Aero-engine low-pressure turbine shaft and torsional vibration design method and system thereof

Abstract

The application relates to the technical field of aero-engines, and discloses an aero-engine low-pressure turbine shaft and a torsional vibration design method and system thereof. The low-pressure turbine shaft is segmented for torsional stiffness calculation according to the actual structure of the low-pressure turbine shaft. On the basis of fully considering the torsional stiffness of the low-pressure turbine shaft, the fan rotor polar moment of inertia and the low-pressure turbine rotor polar moment of inertia, analysis is conducted on the torsional frequency of the low-pressure turbine shaft. The margin analysis between the torsional frequency of the low-pressure turbine shaft and the vibration frequency generated by all the accessories of the engine can be completed without rebuilding a simulation model. The method is more suitable for the requirement of multi-round rapid iteration in the scheme design stage, can rapidly evaluate and optimize the torsional vibration frequency of the low-pressure turbine shaft in the early stage of engine scheme design, guides the structure design of the low-pressure turbine shaft, ensures that the torsional vibration frequency of the low-pressure turbine shaft of the turbofan engine meets the design requirement, can ensure that torsional resonance does not occur within the working speed range, and shortens the overall design cycle.

Description

Technical Field

[0001] This invention relates to the field of aero-engine technology, and discloses a method and system for designing the torsional vibration of a low-pressure turbine shaft for an aero-engine. Background Technology

[0002] As one of the key components of aero-engine turbofan engines, the low-pressure turbine shaft plays an extremely important role in supporting rotating parts and transmitting power and high-speed rotational motion. The quality of the low-pressure turbine shaft design directly affects the reliability and durability of the engine.

[0003] Typical low-pressure rotor structure of aircraft turbofan engines is as follows: Figure 1 As shown, the low-pressure turbine shaft is a hollow cylindrical long shaft, supporting the fan rotor at one end and the low-pressure rotor at the other. Torsional vibration is unavoidable across the entire engine speed range and is easily triggered under complex engine vibration excitation environments. Once torsional vibration of the low-pressure turbine shaft occurs, it will cause significant damage to the engine. Therefore, it is essential to conduct torsional vibration design for the low-pressure turbine shaft of aero-turbofan engines.

[0004] Currently, the torsional vibration design of low-pressure turbine shafts typically employs the finite element method, which can be used to perform calculations through either a whole-engine dynamics model or a three-dimensional solid model of the low-pressure turbine shaft. Both of these methods require the establishment of a finite element model, which is complex and time-consuming to perform calculations and analyses, making it difficult to meet the needs of rapid analysis and optimization design of low-pressure turbine shafts in the early stages of engine design. Summary of the Invention

[0005] The purpose of this invention is to provide a design method and system for the torsional vibration of a low-pressure turbine shaft of an aero-engine. This method and system can quickly assess and optimize the torsional vibration frequency of the low-pressure turbine shaft in the early stages of engine design, guide the structural design of the low-pressure turbine shaft, ensure that the torsional vibration frequency of the turbofan engine's low-pressure turbine shaft meets the design requirements, and ensure that torsional resonance does not occur within the operating speed range, thereby shortening the overall design cycle.

[0006] To achieve the above-mentioned technical effects, the technical solution adopted by the present invention is as follows:

[0007] A design method for torsional vibration of a low-pressure turbine shaft in an aero-engine includes: S1. Based on the three-dimensional solid model of the engine's low-pressure rotor, obtain the polar moment of inertia of the fan rotor and the polar moment of inertia of the low-pressure turbine rotor. S2. Based on the inner diameter, outer diameter, and length of the low-pressure turbine shaft in the low-pressure rotor, the low-pressure turbine shaft is segmented to form multiple hollow circular shaft segments and hollow conical shaft segments. S3. Calculate the overall torsional stiffness of all hollow annular shaft segments of the low-pressure turbine shaft and the overall torsional stiffness of all hollow conical shaft segments, as well as the torsional stiffness of the low-pressure turbine shaft. S4. The torsional frequency of the low-pressure turbine shaft is obtained by analyzing the torsional stiffness of the low-pressure turbine shaft, the polar moment of inertia of the fan rotor, and the polar moment of inertia of the low-pressure turbine rotor. S5. Analyze the margin between the low-pressure turbine shaft torsional frequency and the vibration frequency generated by all components of the engine. If the minimum value of the margin is greater than or equal to the preset margin value, the low-pressure turbine shaft torsional frequency meets the design requirements. Otherwise, adjust the size of the low-pressure turbine shaft until the low-pressure turbine shaft torsional frequency meets the design requirements.

