Blade cover amount adjusting and correcting method and system considering vibration stress

Abstract

The invention relates to the technical field of aero-engine blade design, and discloses a blade cover amount adjusting and correcting method and system considering vibration stress. Obtaining the high-cycle fatigue strength reserve distribution and static strength reserve distribution of the rotor blade under the combined conditions of different circumferential hood amount adjustment values and axial hood amount adjustment values, and finally obtaining the maximum minimum value of the high-cycle fatigue strength reserve distribution. The combination of the circumferential cover amount adjustment value and the axial cover amount adjustment value with the static strength reserve meeting the design requirement serves as the adjustment amount of the blade cover amount, and the rotor blade cover amount is adjusted and corrected. According to the cover amount adjusting and correcting method, the blade static stress distribution and vibration stress distribution conditions are comprehensively considered, so that the cover amount adjusting result is more reasonable, the blade static stress can be reduced, meanwhile, the high-cycle fatigue resistance of the blade is improved, and then the durability and reliability of the engine rotor blade are improved.

Description

Technical Field

[0001] The invention relates to the technical field of aeroengine blade design, and discloses a blade cover amount adjustment and correction method and system taking vibration stress into consideration. Background Art

[0002] The rotor blades of aircraft engines are subjected to centrifugal loads and aerodynamic loads during operation. The aerodynamic load mainly produces a bending moment on the blades, which will cause a high level of bending stress on the blades. In the design process of fan and compressor rotor blades, in order to reduce the bending stress caused by the aerodynamic bending moment of the rotor blades and improve the stress distribution of the blades, the centroid of each section of the rotor blade is generally appropriately offset in the circumferential and axial directions, so that the centrifugal force of the blade's own mass produces a centrifugal bending moment in the opposite direction of the aerodynamic bending moment, thereby achieving the effect of bending moment compensation, improving the stress and deformation of the blades during operation, and increasing the strength reserve of the blades. The offset of the centroid of the section is usually called the shroud amount.

[0003] Blade high-cycle fatigue failure is a common engine failure. In order to improve the blade's resistance to high-cycle fatigue, the existing shroud adjustment scheme is to reduce the static stress of the blade body under the main working state, that is, to increase the static strength reserve, which also improves the fatigue resistance to a certain extent. However, since the blade fatigue strength reserve is related to both static stress and vibration stress, the existing shroud adjustment scheme does not further consider the characteristics of the blade vibration stress distribution and static stress distribution. The result obtained by simply taking the static stress of the blade body as the optimization target cannot meet the requirements of structural strength and vibration well, and is still insufficient in improving the blade's resistance to high-cycle fatigue. Summary of the invention

[0004] The object of the present invention is to provide a blade cover adjustment correction method and system taking vibration stress into consideration, which can reduce the static stress of the blade while improving the blade's ability to resist high-cycle fatigue, thereby improving the durability and reliability of the engine rotor blade.

[0005] In order to achieve the above technical effects, the technical solution adopted by the present invention is:

[0006] A blade cover amount adjustment correction method considering vibration stress comprises:

[0007] Constructing a finite element model of the rotor blade according to the initial blade profile of the rotor blade aerodynamic design;

[0008] The finite element model is subjected to vibration characteristic analysis and static strength analysis under design load by using simulation software to obtain static stress distribution and vibration stress distribution of the rotor blade under different combinations of circumferential shroud adjustment values ​​and axial shroud adjustment values;

[0009] According to the vibration stress distribution and static stress distribution of the rotor blades, analyzing and obtaining the high cycle fatigue strength reserve distribution and static strength reserve distribution of the rotor blades under each of the combination conditions;

[0010] The combination of the circumferential shroud adjustment value and the axial shroud adjustment value whose minimum value of the high cycle fatigue strength reserve distribution is the largest and whose static strength reserve meets the design requirements is selected as the blade shroud adjustment value.

[0011] Furthermore, the static strength reserve distribution of the rotor blade under each of the above combination conditions is σ bi is the tensile strength of the i-th node, σ mi is the static stress at the i-th node.

