Turbine blade tenon design method

Abstract

The invention discloses a turbine blade tenon design method, and relates to the technical field of gas turbines. The turbine blade tenon design method comprises the steps that second yield strength is obtained based on first yield strength; acquiring a first circumferential length; obtaining a first axial length based on the first circumferential length and the second yield strength; obtaining each second circumferential length based on the first axial length; the second circumferential length is the shortest circumferential length of any throat part, except the middle throat part, of the blade tenon around the first axis. According to the turbine blade tenon design method, the designed turbine blade tenon can pass structural strength verification at a time, the complexity degree of design of the turbine blade tenon is simplified, time consumed for design is shortened, and working efficiency is improved.

Description

Technical Field

[0001] The present application relates to the technical field of gas turbines, and in particular to a method for designing a tenon of a turbine blade. Background Art

[0002] The turbine of a gas turbine includes components such as a turbine shaft, a turbine disc, and turbine blades. The turbine blades and the turbine disc are connected by a tenon structure. Figure 3 As shown, the turbine blade includes a blade tenon, and the turbine disk includes a rim tenon. The turbine blade and the turbine disk are mortised by the blade tenon and the rim tenon. Figure 3 As shown, both the blade tenon and the rim tenon have a fir-tree tenon structure. When designing the tenon structure, the throat of the blade tenon and the throat of the rim tenon need to be checked simultaneously to ensure that the structural strength of the blade tenon and the rim tenon meets the requirements. If the verification finds that the structural strength of the blade tenon and / or the rim tenon does not meet the requirements, the design parameters of the blade tenon and the rim tenon need to be modified until the structural strength of the blade tenon and the rim tenon meets the requirements. This process is relatively cumbersome and time-consuming, resulting in low work efficiency. Summary of the Invention

[0003] The purpose of this application is to provide a turbine blade tenon design method to solve the technical problem in the prior art that the turbine blade tenon design process is complicated and time-consuming.

[0004] To achieve the above objectives, this application provides the following technical solutions:

[0005] A method for designing a tenon of a turbine blade, wherein the turbine comprises a turbine shaft, a turbine disk, and a turbine blade; the turbine disk comprises a plurality of rim tenons, with a tenon groove formed between two adjacent rim tenons; the turbine blade comprises a blade tenon; the method for designing a turbine blade tenon comprises:

[0006] Based on the first yield strength, a second yield strength is obtained; the first yield strength is the yield strength of the rim tenon material; the second yield strength is the yield strength of the blade tenon material; the first yield strength is obtained in advance; the second yield strength is less than or equal to the first yield strength;

[0007] Obtaining a first circumferential length; the first circumferential length is the shortest circumferential length of the middle throat of the blade tenon around a first axis; the first axis is the axis of the turbine shaft;

[0008] Based on the first circumferential length and the second yield strength, a first axial length is obtained; the first axial length is the axial length of the blade tenon along the first axial centerline;

[0009] Based on the first axial length, each second circumferential length is obtained; the second circumferential length is the shortest circumferential length of any throat of the blade tenon except the middle throat around the first axis.

[0010] As a specific solution of the technical solution of the present application, the third circumferential length and the fourth circumferential length are equal; the third circumferential length is the shortest circumferential length of the middle throat of the blade tenon around the second axis; the fourth circumferential length is the shortest circumferential length of the middle throat of the rim tenon around the second axis; the second axis intersects the first axis, and the second axis is parallel to the extension direction of the turbine disk tenon groove;

[0011] The obtaining of the first circumferential length includes:

[0012] Obtaining a radius length; the radius length is the distance between the center of the turbine disc cross section and a first arc; the cross section is perpendicular to the second axis, and the second axis passes through the center of the circle; the first arc is the arc corresponding to the shortest circumferential length of the middle throat of the rim tenon around the second axis;

[0013] Obtaining the angle of the middle tenon of the blade tenon and the tenon compensation amount;

[0014] Obtaining the tongue and groove inclination angle of the turbine disc;

[0015] Obtain a first number and a first spacing; the first number being the number of turbine blades corresponding to the turbine disk; the first spacing being the distance between a second arc line and a third arc line; the second arc line being the arc line corresponding to the shortest circumferential length of the middle throat of the blade tenon around the second axis; and the third arc line being the arc line corresponding to the longest circumferential length of the middle tenon of the blade tenon around the second axis;

[0016] The first circumferential length is acquired based on the radius length, the angle of the middle tenon, the compensation amount of the middle tenon, the inclination angle of the tenon groove, the first number and the first spacing.

[0017] As a specific solution in the technical solution of the present application, the calculation formula for obtaining the first circumferential length based on the radius length, the angle of the middle tenon, the compensation amount of the middle tenon, the tenon groove inclination angle, the first number and the first spacing is as follows:

[0018]

[0019] Among them, S represents the first circumferential length; π represents the pi; r represents the radius length; n represents the first number; H represents the first spacing; β represents the angle of the middle tenon of the blade tenon 31; tan represents the sine function; b represents the compensation amount of the middle tenon of the blade tenon 31; θ represents the inclination angle of the tenon groove; cos represents the cosine function.

[0020] As a specific solution in the technical solution of the present application, obtaining the first axial length based on the first circumferential length and the second yield strength includes:

[0021] Obtaining a first tension; the first tension is the maximum tension borne by the middle throat of the blade tenon when the blade tenon is in use;

[0022] Obtaining a first reserve coefficient; the first reserve coefficient is the average centrifugal tensile stress yield strength reserve coefficient of the blade tenon throat;

[0023] obtaining a second axial length based on the first tensile force, the first circumferential length, the second yield strength, and the first reserve coefficient;

[0024] The first axial length is obtained based on the second axial length.

