Skirt damper device

Abstract

A kind of rim plate damping device can have different structural parameters according to different working conditions, wherein the slider can slide radially in the damping groove;The elastic device is arranged in the sliding groove, and a pre-action force is applied to the slider to keep the initial position of the slider at the radial inner end of the sliding groove;The damping block is provided with a first damping surface and a second damping surface in the damping groove;The damping groove has a first friction surface, and the slider has a second friction surface;In one working condition, the damping block is kept in the damping groove by the slider and moves to the frictional contact of the first damping surface and the first friction surface under the action of centrifugal force, and the positive pressure provided by the damping block is applied to the first friction surface;In another working condition, the slider moves radially under the action of centrifugal force by overcoming the pre-action force of the elastic device, releases the damping block, and the damping block slides to the side of the sliding groove under the action of the first friction surface to make the second friction surface and the second damping surface frictional contact, and the positive pressure provided by the damping block is applied to the first friction surface and the second friction surface.

Description

Technical Field

[0001] This invention relates to a blade damping device for gas turbines. Background Technology

[0002] Gas turbine blade design is a key technology in the engine field. Damping and vibration reduction design of blades under high temperature and high speed is crucial for providing high-cycle fatigue life. Current high-pressure turbine blade designs generally place damping blocks under the blade to control blade vibration stress and reduce vibration risk. Once the blade damping device is designed and finalized, its structural parameters cannot be changed. The damping characteristics it provides are only optimized under specific operating conditions and cannot adaptively match the optimal vibration reduction characteristics according to speed and temperature.

[0003] According to dry friction theory, the normal pressure exerted by the damping block on the friction surface affects the critical condition for the damping block to slide. If the normal pressure is not designed properly, the damping block will become sticky and unable to slide. The normal pressure of the damping block is closely related to the turbine speed; therefore, designing damping blocks with different parameters according to different operating conditions can achieve optimal vibration reduction characteristics under various conditions. However, existing damping block designs cannot achieve this goal, and their adaptability to different speed conditions is not ideal. Summary of the Invention

[0004] The purpose of this invention is to provide a flange damping device that can have different structural parameters according to different working conditions.

[0005] According to the present invention, a blade damping device includes a damping groove disposed in one blade blade and a sliding groove disposed in another blade blade, wherein a slider is radially slidable in the damping groove; an elastic device is disposed in the sliding groove and applies a pre-acting force to the slider to keep the slider's initial position at the radially inner end of the sliding groove; and a damping block is disposed in the damping groove, having a first damping surface and a second damping surface; the damping groove has a first friction surface, and the slider has a second friction surface; in a first operating condition, the damping block is held in the damping groove by the slider and moves under centrifugal force until the first damping surface and the first friction surface come into frictional contact, and the positive pressure provided by the damping block is applied to the first friction surface; in a second operating condition, the slider moves radially under centrifugal force to overcome the pre-acting force of the elastic device and releases the damping block, and the damping block slides towards the sliding groove side under centrifugal force guided by the first friction surface to make the second friction surface and the second damping surface come into frictional contact, and the positive pressure provided by the damping block is applied to the first friction surface and the second friction surface.

[0006] In one embodiment, the damping block is provided with an arc-shaped groove, the arc-shaped groove accommodating a movable body, the arc-shaped groove having a first end and a second end, the first end being closer to the sliding groove than the second end; in the first operating condition, the movable body moves to the second end under the action of centrifugal force, so that the center of mass of the damping block as a whole is biased towards the depth of the damping groove; in the second operating condition, the movable body moves to the first end located in the sliding groove under the action of centrifugal force, so as to change the mass distribution of the damping block as a whole.

[0007] In one embodiment, the movable body is a group of granular balls.

[0008] In one embodiment, the group of granules is configured to provide a particle damping effect when compressed due to centrifugal force.

[0009] In one embodiment, the first friction surface is a curved surface on the radially outer wall of the damping groove, and the first damping surface is a curved surface on the radially outer side of the damping block and opposite to the first friction surface. The first damping surface and the first friction surface are fitted with complementary shapes.

[0010] In one embodiment, the second friction surface is an inclined surface on the radially inner side of the slider and near the damping groove, and the second damping surface is an inclined surface on the radially outer side of the damping block and near the groove.