[0012] Furthermore, the high cycle fatigue strength reserve distribution of the rotor blade under each of the above combination conditions is in is the average stress at the ith node, σ bi is the tensile strength of the i-th node, σ ai is the normalized vibration stress of the ith node. The vibration stress normalization is to linearly scale the vibration stress results obtained by simulation so that the maximum value of the vibration stress is limited to 100 MPa. -1,i is the high cycle fatigue limit of the ith node.

[0013] Furthermore, the circumferential cover adjustment value Y X Meet Y X,min ≤Y X ≤Y X,max , axial cover adjustment value Y Z Meet Y Z,min ≤Y Z ≤Y Z,max , where Y X,min Adjust the lower limit value for the circumferential cover design, Y X,max Y is the upper limit value of the circumferential cover design adjustment. Z,min The lower limit value of the axial cover design adjustment, Y Z,max Adjust the upper limit value for axial shroud design.

[0014] In order to achieve the above technical effects, the present invention also provides a blade cover amount adjustment and correction system considering vibration stress, comprising:

[0015] A finite element model building module, used for building a finite element model of a rotor blade according to an initial blade profile of aerodynamic design of the rotor blade;

[0016] A simulation module, for performing vibration characteristic analysis and static strength analysis under design load on the finite element model using simulation software, and obtaining static stress distribution and vibration stress distribution of the rotor blade under different combinations of circumferential shroud adjustment values ​​and axial shroud adjustment values;

[0017] An analysis module is used to analyze and obtain the high cycle fatigue strength reserve distribution and the static strength reserve distribution of the rotor blade under each of the combined conditions according to the vibration stress distribution and the static stress distribution of the rotor blade;

[0018] The adjustment amount optimization module is used to select a combination of a circumferential cover amount adjustment value and an axial cover amount adjustment value whose minimum value of high cycle fatigue strength reserve distribution is the largest and whose static strength reserve meets the design requirements as the blade cover amount adjustment amount.

[0019] Furthermore, in the analysis module, the static strength reserve distribution of the rotor blade under each of the combined conditions is σ bi is the tensile strength of the i-th node, σ mi is the static stress at the i-th node.

[0020] Furthermore, in the analysis module, the high cycle fatigue strength reserve distribution of the rotor blade under each combination condition is in is the average stress at the ith node, σ bi is the tensile strength of the i-th node, σ ai is the normalized vibration stress of the ith node. The vibration stress normalization is to linearly scale the vibration stress results obtained by simulation so that the maximum value of the vibration stress is limited to 100 MPa. -1,i is the high cycle fatigue limit of the ith node.

[0021] Furthermore, in the adjustment amount optimization module, the circumferential cover amount adjustment value Y X Meet Y X,min ≤Y X ≤Y X,max , axial cover adjustment value Y Z Meet Y Z,min ≤Y Z ≤Y Z,max , where Y X,min Adjust the lower limit value for the circumferential cover design, Y X,max Y is the upper limit value of the circumferential cover design adjustment. Z,min The lower limit value of the axial cover design adjustment, Y Z,max Adjust the upper limit value for axial shroud design.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention analyzes the finite element model of the rotor blade to obtain the high cycle fatigue strength reserve distribution and static strength reserve distribution of the rotor blade under different combinations of circumferential cover adjustment values ​​and axial cover adjustment values, and finally uses the combination of the circumferential cover adjustment value and the axial cover adjustment value whose minimum value of the high cycle fatigue strength reserve distribution is the maximum and whose static strength reserve meets the design requirements as the blade cover adjustment amount to adjust and correct the rotor blade cover amount. The cover adjustment and correction method comprehensively considers the static stress distribution and vibration stress distribution of the blade, so that the cover adjustment result is more reasonable, and can improve the blade's ability to resist high cycle fatigue while reducing the blade's static stress, thereby improving the durability and reliability of the engine rotor blade. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a flow chart of a blade cover amount adjustment correction method considering vibration stress in an embodiment;

[0024] Figure 2 It is a structural block diagram of the blade cover amount adjustment and correction system considering vibration stress in the embodiment;

[0025] Among them, 1. Finite element model building module; 2. Simulation module; 3. Analysis module; 4. Adjustment quantity optimization module. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below in conjunction with the embodiments and drawings. However, it should not be understood that the scope of the above subject matter of the present invention is limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

[0027] Example

[0028] See also Figure 1 and Figure 2 , a blade cover amount adjustment correction method considering vibration stress, comprising:

