Gas turbine shroud pre-torsion angle design method and related device thereof

Abstract

The invention discloses a gas turbine shroud pre-torsion angle design method and a related device thereof, and relates to the technical field of gas turbines. The design method for the pre-torsion angle of the shroud of the gas turbine comprises the steps that ideal average extrusion stress is obtained; the ideal average extrusion stress is preset; obtaining a finite element model based on the three-dimensional model of the gas turbine; the finite element model is a single-sector model; and based on the ideal average extrusion stress and the finite element model, the gas turbine shroud pre-torsion angle is obtained. According to the method, the finite element model is established, and the local rigidity and local deformation of the shroud and the local deformation phenomenon of the working face of the shroud caused by factors such as temperature, centrifugation and aerodynamic load when the gas turbine is used are considered. Compared with an existing method that the blade crown pre-torsion angle design problem is approximate to a rigid body torsion problem, the blade crown pre-torsion angle designed through the gas turbine blade crown pre-torsion angle design method is more accurate.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of gas turbines, in particular to a gas turbine shroud pre-twist angle design method and a related device. BACKGROUND

[0002] When designing the shroud pre-twist angle of a gas turbine turbine blade, the average extrusion stress of the shroud working surface (i.e., the first working surface or the second working surface in the following) needs to be within a reasonable range under the condition that the gas turbine is in stable operation and the average extrusion stress of the shroud working surface is within the standard of the average extrusion stress of the shroud of the gas turbine turbine blade. In the forward design, the torsional stiffness of the turbine blade is considered to be known, and the torsional moment is designed by designing the relative twist angle relative to the non-extrusion state of the shroud under the standard condition, and then the average extrusion stress of the shroud working surface is designed. This design method approximates the shroud pre-twist angle design problem to a rigid body torsion problem, which does not consider the local stiffness and local deformation of the shroud.

[0003] The above method designs the overall bending moment and the average extrusion stress of the shroud working surface corresponding to the shroud pre-twist angle by approximation, but it does not accurately describe the local deformation of the shroud working surface caused by factors such as temperature, centrifugal force and aerodynamic load, resulting in that the designed shroud pre-twist angle cannot accurately adapt to the actual working scenario. SUMMARY

[0004] The purpose of the present application is to provide a gas turbine shroud pre-twist angle design method and a related device to solve the technical problem of being unable to accurately design the shroud pre-twist angle.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0006] In a first aspect, the present application provides a gas turbine shroud pre-twist angle design method. The gas turbine shroud pre-twist angle design method comprises:

[0007] obtaining an ideal average extrusion stress; the ideal average extrusion stress is pre-set;

[0008] obtaining a finite element model based on a three-dimensional model of a gas turbine turbine; the finite element model is a single sector model; the input of the finite element model at least includes material parameters, use temperature, use speed and aerodynamic load of the gas turbine turbine blade;

[0009] obtaining the gas turbine shroud pre-twist angle based on the ideal average extrusion stress and the finite element model.

[0010] As one specific solution in the technical solution of the present application, the obtaining of the gas turbine shroud pre-twist angle based on the ideal average extrusion stress and the finite element model comprises:

[0011] obtaining a candidate pre-twist angle; the candidate pre-twist angle is obtained based on a historical pre-twist angle, and the historical pre-twist angle comprises an initial pre-twist angle;

[0012] updating the finite element model based on the candidate pre-twist angle, and obtaining a current average extrusion stress; the current average extrusion stress is an average extrusion stress corresponding to the updated finite element model;

[0013] if a difference between the current average extrusion stress and an ideal average extrusion stress is less than a first preset value, obtaining the gas turbine shroud pre-twist angle; otherwise, updating the candidate pre-twist angle, and updating the finite element model based on the updated candidate pre-twist angle until a difference between the current average extrusion stress and the ideal average extrusion stress is less than the first preset value.

[0014] As a specific solution in the technical scheme of the present application, the updating of the candidate pre-twist angle comprises:

[0015] obtaining a first difference value based on the current average extrusion stress and the ideal average extrusion stress; the first difference value is used at least to represent a difference between the current average extrusion stress and the ideal average extrusion stress;

[0016] obtaining a second difference value based on the current average extrusion stress and a historical average extrusion stress; the second difference value is used at least to represent a difference between the current average extrusion stress and the historical average extrusion stress; the historical average extrusion stress is an average extrusion stress obtained last time before the current average extrusion stress;

[0017] obtaining an updating coefficient based on the first difference value and the second difference value; the updating coefficient is obtained based on a difference or a ratio between the first difference value and the second difference value;

[0018] updating the candidate pre-twist angle based on the updating coefficient.

[0019] As a specific solution in the technical scheme of the present application, the obtaining of the gas turbine shroud pre-twist angle based on the ideal average extrusion stress and the finite element model comprises:

[0020] obtaining a current pre-twist angle; the current pre-twist angle is a pre-twist angle when the gas turbine shroud is designed;

[0021] obtaining a twist angle difference value based on the ideal average extrusion stress and the finite element model; the twist angle difference value is equal to an ideal twist angle minus a current twist angle; the current twist angle is a twist angle corresponding to the finite element model; the ideal twist angle is a twist angle corresponding to a case that an average extrusion stress between adjacent shrouds in the finite element model is equal to the ideal average extrusion stress;

[0022] obtaining the gas turbine shroud pre-twist angle based on the current pre-twist angle and the twist angle difference; the gas turbine shroud pre-twist angle is equal to the sum of the current pre-twist angle and the twist angle difference.

[0023] As a specific solution in the technical scheme of the present application, the obtaining of the twist angle difference based on the ideal average extrusion stress and the finite element model comprises:

[0024] obtaining the current twist angle based on the current pre-twist angle by the finite element model;

[0025] obtaining the ideal twist angle based on the ideal average extrusion stress by the finite element model;

[0026] obtaining the twist angle difference based on the ideal twist angle and the current twist angle.

[0027] As a specific solution in the technical scheme of the present application, the obtaining of the twist angle difference based on the ideal average extrusion stress and the finite element model comprises:

[0028] obtaining the current average extrusion stress based on the finite element model; the current average extrusion stress is the average extrusion stress between adjacent shrouds when the gas turbine in the finite element model is in a hot state;

[0029] obtaining the average stress difference based on the ideal average extrusion stress and the current average extrusion stress; the average stress difference is equal to the ideal average extrusion stress minus the current average extrusion stress;

[0030] obtaining the first shroud based on the finite element model; the first shroud is any one shroud in the finite element model;

[0031] applying a first average stress to a first shroud working surface of the first shroud and a second average stress to a second shroud working surface of the first shroud based on the finite element model being located at the current average extrusion stress, to obtain the twist angle difference; the numerical values of the first average stress and the second average stress are equal to the average stress difference; the first average stress is perpendicular to the first shroud working surface of the first shroud, and the first average stress is directed from the outside to the inside of the first shroud; the second average stress is perpendicular to the second shroud working surface of the first shroud, and the second average stress is directed from the outside to the inside of the first shroud.

[0032] As a specific solution in the technical scheme of the present application, the obtaining of the current average extrusion stress based on the finite element model comprises:

[0033] obtaining a second shroud and a third shroud based on the finite element model; the second shroud and the third shroud are any two adjacent shrouds in the finite element model;

[0034] obtaining a first working surface and a second working surface based on the second shroud and the third shroud; the first working surface is a working surface in the second shroud which meshes with the third shroud; the second working surface is a working surface in the third shroud which meshes with the second shroud;

[0035] applying a current third average stress to the first working surface and a current fourth average stress to the second working surface in the finite element model; the current third average stress and the current fourth average stress are equal in magnitude; the direction of the current third average stress is perpendicular to the first working surface and points from the third shroud to the second shroud; the direction of the current fourth average stress is perpendicular to the second working surface and points from the second shroud to the third shroud; the current third average stress is updated from a historical third average stress; the current fourth average stress is updated from a historical fourth average stress;

[0036] obtaining a distance between the first working surface and the second working surface;

[0037] if the distance is greater than 0 and less than or equal to a second preset value, obtaining a current average extrusion stress; otherwise, updating the current third average stress and the current fourth average stress, and applying the updated current third average stress and the current fourth average stress to the first working surface and the second working surface respectively, re-obtaining the distance between the first working surface and the second working surface until the distance is greater than 0 and less than or equal to the second preset value.