[0008] Furthermore, in step S3, the overall torsional stiffness of all hollow annular shaft segments of the low-pressure turbine shaft is... ,in For the first Shear elastic modulus of a hollow circular ring shaft segment. For the first The outer diameter of the hollow circular shaft segment For the first The inner diameter of the hollow circular shaft segment, For the first The length of each hollow circular ring shaft segment , This represents the number of segments in the hollow circular ring shaft. Overall torsional stiffness of all hollow conical shaft segments ,in For the first Shear modulus of elasticity of a hollow conical shaft segment material For the first The outer diameter of the small end of the hollow conical shaft segment For the first The outer diameter of the large end of the hollow conical shaft segment For the first The inner diameter of the small end of the hollow conical shaft segment For the first The inner diameter of the large end of the hollow conical shaft segment For the first The length of each hollow conical shaft segment , The number of segments in the hollow conical shaft section. The value range is from 0 to Function variables of length interval, It is a micro-unit for the length of a hollow conical shaft segment; Torsional stiffness of low-pressure turbine shaft ,in For the overall torsional stiffness of all hollow annular shaft segments of the low-pressure turbine shaft, The overall torsional stiffness of all hollow conical shaft segments.

[0009] Furthermore, in step S4, the low-pressure turbine shaft torsional frequency is determined according to... Analysis yielded, among which For low-pressure turbine shaft torsional frequency, For the torsional stiffness of the low-pressure turbine shaft, The polar moment of inertia of the fan rotor. This is the low-pressure turbine rotor polar moment of inertia.

[0010] Furthermore, in step S4, the margin between the low-pressure turbine shaft torsional frequency and the vibration frequencies generated by all engine components... ,in For low-pressure turbine shaft torsional frequency, The m-th vibration frequency generated by all components and accessories of the engine.

[0011] To achieve the above-mentioned technical effects, the present invention also provides a design system for torsional vibration of a low-pressure turbine shaft of an aero-engine, used to implement the aforementioned design method for torsional vibration of a low-pressure turbine shaft of an aero-engine, comprising: The polar moment of inertia analysis module is used to obtain the polar moment of inertia of the fan rotor and the polar moment of inertia of the low-pressure turbine rotor based on the three-dimensional solid model of the engine's low-pressure rotor. The segmentation module is used to segment the low-pressure turbine shaft according to the inner diameter, outer diameter and length of the low-pressure turbine shaft in the low-pressure rotor, forming multiple hollow circular shaft segments and hollow conical shaft segments; The stiffness analysis module is used to calculate the overall torsional stiffness of all hollow annular shaft segments of the low-pressure turbine shaft and the overall torsional stiffness of all hollow conical shaft segments, as well as the torsional stiffness of the low-pressure turbine shaft. The torsional frequency analysis module is used to obtain the torsional frequency of the low-pressure turbine shaft based on the torsional stiffness of the low-pressure turbine shaft, the polar moment of inertia of the fan rotor, and the polar moment of inertia of the low-pressure turbine rotor. The discrimination and adjustment module is used to analyze the margin between the low-pressure turbine shaft torsional frequency and the vibration frequency generated by all components of the engine. If the minimum value of the margin is greater than or equal to the preset margin value, the low-pressure turbine shaft torsional frequency meets the design requirements; otherwise, the dimensions of the low-pressure turbine shaft are adjusted until the low-pressure turbine shaft torsional frequency meets the design requirements.