[0029] Constructing a finite element model of the rotor blade according to the initial blade profile of the rotor blade aerodynamic design;

[0030] The finite element model is subjected to vibration characteristic analysis and static strength analysis under design load by using simulation software to obtain static stress distribution and vibration stress distribution of the rotor blade under different combinations of circumferential shroud adjustment values ​​and axial shroud adjustment values;

[0031] According to the vibration stress distribution and static stress distribution of the rotor blades, analyzing and obtaining the high cycle fatigue strength reserve distribution and static strength reserve distribution of the rotor blades under each of the combination conditions;

[0032] The combination of the circumferential shroud adjustment value and the axial shroud adjustment value whose minimum value of the high cycle fatigue strength reserve distribution is the largest and whose static strength reserve meets the design requirements is selected as the blade shroud adjustment value.

[0033] In this embodiment, by analyzing the finite element model of the rotor blade, the high cycle fatigue strength reserve distribution and static strength reserve distribution of the rotor blade under different combinations of circumferential cover adjustment values ​​and axial cover adjustment values ​​are obtained, and finally the combination of the circumferential cover adjustment value and the axial cover adjustment value whose minimum value of the high cycle fatigue strength reserve distribution is the maximum and whose static strength reserve meets the design requirements is used as the blade cover adjustment amount, and the rotor blade cover amount is adjusted and corrected. The cover adjustment correction method comprehensively considers the static stress distribution and vibration stress distribution of the blade, so that the cover adjustment result is more reasonable, and can reduce the static stress of the blade while improving the ability of the blade to resist high cycle fatigue, thereby improving the durability and reliability of the engine rotor blade.

[0034] In this embodiment, the static strength reserve distribution of the rotor blade under each of the above combination conditions is σ bi is the tensile strength of the i-th node, σ mi is the static stress at the i-th node.

[0035] In this embodiment, the high cycle fatigue strength reserve distribution of the rotor blade under each combination condition is in is the average stress of the ith node. σ bi is the tensile strength of the i-th node, σ ai is the normalized vibration stress of the ith node. The vibration stress normalization is to linearly scale the vibration stress results obtained by simulation so that the maximum value of the vibration stress is limited to 100 MPa. -1,i is the high cycle fatigue limit of the i-th node. The high cycle fatigue strength reserve takes into account the influence of the node average stress and vibration stress of the rotor blade finite element model, and can maximize the blade's high cycle fatigue resistance while taking into account the static strength reserve.

[0036] In this embodiment, the circumferential cover amount adjustment value Y X Meet Y X,min ≤Y X ≤Y X,max , axial cover adjustment value Y Z Meet Y Z,min ≤Y Z ≤Y Z,max , where Y X,min Adjust the lower limit value for the circumferential cover design, Y X,max Y is the upper limit value of the circumferential cover design adjustment. Z,minThe lower limit value of the axial cover design adjustment, Y Z,max Adjust the upper limit value for axial shroud design.

[0037] Based on the same inventive concept, this embodiment also provides a blade cover amount adjustment and correction system considering vibration stress, including:

[0038] A finite element model building module 1 is used to build a finite element model of a rotor blade according to an initial blade profile of aerodynamic design of the rotor blade;

[0039] Simulation module 2 is used to perform vibration characteristic analysis and static strength analysis under design load on the finite element model using simulation software to obtain static stress distribution and vibration stress distribution of the rotor blade under different combinations of circumferential shroud adjustment values ​​and axial shroud adjustment values;

[0040] An analysis module 3 is used to analyze and obtain the high cycle fatigue strength reserve distribution and the static strength reserve distribution of the rotor blade under each of the combined conditions according to the vibration stress distribution and the static stress distribution of the rotor blade;

[0041] The adjustment amount optimization module 4 is used to select a combination of a circumferential cover amount adjustment value and an axial cover amount adjustment value whose minimum value of high cycle fatigue strength reserve distribution is the largest and whose static strength reserve meets the design requirements as the blade cover amount adjustment value.

[0042] The above are only 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 in the protection scope of the present invention.

