Engine rotor structure scheme design method

Abstract

The invention discloses an engine rotor structure scheme design method in the technical field of aero-engines, and the method reduces the thickness of a radial plate area of a pressed part in a rotor structure scheme to reduce the rigidity of the pressed part in the axial direction of a rotor, so that the axial direction of the pressed part is not changed under the condition that the pre-tightening force is not changed. The axial compression amount of the whole pressed part is increased, so that the pressed part can store larger axial springback amount to offset the axial shrinkage amount of the pressed part during high-speed rotation in the working state, the effect of reducing the relaxation force is achieved, the final working pre-tightening force F1 and the pre-tightening force reserve K1 at the maximum pre-estimated working rotating speed are increased, and the pre-tightening force reserve K1 at the maximum pre-estimated working rotating speed is increased. The pre-tightening force reserve K1 can meet the design requirement, meanwhile, the rotor structure scheme cannot be greatly changed, large-range rematching design does not need to be conducted on internal accessories of the engine, and the influence on the research and development progress of the engine is small.

Description

Technical Field

[0001] The present invention relates to the technical field of aero-engines, and particularly to a design method for an engine rotor structure scheme. Background Art

[0002] When the aero-engine disk rotates at high speed, it will bear circumferential tensile stress. Under the action of the circumferential tensile stress, the disk will axially contract, reducing the axial pre-tightening force. When the axial pre-tightening force is too small, the disk rotating at high speed is prone to excessive vibration.

[0003] A certain type of engine rotor includes a disk, a central tie rod, a shaft, a pressing block and a nut. The pressing block, the disk and the shaft are arranged in sequence. The tie rod passes through the pressing block, the disk and the shaft and is threadedly engaged with the shaft. One end of the tie rod away from the shaft is engaged with the nut, and an axial pre-tightening force is applied to the pressing block and the disk through the nut;

[0004] Currently, generally, by increasing the pre-tightening force in the assembled state, the disk still has sufficient pre-tightening force at the upper limit speed to avoid excessive vibration of the disk rotating at high speed;

[0005] Assume that the axial relaxation force of the disk at the upper limit speed (pre-tightening force in the assembled state - pre-tightening force in the working state) is ΔF, and the pre-tightening force F0 in the assembled state. Generally, it should be ensured that F0≥1.25×ΔF. However, F0 cannot be increased indefinitely. Excessive F0 will cause strength problems in the rotor, such as tie rod yield, fracture, and thread tooth fracture;

[0006] In the current rotor structure design process, if the final pre-tightening force fails to meet the design requirements and F0 reaches the design limit that the tie rod can withstand, it is necessary to re-design the rotor structure scheme to make the pre-tightening force F0 meet the design requirements, and it is necessary to conduct a large-scale re-matching design of the internal accessories of the engine, which affects the R & D progress of the engine.

[0007] Based on this, the present invention designs a design method for an engine rotor structure scheme to solve the above problems. Summary of the Invention

[0008] To achieve the above object, the present invention provides the following technical solution: A design method for an engine rotor structure scheme, including the following steps:

[0009] S1, rotor structure scheme design: Design a rotor structure scheme according to the engine performance requirements;

[0010] S2, structural finite element analysis: Establish a finite element model according to the rotor structure scheme, apply working loads and pre-tightening forces to the finite element model of the rotor structure scheme, conduct finite element calculation and analysis on each part in the rotor structure scheme, and obtain the stress distribution of each part;

[0011] S3, Strength evaluation: According to the stress distribution obtained from the structural finite element analysis, evaluate whether the yield strength reserve and ultimate strength reserve of the parts both meet the design requirements. If they do not meet the design requirements, return to step S1 to redesign the rotor structure scheme;

[0012] S4, Finite element pre-tightening force calculation: Apply the initial pre-tightening force F0 and the working load on the finite element model established according to the rotor structure scheme, calculate and analyze the working pre-tightening force F1 at the maximum estimated working speed of the rotor structure scheme, and calculate the pre-tightening force reserve K1 at the maximum estimated working speed of the rotor structure scheme through the working pre-tightening force F1,

[0013]

[0014] In the formula, ΔF is the relaxation force at the maximum estimated working speed,