[0011] In one embodiment, the elastic device is a compression spring, which is mounted in the groove and applies the preload force radially outward of the slider.

[0012] In one embodiment, the first friction surface, the second friction surface, the first damping surface, or the second damping surface are coated with different coefficients of friction.

[0013] The embodiments of this invention change the position of the damping block's center of mass based on the rotational speed variation, causing the damping block to slide within the damping groove. This allows for optimal normal pressure matching at high and low speeds to dissipate frictional energy. Furthermore, the internal moving parts of the surface damping block provide a damping effect under blade vibration, further improving damping and vibration reduction characteristics. The embodiments of this invention can achieve multi-condition coverage of the damping block without altering the existing blade design, improving the fatigue life of the blade throughout its entire flight cycle. Attached Figure Description

[0014] The above and other features, properties and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings and embodiments, wherein:

[0015] Figure 1 This is a schematic diagram of the assembly of the blade and the damping block according to one embodiment;

[0016] Figure 2 This is a schematic diagram of the assembly of adjacent blades and sliders according to one embodiment;

[0017] Figure 3 This is a schematic diagram of a flange damping device according to one embodiment;

[0018] Figure 4 This is a schematic diagram of a damping block according to one embodiment;

[0019] Figure 5 This is a schematic diagram of the flange damping device according to an embodiment in a first operating condition;

[0020] Figure 6 This is a schematic diagram of the flange damping device in a second operating condition according to an embodiment;

[0021] Figure 7 This is a damping characteristic curve of the flange damping device. Detailed Implementation

[0022] The present invention will be further described below with reference to specific embodiments and accompanying drawings. More details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention can obviously be implemented in many other ways different from those described herein. Those skilled in the art can make similar extensions and derivations based on actual application situations without departing from the spirit of the present invention. Therefore, the scope of protection of the present invention should not be limited by the content of this specific embodiment.

[0023] It should be noted that these and other accompanying drawings are merely examples and are not drawn to scale, and should not be construed as limiting the scope of protection of the present invention.

[0024] Dry friction dampers are commonly used in the design of turbine blade vibration reduction for aero-engines. However, the existing damper configurations are relatively fixed and their structural parameters cannot be adaptively changed according to operating conditions. They can only provide optimal damping characteristics for specific speed ranges and do not have the ability to adaptively reduce vibrations throughout the entire flight cycle.

[0025] Dry friction dampers primarily rely on the relative displacement between the damping block and the friction surface to dissipate frictional energy. The critical sliding condition and damping characteristics of the damper are closely related to the normal pressure provided by the damper. With a fixed damper mass, the normal pressure changes with the rotational speed, thus affecting the critical normal pressure and damping characteristics. Dampers are typically designed based on the blade resonance speed range. However, in reality, blades face resonance risks across multiple high and low speed ranges, necessitating simultaneous damping optimization design to match both high and low speed conditions. When the turbine enters the high-speed range, the increased centrifugal force raises the damper's critical normal pressure, causing it to jam and become ineffective. Existing flange damping designs cannot adaptively optimize the normal pressure based on rotational speed. To address the issue of fixed and unchangeable damping characteristics in existing dampers, the following embodiment provides a structure that alters the damper's center of mass position based on rotational speed. This structure can increase the friction area and optimize the distribution of damping normal pressure at high speeds, thereby improving the overall damping characteristics of the damper and achieving optimal vibration reduction performance across all speed conditions. In addition, the granular balls installed in the arc-shaped groove can optimize the distribution of positive pressure by changing the position of the structural center of mass based on the rotation speed, and can also provide granular damping effect under resonance conditions, further improving the damping and vibration reduction effect.

[0026] The flange damping device described in the following embodiments improves the damping characteristics of blades at high and low speeds by optimizing the normal pressure. In these embodiments, the blades refer to turbine blades. The flange damping device mainly achieves a change in the center of mass through ingenious mechanical design to optimize the normal pressure, thereby meeting the design requirements for damping characteristics at different speeds. Figures 1 to 7 In the coordinate system, X, Y, and Z represent the axial, circumferential, and radial directions of the turbine rotating component, respectively.

