Nonlinear constant frequency damper structure for gas turbine and design method thereof
By using a nonlinear fixed-frequency vibration isolator structure and modular design, the problems of insufficient low-frequency vibration isolation performance and poor versatility of gas turbines have been solved, achieving stable vibration isolation effect and cost reduction, and enabling rapid adaptation to multiple gas turbine models.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CSIC LONGJIANG GH GAS TURBINE CO LTD
- Filing Date
- 2026-03-26
- Publication Date
- 2026-06-23
AI Technical Summary
Existing gas turbine vibration isolation systems have insufficient vibration isolation performance in the low-frequency range, which cannot meet the requirements for hull vibration and noise control. Furthermore, vibration isolators for different types of gas turbines require customized design, resulting in long development cycles, high costs, and poor versatility.
The nonlinear constant-frequency vibration isolator structure is adopted, and a constant initial vibration isolation frequency is achieved through the nonlinear stiffness characteristics of the spring combination, which is suitable for a wide range of load conditions. Combined with modular design, it reduces R&D costs and improves impact resistance.
It achieves stable vibration isolation over a wide load range, reduces R&D and manufacturing costs, enables rapid adaptation to different types of gas turbines, and enhances shock resistance and displacement suppression performance.
Smart Images
Figure CN122258136A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of marine vibration reduction and noise reduction technology, and in particular to a nonlinear fixed-frequency vibration damper structure and design method for gas turbines, which is applicable to vibration isolation and noise control of gas turbine units and can be adapted to the wide load and low frequency vibration requirements of different types of gas turbines. Background Technology
[0002] As the core equipment of a ship's propulsion system, the vibrations generated by the gas turbine during operation are transmitted to the hull structure through the underframe, causing structural noise and affecting the ship's concealment and crew comfort. The gas turbine vibration isolation system is the core device for isolating gas turbine vibrations and reducing structural noise transmission. Its working principle involves connecting the power equipment to the hull base via vibration isolators, utilizing the damping characteristics of the isolators to attenuate vibrations and reduce the vibration energy propagating to the hull.
[0003] Existing marine gas turbine vibration isolation systems mostly employ passive vibration isolation structures composed of rubber isolators. However, the stiffness and damping characteristics of rubber materials are significantly affected by temperature and frequency, resulting in limited overall vibration isolation performance across the entire frequency range. This makes it difficult to simultaneously address the low-frequency vibration isolation performance of the turbine unit, failing to meet the ship's requirements for controlling main engine vibration and noise. Furthermore, gas turbine models vary widely, with significant differences in mass and vibration spectrum between different models. Traditional isolators require customized designs for each model, leading to long development cycles, high design costs, and poor versatility. This hinders rapid adaptation to multiple gas turbine models, resulting in persistently high design and manufacturing costs for marine gas turbine vibration isolation systems.
[0004] Therefore, there is an urgent need to develop a gas turbine vibration isolator with wide load adaptability, excellent low-frequency vibration isolation effect, and standardized design. Through structural optimization and design method innovation, the technical pain points of existing vibration isolators, such as insufficient low-frequency vibration isolation performance, poor versatility, and high design cost, can be solved. Summary of the Invention
[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a nonlinear fixed-frequency vibration isolator and its design method for gas turbines. This invention achieves a constant initial vibration isolation frequency through the nonlinear stiffness characteristics of a spring combination, adapting to a wide range of load conditions in gas turbines. It solves the problem of excessive mid- and low-frequency (hundred-hertz level) vibration spectrum generated by the rotation of the gas turbine rotor by significantly attenuating the energy transfer ratio of the periodic excitation. Simultaneously, because the fixed-frequency vibration isolator exhibits gradually stiffening mechanical characteristics as the load displacement increases, the vibration isolation system outputs a significantly stronger restoring force than linear vibration isolation systems when the gas turbine is subjected to large-amplitude excitations, thus possessing stronger shock resistance and better displacement suppression performance. Furthermore, standardized design reduces the R&D cost of the vibration isolation system.
[0006] To achieve the above objectives, the technical solution of the present invention is as follows: A nonlinear constant-frequency vibration damper structure for gas turbines is characterized by comprising: a shell, side supports, side shafts, vertical springs, and a central connector; side springs, a central shaft, an outer connector of the side springs, and an inner connector of the side springs. The vertical spring is located between the bottom inner side of the outer shell and the lower surface of the central transition, and the bottom inner side of the outer shell and the lower surface of the central transition cooperate with the vertical spring through an annular groove; One side of the side spring is hinged to the central pivot via an inner hinge; The other side of the side spring is hinged to the side support via a side spring outer junction and a side pivot. The side joint is welded to the side support; The central rotating shaft is welded to the central adapter.
[0007] Preferably, a shim is installed between the lower surface of the vertical spring and the outer casing to increase the compression of the vertical spring, and a sleeve is provided at the junction of the outer casing and the center to prevent the vertical spring from tilting.
[0008] Preferably, multiple housings are mounted in the same plane, and the load is transferred to the upper surface of the central junction.
