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

Abstract

The present application relates to the technical field of aero-engine whole machine vibration, and particularly provides a high-pressure rotor bending deformation distribution optimization method based on configuration design, which comprises the following steps: extracting structural parameters of a high-pressure rotor system to be analyzed; establishing a finite element model to calculate dynamic characteristics of the high-pressure rotor system; extracting a fulcrum dynamic load and drawing a diagram of the fulcrum dynamic load of the high-pressure rotor changing with rotational speed; if the fulcrum dynamic load does not meet the requirements, the configuration of the high-pressure rotor needs to be optimized; controlling the fulcrum dynamic load from three positions of a front axle neck, a drum cylinder shaft and a rear axle neck; after configuration optimization, repeating power response calculation and fulcrum dynamic load analysis until the fulcrum dynamic load of the high-pressure rotor in the working speed range meets the requirements, so as to effectively control the fulcrum dynamic load of the high-pressure rotor.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aero-engine overall vibration, and particularly provides a high-pressure rotor bending deformation distribution optimization method based on configuration design. BACKGROUND

[0002] In a high thrust-to-weight ratio turbofan engine, the high-pressure rotor has high working speed, large working load and complex load environment, which leads to frequent engineering problems of vibration failure. The most prominent problem is that the high-pressure rotor shows large dynamic response at the support point, that is, the dynamic load at the support point is large, which transmits large vibration response to the bearing and stator load-bearing structure, and further leads to problems such as vibration overrun. The control problem of the dynamic load at the support point of the high-pressure rotor has become a key problem in the dynamic design and analysis of the high thrust-to-weight ratio turbofan engine.

[0003] For the control problem of the dynamic load at the support point of the high-pressure rotor of the aero-engine, the related methods in the existing public data are mostly to adjust the support stiffness and increase the damping. The advantage is that the high-pressure rotor structure does not need to be modified, and only the local support structure needs to be adjusted. However, the disadvantage is that it can only adjust the dynamic load at the support point near the critical speed, and it is difficult to suppress the dynamic load at the support point 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 structure layout and design are reasonably designed, and then the effective control of the dynamic load at the support point of the high-pressure rotor is realized, it is an effective technical measure to solve the problem. However, there is still a lack of systematic engineering method for how to realize the effective control of the dynamic load at the support point of the high-pressure rotor through the structure layout and configuration design. SUMMARY

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

[0005] The present application is realized in this way, providing a high-pressure rotor bending deformation distribution optimization method based on configuration design of an aero-engine, the high-pressure rotor being a high-pressure rotor in a high thrust-to-weight ratio turbofan engine, the design method comprising the following steps:

[0006] Step S1: extracting the structure parameters of the analyzed high-pressure rotor system;

[0007] Step S2: based on the structure parameters in step S1, establishing a finite element model, calculating the dynamic characteristics of the high-pressure rotor system, and calculating the dynamic response in the working speed range;

[0008] Step S3: based on the dynamic response calculation result obtained in step S2, extracting the fulcrum dynamic load, drawing a diagram of the fulcrum dynamic load of the high-pressure rotor system varying with the rotating speed, and judging whether the peak value of the fulcrum dynamic load is lower than the dynamic fatigue limit load of the bearing;

[0009] Step S4: based on the analysis result of step S3, performing configuration optimization design of the high-pressure rotor system, and repeating steps S2 and S3 until the fulcrum dynamic load of the high-pressure rotor system in the working rotating speed range meets the requirements.

[0010] Preferably, in step S1, the structural parameters of the high-pressure rotor system include material parameters, structural geometric parameters and loads suffered in the working process.

[0011] Preferably, in step S4, if the fulcrum dynamic load at a certain rotating 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.

[0012] Further preferably, due to the requirements of the overall structural design and aerodynamic performance of the aero-engine, the axial positions and radial dimensions of the front fulcrum, the rear fulcrum and the wheel discs of the high-pressure rotor cannot be adjusted, and based on this situation, the configuration of the high-pressure rotor system is optimized from the front shaft neck, the drum shaft and the rear shaft neck, the local rigidity of the front shaft neck, the drum shaft and the rear shaft neck is adjusted, and the bending deformation distribution of the high-pressure rotor system in the working process is adjusted, so as to effectively control the fulcrum dynamic load of the high-pressure rotor system.