[0038] As a specific solution in the technical scheme of the present application, the updating of the current third average stress comprises:

[0039] obtaining a first difference value based on the current third average stress and the historical third average stress; the first difference value is the absolute value of the difference between the current third average stress and the historical third average stress;

[0040] if the distance is equal to 0, updating the current third average stress based on a first preset coefficient and the first difference value; if the distance is greater than the second preset value, updating the current third average stress based on a second preset coefficient and the first difference value.

[0041] In a second aspect, the present application provides a technical scheme of a gas turbine shroud pre-twist angle design device, which comprises:

[0042] The reading module is configured to obtain an ideal average extrusion stress; the ideal average extrusion stress is pre-set;

[0043] The processing module is configured to obtain a finite element model based on a three-dimensional model of the gas turbine turbine; the finite element model is a single sector model;

[0044] And obtain the gas turbine shroud pre-twist angle based on the ideal average extrusion stress and the finite element model.

[0045] In a third aspect, the present application provides a technical scheme of a gas turbine shroud pre-twist angle design system, which comprises:

[0046] The reader is configured to obtain an ideal average extrusion stress; the ideal average extrusion stress is pre-set;

[0047] The server is configured to obtain a finite element model based on a three-dimensional model of the gas turbine turbine; the finite element model is a single sector model;

[0048] And obtain the gas turbine shroud pre-twist angle based on the ideal average extrusion stress and the finite element model.

[0049] In a fourth aspect, the present application provides a technical scheme of a computer readable storage medium, which stores a computer program; when the computer program is executed by a processor, the gas turbine shroud pre-twist angle design method of any one of the first aspect is realized.

[0050] Compared with the prior art, the present application has the following beneficial effects:

[0051] The present application considers the local stiffness and local deformation of the shroud of the gas turbine in use, as well as the local deformation of the working surface of the shroud caused by factors such as temperature, centrifugal force and aerodynamic load, by establishing a finite element model. Compared with the existing method of approximating the shroud pre-twist angle design problem as a rigid body torsion problem, the gas turbine shroud pre-twist angle design method proposed in the present application can design a more accurate shroud pre-twist angle. BRIEF DESCRIPTION OF DRAWINGS

[0052] Figure 1 It is a structural schematic diagram of a gas turbine turbine proposed in an embodiment of the present application;

[0053] Figure 2 It is a three-dimensional schematic diagram of a turbine blade proposed in an embodiment of the present application;

[0054] Figure 3 It is a three-dimensional schematic diagram of a shroud proposed in an embodiment of the present application;

[0055] Figure 4A structure diagram of a structure for generating a conflicting force between two adjacent shrouds according to an embodiment of the present application;

[0056] Figure 5 A structure diagram of a pre-twist angle according to an embodiment of the present application;

[0057] Figure 6 A structure diagram of a twist angle according to an embodiment of the present application;

[0058] Figure 7 A flow diagram of a gas turbine shroud pre-twist angle design method according to an embodiment of the present application;

[0059] Figure 8 A structure diagram of a gas turbine shroud pre-twist angle design device according to an embodiment of the present application;

[0060] Figure 9 A structure diagram of a gas turbine shroud pre-twist angle design system according to an embodiment of the present application.

[0061] In the figure: 1, turbine disc; 2, turbine blade; 21, tenon; 22, blade body; 23, shroud; 231, shroud body; 232, comb tooth; 233, first shroud working surface; 234, second shroud working surface; 235, first axial centerline; 236, second axial centerline; 237, first median plane; 238, second median plane. DETAILED DESCRIPTION

[0062] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work belong to the scope of protection of the present application.

[0063] It should be noted that in the description of the present application, the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0064] In addition, it should be understood that, for the convenience of description, the sizes of the various components shown in the drawings are not drawn in accordance with the actual proportional relationship, for example, the thickness or width of certain layers can be exaggerated relative to other layers.

[0065] It should be noted that like numerals and letters refer to like items throughout the several views, as such, once an item is defined or illustrated in one view, it need not be discussed or described further in subsequent views.

[0066] Before embodiments of the present application are understood, it is necessary to make clear that the existing gas turbine turbine includes a turbine disk 1 and a plurality of turbine blades 2 as shown in Figure 1 Each turbine blade 2 is uniformly distributed around the circumference of the turbine disk 1, and each turbine blade 2 is tenoned with the turbine disk (the tenon structure is a mature technology, and thus will not be described here). Generally, as shown in Figure 2 The turbine blade 2 includes a tenon 21, a blade body 22 and a shroud 23 connected in sequence. Generally, as shown in Figure 3 The shroud 23 includes a shroud body 231 and a fence 232; the shroud body 231 is provided with a first shroud working surface 233 and a second shroud working surface 234 which are parallel to each other. In use, as shown in Figure 4 The first shroud working surface 233 and the second shroud working surface 234 between two adjacent shrouds 23 are engaged.

[0067] It should be noted that the purpose of designing the shroud pre-torque angle is to form a certain resistance between the first shroud working surface 233 and the second shroud working surface 234 on adjacent turbine blades 2 (i.e. equal to the product of the average extrusion stress and the working surface area as described below). As shown in Figure 4 When the gas turbine is in use, the resistance between the first shroud working surface 233 and the second shroud working surface 234 is equal in size and opposite in direction (i.e. the force F and the force f as shown in Figure 4 It is easy to understand that if the resistance between the first shroud working surface 233 and the second shroud working surface 234 is large enough, after each turbine blade 2 is installed on the turbine disk 1, the resistance between the shrouds 23 can reduce the torsional deformation and bending deformation of the turbine blade 2 in use, enhance the rigidity of the turbine blade 2, and increase the vibration frequency of the turbine blade 2. When the turbine blade 2 vibrates, the shroud 23 of the turbine blade 2 can also rub against the adjacent two shrouds 23 to absorb vibration energy, thereby playing a role in vibration reduction.

[0068] It should also be clear that, as shown in Figure 5 The shroud pre-torque angle refers to the included angle of the space formed by the first axis 235 and the second axis 236 when the gas turbine is not started (i.e. the gas turbine is in a cold state), i.e. the included angle θ as shown in Figure 5 The first axis 235 is a straight line perpendicular to the extension line (which is a circular arc) formed by the fence 232 in the shroud 23. In order to show the relationship between the first axis 235 and the second axis 236,Figure 5 Only the blade crown body 231 is reserved, and the serrations 232 are deleted. The second axis line 236 is a straight line parallel to the axis line of the gas turbine turbine (i.e., the axis line of the turbine disc 1).

[0069] In the embodiment, the greater the blade crown pre-twist angle, the greater the average extrusion stress formed by the working surfaces between the adjacent blade crowns 23 (i.e., the first blade crown working surface 233 and the second blade crown working surface 234); the smaller the blade crown pre-twist angle, the smaller the average extrusion stress formed by the working surfaces between the adjacent blade crowns 23.

[0070] As known from the background art, the prior art approximates the blade crown pre-twist angle design problem as a rigid body torsion problem, without considering the local stiffness and local deformation of the blade crown, and without considering the local deformation of the blade crown working surface caused by factors such as temperature, centrifugal force, and aerodynamic average stress. The blade crown pre-twist angle designed based on this will be either too large (i.e., causing the average extrusion stress between the adjacent blade crowns to be too large) or too small (i.e., causing the average extrusion stress between the adjacent blade crowns to be too small).

[0071] To solve the technical problem of being unable to accurately design the blade crown pre-twist angle as proposed in the background art, an embodiment of a gas turbine blade crown pre-twist angle design method is proposed, as shown in Figure 7 The gas turbine blade crown pre-twist angle design method includes steps S100 to S300.

[0072] Step S100: Obtain an ideal average extrusion stress.

[0073] In the embodiment, the ideal average extrusion stress refers to the average extrusion stress formed between the first blade crown working surface 233 and the second blade crown working surface 234 after the gas turbine is started (i.e., when the gas turbine is in a hot state).

