A high-efficiency prediction method for rotor disk deformation considering centrifugal temperature coupling

Abstract

The application discloses a kind of rotor blade disc deformation high-efficiency prediction method considering centrifugal temperature coupling action, belong to aero-engine technical field, including the following steps: S1, blade analytical model is established, input blade parameter is solved centrifugal, temperature load and the deformation of blade under the coupling action of two and blade centrifugal load;S2, centrifugal load generated by blade is distributed along axial function in discrete form to hub node of wheel disc plane model;S3, establish axisymmetric finite element model, solve disc rim deformation condition;S4, the deformation of blade body obtained by blade analytical method is combined with the disc rim deformation obtained by axisymmetric wheel disc finite element method, the tip deformation of overall blade disc structure under corresponding working condition is obtained, and the deformation caused by tenon connection is corrected.The application adopts the above-mentioned rotor blade disc deformation high-efficiency prediction method considering centrifugal temperature coupling action, realizes the rapid calculation of blade deformation and its load, realizes the rapid calculation of hub deformation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aero-engine, and particularly relates to a rotor disc deformation efficient prediction method considering centrifugal temperature coupling. BACKGROUND

[0002] Rotor disc deformation is an important factor affecting the aerodynamic and thermal efficiency and safety of an aero-engine, and the rotor deformation and the incoordination and asynchronization of the rotor deformation and the stator deformation induced by complex working load are the main reasons leading to the change of the rotor-stator gap, so efficient and accurate calculation of the rotor deformation at the design stage is one of the important prerequisites for realizing the gap prediction. The working load of an aero-engine is extremely complex, including the inertial load generated by the maneuvering overload, the temperature load, the rotating centrifugal load, the aerodynamic load and various vibration loads, among which the load factors affecting the rotor deformation of the engine are the rotating centrifugal load, the temperature load and the inertial load of the maneuvering overload. The rotating centrifugal load and the temperature load mainly cause the deformation of the disc component, which is related to the structural characteristic parameters of the component; and the deformation caused by the inertial load of the maneuvering overload is closely related to the rotor stiffness distribution. The present research report focuses on the deformation prediction and model establishment of the disc component under the action of the rotating centrifugal load and the temperature load.

[0003] At present, the main means for calculating the rotor static deformation and the gap change at home and abroad include the analytical method and the finite element method. Since the analytical method usually needs to greatly simplify the structure, although the calculation efficiency is high, the prediction accuracy is extremely limited. At present, the finite element analysis method is the mainstream method for predicting the rotor deformation and the rotor-stator gap in engineering, and a three-dimensional high-fidelity modeling is usually adopted, and on this basis, a certain dimension reduction processing is carried out through the periodic symmetry characteristics. Although this method is relatively reliable, the calculation amount is large, the calculation time is long, and the calculation cost is high, and it is not suitable for rapid iteration optimization at the design stage. In addition, the analysis method based on the two-dimensional axisymmetric model is also derived, which can quickly calculate the structural deformation and stress, however, it must ignore the blade structure, simplify the tenon and mortise structure and simplify the periodic symmetry to axisymmetry, and a large error is usually generated when the tip deformation is calculated. SUMMARY

[0004] The purpose of the present application is to provide a rotor disc deformation efficient prediction method considering centrifugal temperature coupling, on the basis of the parameterization of the disc structure, the explicit relationship between the blade structure parameters and the load parameters is established by using the analytical method for the blade elongation / centrifugal load of the blade root, so as to realize the rapid calculation of the blade deformation and the load; the axisymmetric finite element method is used for the wheel disc, the axisymmetric finite element model based on the APDL language and the load automatic equivalent application technology are established, so as to realize the rapid calculation of the rim deformation.

[0005] To achieve the above objectives, the present invention provides an efficient prediction method for rotor blade deformation considering the centrifugal temperature coupling effect, comprising the following steps:

[0006] S1. Establish a blade analytical model, input blade geometric characteristic parameters, material parameters and load parameters to solve the centrifugal load, temperature load and the deformation of the blade under the coupling of the centrifugal load and temperature load, as well as the centrifugal load of the blade;

[0007] S2, the centrifugal load generated by the blade is applied to the rim nodes of the disk plane model in a discrete form along the axial distribution function;

[0008] S3. Establish an axisymmetric finite element model, input the wheel's geometric characteristic parameters, material parameters, and load parameters, apply temperature load and centrifugal load to solve the wheel rim deformation;

[0009] S4. Combine the blade deformation obtained by the blade analytical method and the disk edge deformation obtained by the axisymmetric disk finite element method to obtain the tip deformation of the entire disk structure under the corresponding working conditions, and correct the deformation caused by the tenon connection.