[0025] As a specific solution in the technical solution of the present application, the calculation formula for obtaining the second axial length based on the first tension, the first circumferential length, the second yield strength and the first reserve coefficient is as follows:

[0026]

[0027] Wherein, L1 represents the second axial length; F1 represents the first tension; n1 represents the first reserve coefficient; σ1 represents the second yield strength; and S represents the first circumferential length.

[0028] As a specific solution in the technical solution of the present application, after obtaining the second axial length based on the first tension, the first circumferential length, the second yield strength, and the first reserve coefficient, the method further includes:

[0029] Obtaining a first pressure; the first pressure is the maximum pressure borne by the tenon contact surface of the middle tenon when the blade tenon is in use;

[0030] Obtaining the angle and tooth surface width of the middle tenon of the blade tenon;

[0031] Obtaining a second reserve coefficient; the second reserve coefficient is an average compressive stress yield strength reserve coefficient of the tenon tooth contact surface of the blade tenon;

[0032] Obtaining a third axial length based on the first pressure, the angle of the middle tenon of the blade tenon, the tooth surface width of the middle tenon of the blade tenon, the second reserve coefficient, and the second yield strength;

[0033] The acquiring the first axial length based on the second axial length includes:

[0034] The first axial length is obtained based on the second axial length and the third axial length.

[0035] As a specific solution in the technical solution of this application, based on the first pressure, the angle of the middle tenon of the blade tenon, the tooth surface width of the middle tenon of the blade tenon, the second reserve coefficient and the second yield strength, the calculation formula for obtaining the third axial length is as follows:

[0036]

[0037] Among them, L2 represents the third axial length; F2 represents the first pressure; β represents the angle of the middle tenon of the blade tenon 31; cos represents the cosine function; n2 represents the second reserve coefficient; σ1 represents the second yield strength; d represents the tooth surface width of the middle tenon of the blade tenon 31.

[0038] As a specific solution in the technical solution of the present application, obtaining the first axial length based on the second axial length and the third axial length includes:

[0039] If the second axial length is less than or equal to the third axial length, the third axial length is used as the first axial length; if the second axial length is greater than the third axial length, the second axial length is used as the first axial length.

[0040] As a specific solution in the technical solution of this application, a method for obtaining any second circumferential length includes:

[0041] Obtaining a second pulling force; wherein the second pulling force is a maximum pulling force when the throat portion of the blade tenon corresponding to the second circumferential length is in use;

[0042] Obtaining a second yield strength and a first reserve coefficient; the second yield strength is the yield strength corresponding to the material of the blade tenon; the reserve coefficient is the average centrifugal tensile stress yield strength reserve coefficient of the blade tenon throat;

[0043] The second circumferential length is obtained based on the second tensile force, the second yield strength, the first reserve coefficient, and the first axial length.

[0044] As a specific solution in the technical solution of this application, based on the second tensile force, the second yield strength, the first reserve coefficient and the first axial length, a calculation formula for obtaining the second circumferential length is as follows:

[0045]

[0046] Wherein, Sa represents the second circumferential length; Fa represents the second tension; n1 represents the first reserve coefficient; σ1 represents the second yield strength; and L represents the first axial length.

[0047] Compared with the prior art, the present invention has the following advantages:

[0048] The turbine blade tenon design method proposed in this application enables the designed turbine blade tenon to pass the structural strength verification at one time, simplifies the complexity of turbine blade tenon design, reduces the time required for design, and improves work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 A schematic flow chart of a turbine blade tenon design method proposed in an embodiment of the present application;

[0050] Figure 2 This is a schematic diagram of a front view of a turbine proposed in an embodiment of the present application (only the turbine shaft and turbine disk);

[0051] Figure 3 A turbine disc and a turbine blade proposed in the embodiment of the present application are as follows Figure 2 Partial cross-section view of the CC line;

[0052] Figure 4 for Figure 3 Magnified image of;

[0053] Figure 5 for Figure 3 Enlarged view of part A.

[0054] In the figure: 1. turbine shaft; 11. first axis; 2. turbine disc; 21. rim tenon; 22. second axis; 211. first throat of rim; 212. second throat of rim; 213. third throat of rim; 3. turbine blade; 31. blade tenon; 311. first throat of blade; 312. second throat of blade; 313. third throat of blade. DETAILED DESCRIPTION

[0055] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0056] It should be noted that, in the description of this application, the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as a limitation on this application.

[0057] Furthermore, it should be understood that for the sake of ease of description, the sizes of the various components shown in the drawings are not drawn according to actual proportions. For example, the thickness or width of certain layers may be exaggerated relative to other layers.

[0058] The terms "first," "second," and the like in the description of the embodiments of this application and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or precedence. For example, the first circumferential length and the second circumferential length mentioned below are different circumferential lengths. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments described herein can be implemented in an order other than that shown or described herein.

[0059] It should be noted that like numbers and letters represent similar items in the following figures, so once an item is defined or described in one figure, it will not need to be further discussed and described in detail in the description of the subsequent figures.

[0060] In order to solve the technical problem that the design process of turbine blade tenons in the prior art is cumbersome and time-consuming as mentioned in the background art, the present application proposes a turbine blade tenon design method. The turbine blade tenon design method is applied to turbine design, and the turbine includes a turbine shaft 1, a turbine disk 2 and a turbine blade 3. The turbine disk 2 includes a plurality of rim tenons 21, and a tenon groove is formed between two adjacent rim tenons 21. The turbine blade 3 includes a blade tenon 31. In the embodiment of the present application, the preliminary design of the turbine blade 3 has been completed. It should be noted that in the embodiment of the present application, the preliminary design of the turbine blade 3 has been completed, which means that the mass and center of mass of the turbine blade 3 have been determined, the shapes of the throats and tenons in the blade tenon 31 have been determined, and the operating temperature of the turbine blade 3 has also been determined. The only thing that needs to be designed and determined is the axial length of the blade tenon 31 along the first axis 11 (hereinafter referred to as the first axial length, the first axial length is equal to the axial length of the rim tenon 21 along the first axis 11, that is, Figure 2 The axial length S1 shown in FIG1 ), the shortest circumferential length of each throat of the blade tenon 31 around the first axis 11 and the longest circumferential length of each tenon of the blade tenon 31 around the first axis 11. Figure 2 As shown, the first axis 11 is the axis of the turbine shaft 1. Hereinafter, these dimensional parameters that require design and determination are referred to as "undetermined design parameters." In the prior art, the undetermined design parameters of the blade tenon 31 are repeatedly adjusted based on experience until the structural strength of the blade tenon 31 and the rim tenon 21 meet operational requirements.