[0074] In the embodiment, the ideal average extrusion stress is pre-set. A suitable ideal average extrusion stress can be selected according to design requirements, for example, the ideal average extrusion stress can be 40 MPa or 50 MPa, etc.

[0075] Step S200: Obtain a finite element model based on a three-dimensional model of a gas turbine turbine.

[0076] In the embodiment, the three-dimensional model of the gas turbine turbine is pre-obtained.

[0077] It should be noted that obtaining the finite element model corresponding to a product (i.e., a gas turbine) based on a three-dimensional model of the product is a mature technology, which will not be described here. For example, the Chinese invention patent documents with the publication number CN118378495B and the name of "turbine performance reliability simulation method and system of liquid rocket engine" and the publication number CN109102570B and the name of "a modeling method of a three-dimensional finite element model" disclose similar methods.

[0078] It should be noted that when the modal analysis is directly performed on the turbine with a cyclically symmetric structure, the data processing amount will linearly increase with the increase of the number of turbine blades, and the efficiency is extremely low. For example, the finite element model of a turbine with 100 turbine blades needs to be divided into a million grids. It should be clear that the cyclically symmetric structure refers to a structure that has the property of coinciding with itself after rotating a certain angle around an axis (for example, a turbine, a gear, and a fan blade).

[0079] In order to reduce the data processing amount when the modal analysis is performed on the cyclically symmetric structure, the periodic symmetry of the structure is utilized, and only one sector (or several sectors) is modeled, and the periodic constraint is applied through the boundary condition, so that the data processing amount can be greatly reduced. In the embodiments of the present application, in order to reduce the data processing amount when the pre-twist angle of the gas turbine shroud is designed, the finite element model is a single-sector model. Of course, in other embodiments of the present application, the finite element model can also be a multi-sector model.

[0080] In the present embodiment, the input of the finite element model at least includes the material parameters, the use temperature, the use rotation speed and the aerodynamic load of the gas turbine turbine blade. The material parameters of the turbine blade at least include the elastic modulus, the yield strength and the Poisson's ratio of the material.

[0081] Step S300: obtaining the pre-twist angle of the gas turbine shroud based on the ideal average extrusion stress and the finite element model.

[0082] In the embodiments of the present application, the pre-twist angle of the gas turbine shroud can be obtained based on the ideal average extrusion stress and the finite element model by any reasonable way. For example, the pre-twist angle of the gas turbine shroud can be obtained based on the ideal average extrusion stress and the finite element model at least as shown in the following embodiment one or embodiment two.

[0083] Embodiment one for obtaining the pre-twist angle of the gas turbine shroud

[0084] As can be seen from the foregoing, the pre-twist angle refers to the spatial included angle formed by the first axis 235 and the second axis 236 when the gas turbine is in a cold state. The average extrusion stress refers to the average stress formed by the working surface between two adjacent shrouds 23 when the gas turbine is in a hot state. The greater the pre-twist angle, the greater the corresponding average extrusion stress; the smaller the pre-twist angle, the smaller the corresponding average extrusion stress. That is, in the case of a determined finite element model of the gas turbine turbine, each pre-twist angle can obtain a corresponding average extrusion stress, and based on this, the embodiment can obtain the pre-twist angle corresponding to the ideal average extrusion stress closest to the ideal average extrusion stress as the gas turbine shroud pre-twist angle by iterating the finite element model.

[0085] Step S300: obtaining the gas turbine shroud pre-twist angle based on the ideal average extrusion stress and the finite element model, comprising steps S310 to S330.

[0086] Step S310: obtaining a candidate pre-twist angle.

[0087] In the embodiment, the candidate pre-twist angle is obtained by updating the historical pre-twist angle, and the historical pre-twist angle includes an initial pre-twist angle. The initial pre-twist angle can be equal to the pre-twist angle in the finite element model corresponding to the three-dimensional model of the gas turbine turbine. Of course, in other embodiments of the application, the initial pre-twist angle can be directly equal to 0.

[0088] Step S320: updating the finite element model based on the candidate pre-twist angle to obtain a current average extrusion stress. In the embodiment, the current average extrusion stress is the average extrusion stress corresponding to the updated finite element model.

[0089] It should be noted that in the case of a determined finite element model, obtaining the average extrusion stress (i.e. the current average extrusion stress) corresponding to the finite element model is a mature technology, which will not be described here. For specific steps, refer to step S354 below.

[0090] Step S330: if the difference between the current average extrusion stress and the ideal average extrusion stress is less than a first preset value, obtaining the gas turbine shroud pre-twist angle; otherwise, updating the candidate pre-twist angle and updating the finite element model based on the updated candidate pre-twist angle until the difference between the current average extrusion stress and the ideal average extrusion stress is less than the first preset value.

[0091] That is, in the embodiment, if the difference between the current average extrusion stress and the ideal average extrusion stress is less than the first preset value, the candidate pre-twist angle obtained by the last iteration is taken as the gas turbine shroud pre-twist angle.

[0092] In the embodiments of the present application, the first preset value can be set according to requirements, for example, the first preset value can be 0.1 MPa or 0.5 MPa, etc.

[0093] As can be known from the foregoing, the candidate pre-twist angle is positively correlated with the current average extrusion stress. In the embodiments of the present application, if the difference between the current average extrusion stress and the ideal average extrusion stress is greater than or equal to a first preset value, the candidate pre-twist angle is updated. That is, in the case where the difference between the current average extrusion stress and the ideal average extrusion stress is greater than or equal to the first preset value, if the ideal average extrusion stress is greater than the current average extrusion stress, the current average extrusion stress needs to be increased (i.e., the candidate pre-twist angle needs to be increased); if the ideal average extrusion stress is less than the current average extrusion stress, the current average extrusion stress needs to be decreased (i.e., the candidate pre-twist angle needs to be decreased), until the current average extrusion stress and the ideal average extrusion stress are close (i.e., the difference between the current average extrusion stress and the ideal average extrusion stress is less than the first preset value).

[0094] In the embodiments of the present application, the candidate pre-twist angle can be updated in any reasonable manner. For example, in step S330, the calculation formula (hereinafter referred to as the first formula group) for updating the candidate pre-twist angle can be as follows:

[0095]

[0096] wherein A represents the updated candidate pre-twist angle; A1 represents the candidate pre-twist angle before updating; P0 represents the ideal average extrusion stress; P1 represents the current average extrusion stress; b represents a first angle value; c represents a second angle value; the first angle value is greater than the second angle value. In the embodiments of the present application, the first angle value and the second angle value can be set according to requirements, for example, the first angle value b can be 1.0°; the second angle value c can be 0.1°; or the first angle value b can be 0.5°; the second angle value c can be 0.2°, etc.

[0097] It should be noted that the overall iteration of the finite element model requires a large amount of computing power. In order to reduce the overall iteration number of the finite element model and thus save computing power, in an embodiment of the present application, in step S330, the candidate pre-twist angle is updated, including steps S331 to S334.

[0098] In step S331, a first difference value is obtained based on the current average extrusion stress and the ideal average extrusion stress.

[0099] In the embodiment, the first difference value is used to represent at least a difference between the current average extrusion stress and the ideal average extrusion stress. In the embodiment, the first difference value can be a ratio of the current average extrusion stress to the ideal average extrusion stress, or a difference between the current average extrusion stress and the ideal average extrusion stress.

[0100] Step S332: obtaining a second difference value based on the current average extrusion stress and the historical average extrusion stress.

[0101] In the embodiment, the second difference value is used to represent at least a difference between the current average extrusion stress and the historical average extrusion stress. In the embodiment, the second difference value can be a ratio of the current average extrusion stress to the historical average extrusion stress, or a difference between the current average extrusion stress and the historical average extrusion stress. The historical average extrusion stress is an average extrusion stress obtained in a last update of the current average extrusion stress.

[0102] Step S333: obtaining an update coefficient based on the first difference value and the second difference value.

