A damping ring for an integral blade disk of an aero-engine and a design method thereof

Abstract

The present application provides a damping ring for an integral blade disk of an aircraft engine, wherein the damping ring is an elliptical structure, and the outer contour of the damping ring of the elliptical structure satisfies the elliptical equation; the damping ring has an opening, and the opening is located at the vertex of the short axis of the damping ring. Under static installation conditions, the damping ring provided by the present application for the integral blade disk has a certain gap with the mounting groove at other positions except the tangent point. However, as the rotation speed of the wheel increases, the circumferential stress and circumferential deformation of the damping ring continue to increase under the centrifugal action, thereby gradually moving closer to the mounting groove, the contact area and contact stress continue to increase, and the friction vibration reduction effect continues to increase. In this way, the contact pressure between the damping ring and the integral blade disk mounting groove under high speed conditions is significantly reduced, ensuring that the damping ring can continue to undergo relative friction movement, thereby having a better vibration reduction effect on the blades.

Description

Technical Field

[0001] The present application belongs to the technical field of aero-engines, and in particular relates to a damping ring for an aero-engine integral blade disk and a design method thereof. Background Art

[0002] Compared with the traditional structure in which the blades are connected to the blisks through tenons, the integral blisks are thinner and have stronger coupling between the disk and blades. At the same time, the tenon-free structure can greatly reduce the vibration damping of the disk and blades. Therefore, the problem of disk-blade coupling vibration is more prominent.

[0003] In order to improve the above vibration problem, a damping ring is usually added to the mounting edge of the integral blade disk to form a vibration reduction structure, and the friction energy between the damping ring and the mounting edge during the vibration process is used to reduce the vibration of the integral blade disk. Figure 1 The figure shows a typical schematic diagram of the matching relationship between an integral blade disk and a damping ring. A damping ring 13 is respectively arranged at the front and rear (along the airflow direction) of the edge plate of the integral blade disk (i.e., the blade 12 and the blade disk 11 are integrally formed). The damping ring 13 is used to rub against the mounting edge to reduce the vibration of the entire blade.

[0004] The test results of blade edge damper show that under a torsional vibration mode, the peak response amplitude of the blade decreases first and then increases with the increase of the damper contact pressure, and this law becomes more significant with the increase of the exciting force F, which is not conducive to blade vibration reduction. Figure 2 shown.

[0005] Similarly, the dynamic test results of the integral blade disk show that under high speed conditions, there is a large contact pressure between the damping ring and the blade disk mounting groove where the damping ring is installed, making it difficult for relative friction movement to occur, and thus it is impossible to effectively reduce the vibration of the integral blade disk. The existing technology also lacks a reliable integral blade disk damping and vibration reduction structure. Summary of the invention

[0006] The purpose of the present application is to provide a damping ring for an aircraft engine integral blade disk and a design method thereof, so as to solve or alleviate at least one problem in the background technology.

[0007] The technical solution of the present application is: a damping ring for an integral blade disk of an aero-engine, wherein the damping ring is an elliptical structure, and the outer contour of the damping ring of the elliptical structure satisfies:

[0008] In the formula, a is the major semi-axis size, and b is the minor semi-axis size;

[0009] The damping ring has an opening, and the opening is located at the apex of the short axis of the damping ring.

[0010] In a preferred embodiment of the present application, two vertices of the long axis of the damping ring of the elliptical structure are tangent to the inner diameter of the mounting groove of the integral blade disk, and the mounting state of the inner diameter tangent point is an interference fit.

[0011] In a preferred embodiment of the present application, the difference between the outer diameter and the inner diameter of the elliptical damping ring is smaller than the depth of the integral blade disk mounting groove.

[0012] In addition, the present application also provides a damping ring design method for an aero-engine integral blade disk as described above, the design method comprising:

[0013] Determine the inner diameter R and depth d of the installation groove of the integral blade disk;

[0014] The outer contour geometric parameters of the damping ring meet the following conditions: a = R and ad < b < a;

[0015] The geometric parameters a and b of the ellipse are determined according to the inner diameter R of the mounting groove of the integral blade disk and the depth d of the mounting groove, so as to obtain the outer contour of the damping ring and complete the size design of the damping ring.