[0012] Furthermore, in the stiffness analysis module, the overall torsional stiffness of all hollow annular shaft segments of the low-pressure turbine shaft is... ,in For the first Shear elastic modulus of a hollow circular ring shaft segment. For the first The outer diameter of the hollow circular shaft segment For the first The inner diameter of the hollow circular shaft segment, For the first The length of each hollow circular ring shaft segment , This represents the number of segments in the hollow circular ring shaft. Overall torsional stiffness of all hollow conical shaft segments ,in For the first Shear modulus of elasticity of a hollow conical shaft segment material For the first The outer diameter of the small end of the hollow conical shaft segment For the first The outer diameter of the large end of the hollow conical shaft segment For the first The inner diameter of the small end of the hollow conical shaft segment For the first The inner diameter of the large end of the hollow conical shaft segment For the first The length of each hollow conical shaft segment , The number of segments in the hollow conical shaft section. The value range is from 0 to Function variables of length interval, It is a micro-unit for the length of a hollow conical shaft segment; Torsional stiffness of low-pressure turbine shaft ,in For the overall torsional stiffness of all hollow annular shaft segments of the low-pressure turbine shaft, The overall torsional stiffness of all hollow conical shaft segments.

[0013] Furthermore, in the torsional frequency analysis module, the torsional frequency of the low-pressure turbine shaft is determined according to... Analysis yielded, among which For low-pressure turbine shaft torsional frequency, For the torsional stiffness of the low-pressure turbine shaft, The polar moment of inertia of the fan rotor. This is the low-pressure turbine rotor polar moment of inertia.

[0014] Furthermore, in the discrimination and adjustment module, the margin between the low-pressure turbine shaft torsional frequency and the vibration frequencies generated by all engine components is considered. ,in For low-pressure turbine shaft torsional frequency, The m-th vibration frequency generated by all components and accessories of the engine.

[0015] To achieve the above-mentioned technical effects, the present invention also provides a low-pressure turbine shaft for an aero-engine, the configuration of which is designed by the aforementioned aero-engine low-pressure turbine shaft torsional vibration design method.

[0016] Compared with the prior art, the beneficial effects of this invention are as follows: This invention performs segmented torsional stiffness calculation on the low-pressure turbine shaft, and analyzes the torsional frequency of the low-pressure turbine shaft based on fully considering the torsional stiffness of the low-pressure turbine shaft, the polar moment of inertia of the fan rotor, and the polar moment of inertia of the low-pressure turbine rotor. This completes the margin analysis between the torsional frequency of the low-pressure turbine shaft and the vibration frequencies generated by all components of the engine, which is more suitable for the needs of multiple rounds of rapid iteration in the design phase. It can quickly evaluate and optimize the torsional vibration frequency of the low-pressure turbine shaft in the early stage of engine design, guide the structural design of the low-pressure turbine shaft, ensure that the torsional vibration frequency of the turbofan engine's low-pressure turbine shaft meets the design requirements, and ensure that no torsional resonance occurs within the operating speed range, thus shortening the overall design cycle. Attached Figure Description

[0017] Figure 1 A schematic diagram of a typical low-pressure rotor structure for an aircraft turbofan engine; Figure 2 This is a flowchart of the design method for torsional vibration of the low-pressure turbine shaft of an aero-engine in Example 1 or 2; Figure 3 This is a block diagram of the design system for torsional vibration of the low-pressure turbine shaft of an aero-engine in Example 1; Figure 4 This is a schematic diagram of the low-pressure turbine shaft and its segmented structure in Example 1 or 2; The components include: 1. Fan rotor; 2. Low-pressure turbine rotor; 3. Low-pressure turbine shaft; 301. Hollow annular shaft segment; 302. Hollow conical shaft segment; 4. Polar moment of inertia analysis module; 5. Segmentation module; 6. Stiffness analysis module; 7. Torsional frequency analysis module; and 8. Judgment and adjustment module. Detailed Implementation

