Modularized gas turbine rotor system dynamic characteristic test method and device
By modeling the hollow structure of the gas turbine rotor system into a solid structure and controlling the error under finite element analysis, the processing difficulty and cost of the modeled test piece of the gas turbine rotor system were solved, and efficient and economical dynamic testing was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-23
- Publication Date
- 2026-04-03
AI Technical Summary
In the existing technology, the prototype of the gas turbine rotor system is difficult to manufacture and costly due to its complex hollow structure, and the test cycle is long. It is difficult to simplify the structure while ensuring the similarity of dynamic characteristics.
The hollow structure of the wheel hub connection section was equivalently modeled into a solid structure, and the error of the modeled test piece in the first two critical speeds was controlled within 15% through finite element analysis. Conventional materials and processes were used for manufacturing.
It significantly reduced the processing difficulty and cost of test pieces, while maintaining the consistency of key dynamic characteristics, providing reliable test data, supporting design verification and fault diagnosis, and promoting R&D iteration and talent training.
Smart Images
Figure CN121787002A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of gas turbine rotor system dynamics testing technology, and specifically to a modeling method and apparatus for a test device used to simulate the dynamic characteristics of a gas turbine rotor system. Background Technology
[0002] As a key power source in fields such as aerospace propulsion and industrial power generation, the dynamic characteristics of the rotor system of a gas turbine directly affect the overall operational safety, reliability, and lifespan of the machine. During the development of gas turbines, it is typically necessary to verify and analyze the dynamic characteristics of the rotor system (such as critical speed, mode shapes, and unbalanced response) through experimental methods. However, due to the complex structure, large size, and harsh operating conditions of real gas turbine rotor systems, conducting full-scale tests directly is often costly, time-consuming, and poses safety hazards. Therefore, using modular test pieces with similar geometric and dynamic characteristics for alternative testing has become an important method in gas turbine rotor dynamics research.
[0003] Currently, the standardization method for gas turbine rotor systems is mainly based on the principles of geometric and dynamic similarity. The specific process typically involves: first, determining the modeling scale based on the test bench's capabilities and the test objectives, while preserving as much of the original rotor system's main structural features (such as the rotor disk, shaft segments, and connection methods) as possible, scaling only proportionally; then, calculating the first two critical speeds of the modeled rotor system using finite element analysis and other methods, comparing it with the original system, and ensuring the relative error is controlled within a small range (e.g., 5%~10%); finally, determining the test piece structure based on the model that meets the error requirements.
[0004] However, the aforementioned traditional modeling methods face significant technical bottlenecks in practical applications: gas turbine rotor systems, especially low-pressure rotors, often feature complex hollow, thin-walled structures in the connection section between the rotor disk and hub to meet engineering requirements such as lightweighting, cooling, or strength. These hollow structures are geometrically characterized by curved surfaces, thin walls, and internal reinforcing ribs; even after direct proportional modeling, the structure of the corresponding parts of the test piece remains extremely complex. This leads to numerous difficulties in the processing and manufacturing of the modeled test pieces.
[0005] 1. High processing difficulty: Hollow thin-walled structures have extremely high requirements for processing technology (such as precision casting, CNC milling, EDM, etc.), and are prone to defects such as deformation and uneven wall thickness;
[0006] 2. High manufacturing costs: Complex structures require longer machining times, more expensive cutting tools and fixtures, and may lead to a higher scrap rate;
[0007] 3. Material and process limitations: In order to meet the requirements of kinetic similarity, the test piece often needs to use different materials than the prototype (such as aluminum alloy instead of high temperature alloy), and complex hollow structures are more difficult to process with high quality on certain materials;
[0008] 4. Increased testing costs: The high cost of processing test pieces is directly passed on to the overall cost of the testing project, which restricts the widespread implementation and iterative optimization of testing.
[0009] Therefore, there is a pressing contradiction in existing technologies: how to significantly simplify the structure of the prototype while ensuring that the key dynamic characteristics (especially the critical speed) of the modular rotor system are sufficiently similar to those of the original system, so as to reduce its processing difficulty and manufacturing cost. Existing methods, due to their focus on maintaining the geometric similarity of the structure, have failed to effectively overcome this contradiction.
[0010] In view of this, the present invention aims to provide an innovative modeling method and corresponding test device, which aims to simplify and redesign the complex hollow structure of the wheel disk-hub connection section (modeling it into a solid structure) in a purposeful manner, fundamentally solving the problem of test piece processing and manufacturing within the acceptable error range of dynamic characteristics in engineering, and providing an economical, efficient and reliable solution for gas turbine rotor dynamics testing. Summary of the Invention
[0011] To address the challenges of difficult and costly fabrication of molded test specimens and extended testing cycles caused by the complex hollow structure of the disc-hub connection section in gas turbine rotor systems, this invention provides a method for testing the dynamic characteristics of a molded gas turbine rotor system.