[0103] As known from the foregoing, since the pre-twist angle is positively correlated with the average extrusion stress, if a difference between the ideal average extrusion stress and the current average extrusion stress is greater than a difference between the current average extrusion stress and the historical average extrusion stress, it indicates that the current average extrusion stress is greatly different from the ideal average extrusion stress, and thus the increase amplitude of the candidate pre-twist angle should be increased to make the current average extrusion stress in the next iteration quickly approach the ideal average extrusion stress; if the difference between the ideal average extrusion stress and the current average extrusion stress is less than the difference between the current average extrusion stress and the historical average extrusion stress, it indicates that the current average extrusion stress is less different from the ideal average extrusion stress, and thus the increase amplitude of the candidate pre-twist angle should be decreased to avoid the difference between the current average extrusion stress and the ideal average extrusion stress in the next iteration from being increased.

[0104] Step S334: updating the candidate pre-twist angle based on the update coefficient.

[0105] In the embodiments of the present application, the candidate pre-twist angle can be updated based on the update coefficient in any reasonable manner. For example, in one embodiment of the present application, the calculation formula (hereinafter referred to as the second formula group) for updating the candidate pre-twist angle based on the update coefficient in step S334 can be as follows:

[0106]

[0107] Wherein, A represents the updated candidate pre-twist angle; A1 represents the candidate pre-twist angle before updating; A2 represents the historical pre-twist angle; P0 represents the ideal average extrusion stress; P1 represents the current average extrusion stress; P2 represents the historical average extrusion stress; and ΔA represents the updating amplitude value of the pre-twist angle.

[0108] In the embodiment, the first difference value is P0-P1, the second difference value is P1-P2, and the updating coefficient is In the embodiment based on the first formula group, if the first angle value is set to be large and the second angle value is set to be small, the iteration number of the converged candidate pre-twist angle will be seriously high, that is, the calculation power will be seriously wasted. If the first angle value is set to be small and the second angle value is set to be large, the candidate pre-twist angle may not converge after a large number of iterations. Even if the candidate pre-twist angle can converge, the iteration number of the converged candidate pre-twist angle will be seriously high, that is, the calculation power will be seriously wasted. Compared with the embodiment based on the first formula group, the updating amplitude value ΔA (equivalent to the first angle value or the second angle value in the first formula group) in the embodiment is dynamically changed. In the embodiment, the updating amplitude value ΔA is adjusted according to the difference amplitude between the first difference value and the second difference value. If the difference between the first difference value and the second difference value is larger, that is, the difference between the current average extrusion stress and the ideal average extrusion stress is relatively large, the absolute value of the obtained updating amplitude value ΔA is larger, which can greatly reduce the difference between the current average extrusion stress and the ideal average extrusion stress in the next iteration. If the difference between the current average extrusion stress and the ideal average extrusion stress can be greatly reduced, the iteration number will certainly be reduced. If the difference between the first difference value and the second difference value is smaller, that is, the difference between the current average extrusion stress and the ideal average extrusion stress is relatively small, the absolute value of the obtained updating amplitude value ΔA is smaller, which can slightly reduce the difference between the current average extrusion stress and the ideal average extrusion stress in the next iteration. When the current average extrusion stress is closer to the ideal average extrusion stress, if the absolute value of the updating amplitude value is smaller, the phenomenon that the candidate pre-twist angle cannot converge can be avoided, and the phenomenon that the candidate pre-twist angle cannot reach the convergence condition and needs to be iterated repeatedly can also be avoided.

[0109] In another embodiment of the present application, the calculation formula (hereinafter referred to as the third formula group) for updating the candidate pre-twist angle based on the updating coefficient in step S334 can be as follows:

[0110] A=A1+ΔA

[0111]

[0112] Wherein, A represents the updated candidate pre-twist angle; A1 represents the pre-updated candidate pre-twist angle; A2 represents the historical pre-twist angle; P0 represents the ideal average extrusion stress; P1 represents the current average extrusion stress; P2 represents the historical average extrusion stress; and ΔA represents the updating amplitude value of the pre-twist angle.

[0113] In the embodiment, the first difference value is The second difference value is The updating coefficient is The embodiment (i.e. the embodiment corresponding to the third formula group) is similar to the principle of the embodiment corresponding to the second formula group, which is not repeated here.

[0114] It needs to be clear that in the first embodiment of obtaining the gas turbine shroud pre-twist angle, the finite element model needs to be iterated multiple times to obtain the gas turbine shroud pre-twist angle, which has a higher demand for computing power. In order to further reduce the computing power demand when obtaining the gas turbine shroud pre-twist angle, the way of obtaining the gas turbine shroud pre-twist angle can refer to the second embodiment.

[0115] The second embodiment of obtaining the gas turbine shroud pre-twist angle

[0116] Step S300, based on the ideal average extrusion stress and the finite element model, obtaining the gas turbine shroud pre-twist angle, including steps S340 to S360.

[0117] Step S340: obtaining the current pre-twist angle.

[0118] As known from the foregoing, the pre-twist angle refers to the spatial angle formed by the first axis 235 and the second axis 236 of the gas turbine in the cold state in the finite element model. In the embodiment, since the three-dimensional model of the gas turbine has been completely determined, the finite element model of the gas turbine in the cold state is also determined, i.e. the current pre-twist angle is also determined.

[0119] Before understanding step S350, it needs to be clear that in the finite element model, each shroud 23 corresponds to a mid-plane, which is parallel to the first shroud working surface 233 and the second shroud working surface 234 of the corresponding shroud 23, and the distance from the mid-plane to the first shroud working surface 233 and the second shroud working surface 234 is equal. In the finite element model, due to the influence of temperature and centrifugal force and other factors, the position of the mid-plane (i.e. the first mid-plane 237 as shown in Figure 6 ) when the shroud 23 is in the cold state is not the same as the position of the mid-plane (i.e. the second mid-plane 238 as shown in Figure 6 ) when the shroud 23 is in the hot state. The angle (i.e. the angle β as shown in Figure 6 ) formed by the mid-plane when the shroud 23 is in the cold state and the mid-plane when the shroud 23 is in the hot state is the twist angle.

[0120] Step S350: obtaining a twist angle difference value based on the ideal average extrusion stress and the finite element model.

[0121] In the embodiment, the twist angle difference value is equal to an ideal twist angle minus a current twist angle. The current twist angle is a twist angle corresponding to the finite element model. The ideal twist angle is a twist angle corresponding to a case that the average extrusion stress between adjacent shrouds in the finite element model is equal to the ideal average extrusion stress.

[0122] In the embodiments of the present application, the twist angle difference value can be obtained based on the ideal average extrusion stress and the finite element model in any reasonable manner. For example, the twist angle difference value can be obtained as shown in the following embodiment a and embodiment b.

[0123] Embodiment a of obtaining the twist angle difference value

[0124] In the embodiment, step S350 of obtaining the twist angle difference value based on the ideal average extrusion stress and the finite element model comprises steps S351 to S353.

[0125] Step S351: obtaining a current twist angle from the finite element model based on the current pre-twist angle.

[0126] It should be noted that since the current twist angle is a twist angle corresponding to the finite element model, the current twist angle can also be uniquely determined when the finite element model is determined. Specifically, the calculation formula of the current twist angle is as follows:

[0127] β1=θ2-θ1

[0128] Wherein, β1 represents the current twist angle; θ1 represents a twist angle of the shroud in the cold state in the finite element model (i.e. the current pre-twist angle); θ2 represents a twist angle of the shroud in the hot state in the finite element model.

[0129] Step S352: obtaining an ideal twist angle from the finite element model based on the ideal average extrusion stress.

[0130] In the embodiment, the ideal twist angle is the twist angle corresponding to the situation that the average extrusion stress between the adjacent blade crowns in the finite element model is equal to the ideal average extrusion stress. That is, in the embodiment, the ideal average extrusion stress is taken as the input of the finite element model, and the ideal twist angle is taken as the output of the finite element model. In other words, the embodiment (i.e., embodiment a) is different from embodiment one in that the embodiment does not need to iterate the finite element model, but only needs to iterate the average extrusion stress of the blade crown when the finite element model is in the hot state (until the average extrusion stress of the blade crown when the finite element model is in the hot state is close to the ideal average extrusion stress). Compared with iterating the entire finite element model, iterating the extrusion stress in the finite element model requires less computing power and takes less time.

