Air system design method for aero-engine

Abstract

The invention provides an air system design method for an aero-engine, which comprises the following steps of: S1, determining that tolerance data of a throttling element obeys normal distribution according to a basic size D of the throttling element output by a preliminary design scheme of an air system; s2, arranging a sensitivity coefficient matrix of each result parameter y of the air system to a design size parameter b of each throttling element; s3, according to the sensitivity analysis result of each element, dividing the given initial element tolerances into a plurality of types; s4, based on various types of element tolerances, carrying out design adjustment in a targeted manner; s5, according to the adjusted tolerance range, whether the adjusted tolerance range meets the probability requirement of the air system or not is judged; if yes, the adjusted tolerance parameter is output; and if not, repeating the steps S2 to S4 until the requirements are met. According to the invention, by outputting better element parameter tolerance, unnecessary element processing precision is reduced, processing cost is saved, and out-of-tolerance and yielding receiving rate can be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of aeroengines, and in particular to a method for designing an air system for an aeroengine. Background Art

[0002] The aircraft engine air system refers to the air bleed from the compressor, which is formed inside the engine through the flow holes, air bleed gaps, grate teeth and other throttling elements to achieve functions such as disc cooling, anti-icing, active clearance control, and wheel rim sealing.

[0003] The dimensional parameters of these throttling elements are the main output parameters of the air system design, which ensure the normal function of the air system and further affect the rotor and stator structure design and processing and manufacturing of components such as compressors and turbines.

[0004] Due to processing and assembly errors during the manufacturing and assembly process, there is a difference between the actual size and the designed size of the air system throttling element, which makes the design result of the air system uncertain. Strict tolerance requirements can reduce this uncertainty, but it leads to increased difficulty and cost of the manufacturing process. On the contrary, if the tolerance requirements of the throttling element are too loose, it is easy for the actual size of the key throttling element to deviate from the design expectation, and the established air system function cannot be achieved, which in turn affects the performance and operation safety of the engine.

[0005] In view of this, the inventor of the present application has designed an air system design method for an aircraft engine in order to overcome the above-mentioned technical problems. Summary of the invention

[0006] The technical problem to be solved by the present invention is to overcome the defects in the prior art of the air system of an aircraft engine, such as uncertainty in the design results, difficulty in the manufacturing process and increased costs, which easily affect the performance and operational safety of the engine, and to provide a method for designing an air system for an aircraft engine.

[0007] The present invention solves the above technical problems through the following technical solutions:

[0008] A method for designing an air system for an aircraft engine, characterized in that the air system design method comprises the following steps:

[0009] S1. According to the basic size D of the throttling element output by the preliminary design plan of the air system, the preliminary upper and lower limits (a, b) of the machining tolerance values ​​are given, and the tolerance data of the throttling element is set to obey the normal distribution, thereby constructing a probability model of the normal distribution of the size parameters;

[0010] S2, sort out the sensitivity coefficient matrix of various result parameters y of the air system to the design size parameters b of each throttling element;

[0011] S3, according to the sensitivity analysis results of each component in step S2, combined with the structural professional judgment of the difficulty of the processing technology, the given preliminary component tolerances are divided into multiple types;

[0012] S4, based on the tolerances of various types of components in step S3, carry out targeted design adjustments;

[0013] S5. Based on the tolerance range adjusted in step S4, a probability distribution analysis is performed on the target function parameters to determine whether the adjusted tolerance range meets the probability requirements of the air system; if so, the adjusted tolerance parameters are output; if not, steps S2 to S4 are repeated until the requirements are met.

[0014] According to an embodiment of the present invention, step S1 further includes: performing sampling based on a probability model, generating an air system calculation input file with a sample number N, performing air system network calculation, and outputting result parameters that affect the air system function.

[0015] According to an embodiment of the present invention, the number N of generated samples is greater than or equal to 1000.

[0016] According to one embodiment of the present invention, the sensitivity coefficient in step S2 is calculated by the following formula:

[0017]

[0018] Among them, γ is the sensitivity coefficient, N is the number of samples, and b is the design size parameter.