[0016] In a preferred embodiment of the present application, the design method further includes determining the rotation speed when the damping ring is completely fitted with the inner diameter of the mounting groove of the integral blade disk, and the process includes:

[0017] The stress analysis of the elliptical damping ring under centrifugal action is carried out, the inner diameter R of the integral blade is ignored, and the damping ring is simplified to an average radius of R 0 of the ring;

[0018] When the speed is ω, the damping ring microelement corresponding to the speed ω→0 is subjected to the centrifugal force F when it is not in contact with the mounting groove. 离 and the tensile stress F of the adjacent microelement segment 拉 Working together, they have:

[0019]

[0020]

[0021] Where m is the mass of the damping ring;

[0022] ω is the rotation speed;

[0023] R 0 Simplified rear radius for the damping ring;

[0024] ρ is the density of the damping ring material;

[0025] b is the width of the damping ring cross section;

[0026] h is the width of the damping ring cross section;

[0027] is the angle of the damping ring element;

[0028] Ignoring the influence of the inner diameter tangent point and the small opening Δ, the cumulative circumferential deformation of the damping ring is:

[0029]

[0030] Where, ε is the strain of the damping ring at the corresponding speed;

[0031] E is the elastic modulus of the damping ring material;

[0032] The circumference of the damping ring and the opening Δ is approximately:

[0033] L=2πb+4(ab)

[0034] When the damping ring, opening small amount Δ and cumulative circumferential deformation Δ 离 When the sum is consistent with the circumference of the inner diameter of the installation groove, the damping ring will completely fit the inner diameter of the installation groove, and the contact stress distribution will be in an uneven state. At this time, the speed is:

[0035] As the speed increases further, the contact pressure of the outer diameter of all damping rings is as follows: Figure 4 The calculations shown increase evenly to form a contact system that works together

[0036] In the preferred embodiment of the present application, the rotation speed ω is designed to 贴合 The speed is lower than the predetermined value of the resonance speed of the entire blade disk to improve the vibration reduction effect of the damping ring and the mounting groove under the resonance speed condition.

[0037] The damping ring for the integral blade disk provided in the present application has a certain gap with the mounting groove at other positions except the tangent point under static installation conditions. However, as the rotation speed of the wheel increases, the circumferential stress and circumferential deformation of the damping ring continue to increase under the centrifugal action, so that it gradually moves closer to the mounting groove, the contact area and contact stress continue to increase, and the friction vibration reduction effect continues to increase. In this way, the contact pressure between the damping ring and the integral blade disk mounting groove under high speed conditions is significantly reduced, ensuring that the damping ring can continue to have relative friction movement, thereby playing a better vibration reduction role on the blade. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solution provided by the present application, the following is a brief introduction to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the present application.

[0039] Figure 1 It is a schematic diagram of the matching relationship between the integral blade disk and the damping ring in the prior art.

[0040] Figure 2 The figure is a schematic diagram of the corresponding relationship between the damping ring contact pressure and the blade response amplitude in the prior art.

[0041] Figure 3 Schematic diagram of the circumferential distribution of contact pressure between the integral blisk and the traditional damping ring.

[0042] Figure 4 Schematic diagram of the contact stress between the damping ring and the mounting groove under the action of centrifugal force during the rotation of the integral blade.

[0043] Figure 5 This is a schematic diagram of the damping ring and assembly status of the present application.

[0044] Figure 6 This is a schematic diagram of the initial contact pressure of the damping ring of the present application.

[0045] Figure 7 This is a schematic diagram of the circumferential stress of the damping ring of the present application under the action of centrifugal force. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solutions and advantages of the implementation of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below in conjunction with the drawings in the embodiments of this application.

[0047] Taking the damping ring with a rectangular cross section as an example, Figure 1 The nominal radius of the traditional open damping ring shown in the figure is usually larger than the inner diameter of the corresponding mounting groove in the free state. After assembly, the damping ring will fit tightly against the mounting groove under the action of elastic tension. At the same time, under the action of rotating centrifugal force, the damping ring will contact more closely with the integral blade disk to form a contact system that works together.

[0048] After the damping ring is installed in the mounting groove, the contact pressure between them is distributed in a pear shape along the circumferential direction, such as Figure 3 As shown, however, since the opening of the damping ring used in engineering is generally small, it can be considered that the pressure is evenly distributed along the circumference. By deduction, the contact stress of the damping ring under elastic tension can be obtained as:

[0049] Where b and h are the height and width of the damping ring cross section, respectively; △ is the change in the opening volume before and after the damping ring is installed in the installation slot; R 0 and R are the average radius and outer diameter of the damping ring, respectively. E and G are the elastic modulus and shear modulus of the material, respectively. Kγ is the shape coefficient of the cross section, which is 1.2 when the cross section is rectangular.