[0061] In order to simplify the design process of the parameters to be designed of the blade tenon 31, thereby reducing the design time and improving work efficiency, in the embodiment of the present application, the shortest circumferential length of the middle throat of the blade tenon 31 around the second axis 22 (for example: Figure 4 The shortest circumferential length S2 of the second throat portion 312 of the middle blade may be less than or equal to the shortest circumferential length of the middle throat portion of the rim tenon 21 around the second axis 22 (for example: Figure 4 The shortest circumferential length S3 of the second throat portion 212 of the middle rim). Figure 4 For turbine discs and turbine blades Figure 2 The partial cross-sectional view of the CC line is perpendicular to the extension direction of the tongue and groove in the turbine disk 2 (ie, Figure 2 The second axis 22 intersects the first axis 11 and is parallel to the extending direction of the tongue and groove in the turbine disk 2 .

[0062] It should be noted that the number of tenons and throats of the blade tenon is equal, and the number of tenons (that is, the number of throats) of the blade tenon is an odd number. That is to say, if the blade tenon has x tenons, then the blade tenon must also have x throats, and x is a positive odd number greater than or equal to 3. In the embodiment of the present application, the middle throat of the blade tenon 31 refers to the (1+x) / 2th throat on the blade tenon 31. For example: if the blade tenon has 3 throats, the middle throat of the blade tenon is the 2nd (that is, (1+3) / 2=2)th throat; if the blade tenon has 5 throats, the middle throat of the blade tenon is the 3rd (that is, (1+5) / 2=3)th throat, and so on. It is easy to understand that in the embodiment of the present application, the middle throat of the rim tenon 21 refers to the (1+x) / 2th throat on the rim tenon 21, which is not listed here.

[0063] It should be clear that in order to avoid redundancy, such as Figure 3 and Figure 4 As shown, the turbine blade tenon design method proposed in this application is illustrated below by taking the embodiment in which the number of tenons and throats of the blade tenon is 3 as an example. This does not mean that the turbine blade tenon design method proposed in this application is only applicable to the design of turbine blades with 3 tenons and throats. It should be understood that the turbine blade tenon design method proposed in this application is applicable to the design of any turbine blade with an odd number of tenons and throats. Figure 4 As shown, Figure 4 The blade tenon 31 has three throats (i.e., the blade first throat 311, the blade second throat 312 and the blade third throat 313), and the corresponding rim tenon 21 also has three throats (i.e., the rim first throat 211, the rim second throat 212 and the rim third throat 213).

[0064] Specifically, such as Figure 1 As shown, the turbine blade tenon design method includes steps S100 to S400.

[0065] Step S100: obtaining a second yield strength based on the first yield strength.

[0066] In the embodiment of the present application, the first yield strength is the yield strength of the material of the rim tenon 21. The second yield strength is the yield strength of the material of the blade tenon 31. The first yield strength is pre-determined, and the second yield strength is less than or equal to the first yield strength. In other words, in this embodiment, the second yield strength can be any yield strength less than or equal to the first yield strength.

[0067] It should be noted that because the second yield strength is less than or equal to the first yield strength, it is easy to make the structural strength of the rim tenon 21 higher than the structural strength of the blade tenon 31 during design. Because the forces act reciprocally (i.e., the forces generated between the rim tenon 21 and the blade tenon 31 are equal in magnitude and opposite in direction), during the design process, if the structural strength of the blade tenon 31 meets the requirements, the structural strength of the rim tenon 21 will also meet the requirements.

[0068] Step S200: Obtain a first circumferential length.

[0069] In the embodiment of the present application, the first circumferential length is the shortest circumferential length of the middle throat of the blade tenon 31 around the first axial centerline 11 , and the first axial centerline 11 is the axial centerline of the turbine shaft 1 .

[0070] In the embodiment of the present application, the shortest circumferential length of a component (e.g., a blade tenon 31 or a rim tenon 21) around a certain axis (e.g., a first axis 11 or a second axis 21) refers to the shortest circumferential length of the component when the component is cut, and the cut surface (e.g., Figure 4 The section plane shown in FIG. 1 is perpendicular to the axis, and the shortest circumferential length of the component in the section plane is the shortest circumferential length of the component around the axis (for example, Figure 4 The length S2 shown is the shortest circumferential length of the middle throat of the blade tenon 31 around the second axis 22; the length S3 is the shortest circumferential length of the middle throat of the rim tenon 21 around the second axis 22. The longest circumferential length and shortest circumferential length of a component around a particular axis are similar and will not be described in detail below.

[0071] In the embodiments of the present application, any reasonable method can be used to obtain the first circumferential length. For example, the first circumferential length can be obtained as shown in the following two embodiments.

[0072] Example 1 of obtaining the first circumferential length

[0073] In this embodiment, the third circumferential length and the fourth circumferential length are equal, and the yield strength of the material of the rim tenon 21 is higher than the yield strength of the material of the blade tenon 31. The third circumferential length is the shortest circumferential length of the middle throat of the blade tenon 31 around the second axis 22 (for example, Figure 4 The fourth circumferential length is the shortest circumferential length of the middle throat of the rim tenon 21 around the second axis 22 (e.g., Figure 4 The second axis 22 intersects the first axis 11 and is parallel to the extension direction of the tongue and groove of the turbine disk 2.