[0027] Figure 1 The blade shown includes blade body 1, edge plate 2, extension root and tenon 3, and damping groove 4. Figure 2 The adjacent blades shown include a blade body 31, a rim plate 32, an extension root, a tenon 33, and a groove 34. The rim plate damping device includes a damping block 10, a radially movable slider 20, and an elastic device 21 for controlling the movement of the slider. The two blades are mounted on the turbine disk via tenons 3 and 33. The damping block 10 of the rim plate damping device is installed in the damping groove 4 below the rim plate 2, and the slider 20 and the elastic device 21 are installed in the groove 34 of the adjacent blades.

[0028] The elastic device 21 is disposed in the slide groove 34 and applies a pre-force to the slider 20 so that the initial position of the slider 20 is maintained at the radial inner end of the slide groove 34.

[0029] like Figure 4 and Figure 5As shown, the damping block 10 has a first damping surface 101 and a second damping surface 102. Correspondingly, the damping groove 4 has a first friction surface 5, and the slider 20 has a second friction surface 23. Figure 5 In the first operating condition shown, the damping block 10 is held in the damping groove 4 by the slider 20 and moves under the action of centrifugal force until the first damping surface 101 comes into frictional contact with the first friction surface 5. The positive pressure provided by the damping block 10 is applied to the first friction surface 5. Figure 6 In the second working condition shown, the slider 20 moves radially under the action of centrifugal force to overcome the pre-action force of the elastic device 21 and releases the damping block 10. Under the action of centrifugal force, the damping block 10 is guided by the first friction surface 5 to slide towards the slide groove 34 so that the second friction surface 23 and the second damping surface 102 come into frictional contact. The positive pressure provided by the damping block 10 is applied to the first friction surface 5 and the second friction surface 23.

[0030] The first operating condition corresponds to the low-speed operation of the turbine or engine, and the second operating condition corresponds to the high-speed operation of the turbine or engine. In the first operating condition, the centrifugal force of the slider 20 is small, making it difficult to overcome the pre-action force of the elastic device 21. At this time, the radial position of the slider 20 is low, and it acts as a limiter for the damping block 10. The damping block 10 dissipates energy through friction between the first friction surface 5 and the first damping surface 101. In the second operating condition, the centrifugal force of the slider 20 is large, thus overcoming the pre-action force of the elastic device 21. The radial position of the slider 20 rises, losing its limiting effect on the damping block 10. At this time, the damping block 10 slides along the first friction surface 5 under the action of centrifugal force. When it reaches the equilibrium position, the second damping surface 102 on the left side of the damping block 10 contacts the second friction surface 23 of the slider 20, and the first damping surface 101 on the right side contacts the first friction surface 5 of the damping groove 4. In the second operating condition, both contact surfaces provide friction simultaneously, increasing the friction area.

[0031] As used herein, the terms "first," "second," and "third" are used interchangeably to distinguish one component from another and are not intended to indicate the location or importance of individual components. Damping surfaces, or friction surfaces, are primarily responsible for providing friction.

[0032] Reference Figure 4 In a preferred embodiment, the damping block 10 is provided with an arc-shaped groove 11, which accommodates the movable body 12. The arc-shaped groove 11 has a first end 111 and a second end 112, and is combined with... Figure 3 or Figure 5 The first end 111 is closer to the slide groove 34 than the second end 112. In the first working condition, the moving body 12 moves to the second end 112 under the action of centrifugal force, so that the center of mass of the damping block 10 as a whole is biased towards the depth of the damping groove 4; in the second working condition, the moving body 12 moves to the first end 111 located in the slide groove 34 under the action of centrifugal force, so as to change the mass distribution of the damping block 10 as a whole.

[0033] In the embodiment shown in the figure, an arc-shaped groove 11 is designed in the damping block 10 to accommodate the movable body 12. In the first operating condition corresponding to low speed, the left radial position of the arc-shaped groove 11 is lower than the right, causing the movable body 12 to slide to the right under centrifugal force. The overall center of mass of the damping block 10 is positioned to the right, providing full normal pressure to the first friction surface 5. In the second operating condition corresponding to high speed, the damping block 10 slides to the left along the first friction surface 5, causing the left radial position of the arc-shaped groove 11 to be higher than the right. The movable body 12 slides to the left under centrifugal force, shifting the overall center of mass of the damping block 10 to the left. By matching the angle and length of the arc-shaped groove 11 with the damping characteristic analysis method, the position of the center of mass can be changed at different speeds, distributing the normal pressure to both friction surfaces according to the designed ratio, thus reducing the critical normal pressure at high speeds. The size and curvature design of the arc-shaped groove 11, matched with the damping characteristic analysis method, achieves the effect of distributing normal pressure by changing the position of the center of mass at different speeds.