[0050] During the rotation of the integral blade disk, the contact stress between the damping ring and the mounting groove under the action of centrifugal force is as follows: Figure 4 As shown, the contact stress is:

[0051]

[0052] For the above contact stress, for example, when b = h = 20 mm, R = 300 mm, E = 110 GPa, G = 40 GPa, ω = 10000 r / min, we can get σ 弹 =8.43*10 -5 △MPa (△ unit is mm), σ 离 =26.58MPa. Therefore, it can be seen that the contact pressure generated by the centrifugal force is significantly greater than the contact pressure generated by the elastic tension, that is, the contact pressure is mainly contributed by the centrifugal force.

[0053] To this end, the present application proposes a new damping ring structure, which enables the contact pressure between it and the integral blade disk mounting groove to be maintained at an appropriate level under high speed conditions, which can not only generate relative friction to consume energy, but also ensure effective vibration reduction for the integral blade disk.

[0054] like Figure 3 As shown, the damping ring for the integral blade disk of an aero-engine provided by the present application has the following structural features:

[0055] 1) The damping ring 13' is an elliptical structure, and the outer contour of the elliptical damping ring 13' satisfies the geometric formula In the formula, a is the major semi-axis size, and b is the minor semi-axis size;

[0056] 2) After installation, the two vertices of the long axis of the elliptical damping ring are tangent to the inner diameter of the installation groove of the integral blade disk 11, and the inner diameter tangent point is in the initial interference state to ensure the centering stability of the damping ring 13';

[0057] 3) The damping ring 13' adopts an open design, and the position of the opening 131 is at or near the apex of the short axis of the damping ring to ensure the convenience of the damping ring installation;

[0058] 4) The difference between the outer diameter and the inner diameter of the damping ring 13' (ie, the thickness of the damping ring 13') is smaller than the depth of the integral blade installation groove to prevent the damping ring from axially moving under low speed conditions.

[0059] The damping ring provided in the present application can reduce the contact pressure generated by centrifugation so that it can maintain an appropriate contact pressure under high speed conditions, and at the same time can generate relative friction to consume energy to achieve effective vibration reduction effect on the entire blade disk.

[0060] For the above-mentioned elliptical damping ring in the present application, the present application also provides a design method of the elliptical damping ring, which mainly includes the size design and applicable rotation speed design of the damping ring.

[0061] Among them, the size design process for the elliptical damping ring is as follows:

[0062] For a known integral blade disk, the inner diameter R and the depth d of the mounting groove of the integral blade disk are constant. On the premise that the geometric dimensions of the damping ring meet the above structural characteristic conditions 1, 2 and 4, the outer contour geometric parameters of the damping ring 13' meet the following conditions:

[0063] 1) a = R;

[0064] 2) ad<b<a;

[0065] According to the above conditions, the outer contour of the damping ring can be quickly obtained by substituting the elliptical geometric parameters a and b into the formula, thereby completing the structural dimension design of the elliptical damping ring.

[0066] Similar to the traditional damping ring, the contact stress of the damping ring of the present application comes from two aspects: on the one hand, due to the influence of the initial interference design, there is an initial contact pressure at the tangent position between the outer diameter of the damping ring and the inner diameter of the blade disk installation groove, such as Figure 6 As shown in the figure, the pressure is linearly distributed along the axial direction of the integral blade, and the effective area is small, so it is difficult to play an obvious friction vibration reduction role and can be ignored. On the other hand, under static installation conditions, except for the tangent point, there is a certain gap between the other positions of the damping ring and the installation groove. As the wheel speed of the integral blade increases, the circumferential stress and circumferential deformation of the damping ring continue to increase under the centrifugal action, as shown in the figure. Figure 7 As shown in the figure, it gradually moves closer to the installation groove, the contact area and contact stress continue to increase, and the friction vibration reduction effect continues to increase.