[0015] ΔF = F0 - F1

[0016] If the pre-tightening force reserve K1 at the maximum estimated working speed is less than the design requirements, it is determined that the pre-tightening force reserve at the maximum estimated working speed of the rotor structure scheme is insufficient. If the initial pre-tightening force F0 has not reached the maximum tolerable pre-tightening force of the rotor structure scheme, increase the initial pre-tightening force F0 and then re-conduct the finite element pre-tightening force analysis. If the initial pre-tightening force F0 has reached the maximum tolerable pre-tightening force of the rotor structure scheme, then proceed to step S5. If the pre-tightening force reserve K1 at the maximum estimated working speed is not less than the design requirements, it is determined that the pre-tightening force reserve at the maximum estimated working speed of the rotor structure scheme is sufficient, and output the rotor structure scheme;

[0017] S5, Reduce the web thickness: Optimize the rotor structure scheme, reduce the thickness of the web area of at least one compression part in the rotor structure scheme, and return to step S2 to re-conduct the structural finite element analysis.

[0018] As a further solution of the present invention, in step S2, when obtaining the stress distribution of each part, it includes the radial stress distribution and the circumferential stress distribution.

[0019] As a further solution of the present invention, in step S3, when evaluating the strength reserve of the parts, extract the maximum average radial stress on the cylindrical surface of the parts and the minimum meridional average circumferential stress.

[0020] As a further solution of the present invention, in step S4, when applying the initial pre-tightening force F0 to the finite element model, calculate the maximum tolerable pre-tightening force of the rotor structure scheme through the design requirements of the strength reserve of the tie rods in the rotor structure scheme, and the initial pre-tightening force F0 is not greater than the maximum tolerable pre-tightening force of the rotor structure scheme.

[0021] As a further solution of the present invention, in step S4, the design requirements for the strength reserve of the tie rod include the axial tensile yield strength reserve and the axial tensile ultimate strength reserve of the tie rod. The calculation method for the maximum pre-tightening force that the tie rod can withstand is as follows:

[0022] S41. Calculate the maximum pre-tightening force that the tie rod can withstand by using the axial tensile yield strength reserve of the tie rod in the design requirements.

[0023]

[0024] In the formula, F max1 is the axial tensile force borne by the tie rod when the axial tensile yield strength reserve of the tie rod reaches the design requirements, σ1 is the axial tensile yield strength of the tie rod, S is the cross-sectional area of the tie rod, and K2 is the required axial tensile yield strength reserve of the tie rod in the design requirements.

[0025] S42. Calculate the maximum pre-tightening force that the tie rod can withstand by using the axial tensile ultimate strength reserve of the tie rod in the design requirements.

[0026]

[0027] In the formula, F max2 is the axial tensile force borne by the tie rod when the axial tensile ultimate strength reserve of the tie rod reaches the design requirements, σ2 is the axial tensile ultimate strength of the tie rod, and K3 is the required axial tensile ultimate strength reserve of the tie rod in the design requirements.

[0028] S43. Compare F max1 and F max2 , and select the smaller value of F max1 and F max2 as the maximum pre-tightening force that the tie rod can withstand.

[0029] As a further solution of the present invention, the working load includes temperature, rotational speed, and pneumatic load.

[0030] As a further solution of the present invention, in step S4, if the working pre-tightening force F1 = 0, it is directly determined that the working pre-tightening force F1 is insufficient at the maximum estimated working speed of the rotor structure scheme.

[0031] As a further solution of the present invention, in step S5, the web is an equal-thickness area connecting the hub and the rim of the part.

[0032] The present invention has the following beneficial effects:

[0033] When the initial pre - tightening force F0 reaches the maximum tolerable pre - tightening force of the rotor structure scheme, and the pre - tightening force reserve K1 at the maximum estimated operating speed is less than the design requirement, the thickness of the web area of the compression - loaded parts in the rotor structure scheme is reduced to decrease the stiffness of the compression - loaded parts in the axial direction of the rotor. This enables an increase in the overall axial compression of the compression - loaded parts under the condition of constant pre - tightening force, so that the compression - loaded parts can store a greater axial rebound amount to offset the axial shrinkage during high - speed rotation of the compression - loaded parts in the working state. Consequently, the effect of reducing the relaxation force is achieved, increasing the final working pre - tightening force F1 and the pre - tightening force reserve K1 at the maximum estimated operating speed, enabling the pre - tightening force reserve K1 to meet the design requirements. At the same time, it will not cause significant changes to the rotor structure scheme, eliminating the need for a large - scale re - matching design of the internal accessories of the engine and having less impact on the R & D progress of the engine.

