Aero-engine high-pressure rotor bending deformation distribution optimization method based on configuration design

Abstract

The invention relates to the technical field of aero-engine complete machine vibration, and particularly provides an aero-engine high-pressure rotor bending deformation distribution optimization method based on configuration design, which comprises the following steps: extracting structural parameters of an analyzed high-pressure rotor system; establishing a finite element model, and calculating the dynamic characteristics of the high-pressure rotor system; extracting a fulcrum dynamic load, and drawing a change diagram of the fulcrum dynamic load of the high-pressure rotor along with the rotating speed; if the dynamic load of the fulcrum does not meet the requirement, the configuration of the high-pressure rotor needs to be optimally designed; the fulcrum dynamic load is controlled from three positions of a front journal, a drum shaft and a rear journal; and after configuration optimization, dynamic response calculation and fulcrum dynamic load analysis are repeated until the fulcrum dynamic loads of the high-pressure rotor within the working rotating speed range all meet the requirements, and therefore effective control over the fulcrum dynamic loads of the high-pressure rotor is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of complete aircraft engine vibration, and in particular provides an aircraft engine high-pressure rotor bending deformation distribution optimization method based on configuration design. Background Art

[0002] In high-thrust-to-weight ratio turbofan engines, the high-pressure rotor operates at high speeds, under heavy workloads, and in complex load environments, leading to frequent engineering problems related to vibration failures. Most notably, the high-pressure rotor exhibits a large dynamic response at the fulcrum. This large dynamic load at the fulcrum transmits a large vibration response to the bearings and stator load-bearing structures, leading to problems such as excessive vibration. Controlling the dynamic load at the fulcrum of the high-pressure rotor has become a key issue in the dynamic design and analysis of high-thrust-to-weight ratio turbofan engines.

[0003] Regarding the problem of controlling the dynamic load of the fulcrum of the high-pressure rotor of an aircraft engine, the relevant methods in the existing public data mostly use methods such as adjusting the support stiffness and increasing the damping. The advantage is that there is no need to modify the high-pressure rotor structure, and only the support structure needs to be adjusted locally. However, the disadvantage is that it can only adjust the dynamic load of the fulcrum near the critical speed, and it is difficult to suppress the dynamic load of the fulcrum of the high-pressure rotor in the supercritical high speed range. Therefore, if the dynamic characteristics of the high-pressure rotor are fully considered in the overall design stage of the high-thrust-to-weight ratio turbofan engine, and the effective control of the dynamic load of the high-pressure rotor fulcrum is achieved through reasonable structural layout and design, it is an effective technical measure to solve this problem. However, there is still a lack of systematic engineering methods for how to achieve effective control of the dynamic load of the high-pressure rotor fulcrum through structural layout and configuration design. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a method for optimizing the bending deformation distribution of an aero-engine high-pressure rotor based on configuration design, so as to achieve effective control of the dynamic load of the high-pressure rotor support point, and provide technical theory and reference methods for the structural layout and dynamic design of a high thrust-to-weight ratio turbofan engine.

[0005] The present invention is implemented by providing a method for optimizing the bending deformation distribution of an aero-engine high-pressure rotor based on configuration design, wherein the high-pressure rotor is a high-pressure rotor in a high thrust-to-weight ratio turbofan engine. The design method comprises the following steps: Step S1: extracting the structural parameters of the analyzed high-pressure rotor system; Step S2: Based on the structural parameters in step S1, a finite element model is established to calculate the dynamic characteristics of the high-pressure rotor system and the dynamic response within the operating speed range; Step S3: Based on the dynamic response calculation results obtained in step S2, extract the support dynamic load, draw a graph of the high-pressure rotor system support dynamic load versus speed, and determine whether the peak value of the support dynamic load is lower than the dynamic fatigue limit load of the bearing; Step S4: Based on the analysis results of step S3, the high-pressure rotor system configuration is optimized and designed, and steps S2 and S3 are repeated until the dynamic loads of the support points of the high-pressure rotor system within the operating speed range meet the requirements.

[0006] Preferably, in step S1, the structural parameters of the high-pressure rotor system include material parameters, structural geometric parameters, and loads received during operation.

[0007] Preferably, in step S4, if the dynamic load of the fulcrum at a certain speed point is higher than the dynamic fatigue limit load of the bearing, it indicates that the dynamic characteristics of the high-pressure rotor system are insufficient and the configuration of the high-pressure rotor system needs to be optimized.