[0067] The stress of the elliptical damping ring under centrifugal action is analyzed. In the design of the damping ring, the gap between the damping ring and the installation groove is very small and can be ignored relative to the inner diameter R of the wheel. Therefore, the damping ring is simplified to an average radius of R 0 The analysis is carried out on the ring (R0 = Rh / 2). When the speed is ω, for the damping ring microelement corresponding to ω→0, when it is not in contact with the mounting groove, it is subjected to the centrifugal force F 离 and the tensile stress F of the adjacent microelement segment 拉 Working together, we can deduce that:

[0068]

[0069]

[0070] Ignoring the influence of the inner diameter tangent point and the small opening Δ, the cumulative circumferential deformation of the damping ring is:

[0071]

[0072] The circumference of the damping ring and the opening epsilon (i.e. the full ellipse) is approximately:

[0073] L=2πb+4(ab)

[0074] When the damping ring, opening small amount Δ and cumulative circumferential deformation Δ 离 When the sum is consistent with the circumference of the inner diameter of the installation groove, the damping ring will completely fit the inner diameter of the installation groove, and the contact stress distribution will be in an uneven state. At this time, the speed is approximately:

[0075]

[0076] As the speed increases further, the contact pressure of the outer diameter of all damping rings is as follows: Figure 4 The calculations shown increase evenly to form a contact system that works together.

[0077] In the preferred embodiment of the present application, the speed ω is designed to 贴合 Slightly lower than the resonance speed of the entire blade disk (for example, 1% to 5% lower) can make the damping ring and the mounting groove have appropriate contact pressure under the resonance speed condition, thereby achieving a good vibration reduction effect.

[0078] The damping ring for the integral blade disk provided in the present application has a certain gap with the mounting groove at other positions except the tangent point under static installation conditions. However, as the rotation speed of the wheel increases, the circumferential stress and circumferential deformation of the damping ring continue to increase under the centrifugal action, so that it gradually moves closer to the mounting groove, the contact area and contact stress continue to increase, and the friction vibration reduction effect continues to increase. In this way, the contact pressure between the damping ring and the integral blade disk mounting groove under high speed conditions is significantly reduced, ensuring that the damping ring can continue to have relative friction movement, thereby playing a better vibration reduction role on the blade.

[0079] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A damping ring design method for an aero-engine integral blade disk, It is characterized in that The damping ring is an elliptical structure, and the outer contour of the damping ring of the elliptical structure satisfies: Wherein, a is the size of the long semi-axis, b is the size of the short semi-axis, the damping ring has an opening, the opening is located at the vertex of the short axis of the damping ring, the two vertices of the long axis of the damping ring of the elliptical structure are tangent to the inner diameter of the mounting groove of the integral blade disk, and the mounting state of the inner diameter tangent point is an interference fit, and the difference between the outer diameter and the inner diameter of the damping ring of the elliptical structure is less than the depth of the mounting groove of the integral blade disk; The design method comprises: Determine the inner diameter R and depth d of the installation groove of the integral blade disk; The outer contour geometric parameters of the damping ring meet the following conditions: a = R and ad < b < a; Determine the geometric parameters a and b of the ellipse according to the inner diameter R and the depth d of the mounting groove of the integral blade disk, thereby obtaining the outer contour of the damping ring and completing the size design of the damping ring; and Determine the speed at which the damping ring fits perfectly with the inner diameter of the mounting groove of the blisk, including: The stress analysis of the elliptical damping ring under centrifugal action is carried out, the inner diameter R of the integral blade is ignored, and the damping ring is simplified to an average radius of R 0 of the ring; When the speed is ω, the damping ring microelement corresponding to the speed ω→0 is subjected to the centrifugal force F when it is not in contact with the mounting groove. 离 and the tensile stress F of the adjacent microelement segment 拉 Working together, they have: Where m is the mass of the damping ring; ω is the rotation speed; R 0 is the simplified average radius of the damping ring; ρ is the density of the damping ring material; b is the width of the damping ring cross section; h is the height of the damping ring cross section; is the angle of the damping ring element; Ignoring the influence of the inner diameter tangent point and the small opening Δ, the cumulative circumferential deformation of the damping ring is: Where, ε is the strain of the damping ring at the corresponding speed; E is the elastic modulus of the damping ring material; The circumference of the damping ring and the opening Δ is taken as: L=2πb+4(ab) When the damping ring, opening small amount Δ and cumulative circumferential deformation Δ 离 When the sum is consistent with the circumference of the inner diameter of the installation groove, the damping ring will completely fit the inner diameter of the installation groove, and the contact stress distribution will be in an uneven state. At this time, the speed is: As the speed increases further, the contact pressure on the outer diameter of all damping rings increases evenly, forming a contact system that works together.

2. The damping ring design method for an aero-engine blisk as claimed in claim 1, It is characterized in that In the design, the speed ω 贴合 The speed is lower than the predetermined value of the resonance speed of the entire blade disk to improve the vibration reduction effect of the damping ring and the mounting groove under the resonance speed condition.

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