlation coefficient of the k-th component / system with respect to the entropy value of the j-th anti-degradation index of the mature model at time t. for: ； In the above formula, in the above formula, , It is the resolution coefficient, and its value range is set to... Within this range, the degree of difference between the same type of configuration item of a newly designed engine and a mature model can be used as a correction factor for the configuration item; The correlation difference Calculated using the following formula: 。 4. The method for evaluating the anti-attenuation capability of aero-engines based on dissipative structure theory as described in claim 1, characterized in that, In step S500, the limit value H of the anti-fading capability of the newly designed engine is... 新机 Calculated using the following formula:

5. Among them, This represents the performance degradation resistance value of mature models, which is based on statistical data on the performance degradation of mature models.

6. The method for evaluating the anti-attenuation capability of aero-engines based on dissipative structure theory as described in claim 1, characterized in that, In step S400, the process of determining the index weights using the entropy method includes: Calculate the joint distribution value of the j-th index at time t. : ； Calculate the entropy flow value of the index and its coefficient of difference ; ； The difference coefficients are normalized to obtain the indicator weights. ; 。 7. The method for evaluating the anti-attenuation capability of aero-engines based on dissipative structure theory as described in claim 1, characterized in that, In step S200, the anti-attenuation parameter of the configuration term is dimensionless using the mean method, and the calculation formula is as follows: ; in, This represents the original value of the j-th anti-attenuation index of the i-th parameter in the k-th component / system. This represents the average value of the indicator.

8. The method for evaluating the anti-attenuation capability of aero-engines based on dissipative structure theory as described in claim 1, characterized in that, In step S100, the overall configuration items include one or more of the following: rotor support stiffness, rotor system damping, sealing clearance, and hot end component wall temperature.

9. The method for evaluating the anti-attenuation capability of aero-engines based on dissipative structure theory as described in claim 1, characterized in that, In step S200, the internal configuration items of the component include one or more of the following: blade consistency, blade aspect ratio, stage load factor, flow factor, compressor rotor tip speed, and turbine rotor tip speed; the internal configuration items of the system include one or more of the following: lubricating oil supply pressure, lubricating oil supply flow rate, and bearing cavity return oil volume.

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