[0018] The present invention will now be described in further detail with reference to the embodiments and accompanying drawings. However, this should not be construed as limiting the scope of the above-described subject matter of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0019] Example 1 See Figures 1 to 4 A design method for torsional vibration of a low-pressure turbine shaft in an aero-engine, comprising: S1. Based on the three-dimensional solid model of the low-pressure rotor of the engine, obtain the first pole moment of inertia of the fan rotor and the second pole moment of inertia of the low-pressure turbine rotor. S2. Based on the inner diameter, outer diameter and length of the low-pressure turbine shaft 3 in the low-pressure rotor, the low-pressure turbine shaft 3 is segmented to form multiple hollow circular shaft segments 301 and hollow conical shaft segments 302. S3. Calculate the overall torsional stiffness of all hollow annular shaft segments 301 of the low-pressure turbine shaft 3 and the overall torsional stiffness of all hollow conical shaft segments 302, as well as the torsional stiffness of the low-pressure turbine shaft 3. S4. Based on the torsional stiffness of the low-pressure turbine shaft 3, the polar moment of inertia of the fan rotor 1, and the polar moment of inertia of the low-pressure turbine rotor 2, the torsional frequency of the low-pressure turbine shaft 3 is obtained. S5. Analyze the margin between the torsional frequency of the low-pressure turbine shaft 3 and the vibration frequency generated by all components of the engine. If the minimum value of the margin is greater than or equal to the preset margin value, the torsional frequency of the low-pressure turbine shaft 3 meets the design requirements. Otherwise, adjust the size of the low-pressure turbine shaft 3 until the torsional frequency of the low-pressure turbine shaft 3 meets the design requirements.

[0020] In this embodiment, the torsional stiffness of the low-pressure turbine shaft 3 is calculated in a segmented manner, taking into account the actual structure of the low-pressure turbine shaft 3. This eliminates the need for complex mesh generation and simulation iterations, allowing for accurate results through calculations of basic structural parameters, resulting in faster analysis. Furthermore, the torsional frequency of the low-pressure turbine shaft 3 is analyzed based on a thorough consideration of its torsional stiffness, the polar moment of inertia of the fan rotor 1, and the polar moment of inertia of the low-pressure turbine rotor 2. This eliminates the need to rebuild the simulation model, enabling margin analysis between the torsional frequency of the low-pressure turbine shaft 3 and the vibration frequencies generated by all engine components. This approach better meets the requirements of rapid iterations in the design phase, allowing for quick evaluation and optimization of the torsional vibration frequency of the low-pressure turbine shaft 3 in the early stages of engine design. This guides the structural design of the low-pressure turbine shaft 3, ensuring that the torsional vibration frequency of the turbofan engine's low-pressure turbine shaft 3 meets design requirements and that torsional resonance does not occur within the operating speed range, thus shortening the overall design cycle.

[0021] Based on the same inventive concept, this embodiment also provides a low-pressure turbine shaft for an aero-engine, the configuration of which is designed by the aforementioned aero-engine low-pressure turbine shaft torsional vibration design method.

[0022] Based on the same inventive concept, this embodiment also provides a design system for torsional vibration of a low-pressure turbine shaft of an aero-engine, used to implement the aforementioned design method for torsional vibration of a low-pressure turbine shaft of an aero-engine, including: The polar moment of inertia analysis module 4 is used to obtain the polar moment of inertia of fan rotor 1 and low-pressure turbine rotor 2 based on the three-dimensional solid model of the engine low-pressure rotor. The segmentation module 5 is used to segment the low-pressure turbine shaft 3 according to the inner diameter, outer diameter and length of the low-pressure turbine shaft 3 in the low-pressure rotor, forming multiple hollow circular shaft segments 301 and hollow conical shaft segments 302. The stiffness analysis module 6 is used to calculate the overall torsional stiffness of all hollow annular shaft segments 301 of the low-pressure turbine shaft 3 and the overall torsional stiffness of all hollow conical shaft segments 302, as well as the torsional stiffness of the low-pressure turbine shaft 3. Torsional frequency analysis module 7 is used to obtain the torsional frequency of low-pressure turbine shaft 3 based on the torsional stiffness of low-pressure turbine shaft 3, the polar moment of inertia of fan rotor 1 and low-pressure turbine rotor 2. The discrimination and adjustment module 8 is used to analyze the margin between the torsional frequency of the low-pressure turbine shaft 3 and the vibration frequency generated by all components of the engine. If the minimum value of the margin is greater than or equal to the preset margin value, the torsional frequency of the low-pressure turbine shaft 3 meets the design requirements. Otherwise, the dimensions of the low-pressure turbine shaft 3 are adjusted until the torsional frequency of the low-pressure turbine shaft 3 meets the design requirements.