[0074] It should be clear that, when in use, the tension exerted on the middle throat of the rim tenon 21 and the middle throat of the blade tenon 31 is equal. Since the material yield strength of the rim tenon 21 is higher than the material yield strength of the blade tenon 31, and the third circumferential length is equal to the fourth circumferential length, if the structural strength of the middle throat of the blade tenon 31 meets the use requirements, then the structural strength of the middle throat of the rim tenon 21 must also meet the use requirements. That is to say, in this embodiment, it is only necessary to ensure that the mechanical strength of the blade tenon 31 meets the use requirements, so that the overall structural strength of the tenon structure (that is, the blade tenon 31 and the rim tenon 21) can meet the use requirements at one time, that is, there is no need for repeated verification in the future, which simplifies the design process.

[0075] Step S200, obtaining a first circumferential length, includes steps S210 to S250.

[0076] Step S210: Obtain the radius length.

[0077] In this embodiment, the radius length is the center of the cross section of the turbine disk 2 (for example, Figure 4 The distance between the center D shown in FIG. Figure 4 The section is perpendicular to the second axis 22, and the second axis 22 passes through the center of the circle. The first arc is the arc corresponding to the shortest circumferential length of the middle throat of the rim tenon 21 around the second axis 22 (for example, Figure 4 The arc corresponding to the circumferential length S3 of the second throat portion 212 of the rim is shown).

[0078] As can be seen from the foregoing, since the preliminary design of the turbine blade 3 has been completed, the radius length is a known radius and will not be described in detail here.

[0079] Step S220: Obtain the angle of the middle tenon of the blade tenon 31 and the tenon compensation amount.

[0080] In the embodiments of the present application, the definition of the middle tenon is the same as that of the middle throat portion described above. That is, if the blade tenon 31 has x tenons, where x is a positive odd number greater than or equal to 3, then the middle tenon is the (1+x) / 2th tenon on the blade tenon 31, and further description is omitted here.

[0081] In the embodiment of the present application, the angle of the middle tenon of the blade tenon 31 is the angle formed by the projection of the contact surface of the middle tenon of the blade tenon 31 and the middle tenon of the rim tenon 21 in the direction parallel to the second axis 22 and the third arc (the third arc is approximately a straight line, and the definition of the third arc is described below) (for example, Figure 5 The tenon compensation amount of the middle tenon of the blade tenon 31 is as shown in FIG. Figure 5 The distance shown is shown in b.

[0082] It should be noted that, since the preliminary design of the turbine blade 3 has been completed, the angle of the middle tenon of the blade tenon 31 and the tenon compensation amount are both known and will not be described in detail here.

[0083] Step S230: Obtain the tongue and groove inclination angle of the turbine disk 2.

[0084] In this embodiment, the inclination angle of the tongue and groove of the turbine disk 2 refers to the acute angle formed by the first axis 11 and the second axis 22 (ie, Figure 2 The angle θ shown).

[0085] As can be seen from the foregoing, since the preliminary design of the turbine blade 3 has been completed, the inclination angle of the tongue and groove is a known angle and will not be described in detail here.

[0086] Step S240: Obtain a first quantity and a first spacing.

[0087] In this embodiment, the first number is the number of turbine blades 3 corresponding to the turbine disk 2. The first spacing is the distance between the second arc and the third arc (for example, Figure 5 The second arc is the arc corresponding to the shortest circumferential length of the middle throat of the blade tenon 31 around the second axis 22 (that is, Figure 4 The third arc is the arc corresponding to the longest circumferential length of the middle tenon of the blade tenon 31 around the second axis 22 (i.e., Figure 4 The arc corresponding to the circumferential length S4 shown).

[0088] As can be seen from the foregoing, since the preliminary design of the turbine blades 3 has been completed, the first number is a known number and the first spacing is also a known distance, which will not be described in detail here.

[0089] Step S250: Obtain a first circumferential length based on the radius length, the angle of the middle tenon, the compensation amount of the middle tenon, the inclination angle of the tenon groove, the first number and the first spacing.

[0090] It should be noted that in the embodiment of the present application, it is assumed that the number of turbine blades 3 provided on the turbine disk 2 is n, where n is a positive integer. Figure 4 It can be seen that the parameters to be designed for the blade tenon 31 must satisfy the following calculation formula (hereinafter referred to as the first formula):

[0091] (S4+S3)*n=2πr

[0092] Among them, S4 represents the longest circumferential length of the middle tenon of the blade tenon 31 around the second axial centerline 22; S3 represents the shortest circumferential length of the middle throat of the rim tenon 21 around the second axial centerline 22 (that is, the fourth circumferential length); n represents the number of turbine blades 3 arranged on the turbine disk 2 (that is, the first number); π represents the pi; and r represents the radius length.

[0093] based on Figure 5 It can be seen that the parameters to be designed for the blade tenon 31 also satisfy the following calculation formula (hereinafter referred to as the second formula):

[0094] S4≈S2+2a

[0095] Among them, S4 represents the longest circumferential length of the middle tenon of the blade tenon 31 around the second axis 22; S2 represents the shortest circumferential length of the middle throat of the rim tenon 21 around the second axis 22 (i.e., the third circumferential length); a represents the circumferential length of the middle tenon of the blade tenon 31 protruding from the middle throat (i.e., Figure 5 The distance a) is shown.

[0096] based on Figure 5 It can be seen that the parameters to be designed for the blade tenon 31 also satisfy the following calculation formula (hereinafter referred to as the third formula):

[0097] a=H / tanβ-b

[0098] Among them, a represents the circumferential length of the middle tenon of the blade tenon 31 protruding from the middle throat part; H represents the first spacing; β represents the angle of the middle tenon of the blade tenon 31; tan represents the sine function; b represents the compensation amount of the middle tenon of the blade tenon 31.