[0131] Specifically, the calculation formula of the ideal twist angle is as follows:

[0132] β2 = θ3 - θ1

[0133] Wherein, β2 represents the ideal twist angle; θ1 represents the twist angle of the blade crown in the cold state in the finite element model (i.e., the current pre-twist angle); θ3 represents the twist angle corresponding to the situation that the average extrusion stress between the adjacent blade crowns in the finite element model is equal to the ideal average extrusion stress.

[0134] Step S353: Based on the ideal twist angle and the current twist angle, obtain a twist angle difference value.

[0135] In the embodiment, based on the ideal twist angle and the current twist angle, the calculation formula of the twist angle difference value is as follows:

[0136] Δβ = β2 - β1

[0137] Wherein, Δβ represents the twist angle difference value; β1 represents the twist angle corresponding to the current pre-twist angle (i.e., the current twist angle); β2 represents the twist angle corresponding to the ideal average extrusion stress (i.e., the ideal twist angle).

[0138] Embodiment b of obtaining the twist angle difference value

[0139] In the embodiment, step S350, based on the ideal average extrusion stress and the finite element model, obtaining a twist angle difference value, includes steps S354 to S357.

[0140] Step S354: Based on the finite element model, obtain a current average extrusion stress.

[0141] In the embodiment, the current average extrusion stress is the average extrusion stress between the adjacent blade crowns when the gas turbine is in the hot state in the finite element model.

[0142] As can be seen from the foregoing, in the case of determining the finite element model of the gas turbine turbine, the average extrusion stress between the adjacent shrouds is also uniquely determined when the gas turbine is in a hot state in the finite element model.

[0143] In the embodiments of the present application, the current average extrusion stress can be obtained based on the finite element model in any reasonable manner. The commonly used method is to perform finite element analysis in a whole circle, nonlinear contact manner (a common way of finite element analysis), and then obtain the current average extrusion stress corresponding to the finite element model.

[0144] It should be noted that when obtaining the current average extrusion stress based on the finite element model, if the finite element analysis is performed in a whole circle, nonlinear contact manner (a common way of finite element analysis), the result is not easy to converge, the required computing power is large, and the calculation time is long. In order to avoid the result from being unable to converge (i.e. unable to obtain the current average extrusion stress), and to avoid a large amount of calculation resources (such as computing power and time) being consumed, in an embodiment of the present application, step S354, based on the finite element model, obtaining the current average extrusion stress, comprises steps S35a to S35e.

[0145] Step S35a: based on the finite element model, obtaining a second shroud and a third shroud.

[0146] In the present embodiment, the second shroud and the third shroud are any two adjacent shrouds in the finite element model.

[0147] Step S35b: based on the second shroud and the third shroud, obtaining a first working surface and a second working surface.

[0148] In the present embodiment, the first working surface is a working surface in the second shroud which meshes with the third shroud (for example, the first shroud working surface 233 as shown in Figure 4 Fig. 3). The second working surface is a working surface in the third shroud which meshes with the second shroud (for example, the second shroud working surface 234 as shown in Figure 4 Fig. 3).

[0149] Step S35c: applying a current third average stress to the first working surface and a current fourth average stress to the second working surface in the finite element model.

[0150] In the present embodiment, the current third average stress and the current fourth average stress are equal in size. The direction of the current third average stress is perpendicular to the first working surface and is directed from the third shroud to the second shroud. The direction of the current fourth average stress is perpendicular to the second working surface and is directed from the second shroud to the third shroud.

[0151] In the embodiment, the current third average stress is updated by a historical third average stress. The current fourth average stress is updated by a historical fourth average stress. The historical third average stress is based on an initial third average stress. The initial third average stress can be obtained based on a preset initialization mode, for example, the initial third average stress can be 0. When the first update is performed, the updated current third average stress can be obtained based on the initial third average stress (i.e., the current third average stress at this time), and at this time, the initial third average stress is the historical third average stress. The subsequent update process is not described here.

[0152] Step S35d: Obtain the distance between the first working surface and the second working surface.

[0153] It should be noted that in the finite element model, the distance between two surfaces (i.e., the first working surface and the second working surface) is a mature technology, which is not described here.

[0154] Step S35e: If the distance is greater than 0 and less than or equal to a second preset value, obtain the current average extrusion stress; otherwise, update the current third average stress and the current fourth average stress, and apply the updated current third average stress and the current fourth average stress to the first working surface and the second working surface respectively, and re-obtain the distance between the first working surface and the second working surface until the distance is greater than 0 and less than or equal to the second preset value.

[0155] In the embodiment, if the distance is greater than 0 and less than or equal to the second preset value, the size of the last updated current third average stress or the size of the current fourth average stress can be taken as the size of the current average extrusion stress.

[0156] In the embodiment of the present application, the current third average stress and the current fourth average stress whose sizes can approach the size of the current average extrusion stress can be obtained only by continuously iterating the current third average stress and the current fourth average stress. Compared with the finite element analysis using the whole, nonlinear contact mode, the iteration and update of the current third average stress and the current fourth average stress has lower requirement for computing power, faster calculation time, and does not have the phenomenon that the calculation result cannot converge.

[0157] In the embodiment of the present application, the second preset value can be set according to the requirement, for example, the second preset value can be 0.001 mm or 0.002 mm.

[0158] In the embodiments of the present application, the current third average stress and the current fourth average stress can be updated in any reasonable manner. For example, the updating manner of the current third average stress and the current fourth average stress can refer to the iteration of the candidate pre-twist angle in the foregoing. In order to enable the updating process of the current third average stress to converge quickly, in a specific embodiment of the present application, the updating of the current third average stress includes steps S35f and S35g.

[0159] Step S35f: obtaining a first difference value based on the current third average stress and a historical third average stress.

[0160] In the present embodiment, the first difference value is the absolute value of the difference between the current third average stress and the historical third average stress.

[0161] Step S35g: if the distance is equal to 0, updating the current third average stress based on a first preset coefficient and the first difference value; if the distance is greater than a second preset value, updating the current third average stress based on a second preset coefficient and the first difference value.

[0162] In a specific embodiment of the present application, step S35g, the calculation formula for updating the current third average stress is as follows:

[0163]

[0164] wherein F(x) represents the updated current third average stress; F1 represents the current third average stress before updating; F2 represents the historical third average stress; || represents the absolute value; k1 represents the first preset coefficient, which is greater than or equal to 1 and less than or equal to 2; k2 represents the second preset coefficient, which is equal to -0.5; x represents the distance between the first working surface and the second working surface; and a represents the second preset value.

[0165] It should be noted that, since the current third average stress and the current fourth average stress are equal in size, if the current third average stress is updated, the current fourth average stress can be updated by making the size of the current fourth average stress equal to the updated current third average stress.

[0166] It should be noted that, in the application scenario of the first working surface and the second working surface producing piercing in the finite element model, the iteration cannot be performed by the first calculation formula. Based on this, step S35g, the calculation program for updating the current third average stress can be as follows:

[0167] find: P

[0168] obj: min dist = f(P)

[0169] s.t. 0 < P < d

[0170] dist < a

[0171] wherein, d represents a third preset value, the third preset value can be set according to requirements, and when setting, the ideal average extrusion stress needs to be less than the third preset value, for example, d can be 100 MPa or 200 MPa, etc.; P represents the current third average stress, and the value range of P must be between 0 and d (not including the end point, of course, the end point can also be included in other embodiments); f(P) represents the average stress and distance function between the first working surface and the second working surface, wherein the input is the average stress between the first working surface and the second working surface, and the output is the distance between the first working surface and the second working surface; a represents a second preset value. In this embodiment, find: P represents finding the optimal value of the current third average stress P; obj: min dist = f(P) represents that the objective function (that is, the average stress and distance function between the first working surface and the second working surface) is to minimize the distance dist; s.t. 0 < P < d represents the constraint condition that the value range of P is between 0 and d (not including the end point); dist < a represents that the final distance dist (that is, f(P)) must be less than a. It should be noted that the optimal solution is a mature technology in the computer field, which will not be described here.