Claims

1. A blade cover adjustment correction method considering vibration stress, characterized in that: include: Constructing a finite element model of the rotor blade according to the initial blade profile of the rotor blade aerodynamic design; The finite element model is subjected to vibration characteristic analysis and static strength analysis under design load by using simulation software to obtain static stress distribution and vibration stress distribution of the rotor blade under different combinations of circumferential shroud adjustment values ​​and axial shroud adjustment values; According to the vibration stress distribution and static stress distribution of the rotor blades, analyzing and obtaining the high cycle fatigue strength reserve distribution and static strength reserve distribution of the rotor blades under each of the combination conditions; The combination of the circumferential shroud adjustment value and the axial shroud adjustment value whose minimum value of the high cycle fatigue strength reserve distribution is the largest and whose static strength reserve meets the design requirements is selected as the blade shroud adjustment value.

2. The blade cover amount adjustment and correction method considering vibration stress according to claim 1, characterized in that: Static strength reserve distribution of rotor blades under each of the above mentioned combination conditions σ bi is the tensile strength of the i-th node, σ mi is the static stress at the i-th node.

3. The blade cover amount adjustment and correction method considering vibration stress according to claim 1, characterized in that: High cycle fatigue strength reserve distribution of rotor blades under each of the above mentioned combination conditions in is the average stress at the ith node, σ bi is the tensile strength of the i-th node, σ ai is the normalized vibration stress of the ith node. The vibration stress normalization is to linearly scale the vibration stress results obtained by simulation so that the maximum value of the vibration stress is limited to 100 MPa. -1,i is the high cycle fatigue limit of the ith node.

4. The blade cover amount adjustment and correction method considering vibration stress according to claim 1, characterized in that: Circumferential cover adjustment value Y X Meet Y X,min ≤Y X ≤Y X,max , axial cover adjustment value Y Z Meet Y Z,min ≤Y Z ≤Y Z,max , where Y X,min Adjust the lower limit value for the circumferential cover design, Y X,max Y is the upper limit value of the circumferential cover design adjustment. Z,min The lower limit value of the axial cover design adjustment, Y Z,max Adjust the upper limit value for axial shroud design.

5. A blade cover adjustment correction system considering vibration stress, characterized in that: include: A finite element model building module, used for building a finite element model of a rotor blade according to an initial blade profile of aerodynamic design of the rotor blade; A simulation module, for performing vibration characteristic analysis and static strength analysis under design load on the finite element model using simulation software, and obtaining static stress distribution and vibration stress distribution of the rotor blade under different combinations of circumferential shroud adjustment values ​​and axial shroud adjustment values; An analysis module is used to analyze and obtain the high cycle fatigue strength reserve distribution and the static strength reserve distribution of the rotor blade under each of the combined conditions according to the vibration stress distribution and the static stress distribution of the rotor blade; The adjustment amount optimization module is used to select a combination of a circumferential cover amount adjustment value and an axial cover amount adjustment value whose minimum value of high cycle fatigue strength reserve distribution is the largest and whose static strength reserve meets the design requirements as the blade cover amount adjustment amount.

6. The blade cover amount adjustment and correction system considering vibration stress according to claim 5, characterized in that: In the analysis module, the static strength reserve distribution of the rotor blade under each of the combined conditions σ bi is the tensile strength of the i-th node, σ mi is the static stress at the i-th node.

7. The blade cover amount adjustment and correction system considering vibration stress according to claim 5, characterized in that: In the analysis module, the high cycle fatigue strength reserve distribution of the rotor blade under each combination condition in is the average stress at the ith node, σ bi is the tensile strength of the i-th node, σ ai is the normalized vibration stress of the ith node. The vibration stress normalization is to linearly scale the vibration stress results obtained by simulation so that the maximum value of the vibration stress is limited to 100 MPa. -1,i is the high cycle fatigue limit of the ith node.

8. The blade cover amount adjustment and correction system considering vibration stress according to claim 5, characterized in that: In the adjustment amount optimization module, the circumferential cover amount adjustment value Y X Meet Y X,min ≤Y X ≤Y X,max , axial cover adjustment value Y Z Meet Y Z,min ≤Y Z ≤Y Z,max , where Y X,min Adjust the lower limit value for the circumferential cover design, Y X,max Y is the upper limit value of the circumferential cover design adjustment. Z,min The lower limit value of the axial cover design adjustment, Y Z,max Adjust the upper limit value for axial shroud design.

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