[0099] After substituting the second and third formulas into the first formula, we can obtain the following calculation formula (hereinafter referred to as the fourth formula):

[0100]

[0101] Among them, S2 represents the third circumferential length; H represents the first spacing; β represents the angle of the middle tenon of the blade tenon 31; tan represents the sine function; b represents the compensation amount of the middle tenon of the blade tenon 31; S3 represents the fourth circumferential length; r represents the radius length; n represents the first number; π represents pi.

[0102] As can be seen from the foregoing, in this embodiment, the third circumferential length and the fourth circumferential length are equal, that is, S2 = S3. Based on this, the following calculation formula (hereinafter referred to as the fifth formula) can be obtained through the fourth formula:

[0103]

[0104] Among them, S2 represents the third circumferential length; H represents the first spacing; β represents the angle of the middle tenon of the blade tenon 31; tan represents the sine function; b represents the compensation amount of the middle tenon of the blade tenon 31; r represents the radius length; n represents the first number; π represents pi.

[0105] The calculation formula for the third circumferential length (hereinafter referred to as the sixth formula) can be obtained by the fifth formula as follows:

[0106]

[0107] Among them, S2 represents the third circumferential length; H represents the first spacing; β represents the angle of the middle tenon of the blade tenon 31; tan represents the sine function; b represents the compensation amount of the middle tenon of the blade tenon 31; r represents the radius length; n represents the first number; π represents pi.

[0108] By the attached Figure 2 It can be seen that the shortest circumferential length of the middle throat of the blade tenon 31 around the first axis 11 (ie, the first circumferential length) is approximately equal to S2 / cosθ, where S2 represents the third circumferential length and θ represents the inclination angle of the tenon groove.

[0109] Based on this, in step S250, a first circumferential length is obtained based on the radius length, the angle of the middle tenon, the compensation amount of the middle tenon, the inclination angle of the tenon groove, the first number, and the first spacing. The calculation formula for obtaining the first circumferential length is as follows:

[0110]

[0111] Among them, S represents the first circumferential length; π represents the pi; r represents the radius length; n represents the first number; H represents the first spacing; β represents the angle of the middle tenon of the blade tenon 31; tan represents the sine function; b represents the compensation amount of the middle tenon of the blade tenon 31; θ represents the inclination angle of the tenon groove; cos represents the cosine function.

[0112] Example 2 of Obtaining the First Circumferential Length

[0113] In this embodiment, the blade tenon 31 and the rim tenon 21 are made of the same material, that is, the yield strength of the material of the rim tenon 21 is equal to the yield strength of the material of the blade tenon 31. The third circumferential length is less than the fourth circumferential length. The third circumferential length is the shortest circumferential length of the middle throat of the blade tenon 31 around the second axis 22 (for example, Figure 4 The fourth circumferential length is the shortest circumferential length of the middle throat of the rim tenon 21 around the second axis 22 (e.g., Figure 4 The second axis 22 intersects the first axis 11 and is parallel to the extension direction of the tongue and groove of the turbine disk 2.

[0114] It should be clear that, when in use, the tension exerted on the middle throat of the rim tenon 21 and the middle throat of the blade tenon 31 is equal. Since the material yield strength of the rim tenon 21 is equal to the material yield strength of the blade tenon 31, and the third circumferential length is less than the fourth circumferential length, if the structural strength of the middle throat of the blade tenon 31 meets the use requirements, then the structural strength of the middle throat of the rim tenon 21 must also meet the use requirements. That is to say, in this embodiment, it is only necessary to ensure that the mechanical strength of the blade tenon 31 meets the use requirements, so that the overall structural strength of the tenon structure (that is, the blade tenon 31 and the rim tenon 21) can meet the use requirements at one time, that is, there is no need for repeated verification later, which simplifies the design process.

[0115] In this embodiment, step S200, obtaining the first circumferential length, includes step S260 and step S270.

[0116] Step S260: Obtain the selection range.

[0117] In this embodiment, the selection range can be a pre-set empirical range. To quickly obtain the selection range without requiring prior experience, in this embodiment of the present application, steps S210 to S250 can be followed to obtain the first circumferential length S when the third circumferential length and the fourth circumferential length are equal. In other words, in this embodiment, as long as the first circumferential length is less than S, it will suffice.

[0118] In order to obtain a more accurate first circumferential length in step S270, in one embodiment of the present application, the selection range may be greater than or equal to k*S and less than S, where k is any value greater than or equal to 0.8 and less than 1.0. For example, k may be 0.8 or 0.9.

[0119] In this embodiment, the calculation formula of S is as follows:

[0120]

[0121] Among them, S represents the first circumferential length; π represents the pi; r represents the radius length; n represents the first number; H represents the first spacing; β represents the angle of the middle tenon of the blade tenon 31; tan represents the sine function; b represents the compensation amount of the middle tenon of the blade tenon 31; θ represents the inclination angle of the tenon groove; cos represents the cosine function.

[0122] Step S270: randomly obtain the first circumferential length based on the selected range.

[0123] It should be noted that randomly selecting a value (ie, the first circumferential length) from a certain range (ie, the selection range) is a mature technology and will not be described in detail here. Thus, the second embodiment of obtaining the first circumferential length is introduced.

[0124] Step S300: Obtain a first axial length based on the first circumferential length and the second yield strength.

[0125] In the embodiment of the present application, the first axial length is the axial length of the blade tenon 31 along the first axis 11. The first axial length is equal to the length of the rim tenon 21 along the first axis 11 (for example, Figure 2 The axial length S1 is shown).

[0126] In an embodiment of the present application, the first axial length can be obtained based on experience. In order to quickly and accurately obtain the first axial length, in an embodiment of the present application, step S300, based on the first circumferential length, obtains the first axial length, including steps S310 to S340.

[0127] Step S310: Obtain a first pulling force.