[0023] Example 2 See Figure 1 , Figure 2 and Figure 4 This embodiment takes the torsional vibration design of the low-pressure turbine shaft 3 of a certain type of aero-engine as an example to describe in detail the design process of the torsional vibration design method of the low-pressure turbine shaft of the aero-engine of the present invention. The specific design process is as follows: S1. Based on the three-dimensional solid model of the low-pressure rotor of the engine, obtain the first pole moment of inertia of the fan rotor and the second pole moment of inertia of the low-pressure turbine rotor.

[0024] S2. Based on the inner diameter, outer diameter and length of the low-pressure turbine shaft 3 in the low-pressure rotor, the low-pressure turbine shaft 3 is segmented to form multiple hollow circular shaft segments 301 and hollow conical shaft segments 302. In this embodiment, based on the three-dimensional solid model of the engine's low-pressure rotor, the inner and outer diameters and length of the low-pressure turbine shaft 3 are obtained. According to the different inner and outer diameters of the low-pressure turbine shaft 3, the low-pressure turbine shaft 3 is divided into M segments, of which the number of hollow annular shaft segments is... The number of hollow conical shaft segments is .

[0025] like Figure 4 The diagram shown is a schematic of the low-pressure turbine shaft 3 and its segmented structure in this embodiment. Based on different inner and outer diameters, the low-pressure turbine shaft 3 is divided into 5 segments, i.e., M=5, where the number of hollow annular shaft segments is... =3, Number of hollow conical shaft segments =2.

[0026] S3. Calculate the overall torsional stiffness of all hollow annular shaft segments 301 of the low-pressure turbine shaft 3 and the overall torsional stiffness of all hollow conical shaft segments 302, as well as the torsional stiffness of the low-pressure turbine shaft 3. In this embodiment, the overall torsional stiffness of all hollow annular shaft segments 301 of the low-pressure turbine shaft 3 ,in For the first The shear elastic modulus of a hollow circular ring shaft segment made of 301 material. For the first The outer diameter of the hollow circular shaft segment 301 For the first The inner diameter of the hollow circular shaft segment 301 For the first The length of the hollow circular shaft segment 301 , This refers to the number of segments in the hollow circular ring shaft segment 301; Overall torsional stiffness of all hollow conical shaft segments ,in For the first Shear modulus of elasticity of a hollow conical shaft segment material For the first The outer diameter of the small end of the hollow conical shaft segment For the first The outer diameter of the large end of the hollow conical shaft segment For the first The inner diameter of the small end of the hollow conical shaft segment For the first The inner diameter of the large end of the hollow conical shaft segment For the first The length of each hollow conical shaft segment , The number of segments in the hollow conical shaft section. The value range is from 0 to Function variables of length interval, It is a micro-unit for the length of a hollow conical shaft segment; Torsional stiffness of low-pressure turbine shaft 3 ,in For the overall torsional stiffness of all low-pressure turbine shaft 3 hollow annular shaft segments 301, The overall torsional stiffness of all hollow conical shaft segments 302.

[0027] S4. Based on the torsional stiffness of the low-pressure turbine shaft 3, the polar moment of inertia of the fan rotor 1, and the polar moment of inertia of the low-pressure turbine rotor 2, the torsional frequency of the low-pressure turbine shaft 3 is obtained. In this embodiment, the torsional frequency of the low-pressure turbine shaft 3 is based on... Analysis yielded, among which The torsional frequency of the low-pressure turbine shaft 3 For the torsional stiffness of the low-pressure turbine shaft 3, The moment of inertia of the fan rotor is the single-pole moment of inertia. The low-pressure turbine rotor has a two-pole moment of inertia.