[0013] Further preferably, the fulcrum dynamic load of the high-pressure rotor is mainly affected by the bending stiffness distribution characteristics, mainly the numerical value of the bending stiffness of the main structure of the high-pressure rotor (including the compressor, the drum shaft and the turbine) compared with the bending stiffness of the front and rear shaft necks, therefore, the relative rigidity coefficient of the bending stiffness of the front and rear shaft necks of the high-pressure rotor system is defined as:

[0014]

[0015]

[0016] In the formula, is the bending stiffness of the main structure of the high-pressure rotor system, and are the bending stiffness of the front and rear shaft necks, respectively;

[0017] and is a dimensionless coefficient, the larger the value, the greater the bending stiffness of the high-pressure rotor system main structure about the front journal or the rear journal; the bending deformation in the working process is more inclined to concentrate on the front journal or the rear journal, and the rotational inertia load borne by the compressor and the turbine is correspondingly reduced, finally showing the reduction of the fulcrum dynamic load, and vice versa;

[0018] In the specific design process, by optimizing the geometric configuration of the front journal, the drum shaft and the rear journal, the values of and are increased as much as possible within the engineering allowable range, the bending deformation of the high-pressure rotor system in the working process is adjusted to concentrate on the front journal or the rear journal, so that the effective control of the fulcrum dynamic load of the high-pressure rotor system is realized.

[0019] Further preferably, the geometric configuration optimization design of the front journal is specifically as follows:

[0020] The inclination angle and the axial span of the front journal are adjusted, and the position and the form of the connection structure of the front journal and the compressor disc are correspondingly modified, including the position of the connection structure at which stage of the compressor disc and the radial position of the disc, by adjusting the configuration and the bending stiffness of the front journal, the values of are increased, so that the bending deformation of the high-pressure rotor system in the working process concentrates on the front journal position rather than the compressor position.

[0021] Further preferably, the geometric configuration optimization design of the drum shaft is specifically as follows:

[0022] The radial size, the profile and the thickness of the drum shaft are adjusted, and the position and the form of the front and rear flange edges of the drum shaft are correspondingly modified, the bending stiffness of the drum shaft is increased, by adjusting the configuration of the drum shaft, the values of and are increased, and the bending deformation of the high-pressure rotor system main structure of the “compressor-drum shaft-turbine” is reduced in the working process.

[0023] Further preferably, the geometric configuration optimization design of the rear journal is specifically as follows:

[0024] The inclination angle and the axial span of the rear journal are adjusted, and the connection form of the rear journal and the turbine disc is correspondingly modified, by adjusting the configuration and the bending stiffness of the rear journal, the values of are increased, so that the bending deformation of the high-pressure rotor system in the working process concentrates on the rear journal position rather than the turbine position.

[0025] Compared with the prior art, the advantages of the present application are as follows:

[0026] The present application optimizes the geometric configuration of the high-pressure rotor system from three positions of the front neck, the drum shaft and the rear neck, and can obtain very ideal effect. Moreover, based on the understanding of the structural characteristics and dynamic characteristics of the high-pressure rotor of the high thrust-to-weight ratio turbofan engine, three structures sensitive to the fulcrum dynamic load are selected for optimization design, the method flow is simple and clear, the operation process is clear and convenient, and on the basis of relevant engineering experience, better optimization results can be quickly obtained. Most importantly, using the optimization design method proposed in the present application, through effective control of the high-pressure rotor fulcrum dynamic load in the design stage of the aero-engine type, the high-pressure rotor can greatly meet the structural and dynamic design requirements, and avoid possible vibration failure in the test and use process as soon as possible, which has important engineering significance for the overall structural design of the aero-engine and the progress of the type development. BRIEF DESCRIPTION OF DRAWINGS

[0027] The present application will be further described in detail below in combination with the drawings and embodiments:

[0028] Figure 1 is a flow chart of the present application;

[0029] Figure 2 is a high-pressure rotor structure line drawing;

[0030] Figure 3 is a high-pressure rotor deformation schematic diagram of the original design scheme;

[0031] Figure 4 is a high-pressure rotor line drawing after configuration optimization design;

[0032] Figure 5 is a high-pressure rotor deformation schematic diagram after configuration optimization design;

[0033] Figure 6 is a high-pressure rotor fulcrum dynamic load change diagram with speed under two schemes. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical scheme and advantages of the present application more clear and explicit, the present application will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application.