[0008] It is further preferred that, due to the requirements of the overall structural design and aerodynamic performance of the aircraft engine, the axial position and radial dimensions of the front support point, rear support point and each stage of the high-pressure rotor should not be adjusted. Based on this situation, the present invention optimizes the configuration design of the high-pressure rotor system from three positions: the front shaft neck, drum shaft and rear shaft neck of the high-pressure rotor system. By adjusting the local stiffness of the front shaft neck, drum shaft and rear shaft neck, the bending deformation distribution of the high-pressure rotor system during operation is adjusted to achieve effective control of the dynamic load of the support points of the high-pressure rotor system.

[0009] Further preferably, the dynamic load of the high-pressure rotor's support point is mainly affected by the bending stiffness distribution characteristics, mainly the bending stiffness of the high-pressure rotor main structure (including the compressor, drum shaft and turbine) compared with the bending stiffness of the front and rear journals. Therefore, the relative stiffness coefficient of the bending stiffness of the front and rear journals of the high-pressure rotor system is defined as: Where, is the bending stiffness of the main structure of the high-pressure rotor system, and are the bending stiffness of the front and rear journals, respectively; and It is a dimensionless coefficient. The larger the value, the greater the bending stiffness of the main structure of the high-pressure rotor system about the front or rear journal. The bending deformation during operation tends to be concentrated on the front or rear journal, and the rotational inertia load on the compressor and turbine is correspondingly reduced, which ultimately manifests as a reduction in the dynamic load on the support point, and vice versa. During the specific design process, the front journal, drum shaft and rear journal were optimized to improve the performance as much as possible within the scope of engineering. and The value of the high-pressure rotor system is adjusted to concentrate the bending deformation of the high-pressure rotor system on the front journal or the rear journal during operation, thereby achieving effective control of the dynamic load of the high-pressure rotor system support.

[0010] Further preferably, the geometric configuration optimization design of the front journal is specifically as follows: Adjust the inclination angle and axial span of the front journal, and modify the position and form of the connection structure between the front journal and the compressor wheel accordingly, including which stage of the compressor wheel the connection structure is located on and the radial position of the wheel. By adjusting the configuration and bending stiffness of the front journal, the The value of φ makes the bending deformation of the high-pressure rotor system during operation concentrated at the front journal position rather than the compressor position.

[0011] Further preferably, the geometric configuration optimization design of the drum shaft is specifically as follows: Adjust the radial size, profile and thickness of the drum shaft, and modify the position and form of the front and rear flange edges of the drum shaft accordingly to improve the bending stiffness of the drum shaft. and The value of the compressor-drum shaft-turbine high-pressure rotor system is reduced during operation.

[0012] Further preferably, the geometric configuration optimization design of the rear journal is specifically as follows: Adjust the inclination angle and axial span of the rear journal, and modify the connection between the rear journal and the turbine disc accordingly. By adjusting the configuration and bending stiffness of the rear journal, the The value of φ makes the bending deformation of the high-pressure rotor system during operation concentrated at the rear journal position rather than the turbine position.

[0013] Compared with the prior art, the advantages of the present invention are: The present invention optimizes the geometric configuration of the high-pressure rotor system from three positions: the front journal, the drum shaft, and the rear journal, and can achieve very ideal results. In addition, based on the understanding of the structural characteristics and dynamic characteristics of the high-pressure rotor of a high thrust-to-weight ratio turbofan engine, the present invention selects three structures that are sensitive to the dynamic load of the fulcrum for optimization design. The method flow is concise and clear, the operation process is clear and convenient, and better optimization results can be quickly obtained based on relevant engineering experience. The most critical thing is that by using the optimization design method proposed in the present invention, during the aircraft engine model development and design stage, through the effective control of the dynamic load of the high-pressure rotor fulcrum, it can greatly help the high-pressure rotor meet the structural and dynamic design requirements, and avoid possible vibration failures during the test run and use as early as possible, which has important engineering significance for promoting the overall structural design and model development progress of aircraft engines. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments: Figure 1 Flowchart of the present invention; Figure 2 It is a line diagram of the high-pressure rotor structure; Figure 3 This is a schematic diagram of the deformation of the high-pressure rotor in the original design; Figure 4 This is a line drawing of the high-pressure rotor after configuration optimization; Figure 5 This is a schematic diagram of the high-pressure rotor deformation after configuration optimization; Figure 6 The following is a graph showing the change of dynamic load of high-pressure rotor support with speed under two schemes. DETAILED DESCRIPTION

[0015] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0016] Figure 1 The flow chart of the method for optimizing the bending deformation distribution of an aero-engine high-pressure rotor based on configuration design provided by the present invention is as follows: Figures 2 to 6 This application is described in further detail.

[0017] Figure 2 This figure shows the high-pressure rotor structure of a typical high-thrust-to-weight ratio turbofan engine. The figure uses lines to illustrate the structural features of the high-pressure rotor system. Compressor 1 includes six stages of disks and a first-stage sealing disk, while turbine 2 includes a first-stage turbine disk.