[0028] S5. Analyze the margin between the torsional frequency of the low-pressure turbine shaft 3 and the vibration frequency generated by all components of the engine. If the minimum value of the margin is greater than or equal to the preset margin value, the torsional frequency of the low-pressure turbine shaft 3 meets the design requirements. Otherwise, adjust the size of the low-pressure turbine shaft 3 until the torsional frequency of the low-pressure turbine shaft 3 meets the design requirements. The margin between the torsional frequency of the low-pressure turbine shaft 3 and the vibration frequencies generated by all engine components ,in The torsional frequency of the low-pressure turbine shaft 3 The m-th vibration frequency generated by all components and accessories of the engine.

[0029] In this embodiment, for the torsional frequency of the low-pressure turbine shaft 3, a speed margin is recommended. Greater than or equal to 20%. If the torsional frequency margin of the low-pressure turbine shaft 3 does not meet the design requirements, increase the outer diameter of the low-pressure turbine shaft 3 or decrease the length of the low-pressure turbine shaft 3, and iteratively calculate S1 to S5 until the frequency margin requirements are met.

[0030] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A design method for torsional vibration of a low-pressure turbine shaft in an aero-engine, characterized in that, include: S1. Based on the three-dimensional solid model of the engine's low-pressure rotor, obtain the polar moment of inertia of the fan rotor and the polar moment of inertia of the low-pressure turbine rotor. S2. Based on the inner diameter, outer diameter, and length of the low-pressure turbine shaft in the low-pressure rotor, the low-pressure turbine shaft is segmented to form multiple hollow circular shaft segments and hollow conical shaft segments. S3. Calculate the overall torsional stiffness of all hollow annular shaft segments of the low-pressure turbine shaft, the overall torsional stiffness of all hollow conical shaft segments, and the torsional stiffness of the low-pressure turbine shaft itself; among which, the overall torsional stiffness of all hollow annular shaft segments of the low-pressure turbine shaft... ,in For the first Shear elastic modulus of a hollow circular ring shaft segment. For the first The outer diameter of the hollow circular shaft segment For the first The inner diameter of the hollow circular shaft segment, For the first The length of each hollow circular ring shaft segment , This represents the number of segments in the hollow circular ring shaft. Overall torsional stiffness of all hollow conical shaft segments ,in For the first Shear modulus of elasticity of a hollow conical shaft segment material For the first The outer diameter of the small end of the hollow conical shaft segment For the first The outer diameter of the large end of the hollow conical shaft segment For the first The inner diameter of the small end of the hollow conical shaft segment For the first The inner diameter of the large end of the hollow conical shaft segment For the first The length of each hollow conical shaft segment , The number of segments in the hollow conical shaft section. The value range is from 0 to Function variables of length interval, It is a micro-unit for the length of a hollow conical shaft segment; Torsional stiffness of low-pressure turbine shaft ,in For the overall torsional stiffness of all hollow annular shaft segments of the low-pressure turbine shaft, The overall torsional stiffness of all hollow conical shaft segments; S4. The torsional frequency of the low-pressure turbine shaft is obtained by analyzing the torsional stiffness of the low-pressure turbine shaft, the polar moment of inertia of the fan rotor, and the polar moment of inertia of the low-pressure turbine rotor. S5. Analyze the margin between the low-pressure turbine shaft torsional frequency and the vibration frequency generated by all components of the engine. If the minimum value of the margin is greater than or equal to the preset margin value, the low-pressure turbine shaft torsional frequency meets the design requirements. Otherwise, adjust the size of the low-pressure turbine shaft until the low-pressure turbine shaft torsional frequency meets the design requirements.

2. The design method for torsional vibration of a low-pressure turbine shaft in an aero-engine according to claim 1, characterized in that, In step S4, the low-pressure turbine shaft torsional frequency is based on Analysis yielded, among which For low-pressure turbine shaft torsional frequency, For the torsional stiffness of the low-pressure turbine shaft, The polar moment of inertia of the fan rotor. This is the low-pressure turbine rotor polar moment of inertia.