[0172] It needs to be clear that based on the finite element model, the average stress (that is, the current third average stress and the current fourth average stress) is directly applied to the working surface (that is, the first working surface and the second working surface) adjacent to the vane crown, and whether the applied average stress is close to the actual average stress (that is, the current average extrusion stress) between the two working surfaces is determined by the distance between the two working surfaces. Relative to the prior art, the finite element analysis is carried out by adopting the whole circumference and nonlinear contact mode to obtain the current average extrusion stress of the gas turbine vane crown. Since the size of the distance between the two surfaces (that is, the first working surface and the second working surface) is used as a substitute for the size of the stress (that is, the current average extrusion stress) for evaluation, it is equivalent to approximating the complex nonlinear calculation to a simple linear calculation, so the calculation result of the present application will certainly converge, and a large amount of calculation resources (such as computing power and time) can be saved.

[0173] It should be noted that in the present application, the step S320 in the above, obtaining the current average extrusion stress, can also be the steps S35a to S35g proposed in the present application.

[0174] Step S355: Based on the ideal average extrusion stress and the current average extrusion stress, an average stress difference value is obtained.

[0175] In this embodiment, the average stress difference is equal to the ideal average compressive stress minus the current average compressive stress.

[0176] Step S356: Obtain the first leaf crown based on the finite element model.

[0177] In this embodiment, the first leaf crown is any one of the leaf crowns in the finite element model.

[0178] Step S357: Based on the current average compressive stress in the finite element model, apply a first average stress to the first working surface of the first blade crown and a second average stress to the second working surface of the first blade crown to obtain the torsional angle difference value. The values ​​of the first average stress and the second average stress are equal to the average stress difference value. The first average stress is perpendicular to the first working surface of the first blade crown and points from the outside of the first blade crown inward; the second average stress is perpendicular to the second working surface of the first blade crown and points from the outside of the first blade crown inward.

[0179] In this embodiment, as Figure 6 As shown, Figure 6 The outline corresponding to the solid line represents the spatial position of leaf crown 23 when it is in a cold state; Figure 6 The outline corresponding to the dashed line represents the spatial position of the crown 23 when it is in a hot state. Since this embodiment is based on the current average compressive stress in the finite element model (i.e., under...), Figure 6 Based on the outline corresponding to the dashed line, a first average stress is applied to the first working surface of the first blade crown, and a second average stress is applied to the second working surface of the first blade crown. Therefore, as long as the average stress difference is not zero, the spatial position of the balanced blade crown 23 (the mid-surface corresponding to this spatial position of the blade crown 23 is referred to as the third mid-surface) must be the same as the spatial position of the blade crown 23 when it is in a hot state (e.g., Figure 6 The positions of the contours corresponding to the dashed lines are different. In this embodiment, the angle formed by the second mid-surface 238 and the third mid-surface can be regarded as the difference in torsion angle.

[0180] It should be clear that obtaining the included angle between two surfaces (i.e., the second mid-surface 238 and the third mid-surface) in the finite element model is a mature technique, which will not be elaborated here.

[0181] This concludes the description of Example b for obtaining the torsion angle difference.

[0182] Step S360: Based on the difference between the current pre-torsion angle and the torsion angle, obtain the gas turbine blade crown pre-torsion angle.

[0183] In the embodiment, the gas turbine shroud pre-twist angle is equal to the sum of the current pre-twist angle and the twist angle difference. Specifically, the calculation formula of the gas turbine shroud pre-twist angle is as follows:

[0184] θ4=θ1+Δβ

[0185] Wherein, θ4 represents the gas turbine shroud pre-twist angle; θ1 represents the twist angle of the shroud in the finite element model in the cold state (i.e. the current pre-twist angle); Δβ represents the twist angle difference.

[0186] So far, the second embodiment of obtaining the gas turbine shroud pre-twist angle is introduced.

[0187] It should be clear that the gas turbine shroud pre-twist angle design method proposed in the embodiment considers the local stiffness and local deformation of the shroud of the gas turbine in use, as well as the local deformation of the working surface of the shroud caused by factors such as temperature, centrifugal force and aerodynamic load. Compared with the existing method of approximating the shroud pre-twist angle design problem as a rigid body twist problem, the gas turbine shroud pre-twist angle designed by the gas turbine shroud pre-twist angle design method proposed in the application is more accurate.

[0188] After introducing the gas turbine shroud pre-twist angle design method proposed in the embodiment, the following introduces an embodiment of a gas turbine shroud pre-twist angle design device proposed in the application. As shown in the figure, the gas turbine shroud pre-twist angle design device 10 comprises: Figure 8

[0189] The reading module 11 is used to obtain the ideal average extrusion stress; the ideal average extrusion stress is pre-set;

[0190] The processing module 12 is used to obtain a finite element model based on a three-dimensional model of a gas turbine turbine; the finite element model is a single sector model;

[0191] And, based on the ideal average extrusion stress and the finite element model, the gas turbine shroud pre-twist angle is obtained.

[0192] As a specific embodiment in the application, the reading module 11 is also used to obtain a candidate pre-twist angle; the candidate pre-twist angle is obtained based on historical pre-twist angle update, and the historical pre-twist angle includes an initial pre-twist angle;

[0193] The processing module 12 is also used to update the finite element model based on the candidate pre-twist angle to obtain a current average extrusion stress; the current average extrusion stress is the average extrusion stress corresponding to the updated finite element model;

[0194] ​and if a difference between the current average extrusion stress and the ideal average extrusion stress is less than a first preset value, obtaining the pre-twist angle of the gas turbine bucket; otherwise, updating the candidate pre-twist angle, and updating the finite element model based on the updated candidate pre-twist angle until a difference between the current average extrusion stress and the ideal average extrusion stress obtained is less than the first preset value.

[0195] As one specific embodiment in the present application, the processing module 12 is further configured to obtain a first difference value based on the current average extrusion stress and the ideal average extrusion stress; the first difference value is used at least to represent a difference between the current average extrusion stress and the ideal average extrusion stress.

[0196] and obtain a second difference value based on the current average extrusion stress and a historical average extrusion stress; the second difference value is used at least to represent a difference between the current average extrusion stress and the historical average extrusion stress; the historical average extrusion stress is an average extrusion stress obtained last time before the current average extrusion stress is updated;

[0197] and obtain an updating coefficient based on the first difference value and the second difference value; the updating coefficient is a difference or a ratio between the first difference value and the second difference value.

[0198] and update the candidate pre-twist angle based on the updating coefficient.

[0199] As one specific embodiment in the present application, the reading module 11 is further configured to obtain a current pre-twist angle; the current pre-twist angle is a pre-twist angle when the gas turbine bucket is designed.

[0200] The processing module 12 is further configured to obtain a twist angle difference value based on the ideal average extrusion stress and the finite element model; the twist angle difference value is equal to an ideal twist angle minus a current twist angle; the current twist angle is a twist angle corresponding to the finite element model; the ideal twist angle is a twist angle corresponding to a case that an average extrusion stress between adjacent buckets in the finite element model is equal to the ideal average extrusion stress.

[0201] and obtain the pre-twist angle of the gas turbine bucket based on the current pre-twist angle and the twist angle difference value; the pre-twist angle of the gas turbine bucket is equal to a sum of the current pre-twist angle and the twist angle difference value.

[0202] As one specific embodiment in the present application, the processing module 12 is further configured to obtain a current twist angle based on the current pre-twist angle and the finite element model.

[0203] and obtain an ideal twist angle based on the ideal average extrusion stress and the finite element model.

[0204] and, based on the ideal torsion angle and the current torsion angle, obtaining a torsion angle difference value.

[0205] As one specific embodiment in the present application, the processing module 12 is further configured to obtain a current average extrusion stress based on the finite element model; the current average extrusion stress is an average extrusion stress between adjacent shrouds when the gas turbine in the finite element model is in a hot state;

[0206] and, based on the ideal average extrusion stress and the current average extrusion stress, obtaining an average stress difference value; the average stress difference value is equal to the ideal average extrusion stress minus the current average extrusion stress;

[0207] and, based on the finite element model, obtaining a first shroud; the first shroud is any one shroud in the finite element model;

[0208] and, based on the finite element model located at the current average extrusion stress, applying a first average stress to a first shroud working surface of the first shroud and applying a second average stress to a second shroud working surface of the first shroud to obtain the torsion angle difference value; the numerical values of the first average stress and the second average stress are equal to the average stress difference value; the first average stress is perpendicular to the first shroud working surface of the first shroud, and the first average stress is directed from the outside to the inside of the first shroud; the second average stress is perpendicular to the second shroud working surface of the first shroud, and the second average stress is directed from the outside to the inside of the first shroud.