[0034] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The following will refer to the drawings for a more detailed description of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0036] Figure 1 It is a schematic diagram of the engine rotor structure in the present invention.

[0037] Figure 2 It is a schematic diagram of the web of the tension - loaded parts in the rotor structure scheme of the present invention.

[0038] Figure 3 It is a flow chart of the present invention.

[0039] LEGEND DESCRIPTION:

[0040] 1. Disk; 2. Tie rod; 3. Shaft; 4. Compression block; 5. Nut. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0041] The following will describe the embodiments of the present invention in detail with reference to the drawings. However, the present invention can be implemented in many different ways defined and covered by the following.

[0042] Please refer to Figures 1-3 , the present invention provides a technical solution: a design method for an engine rotor structure scheme, including the following steps:

[0043] S1, Design of the rotor structure scheme: Design the rotor structure scheme according to the engine performance requirements;

[0044] First, it is necessary to design an initial rotor structure scheme according to the performance requirements of the engine. The design of the rotor structure scheme belongs to the conventional technical means in this field and will not be elaborated here.

[0045] S2, Structural finite element analysis: Establish a finite element model according to the rotor structure scheme, apply working loads and pre-tightening forces to the finite element model of the rotor structure scheme, conduct finite element calculation and analysis on each part in the rotor structure scheme, and obtain the stress distribution of each part.

[0046] After the design of the rotor structure scheme is completed, it is necessary to evaluate the strength of the rotor structure scheme to determine whether the strength of the rotor structure scheme meets the design requirements. When conducting finite element analysis, apply working loads and pre-tightening forces to the finite element model of the rotor structure scheme. At this time, the magnitude of the pre-tightening force does not affect the strength evaluation of the rotor structure scheme, and the magnitude of the pre-tightening force can be applied according to past experience. After finite element calculation and analysis, obtain the stress distribution of each part in the rotor structure scheme under the working state.

[0047] Finite element analysis software is a conventional technical means in this field. ANSYS, ABAQUS, etc. can be used. The present invention does not limit this. At the same time, establishing a finite element model and conducting finite element calculation and analysis on the finite element model belong to the conventional technical means in this field and will not be elaborated here.

[0048] S3, Strength evaluation: According to the stress distribution obtained from the structural finite element analysis, evaluate whether the yield strength reserve and ultimate strength reserve of each part in the rotor structure scheme meet the design requirements. If they do not meet the design requirements, return to step S1 to redesign the rotor structure scheme.

[0049] After obtaining the stress distribution of each part under the working state, extract different stress values of the parts according to the data required for calculating the strength reserve to evaluate the yield strength reserve and ultimate strength reserve of the parts respectively. When the yield strength reserve and ultimate strength reserve of each part meet the design requirements, it means that the rotor structure scheme meets the design requirements. When the yield strength reserve or ultimate strength reserve of any one of the parts does not meet the design requirements, it is determined that the current rotor structure scheme does not meet the design requirements and it is necessary to return to step S1 to redesign the rotor structure scheme.

[0050] The yield strength reserve and ultimate strength reserve of the parts vary according to the different performance requirements of the engine. Optionally, the yield strength reserve is not less than 1.2, and the ultimate strength reserve is not less than 2.0.

[0051] S4, Finite element pre-tightening force calculation: Apply the initial pre-tightening force F0 and the working load on the finite element model established according to the rotor structure scheme, calculate and analyze the working pre-tightening force F1 at the maximum estimated working speed of the rotor structure scheme, and calculate the pre-tightening force reserve K1 at the maximum estimated working speed of the rotor structure scheme through the working pre-tightening force F1.

[0052]

[0053] In the formula, ΔF is the relaxation force at the maximum estimated working speed.