[0019] According to an embodiment of the present invention, the step S2 can obtain the probability distribution of the function parameters by calculating the mean μ and the mean square error σ of the result parameters of N samples.

[0020] According to one embodiment of the present invention, the functional parameter is within the interval of (μ-3σ, μ+3σ).

[0021] According to one embodiment of the present invention, the types of component tolerances in step S3 include:

[0022] Class A: low processing difficulty and high sensitivity to air system functions;

[0023] Category B: low processing difficulty and low sensitivity to air system function parameters;

[0024] Category C: High processing difficulty and high sensitivity to the gas supply system;

[0025] Category D: High processing difficulty and low sensitivity to air system functional parameters.

[0026] According to an embodiment of the present invention, the step S4 further includes: performing the following design adjustments according to the type of component tolerance:

[0027] Class A: narrow tolerance range;

[0028] Category b: no adjustment;

[0029] Category C: Adjust the upper (lower) limit of the tolerance to a single boundary, away from the functional failure boundary;

[0030] Category D: Enlarged tolerance range.

[0031] According to one embodiment of the present invention, the preliminary design scheme of the air system in step S1 includes: air system design requirements, overall parameters, overall scheme diagram, component performance parameters, component size parameters, and preliminary component tolerances.

[0032] The positive and progressive effects of the present invention are:

[0033] The present invention is used for the air system design method of an aircraft engine. The air system component tolerance design method is adopted. By outputting a more optimal component parameter tolerance, unnecessary component processing accuracy is reduced, processing costs are saved, and component processing accuracy that needs to be strictly controlled is identified, which can reduce the over-tolerance and concession acceptance rate.

[0034] Taking into account the processing difficulty and solution adjustment cycle, based on the air system probability model within a certain tolerance range, it is possible to reduce the sensitivity of key functional parameters and reduce the uncertainty of the air system function realization. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The above and other features, properties and advantages of the present invention will become more apparent through the following description in conjunction with the accompanying drawings and embodiments, in which the same reference numerals always represent the same features, wherein:

[0036] Figure 1 The present invention is a flow chart of the air system design method for aircraft engines.

[0037] Figure 2 The present invention is a schematic diagram of sensitivity distribution considering component tolerances in the air system design method for aircraft engines.

[0038] Figure 3 The present invention is a schematic diagram of the probability distribution of component tolerances in the air system design method for aircraft engines. DETAILED DESCRIPTION

[0039] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0040] Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Reference will now be made in detail to preferred embodiments of the present invention, examples of which are shown in the accompanying drawings. Wherever possible, the same reference numerals will be used throughout the drawings to represent the same or similar parts.

[0041] Furthermore, although the terms used in the present invention are selected from well-known and commonly used terms, some terms mentioned in the present invention specification may be selected by the applicant at his or her discretion, and their detailed meanings are explained in the relevant parts of the description of this document.

[0042] Furthermore, it is required that the present invention be understood not only by the actual terms used but also by the meanings connoted by each term.

[0043] Figure 1 The present invention is a flow chart of the air system design method for aircraft engines.

[0044] like Figure 1 As shown, this method needs to be carried out on the basis of air system design requirements, overall scheme diagram, overall and component performance parameters, and preliminary design plan of the air system. The air system here refers to the air flow system other than the air flow in the main gas channel of the engine.

[0045] The present invention discloses a method for designing an air system for an aeroengine, comprising the following steps:

[0046] Step S1, according to the basic size D of the throttling element output by the preliminary design plan of the air system, the preliminary upper and lower limits (a, b) of the processing tolerance are given, and the tolerance data of the throttling element is set to obey the normal distribution, thereby constructing a probability model of the normal distribution of the size parameters.

[0047] Preferably, step S1 further comprises: performing sampling based on a probability model, generating an air system calculation input file with a sample number N, performing air system network calculation, and outputting result parameters affecting the air system function. The generated sample number N is usually preferably greater than or equal to 1000.