[0010] Preferably, the centrifugal load in S1 includes the centrifugal tensile stress F in the blade height Z direction. blade and centrifugal bending moment M Y1 ;

[0011] Centrifugal tensile stress F blade The calculation formula is as follows:

[0012]

[0013] Where ρ is the density, ω is the rotation speed, A(Z) is the variation law of the cross-sectional area of ​​the blade along the blade height direction, and F crown The centrifugal force generated by the leaf crown;

[0014] For a turbine rotor blade with a shroud, the centrifugal force generated by the shroud is F crown , the calculation formula is as follows:

[0015] F crown =ρω 2 V crown Z crown ;

[0016] Among them, V crown is the canopy volume, Z crown is the leaf crown height coordinate;

[0017] Centrifugal bending moment M Y1 The calculation formula is as follows:

[0018]

[0019] wherein Z bt and Z br are the blade height direction coordinates of the blade tip and blade root respectively, and X(Z) is the function relationship between blade height Z and the axial X coordinate of the section centroid.

[0020] Preferably, the cross section A(Z) is subjected to centrifugal force of the part above the interface:

[0021]

[0022] The deformation Δl1 of the blade due to the centrifugal tensile stress is shown as follows:

[0023]

[0024] wherein E is the elastic modulus;

[0025] The temperature of the blade is the same on the cross section, and changes with the blade height Z direction. Let the temperature of the arbitrary thin cross section A(Z) be T(Z), and the radial deformation of the whole blade part due to the temperature rise is Δl T , and the calculation formula is shown as follows:

[0026]

[0027] wherein α(Z) is the linear expansion coefficient of the blade material, and T0 is the reference temperature;

[0028] Due to the influence of temperature, the elastic modulus E of the blade material is no longer a constant, and the elastic modulus of the blade along the blade height Z direction is E(Z). The comprehensive deformation Δl Z&T of the blade under the centrifugal and temperature load is:

[0029]

[0030] Preferably, the centrifugal load generated by the blade in S2 acts on the disc in the form of distributed force. Due to the complexity of the blade structure characteristics, the distributed force is not ideally uniformly distributed, and the function of the blade centrifugal load density along the axial direction is f(x), which needs to satisfy that the resultant force and the resultant moment of the load distribution are equal to the resultant force F and the resultant moment M Z of the blade:

[0031]

[0032] A distributed function is selected to program the equation of the resultant force F and the resultant moment M Z , and the results of the solution are applied to the rim nodes of the disc plane model in a discrete form. In the case of sufficient grid, it can be considered that the nodes are distributed equidistantly along the axial direction, the total number of nodes is n, and the corresponding axial coordinates are x i(i = 1, 2, …, n), the load value F on each node can be obtained i is:

[0033]

[0034] Preferably, in S3, when the radial deformation of the disk under centrifugal load is solved, the rotating angular velocity is applied to the disk, and the centrifugal load generated by the blade is applied to each node of the disk rim; when the radial deformation of the disk under temperature load is solved, the temperature load is applied to the disk rim and the disk core assembly respectively; when the radial deformation of the disk under the combined action of centrifugal load and temperature is solved, the centrifugal load and the temperature load are applied together.

[0035] Preferably, in S4, the actual tenon connection structure is taken as the object, the three-dimensional solid finite element model considering the contact of the tenon connection interface is established, and the deformation thereof is calculated; on the other hand, the gap of the tenon head and the tenon groove structure is ignored, and the gap is treated as a whole blisk structure, and the deformation thereof is calculated; by comparing the deformation results of the two models, the influence of the tenon connection structure on the blade tip deformation is analyzed; the average value of the radial deformation of the blade tip of the whole blisk and the tenon connection blisk is obtained tenon and Δl blisk Finally, the range of the correction coefficient K2 is obtained, as shown below:

[0036] Δl tenon = K2Δl blisk .