[0012] In one aspect, this invention provides a method for testing the dynamic characteristics of a modeled gas turbine rotor system, comprising the following steps:
[0013] S1. Establish a finite element dynamic model of the gas turbine prototype rotor system and obtain the first two critical speeds of the prototype rotor system.
[0014] S2. The prototype rotor system is modeled, wherein the hollow structure of the disc-hub connection section is modeled as a solid structure.
[0015] S3. Based on the modular design in S2, establish a finite element dynamic model of the modular rotor system and calculate the first two critical speeds of the modular rotor system.
[0016] S4. Compare the first two critical speeds of the modular rotor system with the first two critical speeds of the prototype rotor system.
[0017] S5. If the comparison results meet the preset error tolerance, the final modular rotor test piece structure is determined based on the modular design.
[0018] Preferably, step S1 includes:
[0019] A three-dimensional solid model of the prototype rotor system was created in a 3D modeling software, and meshing, material properties and boundary conditions were set to calculate its first two critical speeds.
[0020] Preferably, in step S2, the equivalent modeling of the hollow structure of the wheel disc-hub connection section into a solid structure includes:
[0021] The radial dimension of the wheel-hub connection section is reduced, and its internal cavity is filled with a solid body.
[0022] Preferably, after molding the wheel disc-hub connection section into a solid structure, step S2 further includes:
[0023] Based on the geometric dimensions of the modular rotor system, it is divided into multiple continuous shaft segments along the axial direction.
[0024] Preferably, in step S3, establishing the finite element dynamic model of the modular rotor system includes one or a combination of the following methods:
[0025] Based on the multiple continuous shaft segments, a one-dimensional beam element finite element model of the modular rotor system is established.
[0026] A three-dimensional solid finite element model of the modular rotor system is established.
[0027] Preferably, the method further includes step S6:
[0028] If the comparison result in S4 does not meet the preset error tolerance, return to step S2, adjust the modeling parameters of the wheel-hub connection section, and repeat steps S2 to S4 until the error tolerance is met.
[0029] The modeling parameters include at least one of the radius, length, or material properties of the solid structure.
[0030] Preferably, the preset error tolerance is: the relative error of the first two critical speeds is less than or equal to 15%.
[0031] Preferably, the method further includes:
[0032] S7. Based on the determined final molded rotor test piece structure, draw up the machining drawings and manufacture the physical test piece.
[0033] In another aspect, the present invention provides a modeled gas turbine rotor system dynamics test apparatus, comprising a modeled rotor test piece designed and manufactured using the method described above.
[0034] Preferably, the disk-hub connection section of the modeled rotor test piece is a solid structure, and its radius is smaller than the outer wall radius of the corresponding connection section of the prototype rotor system it simulates.
[0035] The beneficial effects of this invention are:
[0036] 1. Significantly simplifies the structure of the test piece, greatly reducing processing difficulty and cost.
[0037] This invention creatively transforms the hollow, thin-walled structure of the disk-hub connection section, the most complex component in a gas turbine rotor system, into a solid structure, and appropriately reduces the radial dimension of this section. This fundamental change allows the molded rotor test piece to completely overcome the difficulties in machining due to its complex internal cavities, thin walls, and curved surfaces. The test piece can be manufactured using conventional materials (such as structural steel) through standard turning and milling processes, avoiding expensive precision casting, special welding, or five-axis machining. This significantly reduces the unit processing cost, shortens the manufacturing cycle, and improves the yield rate.
[0038] 2. Effectively maintain core kinetic similarity to ensure the reliability of experimental data.
[0039] This invention is not a simple geometric simplification, but rather uses equivalence of dynamic characteristics as its core criterion. By establishing and comparing finite element models of the prototype and the modeled rotor system, and using the relative error of the first two critical speeds (e.g., ≤15%) as a quantitative criterion, it ensures that the modeled test piece is highly consistent with the prototype system in the most important low-order modal characteristics. Figures 2 to 9 The modal shape comparison shown demonstrates that the modeled rotor system successfully reproduced the first and second bending modes of the prototype system. This ensures that the dynamic test data obtained using this experimental setup (such as critical speed, mode shape, and unbalanced response) has high reference value and reliability for the prototype system, effectively supporting design verification and fault diagnosis.
[0040] 3. Provide a clear and operable modular design process and verification standards.