[0048] Here, the preliminary design scheme of the air system in step S1 may preferably include: air system design requirements, overall parameters, overall scheme diagram, component performance parameters, component size parameters, and preliminary component tolerances.

[0049] Step S2, sorting out the sensitivity coefficient matrix of various result parameters y of the air system to the design size parameters b of each throttling element.

[0050] Preferably, the sensitivity coefficient in step S2 is calculated by the following formula, and the sensitivity linear graph is as follows: Figure 2 shown.

[0051]

[0052] Among them, γ is the sensitivity coefficient, N is the number of samples, and b is the design size parameter.

[0053] Here, preferably, by calculating the mean μ and the mean square error σ of the result parameters of N samples, the probability distribution of the function parameters can be obtained.

[0054] The functional parameters are preferably, for example, 99.7% probability falls within the interval (μ-3σ, μ+3σ), and the sample distribution diagram is as follows: Figure 3 shown.

[0055] Sensitivity analysis here refers to an uncertainty analysis method that studies the impact of changes in relevant factors on key indicators from a quantitative analysis perspective.

[0056] Step S3: Based on the sensitivity analysis results of each component in step S2 and combined with the structural professional judgment of the difficulty of the processing technology, the given preliminary component tolerance (referring to the absolute value of the difference between the maximum limit size and the minimum limit size allowed) is divided into multiple types.

[0057] For example, the types of component tolerances in step S3 include:

[0058] Class A: low processing difficulty and high sensitivity to air system functions;

[0059] Category B: low processing difficulty and low sensitivity to air system function parameters;

[0060] Category C: High processing difficulty and high sensitivity to the gas supply system;

[0061] Category D: High processing difficulty and low sensitivity to air system functional parameters.

[0062] Step S4: Based on the tolerances of various types of components in step S3, targeted design adjustments are carried out.

[0063] For example, the step S4 further includes: performing the following design adjustments for the above four types of component tolerances:

[0064] Class A: narrow tolerance range;

[0065] Category b: no adjustment;

[0066] Category C: Adjust the upper (lower) limit of the tolerance to a single boundary, away from the functional failure boundary;

[0067] Category D: Enlarged tolerance range.

[0068] Step S5, performing probability distribution analysis on the target function parameter according to the tolerance range adjusted in step S4, and determining whether the adjusted tolerance range meets the probability requirement of the air system;

[0069] If satisfied, the adjusted tolerance parameters are output;

[0070] If not, repeat step S2 to step S4 until the requirement is met.

[0071] Combining the above-mentioned methods for obtaining the probability model of the air system, the methods for determining the tolerances of the four types of components, and the principles for adjusting the component tolerances according to a certain logic, a forward design method for the tolerances of engine air system components can be obtained (e.g. Figure 1 shown).

[0072] According to the above step description, the present invention establishes a dynamic tolerance design method for an air system. During the design process, a probability model of the air system function realization is established, thereby outputting an air system solution with a tolerance range, effectively reducing the difficulty of the processing technology and the part tolerance rate on the basis of functional feasibility, and reducing the uncertainty of the design results.

[0073] The present invention is used for the air system design method of an aircraft engine, and clarifies the following contents:

[0074] 1. The method of obtaining the probability model of the air system is clarified;

[0075] 2. Clarify the principles for determining the four types of tolerances for air system components;

[0076] 3. Clarify the adjustment methods for the four types of tolerances of the air system;

[0077] 4. Define the method for obtaining the tolerances of output air system components.

[0078] By combining the above methods according to a certain logic, a method for forward design of tolerances of air system components is obtained.

[0079] In summary, the present invention is used for the air system design method of an aircraft engine, adopts the air system component tolerance design method, outputs a better component parameter tolerance, reduces unnecessary component processing accuracy, saves processing costs, identifies the component processing accuracy that needs to be strictly controlled, and can reduce the over-tolerance and concession acceptance rate;

[0080] Taking into account the processing difficulty and solution adjustment cycle, based on the air system probability model within a certain tolerance range, it is possible to reduce the sensitivity of key functional parameters and reduce the uncertainty of the air system function realization.