[0037] Therefore, the above-mentioned efficient rotor blisk deformation prediction method considering centrifugal temperature coupling is adopted, on the basis of blisk structure parameterization, the explicit relationship between blade elongation / centrifugal load at the root and blade structure parameters and load parameters is established by using an analytical method for the blade, the rapid calculation of blade deformation and load is realized; for the disk, the axisymmetric finite element method is used, the axisymmetric finite element model based on APDL language and the load automatic equivalent application technology are established, and the rapid calculation of the rim deformation is realized.

[0038] The technical solutions of the present application will be further described in detail below with reference to the drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 is a flowchart of an efficient rotor blisk deformation prediction method considering centrifugal temperature coupling of the present application;

[0040] Figure 2 is a blade analytical model schematic diagram of an efficient rotor blisk deformation prediction method considering centrifugal temperature coupling of the present application;

[0041] Figure 3is a wheel disc plane model drawing schematic diagram of a rotor disc deformation efficient prediction method considering centrifugal temperature coupling effect, wherein Figure 3 a is a wheel disc three-dimensional model in the formula, Figure 3 b is a wheel disc plane model in the formula;

[0042] Figure 4 is a wheel disc plane finite element model load application schematic diagram of the rotor disc deformation efficient prediction method considering centrifugal temperature coupling effect. DETAILED DESCRIPTION

[0043] The technical solutions of the present application are further described below by means of the accompanying drawings and examples.

[0044] Unless otherwise defined, technical terms or scientific terms used in the present application shall be understood as having the usual meaning as understood by a person having ordinary skill in the art to which the present application pertains. The terms "first", "second" and similar words used in the present application do not represent any order, number or importance, but are only used to distinguish different components. The terms "include" or "contain" and similar words mean that the elements or objects before the words cover the elements or objects listed after the words and their equivalents, and do not exclude other elements or objects. The terms "connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms "up", "down", "left", "right" and the like are only used to represent relative positional relationships, and when the absolute positions of the described objects change, the relative positional relationships may also change accordingly.

[0045] Example 1

[0046] As shown in Figure 1 , the present application provides a rotor disc deformation efficient prediction method considering centrifugal temperature coupling effect, comprising the following steps:

[0047] S1, establishing a blade analytical model, inputting blade geometric characteristic parameters, material parameters and load parameters to solve the deformation of the blade under centrifugal, temperature load and coupling effect of the two, and the blade centrifugal load;

[0048] The required geometric characteristic parameters of the blade are as shown in Figure 2 , Z is the radial direction of the blade, Y is the axial direction of the engine, X is perpendicular to the two, and the radial positions of the blade tip and blade root section are Z bt and Z br , respectively. The curve composed of the centroid of each section of the blade is called the blade stacking line, which is described by X(Z), Y(Z), which determines the sweep form of the blade, A(Z) describes the variation law of the blade cross-sectional area, Z crown , V crownrepresents the radial position and volume of the centroid of the blade crown, and ω represents the angular velocity of rotation. The centrifugal load includes the centrifugal tensile stress F in the Z direction of the blade height. blade and centrifugal bending moment M Y1 ;

[0049] Centrifugal tensile stress F blade The calculation formula is as follows:

[0050]

[0051] Where ρ is the density, ω is the rotation speed, A(Z) is the variation law of the cross-sectional area of ​​the blade along the blade height direction, and F crown The centrifugal force generated by the leaf crown;

[0052] For a turbine rotor blade with a shroud, the centrifugal force generated by the shroud is F crown , the calculation formula is as follows:

[0053] F crown =ρω 2 V crown Z crown ;

[0054] Among them, V crown is the canopy volume, Z crown is the leaf crown height coordinate;

[0055] Centrifugal bending moment The calculation formula is as follows:

[0056]

[0057] Among them, Z bt and Z br are the blade height coordinates of the blade tip and blade root respectively, and X(Z) is the function relationship between the blade height Z and the X coordinate of the cross-section centroid axis.

[0058] The cross section A(Z) is subjected to the centrifugal force above the interface:

[0059]

[0060] The deformation Δl1 of the blade due to centrifugal tensile stress is shown as follows:

[0061]

[0062] Where E is the elastic modulus.