[0041] This invention proposes a complete and clear modular design methodology (such as...). Figure 10As shown in the figure, it covers the entire process from initial modeling, structural simplification, model calculation to iterative optimization. In particular, it clarifies a 15% acceptable tolerance for critical speed error, providing a quantitative standard for successful modular design. This process is logically rigorous and highly repeatable, overcoming the shortcomings of traditional modular methods that rely too heavily on experience and have ambiguous processes. It enables engineers to conduct modular design work in a systematic and standardized manner, improving R&D efficiency.
[0042] 4. Expanded the feasibility of experiments, facilitating R&D iteration and talent development.
[0043] The significant reduction in the cost and processing barriers of test components makes it possible to conduct multiple rounds of comparative testing with various schemes in the early stages of R&D. Enterprises and research institutions can more economically and quickly conduct studies on rotor dynamics characteristics, test new bearings or dampers, and perform fault simulations, accelerating the product development and iteration process. At the same time, the lower-cost testing equipment is also more suitable for teaching and basic research in universities and research institutes, which is beneficial for cultivating technical talent in related fields.
[0044] 5. It balances computational efficiency and accuracy, achieving complementary methods.
[0045] In the modeling stage, this invention employs both one-dimensional beam element models and three-dimensional solid models for mutual verification and supplementation. The one-dimensional model offers fast computation speed and flexible parameter adjustment, making it suitable for preliminary design and rapid iteration; the three-dimensional model boasts high accuracy and can be used for final verification. This "one-dimensional + three-dimensional" combination strategy optimizes the computational efficiency of the overall design process while ensuring the reliability of the results.
[0046] In summary, this invention, through an innovative approach combining structural simplification and dynamic equivalence, successfully resolves the long-standing contradiction between manufacturing difficulties, high costs, and fidelity requirements in the modeling testing of gas turbine rotor systems. The proposed method and apparatus combine economy, reliability, and engineering practicality, providing an efficient and high-quality solution for the dynamic testing of gas turbines and similar rotating machinery, with broad engineering application prospects and market value. Attached Figure Description
[0047] Figure 1 This is a schematic diagram of a three-dimensional solid model of a gas turbine prototype rotor system;
[0048] Figure 2 It is the first-order mode shape of the three-dimensional solid model of the gas turbine prototype rotor system;
[0049] Figure 3 It is the second-order mode shape of the three-dimensional solid model of the prototype rotor system of the gas turbine;
[0050] Figure 4This is a schematic diagram of a three-dimensional solid model of a gas turbine rotor system;
[0051] Figure 5 This is a schematic diagram of a one-dimensional modular rotor for a gas turbine modular rotor system;
[0052] Figure 6 It is the first-order mode shape of the three-dimensional solid model of the gas turbine rotor;
[0053] Figure 7 It is the second-order mode shape of the modular three-dimensional solid model of the gas turbine rotor;
[0054] Figure 8 It is the first-order mode shape of a modular gas turbine rotor, a one-dimensional modular rotor.
[0055] Figure 9 It is the second-order mode shape of a modular one-dimensional gas turbine rotor;
[0056] Figure 10 This is a flowchart of a method for testing the dynamic characteristics of a modeled gas turbine rotor system as described in this invention. Detailed Implementation
[0057] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0058] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.
[0059] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention.
[0060] Example 1: A Modeled Test Method for Dynamic Characteristics of a Gas Turbine Rotor System
[0061] This embodiment provides a modeled test method for the dynamic characteristics of a gas turbine rotor system, such as... Figures 1 to 10 As shown in Table 1, this method is implemented through the following steps:
[0062] Step S1: Establish a finite element dynamic model of the gas turbine prototype rotor system and obtain the first two critical speeds of the prototype rotor system.
[0063] First, in 3D modeling software (such as UG-NX), a precise 3D solid model of the low-pressure rotor of a certain type of gas turbine is created based on the actual design drawings. Figure 1 As shown, this prototype rotor system includes a main shaft, multiple discs, a hub, and a complex hollow, thin-walled connecting section that links the discs to the hub.
[0064] Next, the 3D solid model is imported into finite element analysis software (such as ANSYS). The model is then meshed using a structured mesh, with SOLID186 hexahedral elements selected to ensure mesh quality meets computational accuracy requirements. Then, material properties are defined: the rotor material is a high-temperature alloy, and its elastic modulus, Poisson's ratio, and density parameters are set. Boundary conditions are set as follows: simplified spring constraints are applied at the bearing support locations to simulate actual support stiffness.