[0081] For those skilled in the art, the above invention disclosure is only used as an example and does not constitute a limitation of the present application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements and amendments to the present application. Such modifications, improvements and amendments are suggested in the present application, so such modifications, improvements and amendments still belong to the spirit and scope of the exemplary implementation of the present application.

[0082] At the same time, the present application uses specific words to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different positions in this specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0083] Similarly, it should be noted that in order to simplify the description of the disclosure of this application and thus facilitate the understanding of one or more embodiments of the invention, in the foregoing description of the embodiments of this application, multiple features are sometimes grouped into one embodiment, drawing, or description thereof. However, this disclosure method does not mean that the subject matter of this application requires more features than those mentioned in the claims. In fact, the features of an embodiment are less than all the features of a single embodiment disclosed above.

[0084] Although the specific embodiments of the present invention are described above, it should be understood by those skilled in the art that these are only examples, and the protection scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A method for designing an air system for an aircraft engine, characterized in that: The air system design method comprises the following steps: S1. According to the basic size D of the throttling element output by the preliminary design plan of the air system, the preliminary upper and lower limits (a, b) of the machining tolerance values ​​are given, and the tolerance data of the throttling element is set to obey the normal distribution, thereby constructing a probability model of the normal distribution of the size parameters; S2, sort out the sensitivity coefficient matrix of various result parameters y of the air system to the design size parameters b of each throttling element; S3, according to the sensitivity analysis results of each component in step S2, combined with the structural professional judgment of the difficulty of the processing technology, the given preliminary component tolerances are divided into multiple types; S4, based on the tolerances of various types of components in step S3, carry out targeted design adjustments; S5. Based on the tolerance range adjusted in step S4, a probability distribution analysis is performed on the target function parameter to determine whether the adjusted tolerance range meets the probability requirement of the air system; If satisfied, the adjusted tolerance parameters are output; If not, repeat step S2 to step S4 until the requirement is met.

2. The method for designing an air system for an aircraft engine according to claim 1, characterized in that: The step S1 also includes: performing sampling based on a probability model, generating an air system calculation input file with a sample number N, performing air system network calculation, and outputting result parameters that affect the air system function.

3. The method for designing an air system for an aircraft engine according to claim 2, characterized in that: The number of generated samples N is greater than or equal to 1000.

4. The method for designing an air system for an aircraft engine according to claim 1, characterized in that: The sensitivity coefficient in step S2 is calculated by the following formula: Among them, γ is the sensitivity coefficient, N is the number of samples, and b is the design size parameter.

5. The method for designing an air system for an aircraft engine according to claim 4, characterized in that: In step S2, the probability distribution of the function parameters can be obtained by calculating the mean μ and the mean square error σ of the result parameters of N samples.

6. The method for designing an air system for an aircraft engine according to claim 5, characterized in that: The functional parameters are within the interval of (μ-3σ, μ+3σ).

7. The method for designing an air system for an aircraft engine according to claim 1, characterized in that: The types of component tolerances in step S3 include: Class A: low processing difficulty and high sensitivity to air system functions; Category B: low processing difficulty and low sensitivity to air system function parameters; Category C: High processing difficulty and high sensitivity to the gas supply system; Category D: High processing difficulty and low sensitivity to air system functional parameters.

8. The method for designing an air system for an aircraft engine according to claim 7, characterized in that: The step S4 also includes: performing the following design adjustments according to the type of component tolerance: Class A: narrow tolerance range; Category b: no adjustment; Category C: Adjust the upper (lower) limit of the tolerance to a single boundary, away from the functional failure boundary; Category D: Enlarged tolerance range.

9. The method for designing an air system for an aircraft engine according to claim 1, characterized in that: The preliminary design scheme of the air system in step S1 includes: Air system design requirements, general parameters, general scheme drawings, component performance parameters, component dimensional parameters, and preliminary component tolerances.

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