[0063] The temperature of the blade is the same on the cross section, and the temperature in the Z direction varies with the blade height. Let the temperature of any thin section A(Z) be T(Z), then the radial deformation of the entire blade due to the temperature increase is Δl T, the calculation formula is shown as follows:

[0064]

[0065] Wherein, α(Z) is the linear expansion coefficient of the blade material, T0 is the reference temperature;

[0066] Due to the influence of temperature, the elastic modulus E of the blade material is no longer a constant, and the elastic modulus of the blade in the direction of blade height Z is E(Z). The comprehensive deformation Δl of the blade under the centrifugal and temperature load is Z&T

[0067]

[0068] S2, the centrifugal load generated by the blade is applied to the rim nodes of the disc plane model in a discrete form along the axial distribution function;

[0069] For the centrifugal load generated by the blade, it acts on the disc in the form of distributed force. Due to the complexity of the structural characteristics of the blade, the distributed force is not ideally uniformly distributed. The function of the axial distribution of the blade centrifugal load density (referred to as the centrifugal load density distribution function) is f(x), which needs to satisfy that the resultant force and the resultant moment of the load distribution are equal to the resultant force F and the resultant moment M generated by the blade Z :

[0070]

[0071] A distribution function (uniform equivalent distribution, linear non-uniform distribution and quadratic function distribution) is selected to program and solve the above equation. The results of the solution are applied to the rim nodes of the disc plane model in a discrete form. In the case of sufficient grid, it can be considered that the nodes are distributed equidistantly in the axial direction, and the total number of nodes is n. The corresponding axial coordinates are x i (i = 1, 2, …, n), then the load value F i on each node can be obtained.

[0072]

[0073] S3, an axisymmetric finite element model is established, the geometric characteristic parameters, material parameters and load parameters of the disc are input, the temperature load and the centrifugal load are applied to solve the rim deformation condition.

[0074] A plane model of the meridian section of the disc is drawn in the drawing software, as shown in Figure 3 , wherein Figure 3 a in the three-dimensional model of the disc Figure 3 ​b in the formula is a plane model of the wheel disc. The axial symmetric finite element model based on ANSYS APDL command stream language and load automatic equivalent application technology are established, and the rapid calculation of the rim deformation is realized. Through the command stream, ANSYS automatically imports the wheel disc model file, sets the unit type as a plane axial symmetry, gives the material, identifies the centroid coordinates of each side of the wheel disc, defines the edge with the maximum radial coordinate as the disc rim, and defines the edge with the minimum radial coordinate as the disc core. The wheel disc is divided into grids, and the number of nodes at the disc rim is n.

[0075] When the radial deformation of the wheel disc under centrifugal load is solved, the rotational angular velocity is applied to the wheel disc, and the centrifugal load generated by the blade is applied to each node of the disc rim. When the radial deformation of the wheel disc under temperature load is solved, the temperature load is applied to the disc rim and disc core assembly of the wheel disc respectively. When the radial deformation of the wheel disc under the combined action of centrifugal load and temperature is solved, the two types of loads are applied together. The specific load and constraint application conditions are shown in Figure 4 . Different combinations of temperature and rotational speed are used as a working condition, the command stream is used to solve the radial deformation of the wheel disc, and the radial deformation of all nodes of the disc rim assembly is extracted to solve the disc rim deformation.

[0076] S4, the blade deformation obtained by the blade analysis method and the disc rim deformation obtained by the axial symmetric wheel disc finite element method are combined to obtain the tip deformation of the overall bladed disc structure under the corresponding working condition, and the deformation caused by the tenon connection is corrected.

[0077] Taking the actual tenon connection structure as the object, the three-dimensional solid finite element model considering the contact of the tenon connection interface is established, and the deformation is calculated. On the other hand, the gap of the tenon head and tenon groove structure is ignored, and the gap is treated as an overall bladed disc structure, and the deformation is calculated. By comparing the deformation results of the two models, the influence of the tenon connection structure on the tip deformation is analyzed. The average values of the tip radial deformation of the overall bladed disc and the tenon connection bladed disc are Δl tenon and Δl blisk , and the range of the correction coefficient K2 is finally obtained, as shown below:

[0078] Δl tenon = K2 Δl blisk .

[0079] Therefore, the above-mentioned efficient rotor bladed disc deformation prediction method considering centrifugal temperature coupling is adopted, on the basis of the parameterization of the bladed disc structure, the explicit relationship between the blade elongation / blade structure parameters and load parameters under centrifugal load is established by using the analytical method for the blade, the rapid calculation of the blade deformation and load is realized, the axial symmetric finite element method is used for the wheel disc, the axial symmetric finite element model based on APDL language and the load automatic equivalent application technology are established, and the rapid calculation of the rim deformation is realized.