[0209] As one specific embodiment in the present application, the reading module 11 is further configured to obtain a second shroud and a third shroud based on the finite element model; the second shroud and the third shroud are any two adjacent shrouds in the finite element model;

[0210] based on the second shroud and the third shroud, obtaining a first working surface and a second working surface; the first working surface is a working surface in the second shroud engaged with the third shroud; the second working surface is a working surface in the third shroud engaged with the second shroud;

[0211] The processing module 12 is further configured to apply a current third average stress to the first working surface and a current fourth average stress to the second working surface in the finite element model; the current third average stress and the current fourth average stress have equal magnitudes; the current third average stress is perpendicular to the first working surface and is directed from the third blade crown to the second blade crown; the current fourth average stress is perpendicular to the second working surface and is directed from the second blade crown to the third blade crown; the current third average stress is updated from a historical third average stress; and the current fourth average stress is updated from a historical fourth average stress.

[0212] The distance between the first working surface and the second working surface is obtained.

[0213] If the distance is greater than 0 and less than or equal to a second preset value, a current average extrusion stress is obtained; otherwise, the current third average stress and the current fourth average stress are updated, and the updated current third average stress and the updated current fourth average stress are applied to the first working surface and the second working surface respectively, the distance between the first working surface and the second working surface is obtained again until the distance is greater than 0 and less than or equal to the second preset value.

[0214] As a specific embodiment in the present application, the processing module 12 is further configured to obtain a first difference value based on the current third average stress and the historical third average stress; the first difference value is an absolute value of a difference between the current third average stress and the historical third average stress.

[0215] If the distance is equal to 0, the current third average stress is updated based on a first preset coefficient and the first difference value; and if the distance is greater than the second preset value, the current third average stress is updated based on a second preset coefficient and the first difference value.

[0216] It should be noted that the gas turbine blade crown pre-twist angle design device provided in the embodiments of the present application considers the local stiffness and local deformation of the blade crown of the gas turbine in use, as well as the local deformation of the working surface of the blade crown caused by factors such as temperature, centrifugal force and aerodynamic load, by establishing a finite element model. Compared with the existing method of approximating the blade crown pre-twist angle design problem as a rigid body torsion problem, the blade crown pre-twist angle designed by the gas turbine blade crown pre-twist angle design device provided in the present application is more accurate.

[0217] After introducing the gas turbine blade crown pre-twist angle design device provided in the embodiments of the present application, an embodiment of a gas turbine blade crown pre-twist angle design system provided in the present application is introduced below. As shown in Figure 9 The gas turbine blade crown pre-twist angle design system 20 includes:

[0218] a reader 21, configured to acquire an ideal average extrusion stress; the ideal average extrusion stress is preset;

[0219] a server 22, configured to acquire a finite element model based on a three-dimensional model of a gas turbine turbine; the finite element model is a single-sector model;

[0220] and acquire the pre-twist angle of the gas turbine blade crown based on the ideal average extrusion stress and the finite element model.

[0221] As one specific embodiment in the present application, the reader 21 is further configured to acquire a candidate pre-twist angle; the candidate pre-twist angle is updated based on a historical pre-twist angle; the historical pre-twist angle includes an initial pre-twist angle;

[0222] The server 22 is further configured to update the finite element model based on the candidate pre-twist angle to acquire a current average extrusion stress; the current average extrusion stress is the average extrusion stress corresponding to the updated finite element model;

[0223] and if the difference between the current average extrusion stress and the ideal average extrusion stress is less than a first preset value, acquire the pre-twist angle of the gas turbine blade crown; otherwise, update the candidate pre-twist angle and update the finite element model based on the updated candidate pre-twist angle until the difference between the current average extrusion stress and the ideal average extrusion stress is less than the first preset value.

[0224] As one specific embodiment in the present application, the server 22 is further configured to acquire a first difference value based on the current average extrusion stress and the ideal average extrusion stress; the first difference value is at least used to represent the difference between the current average extrusion stress and the ideal average extrusion stress;

[0225] and acquire a second difference value based on the current average extrusion stress and a historical average extrusion stress; the second difference value is at least used to represent the difference between the current average extrusion stress and the historical average extrusion stress; the historical average extrusion stress is the average extrusion stress obtained by updating the current average extrusion stress last time;

[0226] and acquire an update coefficient based on the first difference value and the second difference value; the update coefficient is the difference or ratio of the first difference value and the second difference value;

[0227] and update the candidate pre-twist angle based on the update coefficient.

[0228] As one specific embodiment in the present application, the reader 21 is further configured to acquire a current pre-twist angle; the current pre-twist angle is the pre-twist angle when the gas turbine blade crown is designed;

[0229] The server 22 is further configured to obtain a twist angle difference value based on the ideal average extrusion stress and the finite element model; the twist angle difference value is equal to an ideal twist angle minus a current twist angle; the current twist angle is a twist angle corresponding to the finite element model; the ideal twist angle is a twist angle corresponding to a case where an average extrusion stress between adjacent shrouds in the finite element model is equal to the ideal average extrusion stress;

[0230] And obtain the gas turbine shroud pre-twist angle based on the current pre-twist angle and the twist angle difference value; the gas turbine shroud pre-twist angle is equal to a sum of the current pre-twist angle and the twist angle difference value.

[0231] As a specific embodiment in the present application, the server 22 is further configured to obtain a current twist angle based on the current pre-twist angle and the finite element model;

[0232] And obtain an ideal twist angle based on the ideal average extrusion stress and the finite element model;

[0233] And obtain a twist angle difference value based on the ideal twist angle and the current twist angle.

[0234] As a specific embodiment in the present application, the server 22 is further configured to obtain a current average extrusion stress based on the finite element model; the current average extrusion stress is an average extrusion stress between adjacent shrouds when the gas turbine is in a hot state in the finite element model;

[0235] And obtain an average stress difference value based on the ideal average extrusion stress and the current average extrusion stress; the average stress difference value is equal to the ideal average extrusion stress minus the current average extrusion stress;

[0236] And obtain a first shroud based on the finite element model; the first shroud is any one shroud in the finite element model;

[0237] And apply a first average stress to a first shroud working surface of the first shroud and a second average stress to a second shroud working surface of the first shroud based on the current average extrusion stress in the finite element model to obtain the twist angle difference value; the first average stress and the second average stress are equal in value to the average stress difference value; the first average stress is perpendicular to the first shroud working surface of the first shroud and points from the outside to the inside of the first shroud; the second average stress is perpendicular to the second shroud working surface of the first shroud and points from the outside to the inside of the first shroud.

[0238] As a specific embodiment in the present application, the reader 21 is further configured to acquire a second leaf crown and a third leaf crown based on the finite element model; the second leaf crown and the third leaf crown are any two adjacent leaf crowns in the finite element model;

[0239] acquire a first working surface and a second working surface based on the second leaf crown and the third leaf crown; the first working surface is a working surface in the second leaf crown that meshes with the third leaf crown; and the second working surface is a working surface in the third leaf crown that meshes with the second leaf crown;

[0240] The server 22 is further configured to apply a current third average stress to the first working surface and a current fourth average stress to the second working surface in the finite element model; the current third average stress and the current fourth average stress are equal in magnitude; the direction of the current third average stress is perpendicular to the first working surface and points from the third leaf crown to the second leaf crown; and the direction of the current fourth average stress is perpendicular to the second working surface and points from the second leaf crown to the third leaf crown; the current third average stress is updated from a historical third average stress; and the current fourth average stress is updated from a historical fourth average stress;

[0241] and acquire a distance between the first working surface and the second working surface;

[0242] and if the distance is greater than 0 and less than or equal to a second preset value, acquire a current average extrusion stress; otherwise, update the current third average stress and the current fourth average stress, and apply the updated current third average stress and the current fourth average stress to the first working surface and the second working surface respectively, reacquire the distance between the first working surface and the second working surface, until the distance is greater than 0 and less than or equal to the second preset value.