[0065] After submitting the calculations, the first two natural frequencies of the prototype rotor system were obtained through modal analysis and converted into critical speeds. The calculation results show that the mode shape corresponding to the first critical speed is the overall first-order bending mode, such as... Figure 2 As shown; the mode shape corresponding to the second critical speed is the overall second-order bending, such as... Figure 3 As shown.
[0066] Table 1 Calculation results of critical speed
[0067]
[0068] Table 1 compares the calculation results of the first two critical speeds before and after the gas turbine rotor system was modeled.
[0069] Step S2: Perform a modular design on the prototype rotor system, wherein the hollow structure of the disc-hub connection section is equivalently modularized into a solid structure;
[0070] The core innovation of this step lies in the simplification and redesign of the complex wheel-hub connection section.
[0071] 1. Structural Simplification (Solidification): The complex hollow thin-walled structure of the original connecting section (which may contain cooling channels and reinforcing ribs) is equivalently modeled as a solid structure. Specifically, the radial dimension of the connecting section is reduced (e.g., the outer diameter is scaled down proportionally), and its internal cavity is completely filled with a solid body. This design significantly reduces the difficulty of subsequent prototype fabrication. The simplified 3D solid model structure is as follows: Figure 4 As shown in the diagram, the one-dimensional modular rotor is divided into the following figures: Figure 5 As shown.
[0072] 2. Shaft segment division: To facilitate the establishment of a simplified one-dimensional model, the rotor is divided into multiple continuous shaft segments along the axial direction based on the geometric dimensions (diameter and length of each segment) after modeling. Each shaft segment is considered as a beam element with a uniform cross-section.
[0073] Step S3: Based on the modular design in S2, establish a finite element dynamic model of the modular rotor system and calculate the first two critical speeds of the modular rotor system.
[0074] Two mutually verified methods were used to establish the dynamic model of the modular rotor system and calculate its critical speed:
[0075] 1. Establish a one-dimensional beam element model: Input the geometric parameters (length, diameter), material properties, and bearing support stiffness parameters of the multiple shaft segments divided in step S2 into a dedicated rotor dynamics software (such as Dynamics R4). Establish a one-dimensional beam element finite element model in the software. Calculate the first two critical speeds of the one-dimensional modeled rotor; the corresponding first-order mode shapes are as follows: Figure 8 As shown, the second-order mode shape is as follows Figure 9 As shown.
[0076] 2. Establish a 3D solid model: Simultaneously, based on the simplified 3D structure designed in step S2, a new 3D solid model of the modeled rotor is created directly in the 3D modeling software. Using the same meshing strategy, material properties, and boundary conditions as in step S1, modal analysis is performed in the finite element software. The first two critical speeds of the 3D modeled rotor are calculated, and their corresponding first-order mode shapes are as follows: Figure 6 As shown, the second-order mode shape is as follows Figure 7 As shown.
[0077] Steps S4 to S6: Compare the first two critical speeds of the modular rotor system with the first two critical speeds of the prototype rotor system, and verify the error.
[0078] The critical speeds of the modular rotor system and the original rotor system are compared.
[0079] Initial comparison: Calculate the relative error of the critical speed between the modeled model and the original model.
[0080] Error Judgment and Iteration: The preset error tolerance in this embodiment is 15%. If all errors in the initial calculation are less than 15%, the requirement is met, no iteration is needed, and the current model design can be directly determined. If the requirement is not met, return to step S2, adjust the modeling parameters (for example, fine-tune the radius and length of the solid connecting section, or try changing the material used for the modeling test piece to a material with similar density but easier processing), and repeat S2 to S6 until the error requirement is met.
[0081] Step S7: Based on the determined final molded rotor test piece structure, draw up the machining drawings and manufacture the physical test piece.
[0082] Since the modeling results meet the error requirements, the rotor structure designed in step S2, which solidifies the hollow connecting section and appropriately reduces its diameter, is determined as the final modeling test piece design.
[0083] Based on the determined modular rotor structure, detailed machining drawings were created using computer-aided design (CAD) software. Easily machinable materials were selected for the test specimen. A contract manufacturing company was commissioned to produce a physical modular rotor test specimen using conventional machining processes. This test specimen completely avoided the need for precision casting or special machining of complex hollow structures, significantly reducing machining difficulty and cost.
[0084] Example 2: A model gas turbine rotor system dynamic characteristic test device
[0085] This embodiment provides an experimental device designed and manufactured using the method described in Embodiment 1.