[0054] ΔF = F0 - F1

[0055] If the pre-tightening force reserve K1 at the maximum estimated working speed is less than the design requirement, it is determined that the pre-tightening force reserve at the maximum estimated working speed of the rotor structure scheme is insufficient. If the initial pre-tightening force F0 does not reach the maximum tolerable pre-tightening force of the rotor structure scheme, increase the initial pre-tightening force F0 and then re-conduct the finite element pre-tightening force analysis. If the initial pre-tightening force F0 reaches the maximum tolerable pre-tightening force of the rotor structure scheme, proceed to step S5. If the pre-tightening force reserve K1 at the maximum estimated working speed is not less than the design requirement, it is determined that the pre-tightening force reserve at the maximum estimated working speed of the rotor structure scheme is sufficient, and output the rotor structure scheme.

[0056] By applying the initial pre-tightening force F0 and the working load on the finite element model of the rotor structure scheme, calculate and analyze the working pre-tightening force F1 at the maximum estimated working speed of the rotor structure scheme. The reduction of the pre-tightening force at the maximum estimated working speed is the difference between the initial pre-tightening force F0 and the working pre-tightening force F1 at the maximum estimated working speed, that is, the relaxation force ΔF at the maximum estimated working speed. After obtaining the relaxation force ΔF at the maximum estimated working speed, the pre-tightening force reserve K1 can be calculated through the pre-tightening force reserve K1 calculation formula. Calculate the pre-tightening force reserve K1 at the maximum estimated working speed of the rotor structure scheme, and judge whether the currently applied initial pre-tightening force F0 is sufficient. When the initial pre-tightening force F0 reaches the maximum tolerable pre-tightening force of the rotor structure scheme, it means that the initial pre-tightening force F0 cannot be increased further. At the same time, when the pre-tightening force reserve K1 at the maximum estimated working speed is less than the design requirement, step S5 needs to be carried out.

[0057] Similarly, the pre-tightening force reserve K1 varies according to different engine performance requirements. Optionally, the pre-tightening force reserve K1 is not less than 1.25.

[0058] S5, Reduce the web thickness: Optimize the rotor structure scheme, reduce the thickness of the web area of at least one compression part in the rotor structure scheme, and return to step S2 to re-conduct the structural finite element analysis.

[0059] Such as Figure 1As shown in the figure, a certain type of engine rotor includes a disk 1, a central tie rod 2, a shaft 3, a pressing block 4, and a nut 5. Among them, the parts under pressure include the disk 1, the shaft 3, and the pressing block 4, that is, the parts subjected to pressure by the tie rod 2 and the nut 5. Among the parts under pressure, there will be some parts under pressure with web parts, such as Figure 2 As shown in the figure, the web part is the equal-thickness area connecting the hub and the rim of the part under pressure. Reducing the web part of the part under pressure can reduce the stiffness of the part under pressure in the axial direction of the rotor, so that under the condition of unchanged pre-tightening force, the overall axial compression of the part under pressure increases, so that the part under pressure can store a larger axial rebound amount to offset the axial shrinkage amount when the part under pressure rotates at high speed under working conditions, and then achieve the effect of reducing the relaxation force, so that the final working pre-tightening force F1 and the pre-tightening force reserve K1 at the maximum estimated working speed increase, so that the pre-tightening force reserve K1 can meet the design requirements;

[0060] When reducing the web thickness, the reduction amount of the web thickness can be comprehensively judged according to the yield strength reserve, ultimate strength reserve of the parts in the rotor structure scheme and the pre-tightening force reserve K1. When using this method for the first time, the method of reducing the web thickness in small amounts and multiple times can be adopted;

[0061] When the initial pre-tightening force F0 of this method reaches the maximum tolerable pre-tightening force of the rotor structure scheme, and at the same time the pre-tightening force reserve K1 at the maximum estimated working speed is less than the design requirements, the thickness of the web area of the parts under pressure in the rotor structure scheme is reduced to reduce the stiffness of the parts under pressure in the axial direction of the rotor, so that under the condition of unchanged pre-tightening force, the overall axial compression of the parts under pressure increases, so that the parts under pressure can store a larger axial rebound amount to offset the axial shrinkage amount when the parts under pressure rotate at high speed under working conditions, and then achieve the effect of reducing the relaxation force, so that the final working pre-tightening force F1 and the pre-tightening force reserve K1 at the maximum estimated working speed increase, so that the pre-tightening force reserve K1 can meet the design requirements. At the same time, it will not cause great changes to the rotor structure scheme, and there is no need to carry out a large-scale re-matching design for the internal accessories of the engine, which has little impact on the R & D progress of the engine.