[0034] In an optional embodiment, the moving body 12 is a group of granular balls. The granular balls provide smoother movement, reaching the desired position with almost no delay as operating conditions change, thereby altering the center of mass position of the damping block 10.

[0035] In an optional embodiment, the grouped granules are configured to provide a particle damping effect when compressed due to centrifugal force, thereby further improving the frictional energy dissipation effect. The granules are of varying sizes to better achieve the particle damping effect.

[0036] like Figures 3 to 5 As shown, the first friction surface 23 is an inclined surface on the radially inner side of the slider 20 and close to the damping groove 4, and the first damping surface 102 is an inclined surface on the radially outer side of the damping block 10 and close to the slide groove 34. When the turbine or engine transitions from low speed to high speed, the slider 20 overcomes the pre-action force of the elastic device 21 under the action of centrifugal force and moves radially upward. The inclined surfaces of the first friction surface 23 and the first damping surface 102 facilitate the gradual transition of the two to friction at the maximum contact area, achieving a smooth transition between different damping effects.

[0037] In an optional embodiment, the elastic device 21 is a compression spring, such as... Figure 1 and Figure 2 As shown, two compression springs are installed in the slide groove 34 and apply a preload to the radially outer side of the slider 20. By adjusting the stiffness of the compression springs, different damping effect requirements can be flexibly adapted.

[0038] By using coatings with different friction coefficients on the first friction surface, the second friction surface, the first damping surface, or the second damping surface, the damping block characteristics can be optimized under both high and low speed conditions.

[0039] The following describes the working state of the damping block in the damping groove of the flange plate at different rotational speeds. (Appendix) Figure 4 In the process, when the turbine is operating at low speed, the centrifugal force on the slider 20 is relatively small, and the compression deformation of the elastic device 21 is slightly smaller. At this time, the vertical surface 22 of the slider 20 provides a limit for the damping block 10 and transmits the circumferential displacement of the left blade edge plate 32. The damping block 10 is located in the damping groove 4, and the friction surface 5 rubs against the damping block 10. At the same time, the radial direction of the left position A of the arc groove 11 is lower than that of the right position B. The particle ball or moving body 12 slides along the arc groove to position B under its own centrifugal force. The overall center of mass of the damping block is shifted to the right, and the normal pressure is entirely applied to the friction surface 5. At low speed, due to the low temperature, the friction coefficient of the damping block 10 is relatively low. At this time, the optimal critical normal pressure at low speed can be obtained by designing the mass of the damping block 10 and the inclination angle of the first friction surface 5.

[0040] like Figure 6 As shown, when the turbine transitions from low to high speed, the centrifugal force of the slider 20 increases, compressing the elastic device 21 and causing it to move in the direction of radial arrow 42. The slider 20 loses its limiting effect on the damping block 10, and the damping block 10 moves to the left along the first friction surface 5. Through the design of the mass of the slider 10 and the stiffness of the elastic device 21, the slider is positioned as shown in the figure at high speed. At this time, the left side of the damping block 10 contacts the inclined surface or the second friction surface 23 of the slider 20. When the blade vibrates, the inclined surface 23 of the slider 20 and the first friction surface 5 of the damping groove 4 simultaneously provide dry friction, increasing the friction area. At high speed, the radial direction of position A on the left side of the arc groove 11 is higher than that on the right side, B. Under its own centrifugal force, the particle sphere 12 slides along the arc groove 11 to position A, changing the position of the center of mass of the damping block 10. The normal pressure of the damping block 10 is distributed to the inclined surface 23 and the first friction surface 5. By matching the arc groove 11 and the particle sphere 12, the mass of the damping block is changed to distribute the normal pressure on both sides of the friction surface, thereby optimizing the critical macro-slip condition under high speed. When the turbine returns from high speed to low speed, the slider 20... Figure 4 Move in the direction of radial arrow 41, and the damping block returns to its original position. Figure 4 Low to medium speed.