[0128] In this embodiment, the first tension is the maximum tension that the middle throat of the blade tenon 31 bears when it is in use. It should be clear that the maximum tension that the middle throat of the blade tenon 31 bears depends on the mass of the turbine blade 3 and the rotational speed of the turbine when it is in use. Since the preliminary design of the turbine blade 3 has been completed, the mass of the turbine blade 3 and the rotational speed of the turbine when it is in use are both known. In other words, when the mass of the turbine blade 3 and the rotational speed of the turbine when it is in use are both known, the maximum tension (i.e., the first tension) that the middle throat of the blade tenon 31 bears when it is in use can be calculated through force analysis. Calculating the maximum tension that the middle throat of the blade tenon 31 bears when it is in use through force analysis is a mature technology and will not be elaborated here. For example, a similar force analysis calculation method is disclosed in the graduation design paper titled "Calculation and Analysis of Force Characteristics of Gas Turbine Turbine Blades" by Zhang Hainuo.

[0129] Step S320: Obtain a first reserve coefficient.

[0130] In the embodiment of the present application, the reserve coefficient is the average centrifugal tensile stress yield strength reserve coefficient of the throat of the blade tenon 31 .

[0131] It should be understood that, when the preliminary design of the turbine blade 3 has been completed, the average centrifugal tensile stress yield strength reserve coefficient of the throat of the blade tenon 31 is already known, and will not be described in detail here.

[0132] Step S330: Obtaining a second axial length based on the first tension, the first circumferential length, the second yield strength, and the first reserve coefficient.

[0133] In this embodiment, the second axial length refers to the shortest axial length of the middle throat portion of the blade tenon 31 when the structural strength meets the usage requirements. In other words, the second axial length is the axial length when the maximum tensile force that the middle throat portion of the blade tenon 31 can withstand is equal to the first tensile force. Based on this, the following calculation formula (hereinafter referred to as the seventh formula) can be obtained:

[0134] F1=n1*σ1*S*L1

[0135] Among them, F1 represents the first tension; n1 represents the first reserve coefficient; σ1 represents the second yield strength; S represents the first circumferential length; L1 represents the second axial length; n1*σ1*S*L1 represents the tension that the middle throat of the blade tenon 31 can withstand.

[0136] Based on the seventh formula, in step S330, based on the first tension, the first circumferential length, the second yield strength and the first reserve coefficient, the calculation formula for the second axial length is obtained as follows:

[0137]

[0138] Wherein, L1 represents the second axial length; F1 represents the first tension; n1 represents the first reserve coefficient; σ1 represents the second yield strength; and S represents the first circumferential length.

[0139] Step S340: Based on the second axial length, obtain the first axial length.

[0140] It should be understood that the maximum tensile force that the central throat portion of the blade tenon 31 can withstand is equal to the product of the first reserve coefficient, the first circumferential length, the first axial length, and the second yield strength. In other words, in the embodiments of the present application, as long as the first axial length is greater than or equal to the second axial length (i.e., the maximum tensile force that the central throat portion of the blade tenon 31 can withstand is greater than the first tensile force), the structural strength of the central throat portion of the blade tenon 31 will meet the requirements of use. In other words, in the embodiments of the present application, the first axial length can be any suitable length that is greater than or equal to the second axial length.

[0141] It should be noted that during use, the middle tenon of the blade tenon 31 and the middle tenon of the rim tenon 21 will generate a compressive force. In order to ensure that the structural strength of the middle tenon of the blade tenon 31 also meets the use requirements and further reduce the complexity of subsequent design, in one embodiment of the present application, after obtaining the second axial length based on the first tensile force, the first circumferential length, the second yield strength, and the first reserve coefficient in step S330, the method further includes steps S350 to S380.

[0142] Step S350: Acquire the first pressure.

[0143] In this embodiment, the first pressure is the maximum pressure borne by the tenon contact surface of the middle tenon when the blade tenon 31 is in use. It should be clear that the maximum pressure borne by the middle tenon of the blade tenon 31 depends on the mass of the turbine blade 3 and the rotational speed of the turbine when in use. Since the preliminary design of the turbine blade 3 has been completed, the mass of the turbine blade 3 and the rotational speed of the turbine when in use are both known. In other words, when the mass of the turbine blade 3 and the rotational speed of the turbine when in use are both known, the maximum pressure (i.e., the first pressure) borne by the middle tenon of the blade tenon 31 when in use can be calculated through force analysis. Calculating the maximum pressure borne by the middle tenon of the blade tenon 31 when in use through force analysis is a mature technology and will not be elaborated here.

[0144] Step S360: Obtain the angle and tooth surface width of the middle tenon of the blade tenon 31.

[0145] In the embodiment of the present application, the angle of the middle tenon of the blade tenon 31 is the angle formed by the projection of the contact surface of the middle tenon of the blade tenon 31 and the middle tenon of the rim tenon 21 in the direction parallel to the second axis 22 and the third arc (the third arc is approximately a straight line, and the definition of the third arc is described below) (for example, Figure 5 The angle β shown).

[0146] In the embodiment of the present application, the tooth surface width of the middle tenon of the blade tenon 31 is the width of the contact surface formed by the middle tenon of the blade tenon 31 and the middle tenon of the rim tenon 21 (for example, Figure 5 Width d) shown.

[0147] It should be noted that, since the preliminary design of the turbine blade 3 has been completed, the angle and tooth surface width of the middle tenon of the blade tenon 31 are known and will not be described in detail here.

[0148] Step S370: Obtain a second reserve coefficient.

[0149] In this embodiment, the second reserve coefficient is the average compressive stress yield strength reserve coefficient of the tenon-tooth contact surface of the blade tenon 31. Since the preliminary design of the turbine blade 3 has been completed, the average compressive stress yield strength reserve coefficient of the tenon-tooth contact surface of the blade tenon 31 is already known and will not be described in detail here.