[0062] Furthermore, in step S2, when obtaining the stress distribution of each part, it includes the radial stress distribution and the circumferential stress distribution. During the working process, the rotor structure scheme is subjected to a torque load and then rotates at high speed. During the rotation process, the parts under pressure in the rotor structure scheme mainly generate radial stress and circumferential stress. Therefore, it is necessary to obtain the radial stress distribution and the circumferential stress distribution of the parts under pressure to provide a basis for the subsequent strength evaluation of the rotor structure scheme;

[0063] Further, in step S3, when evaluating the strength reserve of the part, the maximum average radial stress of the cylindrical surface of the part and the minimum meridional average circumferential stress are extracted. Among them, when calculating the strength reserve (strength ÷ average stress), the radial stress and circumferential stress of the part need to be selected. When selecting the radial stress, the cylindrical surface with the maximum average radial stress is selected, and the maximum average radial stress received by the part is used to judge whether the yield strength reserve and ultimate strength reserve of the part meet the requirements, so as to ensure that both the yield strength reserve and ultimate strength reserve of the whole part meet the requirements. Similarly, when selecting the circumferential stress, the average circumferential stress of the minimum meridional plane is extracted. The minimum meridional plane refers to the cross-section with the smallest area passing through the axis 3 of the rotor, so as to ensure that both the yield strength reserve and ultimate strength reserve of the whole part meet the requirements.

[0064] Further, in step S4, when applying the initial pre-tightening force F0 to the finite element model, the maximum pre-tightening force that the rotor structure scheme can withstand is calculated according to the strength reserve design requirements of the tie rod 2 in the rotor structure scheme, and the initial pre-tightening force F0 is not greater than the maximum pre-tightening force that the rotor structure scheme can withstand;

[0065] After applying the pre-tightening force to the compressed parts in the rotor structure scheme through the tie rod 2 and the nut 5, the tie rod 2 will be subjected to an axial tension force with the same magnitude but opposite direction to the pre-tightening force. When the axial tension force received by the tie rod 2 is too large, it will cause the tie rod 2 to yield, break or the thread teeth to break. Therefore, when designing the rotor structure scheme, the tie rod 2 in the rotor structure scheme has the design requirements for strength reserve, so as to prevent the tie rod 2 from yielding, breaking or the thread teeth from breaking due to excessive axial tension force. Also, because the pre-tightening force is the same as the tension force received by the tie rod 2, therefore, the maximum axial tension force that the tie rod 2 can withstand can be deduced from the design requirements for the strength reserve of the tie rod 2. The maximum axial tension force that the tie rod 2 can withstand is the maximum pre-tightening force that the tie rod 2 and the nut 5 can apply to the compressed parts, that is, the maximum pre-tightening force that the current rotor structure scheme can withstand. On the premise that the pre-tightening force does not exceed the maximum pre-tightening force that the rotor structure scheme can withstand, it can ensure that the strength reserve of the tie rod 2 meets the design requirements, providing a basis for the application range of the initial pre-tightening force F0;

[0066] Further, in the design requirements, the tie rod 2 has the requirements for axial tensile yield strength reserve and axial tensile ultimate strength reserve, so it needs to be calculated separately. The calculation method for the maximum pre-tightening force that the tie rod 2 can withstand is as follows:

[0067] S41, calculate the maximum pre-tightening force that the tie rod 2 can withstand by using the axial tensile yield strength reserve of the tie rod 2 in the design requirements,

[0068]

[0069] In the formula, F max1When the axial tensile yield strength reserve of the tie rod 2 reaches the design requirement, the axial tensile force borne by the tie rod 2 is considered. Let σ1 be the axial tensile yield strength of the tie rod 2. According to the material of the tie rod 2, the cross-sectional area S of the tie rod 2 can be obtained by referring to relevant materials, which is a known parameter of the tie rod 2. K2 is the required axial tensile yield strength reserve of the tie rod 2 in the design requirement and can be obtained from the design requirements of the rotor structure scheme.

[0070] First, use the design requirement of the axial tensile yield strength reserve of the tie rod 2 to calculate the maximum axial tensile force that the tie rod 2 can withstand. When the magnitude of the initial pre-tightening force F0 does not exceed F max1 it can ensure that the axial tensile yield strength reserve of the tie rod 2 reaches the design requirement.