[0080] It should be pointed out finally that the above examples are only used to illustrate the technical solutions of the present application but not to limit it, and although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can still be modified or replaced equivalently, and these modifications or equivalent replacements should not make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present application.

Claims

1. An efficient prediction method for rotor blade deformation considering centrifugal temperature coupling, characterized by: The following steps are involved: S1. Establish a blade analytical model, input blade geometric characteristic parameters, material parameters and load parameters to solve the centrifugal load, temperature load and the deformation of the blade under the coupling of the centrifugal load and temperature load, as well as the centrifugal load of the blade; Centrifugal loads are included in the blade height Centrifugal tensile stress in the direction and centrifugal bending moment ; Centrifugal tensile stress The calculation formula is as follows: ； in, is the density, is the rotation speed, is the variation law of the cross-sectional area of ​​the blade along the height direction, The centrifugal force generated by the leaf crown; For a turbine rotor blade with a shroud, the centrifugal force generated by the shroud is , the calculation formula is as follows: ； in, is the canopy volume, is the leaf crown height direction coordinate; Centrifugal bending moment The calculation formula is as follows: ； in, and are the leaf height coordinates of the leaf tip and leaf root respectively, For Ye Gao Axis with cross-section centroid Functional relationship of coordinates; cross section The centrifugal force above the interface is: ； Deformation of blades due to centrifugal tensile stress As shown below: ； in, is the elastic modulus; The temperature of the leaf is the same in the cross section, and the temperature increases with the leaf height. The temperature in the direction changes, making any thin section The temperature is , then the radial deformation of the entire blade due to temperature increase is , the calculation formula is as follows: ； in, is the linear expansion coefficient of the blade material, is the reference temperature; Due to the influence of temperature, the elastic modulus of the blade material No longer a constant, it changes with the height of the leaf direction, the elastic modulus of the blade is , then the combined deformation of the blade under centrifugal and temperature loads is for: ； S2, the centrifugal load generated by the blade is applied to the rim nodes of the disk plane model in a discrete form along the axial distribution function; S3. Establish an axisymmetric finite element model, input the wheel's geometric characteristic parameters, material parameters, and load parameters, apply temperature load and centrifugal load to solve the wheel rim deformation; S4. Combine the blade deformation obtained by the blade analytical method and the disk edge deformation obtained by the axisymmetric disk finite element method to obtain the tip deformation of the entire disk structure under the corresponding working conditions, and correct the deformation caused by the tenon connection.

2. The efficient prediction method for rotor blade deformation considering centrifugal temperature coupling according to claim 1 is characterized by: The centrifugal load generated by the blade in S2 acts on the wheel in the form of distributed force. Due to the complexity of the blade structure, the distributed force is not ideally uniformly distributed. The function of the centrifugal load density of the blade along the axial direction is: , it is necessary to satisfy the resultant force and moment corresponding to the load distribution equal to the resultant force generated by the blade and resultant moment : ； Choose a distribution function to solve the resultant force and resultant moment The equation is used to apply the solution to the rim nodes of the wheel plane model in a discrete form. When the grid is dense enough, it is assumed that the nodes are equidistantly distributed in the axial direction, and the total number of nodes is , the corresponding axial coordinate is , then the load value on each node is obtained for: 。 3. The efficient prediction method for rotor blade deformation considering centrifugal temperature coupling according to claim 1 is characterized by: In S3, when calculating the radial deformation of the disk under centrifugal load, the rotational angular velocity is applied to the disk, and the centrifugal load generated by the blades is applied to each node of the disk rim; when calculating the radial deformation of the disk under temperature load, the temperature load is applied to the disk rim and disk core components respectively; Calculate the radial deformation of the wheel under the combined action of centrifugal load and temperature. When centrifugal load and temperature load are applied together.

4. The efficient prediction method for rotor blade deformation considering centrifugal temperature coupling according to claim 1 is characterized by: In S4, the actual tenon joint structure is used as the object, and its deformation is calculated by establishing a three-dimensional solid finite element model that takes into account the tenon joint interface contact. On the other hand, the influence of the tenon joint contact interface is ignored and the gap of the tenon and groove structure is filled, and it is treated as an integral blade disk structure to calculate its deformation. By comparing the deformation results of the two models, the influence of the tenon connection structure on the blade tip deformation is analyzed; the average radial deformation of the blade tip of the integral blade disk and the tenon connection blade disk is obtained. and , and finally obtain the correction coefficient The range is as follows: 。

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