[0009] Preferably, the restoring force curve f(x) of the combination of the vertical spring and the side spring is symmetrical about the point (0, m0g) and satisfies: ; Wherein, m0 is the bearing mass when the side spring (6) is in a horizontal state; mmin is the mass distributed to the vertical spring and the side spring when the vibration isolator is under minimum load; mmax is the mass distributed to the vertical spring and the side spring when the vibration isolator is under maximum load; ω0 is the design target value of the natural frequency of the isolation system composed of gas turbine and vibration isolator.
[0010] This invention also provides a design method for a nonlinear fixed-frequency vibration damper structure for gas turbines, comprising the following steps: Step 1: Determine the natural frequency ω0, the original length L of the lateral spring, and its horizontal projection L0 to obtain the restoring force curve of the combination of the vertical spring and the lateral spring: ; Step 2: Determine the stiffness k1 and k2 of the vertical spring and the side spring respectively based on the conditions satisfied by the restoring force curve f(x) as described in claim 4.
[0011] Based on the application of the above technical solution, the beneficial effects presented by the present invention are as follows: 1. Stable vibration isolator performance: Through the nonlinear stiffness characteristics of the spring combination, a constant initial vibration isolation frequency is achieved within a wide load range, ensuring that the isolation system maintains consistent vibration isolation performance under the cyclic excitation load of the gas turbine as well as loads such as ship tilting, rolling, and impact, effectively blocking vibration transmission; 2. High versatility: Adopting a modular and standardized design, it can be quickly adapted to different models of gas turbines by increasing or decreasing the number of vibration isolator modules, without the need to redesign the entire vibration isolator, which greatly reduces R&D and manufacturing costs. Attached Figure Description
[0012] Figure 1 A cross-sectional view of a nonlinear fixed-frequency vibration isolator for gas turbines provided by the present invention; Figure 2 This invention provides a nonlinear fixed-frequency vibration isolator structure for gas turbines; Figure 3 Restoring force curves and stiffness curves for different masses; Figure 4 This relates the natural frequency to the quality.
[0013] Detailed description of the attached diagram: Figure 1 The axial cross-sectional view of the vibration isolator indicates the names of each component, clarifies the fit between the vertical spring and the housing, the hinge structure between the side spring and the adapter, the hinge structure of the shaft, and the position of the bearing on the shaft, etc. Figure 2 The overall assembly structure of the vibration isolator is shown, clearly presenting the relative positional relationship of each part. The outer shell is a cylindrical structure, but it can also be changed to a square, rectangular or other structures. The side supports are evenly distributed along the circumference of the inner wall of the outer shell (4 in this example). The center transition is located at the center of the outer shell and is connected to the bottom of the outer shell through a vertical spring. The side springs are symmetrically distributed between the center transition and the side supports. Figure 3 The upper-middle view shows the curves of the restoring force and equivalent stiffness of the vibration isolator as a function of displacement under different load masses. It can be seen that the four curves are symmetrical about the origin, and the restoring force matches the mass under the same displacement, which reflects nonlinear characteristics. The lower view shows the curves of the equivalent stiffness as a function of displacement under different masses. The curve trend shows that the surface stiffness changes nonlinearly with displacement, but the natural frequency can be kept stable within the effective stroke range. Figure 4 The curve showing the relationship between load capacity and natural frequency shows that the natural frequency fluctuates very little (≤1%) within the range of mmin to mmax. Within this range, the vibration isolation frequency of the vibration isolator can be considered constant. Detailed Implementation
[0014] Embodiments of the present invention are described in detail below. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar symbols denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.
[0015] like Figure 1 - Figure 4 The diagram shows a nonlinear constant-frequency vibration damper structure for a gas turbine, comprising a housing 1, side supports 2, side shafts 3, vertical springs 4, a central connector 5, side springs 6, a central shaft 7, an outer side spring connector 8, and an inner side spring connector 9. The connections and functions of each component are as follows: Outer shell 1: As the overall load-bearing structure of the vibration isolator, it provides installation space and protection for internal components. An annular groove for fixing and assembling the vertical spring 4 is provided on its inner bottom, and the inner wall is used to fix the side support 2. Side support 2: Fixed to the inner wall of the outer casing 1 by welding or other connection methods, used to provide a hinge support point for the side spring 6; Vertical spring 4 and side spring 6: These are the core elastic elements of the vibration isolator, used to provide the elastic force required for the vibration isolator to bear the load. Both adopt a detachable ring design, which can be flexibly combined according to the load and vibration requirements of the gas turbine. Adapter and shaft assembly: The upper surface of the center adapter 5 is used to connect with the gas turbine base frame, and the lower surface has an annular groove, which cooperates with the annular groove at the bottom of the outer shell 1 to achieve precise positioning and assembly of the vertical spring 4; the inner adapter 9 of the side spring, the center shaft 7, the outer adapter 8 of the side spring, and the side shaft 3 constitute a hinge mechanism. Bearings are fixedly mounted on both the center shaft 7 and the side shaft 3, which can reduce the rotational friction caused by the side spring 6 during vibration and ensure the stable performance of the spring's elastic characteristics; the two ends of the side spring 6 are connected to the center adapter 5 and the side support 2 respectively through this hinge mechanism to realize force transmission and nonlinear stiffness adjustment.