[0086] The core component of this experimental setup is the modular rotor prototype. The main difference between this prototype and the prototype rotor is that its disc-hub connection section is a solid structure, and the radius of this solid connection section is smaller than the outer wall radius of the corresponding hollow connection section on the prototype rotor. Its three-dimensional solid model structure can be found in [reference needed]. Figure 4 A one-dimensional modular structure can be referenced. Figure 5 .
[0087] The test apparatus also includes a drive motor, bearing support, lubrication system, speed control and data acquisition system, etc. By mounting the modular rotor test piece on this test bench, speed-up / deceleration tests, modal impact tests, etc., can be performed to study the dynamic characteristics of the rotor system, such as critical speed, mode shape, and unbalanced response, providing reliable test data support for the design and optimization of the prototype rotor system.
[0088] Verification of the beneficial effects of the present invention
[0089] As can be seen from the two embodiments above, the method and apparatus proposed in this invention successfully simplify the complex hollow structure into a solid structure. Comparative data demonstrates that, within an acceptable engineering error range of 15%, the modular rotor system effectively maintains the same key dynamic characteristics (the first two critical speeds and mode shapes) as the original system. Furthermore, the use of a solid structure allows the test piece to be manufactured using conventional materials and processes, fundamentally solving the problems of difficult processing, long cycles, and high costs associated with the original modularization method. This provides a completely new solution for rapid, economical, and reliable dynamic testing of gas turbine rotor systems.
[0090] While the invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.
Claims
1. A method for testing the dynamic characteristics of a modeled gas turbine rotor system, characterized in that, Includes the following steps: S1. Establish a finite element dynamic model of the gas turbine prototype rotor system and obtain the first two critical speeds of the prototype rotor system. S2. The prototype rotor system is modeled, wherein the hollow structure of the disc-hub connection section is modeled as a solid structure. S3. Based on the modular design in S2, establish a finite element dynamic model of the modular rotor system and calculate the first two critical speeds of the modular rotor system. S4. Compare the first two critical speeds of the modular rotor system with the first two critical speeds of the prototype rotor system. S5. If the comparison results meet the preset error tolerance, the final modular rotor test piece structure is determined based on the modular design.
2. The method for testing the dynamic characteristics of a modeled gas turbine rotor system according to claim 1, characterized in that, Step S1 includes: A three-dimensional solid model of the prototype rotor system was created in a 3D modeling software, and meshing, material properties and boundary conditions were set to calculate its first two critical speeds.
3. The method for testing the dynamic characteristics of a modeled gas turbine rotor system according to claim 1, characterized in that, In step S2, the process of equivalently modeling the hollow structure of the wheel disc-hub connection section into a solid structure includes: The radial dimension of the wheel-hub connection section is reduced, and its internal cavity is filled with a solid body.
4. The method for testing the dynamic characteristics of a modeled gas turbine rotor system according to claim 1 or 3, characterized in that, Step S2, after molding the wheel disc-hub connection section into a solid structure, further includes: Based on the geometric dimensions of the modular rotor system, it is divided into multiple continuous shaft segments along the axial direction.
5. The method for testing the dynamic characteristics of a modeled gas turbine rotor system according to claim 4, characterized in that, In step S3, establishing the finite element dynamic model of the modular rotor system includes one or a combination of the following methods: Based on the multiple continuous shaft segments, a one-dimensional beam element finite element model of the modular rotor system is established. A three-dimensional solid finite element model of the modular rotor system is established.
6. The method for testing the dynamic characteristics of a modeled gas turbine rotor system according to claim 1, characterized in that, The method further includes step S6: If the comparison result in S4 does not meet the preset error tolerance, return to step S2, adjust the modeling parameters of the wheel-hub connection section, and repeat steps S2 to S4 until the error tolerance is met. The modeling parameters include at least one of the radius, length, or material properties of the solid structure.
7. The method for testing the dynamic characteristics of a modeled gas turbine rotor system according to claim 1 or 6, characterized in that, The preset error tolerance is: the relative error of the first two critical speeds is less than or equal to 15%.
8. The method for testing the dynamic characteristics of a modeled gas turbine rotor system according to claim 1, characterized in that, The method further includes: S7. Based on the determined final molded rotor test piece structure, draw up the machining drawings and manufacture the physical test piece.
9. A modular gas turbine rotor system dynamic characteristic test apparatus, comprising a modular rotor test piece designed and manufactured using the method described in any one of claims 1-8.
10. The experimental apparatus for testing the dynamic characteristics of a modeled gas turbine rotor system according to claim 9, characterized in that, The disk-hub connection section of the simulated rotor test piece is a solid structure, and its radius is smaller than the outer wall radius of the corresponding connection section of the prototype rotor system it simulates.