3. The design method for torsional vibration of a low-pressure turbine shaft in an aero-engine according to claim 1, characterized in that, In step S4, the margin between the low-pressure turbine shaft torsional frequency and the vibration frequencies generated by all engine components is as follows: ,in For low-pressure turbine shaft torsional frequency, The m-th vibration frequency generated by all components and accessories of the engine.

4. A design system for torsional vibration of a low-pressure turbine shaft of an aero-engine, used to implement the design method for torsional vibration of a low-pressure turbine shaft of an aero-engine as described in any one of claims 1-3, characterized in that, include: The polar moment of inertia analysis module is used to obtain the polar moment of inertia of the fan rotor and the polar moment of inertia of the low-pressure turbine rotor based on the three-dimensional solid model of the engine's low-pressure rotor. The segmentation module is used to segment the low-pressure turbine shaft according to the inner diameter, outer diameter and length of the low-pressure turbine shaft in the low-pressure rotor, forming multiple hollow circular shaft segments and hollow conical shaft segments; The stiffness analysis module is used to calculate the overall torsional stiffness of all hollow annular shaft segments of the low-pressure turbine shaft, the overall torsional stiffness of all hollow conical shaft segments, and the torsional stiffness of the low-pressure turbine shaft itself; among them, the overall torsional stiffness of all hollow annular shaft segments of the low-pressure turbine shaft... ,in For the first Shear elastic modulus of a hollow circular ring shaft segment. For the first The outer diameter of the hollow circular shaft segment For the first The inner diameter of the hollow circular shaft segment, For the first The length of each hollow circular ring shaft segment , This represents the number of segments in the hollow circular ring shaft. Overall torsional stiffness of all hollow conical shaft segments ,in For the first Shear modulus of elasticity of a hollow conical shaft segment material For the first The outer diameter of the small end of the hollow conical shaft segment For the first The outer diameter of the large end of the hollow conical shaft segment For the first The inner diameter of the small end of the hollow conical shaft segment For the first The inner diameter of the large end of the hollow conical shaft segment For the first The length of each hollow conical shaft segment , The number of segments in the hollow conical shaft section. The value range is from 0 to Function variables of length interval, It is a micro-unit for the length of a hollow conical shaft segment; Torsional stiffness of low-pressure turbine shaft ,in For the overall torsional stiffness of all hollow annular shaft segments of the low-pressure turbine shaft, The overall torsional stiffness of all hollow conical shaft segments; The torsional frequency analysis module is used to obtain the torsional frequency of the low-pressure turbine shaft based on the torsional stiffness of the low-pressure turbine shaft, the polar moment of inertia of the fan rotor, and the polar moment of inertia of the low-pressure turbine rotor. The discrimination and adjustment module is used to analyze the margin between the low-pressure turbine shaft torsional frequency and the vibration frequency generated by all components of the engine. If the minimum value of the margin is greater than or equal to the preset margin value, the low-pressure turbine shaft torsional frequency meets the design requirements; otherwise, the dimensions of the low-pressure turbine shaft are adjusted until the low-pressure turbine shaft torsional frequency meets the design requirements.

5. The aero-engine low-pressure turbine shaft torsional vibration design system according to claim 4, characterized in that, In the torsional frequency analysis module, the torsional frequency of the low-pressure turbine shaft is based on... Analysis yielded, among which For low-pressure turbine shaft torsional frequency, For the torsional stiffness of the low-pressure turbine shaft, The polar moment of inertia of the fan rotor. This is the low-pressure turbine rotor polar moment of inertia.

6. The aero-engine low-pressure turbine shaft torsional vibration design system according to claim 4, characterized in that, In the discrimination and adjustment module, the margin between the low-pressure turbine shaft torsional frequency and the vibration frequencies generated by all engine components is considered. ,in For low-pressure turbine shaft torsional frequency, The m-th vibration frequency generated by all components and accessories of the engine.

7. A low-pressure turbine shaft for an aero-engine, characterized in that, Its configuration is designed by the torsional vibration design method for low-pressure turbine shafts of aero-engines as described in any one of claims 1-3.

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