[0243] As a specific embodiment in the present application, the server 22 is further configured to acquire a first difference value based on the current third average stress and the historical third average stress; the first difference value is an absolute value of a difference between the current third average stress and the historical third average stress;

[0244] and if the distance is equal to 0, update the current third average stress based on a first preset coefficient and the first difference value; and if the distance is greater than the second preset value, update the current third average stress based on a second preset coefficient and the first difference value.

[0245] It is important to understand that the gas turbine blade pre-torsion angle design system proposed in this application, through the establishment of a finite element model, considers the local stiffness and deformation of the blade crown during gas turbine operation, as well as the local deformation phenomena of the blade crown working surface caused by factors such as temperature, centrifugal force, and aerodynamic loads. Compared to existing methods that approximate the blade pre-torsion angle design problem as a rigid body torsion problem, the gas turbine blade pre-torsion angle design system proposed in this application designs a more accurate blade pre-torsion angle.

[0246] Having introduced the gas turbine blade pre-torsion angle design system proposed in the embodiments of this application, the following describes an embodiment of a computer-readable storage medium proposed in this application. This computer-readable storage medium stores a computer program, which, when executed by a processor, implements the gas turbine blade pre-torsion angle design method as described in any of the above embodiments.

[0247] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method of gas turbine shroud pre-twist angle design, characterized by, The method comprises: obtaining an ideal average extrusion stress; the ideal average extrusion stress is preset; obtaining a finite element model based on a three-dimensional model of a gas turbine turbine; the finite element model is a single sector model; the input of the finite element model at least includes material parameters, service temperature, service speed and aerodynamic load of the gas turbine turbine blade; obtaining the gas turbine shroud pre-twist angle based on the ideal average extrusion stress and the finite element model.

2. The gas turbine shroud pretwist angle design method of claim 1, wherein, The method comprises: obtaining a candidate pre-twist angle; the candidate pre-twist angle is obtained based on historical pre-twist angle update, and the historical pre-twist angle includes an initial pre-twist angle; updating the finite element model based on the candidate pre-twist angle to obtain a current average extrusion stress; the current average extrusion stress is the average extrusion stress corresponding to the updated finite element model; if the difference between the current average extrusion stress and the ideal average extrusion stress is less than a first preset value, obtaining the gas turbine shroud pre-twist angle; otherwise, updating the candidate pre-twist angle, and updating the finite element model based on the updated candidate pre-twist angle until the difference between the current average extrusion stress and the ideal average extrusion stress is less than the first preset value.

3. The gas turbine shroud pretwist angle design method of claim 2, wherein The method comprises: obtaining a first difference value based on the current average extrusion stress and the ideal average extrusion stress; the first difference value is used at least to represent the difference between the current average extrusion stress and the ideal average extrusion stress; obtaining a second difference value based on the current average extrusion stress and a historical average extrusion stress; the second difference value is used at least to represent the difference between the current average extrusion stress and the historical average extrusion stress; the historical average extrusion stress is the average extrusion stress obtained last time before the current average extrusion stress; obtaining an update coefficient based on the first difference value and the second difference value; the update coefficient is obtained based on the difference or ratio of the first difference value and the second difference value; updating the candidate pre-twist angle based on the update coefficient.

4. The gas turbine shroud pretwist angle design method of claim 1, wherein The method comprises: obtaining a current pre-twist angle; the current pre-twist angle is the pre-twist angle when the gas turbine shroud is designed; obtaining a twist angle difference value based on the ideal average extrusion stress and the finite element model; the twist angle difference value is equal to the ideal twist angle minus the current twist angle; the current twist angle is the twist angle corresponding to the finite element model; the ideal twist angle is the twist angle corresponding to the average extrusion stress equal to the ideal average extrusion stress between adjacent shrouds in the finite element model; obtaining the gas turbine shroud pre-twist angle based on the current pre-twist angle and the twist angle difference value; the gas turbine shroud pre-twist angle is equal to the sum of the current pre-twist angle and the twist angle difference value.

5. The gas turbine shroud pretwist angle design method of claim 4, wherein The method comprises: obtaining a current twist angle based on the finite element model and the current pre-twist angle; acquiring, based on the ideal average extrusion stress and the finite element model, a torsion angle difference value; acquiring, based on the ideal torsion angle and the current torsion angle, a torsion angle difference value.

6. The gas turbine shroud pretwist angle design method of claim 4, wherein The acquiring, based on the ideal average extrusion stress and the finite element model, of the torsion angle difference value comprises: acquiring, based on the finite element model, a current average extrusion stress; the current average extrusion stress being an average extrusion stress between adjacent shrouds in the finite element model when the gas turbine is in a hot state; acquiring, based on the ideal average extrusion stress and the current average extrusion stress, an average stress difference value; the average stress difference value being equal to the ideal average extrusion stress minus the current average extrusion stress; acquiring, based on the finite element model, a first shroud; the first shroud being any one shroud in the finite element model; applying, to a first shroud working surface of the first shroud, a first average stress and to a second shroud working surface of the first shroud, a second average stress, based on the finite element model being located at the current average extrusion stress, to acquire the torsion angle difference value; the first average stress and the second average stress being equal in value to the average stress difference value; the first average stress being perpendicular to the first shroud working surface of the first shroud and pointing from the outside to the inside of the first shroud; the second average stress being perpendicular to the second shroud working surface of the first shroud and pointing from the outside to the inside of the first shroud.

7. The gas turbine shroud pretwist angle design method of claim 2 or 6, wherein The acquiring, based on the finite element model, of the current average extrusion stress comprises: acquiring, based on the finite element model, a second shroud and a third shroud; the second shroud and the third shroud being any two adjacent shrouds in the finite element model; acquiring, based on the second shroud and the third shroud, a first working surface and a second working surface; the first working surface being a working surface of the second shroud engaged with the third shroud; the second working surface being a working surface of the third shroud engaged with the second shroud; applying, to the first working surface, a current third average stress and to the second working surface, a current fourth average stress, in the finite element model; the current third average stress and the current fourth average stress being equal in magnitude; the current third average stress being perpendicular to the first working surface and pointing from the third shroud to the second shroud; the current fourth average stress being perpendicular to the second working surface and pointing from the second shroud to the third shroud; the current third average stress being updated from a historical third average stress; the current fourth average stress being updated from a historical fourth average stress; acquiring a distance between the first working surface and the second working surface; and acquiring, based on the distance, the current average extrusion stress. If the distance is greater than 0 and less than or equal to a second preset value, the current average extrusion stress is obtained; otherwise, the current third average stress and the current fourth average stress are updated, and the updated current third average stress and the current fourth average stress are applied to the first working surface and the second working surface respectively, the distance between the first working surface and the second working surface is re-obtained until the distance is greater than 0 and less than or equal to the second preset value.

8. The gas turbine shroud pretwist angle design method of claim 7, wherein, The updating the current third average stress comprises: obtaining a first difference value based on the current third average stress and a historical third average stress; the first difference value is an absolute value of a difference between the current third average stress and the historical third average stress; if the distance is equal to 0, updating the current third average stress based on a first preset coefficient and the first difference value; if the distance is greater than a second preset value, updating the current third average stress based on a second preset coefficient and the first difference value.

9. A gas turbine shroud pre-twist angle design apparatus characterized by, comprises: a reading module configured to obtain an ideal average extrusion stress; the ideal average extrusion stress is pre-set; a processing module configured to obtain a finite element model based on a three-dimensional model of a gas turbine turbine; the finite element model is a single sector model; and obtain the gas turbine blade crown pre-twist angle based on the ideal average extrusion stress and the finite element model.

10. A gas turbine shroud pre-twist angle design system characterized by, comprises: a reader configured to obtain an ideal average extrusion stress; the ideal average extrusion stress is pre-set; a server configured to obtain a finite element model based on a three-dimensional model of a gas turbine turbine; the finite element model is a single sector model; and obtain the gas turbine blade crown pre-twist angle based on the ideal average extrusion stress and the finite element model.

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