[0150] Step S380: Obtain a third axial length based on the first pressure, the angle of the middle tenon of the blade tenon 31, the tooth surface width of the middle tenon of the blade tenon 31, the second reserve coefficient and the second yield strength.

[0151] In this embodiment, the third axial length refers to the shortest axial length of the middle tenon of the blade tenon 31 when the structural strength meets the use requirements. In other words, the third axial length is the axial length when the maximum pressure that the middle tenon of the blade tenon 31 can withstand is equal to the first pressure. Based on this, the following calculation formula (hereinafter referred to as the eighth formula) can be obtained:

[0152] F2=cosβ*n2*σ1*d*L2

[0153] Among them, F2 represents the first pressure; β represents the angle of the middle tenon of the blade tenon 31; cos represents the cosine function; n2 represents the second reserve coefficient; σ1 represents the second yield strength; d represents the tooth surface width of the middle tenon of the blade tenon 31; L2 represents the third axial length; cosβ*n2*σ1*d*L2 represents the pressure that the middle tenon can withstand.

[0154] Based on the eighth formula, in step S380, based on the first pressure, the angle of the middle tenon of the blade tenon 31, the tooth surface width of the middle tenon of the blade tenon 31, the second reserve coefficient, and the second yield strength, a calculation formula for obtaining the third axial length is as follows:

[0155]

[0156] Among them, L2 represents the third axial length; F2 represents the first pressure; β represents the angle of the middle tenon of the blade tenon 31; cos represents the cosine function; n2 represents the second reserve coefficient; σ1 represents the second yield strength; d represents the tooth surface width of the middle tenon of the blade tenon 31.

[0157] The step S340 of acquiring the first axial length based on the second axial length includes acquiring the first axial length based on the second axial length and the third axial length.

[0158] It should be understood that, in this embodiment, if the first axial length is greater than both the second axial length and the third axial length, the structural strength of the blade tenon 31 will certainly meet the requirements of use. In other words, in the embodiment of the present application, the first axial length can be any suitable length that is greater than both the second axial length and the third axial length.

[0159] In a specific embodiment of the present application, step S340, obtaining the first axial length based on the second axial length and the third axial length, includes:

[0160] If the second axial length is less than or equal to the third axial length, the third axial length is used as the first axial length; if the second axial length is greater than the third axial length, the second axial length is used as the first axial length. That is, in this embodiment, the first axial length is equal to the maximum of the second and third axial lengths.

[0161] It should be understood that in the embodiments of the present application, the sequence numbers of the steps do not represent the order in which the steps are to be executed; they are merely used to distinguish different steps. For example, in the embodiments of the present application, step S310 may be executed first, followed by step S350; step S350 may be executed first, followed by step S310; or step S310 and step S350 may be executed simultaneously. The same applies to the sequence numbers of the other steps in the embodiments of the present application, and they will not be listed or detailed hereafter.

[0162] Step S400: Based on the first axial length, obtain each second circumferential length.

[0163] In the embodiment of the present application, the second circumferential length is the shortest circumferential length of any throat portion of the blade tenon 31 except the middle throat portion around the first axial centerline 11 .

[0164] Any reasonable method can be used to obtain each second circumferential length based on the first axial length. For example, when the first axial length is determined, each second circumferential length can be set based on experience. To accurately obtain each second circumferential length, any method for obtaining a second circumferential length can include steps S410 to S430.

[0165] Step S410: Obtain a second pulling force.

[0166] In this embodiment, the second tension is the maximum tension when the throat portion corresponding to the second circumferential length of the blade tenon 31 is in use. As can be seen from the foregoing, obtaining the maximum tension corresponding to a throat portion of the blade tenon 31 is a mature technology and will not be described in detail here.

[0167] Step S420: Obtain the second yield strength and the first reserve coefficient.

[0168] In this embodiment, the second yield strength is the yield strength corresponding to the material of the blade tenon 31 ; the reserve coefficient is the average centrifugal tensile stress yield strength reserve coefficient of the throat of the blade tenon 31 .

[0169] Step S430: Obtaining a second circumferential length based on the second tension, the second yield strength, the first reserve coefficient, and the first axial length.

[0170] Specifically, based on the second tensile force, the second yield strength, the first reserve coefficient, and the first axial length, a calculation formula for obtaining the second circumferential length is as follows:

[0171]

[0172] Wherein, Sa represents the second circumferential length; Fa represents the second tension; n1 represents the first reserve coefficient; σ1 represents the second yield strength; and L represents the first axial length.

[0173] After many verifications, the turbine blade tenon of the turbine blade is designed using the turbine blade tenon design method proposed in this application. The designed turbine blade tenon can pass the structural strength verification at one time, which simplifies the design complexity, reduces the time required for the design, and improves work efficiency.

[0174] Although the embodiments of the present application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A method for designing a turbine blade tenon, wherein the turbine comprises a turbine shaft (1), a turbine disk (2), and a turbine blade (3); the turbine disk (2) comprises a plurality of wheel rim tenons (21), and a tenon groove is formed between two adjacent wheel rim tenons (21); the turbine blade (3) comprises a blade tenon (31); and the method is characterized in that: The turbine blade tenon design method comprises: Based on the first yield strength, a second yield strength is obtained; the first yield strength is the yield strength of the material of the rim tenon (21); the second yield strength is the yield strength of the material of the blade tenon (31); the first yield strength is obtained in advance; the second yield strength is less than or equal to the first yield strength; Obtaining a first circumferential length; the first circumferential length is the shortest circumferential length of the middle throat of the blade tenon (31) around the first axis (11); the first axis (11) is the axis of the turbine shaft (1); Based on the first circumferential length and the second yield strength, a first axial length is obtained; the first axial length is the axial length of the blade tenon (31) along the first axial centerline (11); Based on the first axial length, each second circumferential length is obtained; the second circumferential length is the shortest circumferential length of any throat of the blade tenon (31) except the middle throat around the first axis (11).