[0016] A design method for a nonlinear constant-frequency vibration isolator structure for gas turbines mainly includes the following steps: Step 1: Based on the total mass of the gas turbine unit, design and allocate the number of vibration isolators and the mass m required to be borne by each vibration isolator, and then give the additional mass Δm according to the design requirements; Step 2: Based on the installation space of the isolation system between the gas turbine and the ship's cabin, determine the vibration isolator size R and the horizontal projection length L0 of the side spring (horizontal 6). Both should satisfy the following: Space needs to be reserved here for the adapters on both sides of the side spring 6.
[0017] Step 3: Determine the initial vibration isolation frequency ωT based on the vibration isolation requirements, and then select the natural frequency ω0 of the vibration isolator, which should satisfy: Step 4: Based on the restoring force function of the combined springs, the system's natural frequency conditions at the range of mass variation (mmin, mmax), and the relationship between the original length and projection of the side springs, the calculation formula is as follows: The stiffness k1 and k2 of the vertical spring 4 and the side spring 6, as well as the initial length L of the side spring 6, are obtained by solving the problem.
[0018] Step 5: Based on the stiffness k1 and k2 of the vertical spring 4 and the side spring 6, as well as the spatial size constraints, design the specific dimensional parameters such as the wire diameter and number of turns of the vertical spring 4 and the side spring 6 to complete the overall structural design of the vibration isolator.
[0019] Furthermore, any content not described in detail in this specification is existing technology known to those skilled in the art.
[0020] In the embodiments provided by this invention, it should be understood that the disclosed system or method can be implemented in other ways. For example, the embodiments of the invention described above are merely illustrative; for instance, the division of modules is only a logical functional division, and there may be other division methods in actual implementation.
[0021] The modules described as separate components may or may not be physically separate. The components shown as modules may or may not be physical modules; they may be located in one place or distributed across multiple network modules. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.
[0022] Furthermore, the functional modules in the various embodiments of this invention can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module. The integrated module can be implemented in hardware or in a combination of hardware and software functional modules.
[0023] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the basic characteristics of the present invention.
[0024] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.
Claims
1. A nonlinear fixed-frequency vibration damper structure for gas turbines, characterized in that: Includes outer shell (1), side support (2), side pivot (3), vertical spring (4), center connector (5), side spring (6), center pivot (7), side spring outer connector (8), and side spring inner connector (9). The vertical spring (4) is located between the bottom inner side of the outer shell (1) and the lower surface of the center transition (5). The bottom inner side of the outer shell (1) and the lower surface of the center transition (5) cooperate with the vertical spring (4) through an annular groove. One side of the side spring (6) is hinged to the central pivot (5) via the inner pivot (9) of the side spring; The other side of the side spring (6) is hinged to the side support (2) via the side spring outer adapter (8) and the side pivot (3); The side adapter (3) is welded to the side support (2); The central pivot (7) is welded to the central adapter (5).
2. The structure of a nonlinear fixed-frequency vibration isolator for a gas turbine according to claim 1, characterized in that, A shim is installed between the lower surface of the vertical spring (4) and the outer shell (1). The shim is used to increase the compression of the vertical spring (4). A sleeve is provided on the outer shell (1) and the center junction (5). The sleeve is used to prevent the vertical spring from tilting.
3. The structure of a nonlinear fixed-frequency vibration damper for a gas turbine according to claim 1, characterized in that, The load is transferred to the upper surface of the center transfer (5) by multiple housings (1) mounted in the same plane.
4. The structure of a nonlinear fixed-frequency vibration isolator for a gas turbine according to claim 1, characterized in that, The restoring force curve f(x) of the combination of the vertical spring (4) and the side spring (6) is symmetrical about the point (0, m0g) and satisfies: ； Wherein, m0 is the bearing mass when the side spring (6) is in a horizontal state; mmin is the mass distributed to the vertical spring (4) and the side spring (6) when the vibration isolator has the minimum load; mmax is the mass distributed to the vertical spring (4) and the side spring (6) when the vibration isolator has the maximum load; ω0 is the design target value of the natural frequency of the isolation system composed of gas turbine and vibration isolator.
5. A design method for a nonlinear fixed-frequency vibration isolator structure for gas turbines, applied to the nonlinear fixed-frequency vibration isolator structure for gas turbines as described in any one of claims 1-4, characterized in that, The design methodology includes the following steps: Step 1: Determine the natural frequency ω0, the original length L of the lateral spring (6), and its horizontal projection L0 to obtain the restoring force curve of the combination of the vertical spring (4) and the lateral spring (6): ； Step 2: Determine the stiffness k1 and k2 of the vertical spring (4) and the side spring (6) respectively based on the conditions satisfied by the determined restoring force curve f(x).