[0018] The high-pressure rotor system's front journal 3 extends from the bearing seat at the front pivot point and is bolted to the radial center of the compressor's second-stage disc. It is also integrally bolted to the first, second, and third-stage discs of the compressor. This location provides high bending stiffness.

[0019] The high-pressure rotor's drum shaft 4 extends from the radial center of the sealing disk at a slight inclination angle. This inclined drum shaft 4 is then flush with the center of the combustion chamber and bolted to the front shaft of the turbine disk. At the sealing disk, long bolts connect the compressor stage six disk, sealing disk, and drum shaft 4 as a single unit. Due to the shallow inclination angle and small radial dimensions of the drum shaft 4, its bending stiffness is low.

[0020] The rear journal 5 of the high-pressure rotor extends from the rear end face of the turbine disc and is connected to the rear end face of the turbine disc by bolts, and is connected to the bearing seat of the rear support at a large inclination angle. The rear journal 5 position has a high bending stiffness.

[0021] In general, Figure 2 The high-pressure rotor system shown has a higher bending stiffness at the front journal 3 and rear journal 5, and a lower bending stiffness at the drum shaft 4. and The values ​​of are lower, at 0.73 and 0.41 respectively.

[0022] Figure 3 The deformation of the high-pressure rotor system within the operating speed range is shown. Bending deformation is concentrated at the drum axis, and the dynamic response is larger at the front and rear bearings, indicating significant pivot dynamic loads. Therefore, the pivot dynamic loads of this high-pressure rotor are likely to exceed the limit within the operating speed range, failing to meet the requirements for long-term stable operation of aircraft engines, necessitating structural optimization.

[0023] Figure 4 The structure of the high-pressure rotor system after configuration optimization is shown. Light lines are used to represent the original design scheme, and dark lines are used to represent the optimized design scheme, to show the comparison between the two schemes.

[0024] After the configuration optimization, the front journal of the high-pressure rotor system has a significantly increased inclination angle and is bolted to the compressor's second-stage disc at the disc edge. The connection structure between the first and third-stage compressor discs and the second-stage disc has been adjusted accordingly. The front journal's larger inclination angle and the larger radial position of the bolted connection structure ensure good integrity between the front journal and the compressor, resulting in high bending stiffness. However, the large angle at the connection between the front pivot bearing seat and the front journal results in low local bending stiffness, making it susceptible to significant bending deformation when subjected to load.

[0025] After the optimized configuration, the high-pressure rotor's drum shaft extends from the edge of the sealing disk at a steep angle, becoming flush in the middle. It is then bolted to the front shaft of the turbine disk. At the edge of the sealing disk, long bolts connect the compressor stage six disk, sealing disk, and drum shaft as a single unit. Due to the drum shaft's steep inclination and large radial dimensions, its bending stiffness is high.

[0026] The optimized high-pressure rotor's rear journal extends from the center of the turbine disc's rear end. It adopts a one-piece structure and is not bolted, but directly connected to the bearing seat at the rear pivot at a slight angle. The rear journal has a smaller radial dimension and a smaller inclination angle, resulting in lower bending stiffness.

[0027] In general, Figure 4 The high-pressure rotor with optimized configuration shown in the figure has lower bending stiffness at the front and rear journal positions and higher bending stiffness at the drum shaft position. and The values ​​were 7.91 and 5.17 respectively, both of which were greatly improved.

[0028] Figure 5 The deformation of the optimized high-pressure rotor within the operating speed range is demonstrated. The bending deformation of the main "compressor-drum shaft-turbine" structure is minimal, concentrated at the front and rear journals. The dynamic response at the front and rear bearings is also low, indicating minimal dynamic loads at the pivot points. Therefore, the optimized high-pressure rotor system exhibits minimal dynamic loads at the pivot points within the operating speed range, meeting the requirements for long-term stable operation of aircraft engines and achieving a relatively ideal optimized design result.

[0029] Figure 6 The paper shows how the dynamic load on the high-pressure rotor system's pivot point changes with speed under two schemes. For high-thrust-to-weight ratio turbofan engines, the high-pressure rotor generally operates above the second-order critical speed, resulting in two response peaks within the low-speed range. In the original design, after the speed exceeds the second-order critical speed, the pivot dynamic load continues to increase, even though it is far from the third-order critical speed, and only decreases when it reaches the third-order critical speed. Therefore, within the operating speed range, the high-pressure rotor's pivot dynamic load will be at a high level, resulting in excessive vibration and not meeting the requirements for long-term stable operation of the aircraft engine. In the improved scheme, after the speed exceeds the second-order critical speed, the pivot dynamic load will remain at a low level within a larger speed range until a third response peak is generated near the third-order critical speed. Therefore, within the operating speed range, the high-pressure rotor's pivot dynamic load will be at a low level, which is beneficial to the long-term stable operation of the aircraft engine. The pivot dynamic load optimization method proposed in this invention achieves ideal results.