[0035] Figure 1 is a flow chart of the aero-engine high-pressure rotor bending deformation distribution optimization method based on configuration design provided by the present application, and the following Figures 2-6 will be further described in detail.

[0036] Figure 2A typical high pressure rotor structure of a high thrust-to-weight ratio turbofan engine is shown. The structural features of the high pressure rotor system are expressed in the form of lines. The compressor 1 includes six stages of wheel disks and one stage of seal disks, and the turbine 2 includes one stage of turbine disks.

[0037] The front journal 3 of the high pressure rotor system extends from the bearing seat of the front fulcrum, is connected by bolts at the radial middle position of the second stage disk of the compressor, and is connected as a whole with the first, second, and third stage disks of the compressor by bolts. The front journal 3 has a high bending stiffness.

[0038] The drum shaft 4 of the high pressure rotor extends from the radial middle position of the seal disk with a small inclination angle. The inclined drum shaft 4 is changed to be flush at the middle position of the combustion chamber and is connected with the front shaft of the turbine disk by bolts. At the position of the seal disk, the sixth stage disk of the compressor, the seal disk, and the drum shaft 4 are connected as a whole by long bolts. Since the drum shaft 4 has a small inclination angle and a small radial dimension, it has a low bending stiffness.

[0039] The rear journal 5 of the high pressure rotor extends from the rear end surface of the turbine disk, is connected with the rear end surface of the turbine disk by bolts, and is connected to the bearing seat of the rear fulcrum with a large inclination angle. The rear journal 5 has a high bending stiffness.

[0040] Overall, Figure 2 The high pressure rotor system shown has a high bending stiffness at the positions of the front journal 3 and the rear journal 5, and a low bending stiffness at the position of the drum shaft 4, and the values of which are 0.73 and 0.41, respectively.

[0041] Figure 3 The deformation of the high pressure rotor system in the working speed range is shown, and the bending deformation is concentrated at the position of the drum shaft, and the dynamic response at the front and rear bearings is large, showing a large fulcrum dynamic load. Therefore, the fulcrum dynamic load of the high pressure rotor in the working speed range is prone to exceed the limit, which does not meet the requirements of long-term stable operation of the aero-engine, and the structure needs to be optimized.

[0042] Figure 4 The structure of the high pressure rotor system after the configuration optimization design is shown. The original design scheme is represented by light-colored lines, and the optimized design scheme is represented by dark-colored lines to show the comparison between the two schemes.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] Figure 6The dynamic load of the bearing point of the high-pressure rotor system under two schemes is shown. The high-pressure rotor of the high thrust-weight ratio turbofan engine generally works above two critical speeds, so there are two response peaks in the low speed range. In the original design scheme, although the third critical speed is far away, the dynamic load of the bearing point still has a sustained growth trend after the speed exceeds the two critical speeds, and then decreases until the third critical speed. Therefore, in the working speed range, the dynamic load of the bearing point of the high-pressure rotor is at a high level, thereby showing vibration overrun, which does not meet the requirements of long-term stable work of the aero-engine. In the improved scheme, the dynamic load of the bearing point is always at a low level in a large speed range after the speed exceeds the two critical speeds, and then a third response peak is generated near the third critical speed. Therefore, in the working speed range, the dynamic load of the bearing point of the high-pressure rotor is at a low level, which is beneficial to the long-term stable work of the aero-engine. The optimization method of the dynamic load of the bearing point proposed in the application achieves ideal effect.

[0049] So far, the technical scheme of the application has been described in combination with the preferred embodiments shown in the drawings, and those skilled in the art should understand that the protection scope of the application is obviously not limited to these specific embodiments, and those skilled in the art can make equivalent changes or replacements to the related technical features without departing from the principles of the application, and the technical scheme after the changes or replacements will fall within the protection scope of the 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; 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 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; The high-pressure rotor system is optimized at three locations: 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 to effectively control the dynamic load at the support points of the high-pressure rotor system. 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 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.

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: 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.

4. 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: 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.

5. The method for optimizing the bending deformation distribution of an aero-engine high-pressure rotor based on configuration design according to claim 1, 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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