[0041] Based on the above design and damping characteristic analysis method, damping characteristic curves at different speeds are obtained, such as... Figure 7 As shown, rectangle C represents the working area of ​​the blade. Based on Figure 5 The damping characteristics provided by the first friction surface 5 under medium and low speed conditions are as follows: Figure 7 As shown by the solid line, within the blade's operating range (blade vibration stress below 100 MPa), the peak damping ratio provided by the edge plate damping device is approximately 1.1%. If a traditional damping block design is used, the critical normal pressure increases rapidly with increasing rotational speed, such as... Figure 7As shown by the dashed line, within the operating range of 100 MPa, a damping ratio decrease of less than 0.1% results in the damping block losing its vibration reduction function. If the design of the aforementioned embodiment is adopted (i.e.... Figure 6 At medium to high speeds, due to optimized positive pressure and increased friction area, such as... Figure 7 As shown by the dashed line, within the operating range of 100 MPa, the critical stress decreases and the peak damping ratio increases, reaching approximately 1.3%. This represents an optimization and improvement compared to the original design under both high and low speed conditions. Simultaneously, the particle damping provided by the granular balls also contributes to the damping and vibration reduction effect.

[0042] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any variations and modifications can be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention, without departing from the scope of the invention, fall within the protection scope defined by the claims of the present invention.

Claims

1. A skirting damping device, characterised in that, The damper device comprises a damping groove arranged in one blade edge plate, a sliding groove arranged in another blade edge plate, and further comprises: a sliding block radially sliding in the sliding groove; a resilient device arranged in the sliding groove and exerting a pre-action force on the sliding block to keep the initial position of the sliding block at the radially inner end of the sliding groove; and a damping block arranged in the damping groove and having a first damping surface and a second damping surface; wherein the damping groove has a first friction surface, the sliding block has a second friction surface; in a first working condition, the damping block is kept in the damping groove by the sliding block and moves to the frictional contact between the first damping surface and the first friction surface under the action of centrifugal force, and the positive pressure provided by the damping block is applied on the first friction surface; in a second working condition, the sliding block moves radially under the action of centrifugal force and releases the damping block by overcoming the pre-action force of the resilient device, and the damping block is guided to slide to the side of the sliding groove by the first friction surface under the action of centrifugal force to make the second friction surface and the second damping surface frictionally contact, and the positive pressure provided by the damping block is applied on the first friction surface and the second friction surface; the damping block is provided with an arc-shaped groove accommodating a movable body, the arc-shaped groove has a first end and a second end, and the first end is closer to the sliding groove than the second end; in the first working condition, the movable body moves to the second end under the action of centrifugal force to make the center of mass of the damping block as a whole deviate to the depth of the damping groove; in the second working condition, the movable body moves to the first end located in the sliding groove under the action of centrifugal force to change the mass distribution of the damping block as a whole.

2. The skid damping device of claim 1, wherein The movable body is a group of granular balls.

3. The skid damping device of claim 2, wherein The group of granular balls is arranged to provide granular damping effect when in a compacted state due to centrifugal force.

4. The edge dam apparatus of any one of claims 1 to 2, wherein, The first friction surface is a curved surface on the radially outer side wall surface of the damping groove, the first damping surface is a curved surface on the radially outer side of the damping block and opposite to the first friction surface, and the first damping surface and the first friction surface are matched in complementary shapes.

5. The edge dam apparatus of any of claims 1 to 2, wherein, The second friction surface is an inclined surface on the radially inner side of the sliding block and close to the side of the damping groove, and the second damping surface is an inclined surface on the radially outer side of the damping block and close to the side of the sliding groove.

6. The edge dam apparatus of any of claims 1 to 2, wherein, The resilient device is a compression spring arranged in the sliding groove and exerting the pre-action force on the radially outer side of the sliding block.

7. The edge dam apparatus of any of claims 1 to 2, wherein, The first friction surface, the second friction surface, the first damping surface or the second damping surface adopts a coating with different coefficients of friction.

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