[0030] So far, the technical solution of the present application has been described in conjunction with the preferred embodiments shown in the accompanying drawings. Those skilled in the art should understand that the scope of protection of the present application is obviously not limited to these specific embodiments. Without departing from the principles of the present application, those skilled in the art can make equivalent changes or replacements to the relevant technical features, and the technical solutions after these changes or replacements will fall within the scope of protection of the present application.

Claims

1. A method for optimizing the bending deformation distribution of an aero-engine high-pressure rotor based on configuration design, characterized in that: The high-pressure rotor is a high-pressure rotor in a high-thrust-to-weight ratio turbofan engine, and the distribution optimization method comprises the following steps: Step S1: extracting the structural parameters of the analyzed high-pressure rotor system; Step S2: Based on the structural parameters in step S1, a finite element model is established to calculate the dynamic characteristics of the high-pressure rotor system and the dynamic response within the operating speed range; Step S3: Based on the dynamic response calculation results obtained in step S2, extract the support dynamic load, draw a graph of the high-pressure rotor system support dynamic load versus speed, and determine whether the peak value of the support dynamic load is lower than the dynamic fatigue limit load of the bearing; Step S4: Based on the analysis results of step S3, the high-pressure rotor system configuration is optimized and designed, and steps S2 and S3 are repeated until the dynamic loads of the support points of the high-pressure rotor system within the operating speed range meet the requirements.

2. The method for optimizing the bending deformation distribution of an aero-engine high-pressure rotor based on configuration design according to claim 1 is characterized in that: In step S1 , the structural parameters of the high-pressure rotor system include material parameters, structural geometric parameters, and loads received during operation.

3. The method for optimizing the bending deformation distribution of an aero-engine high-pressure rotor based on configuration design according to claim 1 is characterized in that: In step S4, if the dynamic load of the support at a certain speed point is higher than the dynamic fatigue limit load of the bearing, it means that the dynamic characteristics of the high-pressure rotor system are insufficient and the configuration of the high-pressure rotor system needs to be optimized.

4. The method for optimizing the bending deformation distribution of an aero-engine high-pressure rotor based on configuration design according to claim 3 is characterized in that: The high-pressure rotor system is optimized from three positions: the front journal, drum shaft and rear journal. By adjusting the local stiffness of the front journal, drum shaft and rear journal, the bending deformation distribution of the high-pressure rotor system during operation is adjusted.

5. The method for optimizing the bending deformation distribution of an aero-engine high-pressure rotor based on configuration design according to claim 4 is characterized in that: The relative stiffness coefficient of the front and rear journal bending stiffness of the high-pressure rotor system is defined as: Where, is the bending stiffness of the main structure of the high-pressure rotor system, and are the bending stiffness of the front and rear journals, respectively; and It is a dimensionless coefficient. The larger the value, the greater the bending stiffness of the main structure of the high-pressure rotor system about the front journal or the rear journal. The bending deformation during operation tends to be concentrated on the front journal or the rear journal, and the rotational inertia load on the compressor and the turbine is reduced accordingly, which is ultimately manifested as a reduction in the dynamic load of the support, and vice versa.

6. The method for optimizing the bending deformation distribution of an aero-engine high-pressure rotor based on configuration design according to claim 5 is characterized in that: The geometric optimization design of the front journal is as follows: Adjust the inclination angle and axial span of the front journal, and modify the position and form of the connection structure between the front journal and the compressor wheel, including which stage of the compressor wheel the connection structure is located on and the radial position of the wheel, to improve The value of φ makes the bending deformation of the high-pressure rotor system during operation concentrated at the front journal position rather than the compressor position.

7. The method for optimizing the bending deformation distribution of an aero-engine high-pressure rotor based on configuration design according to claim 5, characterized in that: The specific optimization design of the geometric configuration of the drum shaft is as follows: Adjust the radial size, profile and thickness of the drum shaft, and modify the position and form of the front and rear flange edges of the drum shaft to increase the bending stiffness of the drum shaft and improve and The value of the high-pressure rotor system is reduced during operation.

8. The method for optimizing the bending deformation distribution of an aero-engine high-pressure rotor based on configuration design according to claim 5 is characterized in that: The geometric optimization design of the rear journal is as follows: Adjust the inclination angle and axial span of the rear journal, and modify the connection between the rear journal and the turbine disc to improve The value of φ makes the bending deformation of the high-pressure rotor system during operation concentrated at the rear journal position rather than the turbine position.

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