[0071] S42. Calculate the maximum pre-tightening force that the tie rod 2 can withstand using the axial tensile ultimate strength reserve of the tie rod 2 in the design requirement

[0072]

[0073] In the formula, F max2 is the axial tensile force borne by the tie rod 2 when the axial tensile ultimate strength reserve of the tie rod 2 reaches the design requirement. Let σ2 be the axial tensile ultimate strength of the tie rod 2. According to the material of the tie rod 2, the cross-sectional area S of the tie rod 2 can be obtained by referring to relevant materials, which is a known parameter of the tie rod 2. K3 is the required axial tensile ultimate strength reserve of the tie rod 2 in the design requirement and can be obtained from the design requirements of the rotor structure scheme.

[0074] Secondly, use the design requirement of the axial tensile ultimate strength reserve of the tie rod 2 to calculate the maximum axial tensile force that the tie rod 2 can withstand. When the magnitude of the initial pre-tightening force F0 does not exceed F max2 it can ensure that the axial tensile ultimate strength reserve of the tie rod 2 reaches the design requirement.

[0075] S43. Compare F max1 and F max2 and select the smaller value of F max1 and F max2 as the maximum pre-tightening force that the tie rod can withstand. Due to the difference between the axial tensile yield strength and the axial tensile ultimate strength of the tie rod 2, and at the same time, there is a difference between the axial tensile yield strength reserve and the axial tensile ultimate strength reserve of the tie rod 2 in the design requirement, which will lead to a difference between the final F max1 and F max2 . And the axial tensile force borne by the tie rod 2 must be less than both F max1 and F max2 . Therefore, select the smaller value of F max1 and F max2 as the maximum pre-tightening force that the tie rod can withstand to ensure that both the axial tensile yield strength reserve and the axial tensile ultimate strength reserve of the tie rod 2 reach the design requirement after applying the initial pre-tightening force F0, providing the maximum value for the application range of the initial pre-tightening force F0.

[0076] The axial tensile yield strength reserve K2 and the axial tensile ultimate strength reserve K3 of the tie rod 2 vary according to different engine performance requirements. Optionally, the axial tensile yield strength reserve K2 is not less than 1.2, and the axial tensile ultimate strength reserve K3 is not less than 1.5.

[0077] Further, in step S4, if the working preload F1 = 0, it is directly determined that the working preload F1 is insufficient at the maximum estimated working speed of the rotor structure scheme.

[0078] In step S4, the preload reserve K1 needs to be calculated through the calculation formula of the preload reserve K1. When the working preload F1 = 0, it means that the preload at the maximum estimated working speed of the current rotor structure scheme is 0, that is, there is no preload. Therefore, it can be directly determined that the working preload F1 is insufficient at the maximum estimated working speed of the rotor structure scheme, and there is no need to perform calculations, saving time.

[0079] Further, the working loads include temperature, speed, and aerodynamic loads. In steps S2 and S4, working loads need to be applied to the finite element model of the rotor structure scheme. The working loads include temperature loads, speed loads, and aerodynamic loads to achieve the effect of fully simulating the working state, thereby ensuring the accuracy of the stress distribution of each part and the working preload F1 in the end, and making the final design result accurate.

[0080] Further, in step S4, when applying the preload to the compressed part through the tie rod 2 and the nut 5, an interference amount is set between the nut 5 and the compressed part in contact with the nut 5, so as to achieve the effect of applying the preload. At the same time, when determining the magnitude of the preload, the pressure received by the contact surface between the nut 5 and the compressed part is extracted, and the pressure received by the surface of the nut 5 in contact with the compressed part is the preload.