2. The turbine blade tenon design method according to claim 1, characterized in that: The third circumferential length and the fourth circumferential length are equal; the third circumferential length is the shortest circumferential length of the middle throat of the blade tenon (31) around the second axis (21); the fourth circumferential length is the shortest circumferential length of the middle throat of the rim tenon (21) around the second axis (21); the second axis (21) intersects with the first axis (11), and the second axis (21) is parallel to the extension direction of the tenon groove of the turbine disk (2); The obtaining of the first circumferential length includes: Obtaining a radius length; the radius length is the distance between the center of a section of the turbine disk (2) and a first arc; the section is perpendicular to the second axis (21), and the second axis (21) passes through the center of the circle; the first arc is the arc corresponding to the shortest circumferential length of the middle throat of the rim tenon (21) around the second axis (21); Obtaining the angle of the middle tenon of the blade tenon (31) and the tenon compensation amount; Obtaining the tongue and groove inclination angle of the turbine disc (2); Obtaining a first number and a first spacing; the first number being the number of turbine blades (3) corresponding to the turbine disk (2); the first spacing being the distance between a second arc line and a third arc line; the second arc line being the arc line corresponding to the shortest circumferential length of the middle throat of the blade tenon (31) around the second axis (21); and the third arc line being the arc line corresponding to the longest circumferential length of the middle tenon of the blade tenon (31) around the second axis (21); The first circumferential length is acquired based on the radius length, the angle of the middle tenon, the compensation amount of the middle tenon, the inclination angle of the tenon groove, the first number and the first spacing.

3. The turbine blade tenon design method according to claim 2, characterized in that: The calculation formula for obtaining the first circumferential length based on the radius length, the angle of the middle tenon tooth, the compensation amount of the middle tenon tooth, the tenon groove inclination angle, the first number, and the first spacing is as follows: Among them, S represents the first circumferential length; π represents the pi; r represents the radius length; n represents the first number; H represents the first spacing; β represents the angle of the middle tenon of the blade tenon 31; tan represents the sine function; b represents the compensation amount of the middle tenon of the blade tenon 31; θ represents the inclination angle of the tenon groove; cos represents the cosine function.

4. The turbine blade tenon design method according to any one of claims 1 to 3, characterized in that: The obtaining of a first axial length based on the first circumferential length and the second yield strength includes: Obtaining a first pulling force; the first pulling force being the maximum pulling force borne by the middle throat portion of the blade tenon (31) when in use; Obtaining a first reserve coefficient; the first reserve coefficient is an average centrifugal tensile stress yield strength reserve coefficient of the throat of the blade tenon (31); obtaining a second axial length based on the first tensile force, the first circumferential length, the second yield strength, and the first reserve coefficient; The first axial length is obtained based on the second axial length.

5. The turbine blade tenon design method according to claim 4, characterized in that: The calculation formula for obtaining the second axial length based on the first tension, the first circumferential length, the second yield strength, and the first reserve coefficient is as follows: Wherein, L1 represents the second axial length; F1 represents the first tension; n1 represents the first reserve coefficient; σ1 represents the second yield strength; and S represents the first circumferential length.

6. The turbine blade tenon design method according to claim 4, characterized in that: After obtaining the second axial length based on the first tension, the first circumferential length, the second yield strength, and the first reserve coefficient, the method further includes: Obtaining a first pressure; the first pressure being the maximum pressure borne by the tenon contact surface of the middle tenon when the blade tenon (31) is in use; Obtaining the angle and tooth surface width of the middle tenon of the blade tenon (31); Obtaining a second reserve coefficient; the second reserve coefficient is an average extrusion stress yield strength reserve coefficient of the tenon tooth contact surface of the blade tenon (31); Obtaining a third axial length based on the first pressure, the angle of the middle tenon of the blade tenon (31), the tooth surface width of the middle tenon of the blade tenon (31), the second reserve coefficient, and the second yield strength; The acquiring the first axial length based on the second axial length includes: The first axial length is obtained based on the second axial length and the third axial length.

7. The turbine blade tenon design method according to claim 6, characterized in that: Based on the first pressure, the angle of the middle tenon of the blade tenon (31), the tooth surface width of the middle tenon of the blade tenon (31), the second reserve coefficient and the second yield strength, a calculation formula for obtaining the third axial length is as follows: Among them, L2 represents the third axial length; F2 represents the first pressure; β represents the angle of the middle tenon of the blade tenon 31; cos represents the cosine function; n2 represents the second reserve coefficient; σ1 represents the second yield strength; d represents the tooth surface width of the middle tenon of the blade tenon 31.

8. The turbine blade tenon design method according to claim 6, characterized in that: The acquiring the first axial length based on the second axial length and the third axial length includes: If the second axial length is less than or equal to the third axial length, the third axial length is used as the first axial length; if the second axial length is greater than the third axial length, the second axial length is used as the first axial length.

9. The turbine blade tenon design method according to any one of claims 1 to 3, characterized in that: Methods for obtaining any second circumferential length include: Obtaining a second pulling force; the second pulling force is the maximum pulling force when the throat portion of the blade tenon (31) corresponding to the second circumferential length is in use; Obtaining a second yield strength and a first reserve coefficient; the second yield strength is the yield strength corresponding to the material of the blade tenon (31); the reserve coefficient is the average centrifugal tensile stress yield strength reserve coefficient of the throat of the blade tenon (31); The second circumferential length is obtained based on the second tensile force, the second yield strength, the first reserve coefficient, and the first axial length.

10. The turbine blade tenon design method according to claim 9, characterized in that: Based on the second tensile force, the second yield strength, the first reserve coefficient, and the first axial length, a calculation formula for obtaining the second circumferential length is as follows: Wherein, Sa represents the second circumferential length; Fa represents the second tension; n1 represents the first reserve coefficient; σ1 represents the second yield strength; L represents the first axial length.

Images