[0081] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A design method for an engine rotor structure, characterized in that, It includes the following steps: S1. Rotor structure scheme design: Design the rotor structure scheme according to the engine performance requirements; S2. Structural finite element analysis: Establish a finite element model according to the rotor structure scheme, apply working loads and pre-tightening forces to the finite element model of the rotor structure scheme, conduct finite element calculation and analysis on each part in the rotor structure scheme, and obtain the stress distribution of each part; S3. Strength evaluation: According to the stress distribution obtained from the structural finite element analysis, evaluate whether the yield strength reserve and ultimate strength reserve of each part in the rotor structure scheme meet the design requirements. If they do not meet the design requirements, return to step S1 to redesign the rotor structure scheme; S4. Finite element pre-tightening force calculation: Apply the initial pre-tightening force F0 and working loads to the finite element model established according to the rotor structure scheme, calculate and analyze the working pre-tightening force F1 at the maximum estimated working speed of the rotor structure scheme, and calculate the pre-tightening force reserve K1 at the maximum estimated working speed of the rotor structure scheme through the working pre-tightening force F1, where ΔF is the relaxation force at the maximum estimated working speed, ΔF = F0 - F1 If the pre-tightening force reserve K1 at the maximum estimated working speed is less than the design requirement, it is determined that the pre-tightening force reserve at the maximum estimated working speed of the rotor structure scheme is insufficient. If the initial pre-tightening force F0 has not reached the maximum tolerable pre-tightening force of the rotor structure scheme, increase the initial pre-tightening force F0 and then re-conduct the finite element pre-tightening force analysis. If the initial pre-tightening force F0 has reached the maximum tolerable pre-tightening force of the rotor structure scheme, then proceed to step S5. If the pre-tightening force reserve K1 at the maximum estimated working speed is not less than the design requirement, it is determined that the pre-tightening force reserve at the maximum estimated working speed of the rotor structure scheme is sufficient, and output the rotor structure scheme; S5. Reduce the web thickness: Optimize the rotor structure scheme, reduce the thickness of the web area of at least one compression part in the rotor structure scheme, and return to step S2 to re-conduct the structural finite element analysis.

2. A design method for an engine rotor structure scheme according to claim 1, characterized in that: In step S2, when obtaining the stress distribution of each part, it includes the radial stress distribution and the circumferential stress distribution.

3. A design method for an engine rotor structure solution according to claim 1, characterized in that: In step S3, when evaluating the strength reserve of the part, extract the maximum average radial stress on the cylindrical surface of the part and the minimum meridional average circumferential stress.

4. A design method for an engine rotor structure solution according to claim 1, characterized in that: In step S4, when applying the initial pre-tightening force F0 to the finite element model, calculate the maximum tolerable pre-tightening force of the rotor structure scheme through the design requirements for the strength reserve of the tie rod in the rotor structure scheme, and the initial pre-tightening force F0 is not greater than the maximum tolerable pre-tightening force of the rotor structure scheme.

5. A design method for an engine rotor structure solution according to claim 4, characterized in that In step S4, the design requirements for the strength reserve of the tie rod include the axial tensile yield strength reserve and the axial tensile ultimate strength reserve of the tie rod. The calculation method for the maximum tolerable pre-tightening force of the tie rod is as follows: S41. Calculate the maximum tolerable pre-tightening force of the tie rod by using the axial tensile yield strength reserve of the tie rod in the design requirements, where F max1 is the axial tensile force borne by the tie rod when the axial tensile yield strength reserve of the tie rod reaches the design requirement, σ1 is the axial tensile yield strength of the tie rod, S is the cross-sectional area of the tie rod, and K2 is the required axial tensile yield strength reserve of the tie rod in the design requirement; S42. Calculate the maximum tolerable pre-tightening force of the tie rod by using the axial tensile ultimate strength reserve of the tie rod in the design requirements In the formula, F max2 is the axial tensile force borne by the tie rod when the axial tensile ultimate strength reserve of the tie rod reaches the design requirement, σ2 is the axial tensile ultimate strength of the tie rod, and K3 is the axial tensile ultimate strength reserve required for the tie rod in the design requirement; S43, compare F max1 with F max2 , and select the smaller value between F max1 and F max2 as the maximum pre-tightening force that the tie rod can withstand.

6. A design method for an engine rotor structure solution according to claim 1, characterized in that: The working loads include temperature, speed and aerodynamic loads.

7. A design method for an engine rotor structure scheme according to claim 1, characterized in that: In step S4, if the working pre-tightening force F1 = 0, it is directly determined that the working pre-tightening force F1 at the maximum estimated working speed of the rotor structure scheme is insufficient.

8. A design method for an engine rotor structure solution according to claim 1, characterized in that: In step S5, the web is an equal-thickness area connecting the hub and the rim of the part.

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