Parameter identification method and testing device for rotor gap supporting structure

Abstract

The invention discloses a parameter identification method and a testing device for a rotor clearance supporting structure, and belongs to the technical field of dynamic analysis of rotors with clearance supporting structures. The method comprises the following steps of: establishing a rotor dynamic model consisting of a disc, a shaft, a rigid front support and a clearance rear support of a rotor by adopting a finite element method, and constructing a rotor clearance support nonlinear structure dynamic equation; building a rotor clearance bearing test bed; carrying out a rotor dynamic test under different gap conditions, and obtaining an influence rule of different gaps on the dynamic characteristics of the rotor; and identifying rigidity and damping parameters of the gap support based on model simulation and test results. The rotor dynamic test and parameter identification of the rotor gap supporting structure can be realized, the rigidity and damping parameters of the rotor gap supporting structure are accurately identified based on model simulation and experimental test data, reference is provided for the dynamic design of the rotor with the gap supporting structure, and the structural design efficiency of a rotor system is improved.

Description

Technical Field

[0001] The invention relates to a parameter identification method and a testing device for a rotor gap support structure, belonging to the technical field of rotor dynamics analysis with a gap support structure. Background Art

[0002] In order to improve the assembly process, increase assembly efficiency and reduce production costs. A clearance fit is used between the rotor journal and the inner ring of the bearing at the hot end of the small turbine engine rotor. There is a gap between the shaft diameter and the inner ring of the bearing, and other supporting structures such as the outer ring of the bearing and the bearing seat provide support stiffness. This fit will introduce nonlinearity to the rotor system, and slip friction may occur between the shaft diameter and the inner ring of the bearing. It is a segmented non-smooth strong nonlinear behavior. If the clearance fit is not designed properly, it may cause the rotor system to become unstable or even destroyed.

[0003] In view of this, a rotor dynamics test device was designed for the typical structure of gap support between the rotor and the bearing of a small turbine engine. The gap support structure was installed on the test device, and a rotor dynamics test platform with a gap support structure was built. Rotor dynamics tests under different gap conditions were carried out. Combined with the model simulation results, the parameters such as stiffness and damping of the gap support structure were identified, and an accurate dynamic model of the gap support structure was established, which provided support for the rotor dynamics design with the gap support structure, and has important engineering significance. Summary of the invention

[0004] The purpose of the present invention is to overcome the technical defects of the prior art, propose a parameter identification method and a testing device for a rotor gap support structure, and solve the following technical problems: first, simulate the installation conditions of the gap support structure to achieve rapid installation of the gap support device; second, accurately identify the stiffness and damping parameters of the rotor gap support structure based on model simulation and experimental test data, provide a reference for the rotor dynamics design with the gap support structure, and improve the design efficiency.

[0005] The present invention specifically adopts the following technical solution: a parameter identification method of a rotor gap support structure, comprising the following steps:

[0006] Step SS1: using the finite element method to establish a rotor dynamics model consisting of a rotor disk, a shaft, a rigid front support, and a gap rear support, and constructing a nonlinear structural dynamics equation of the rotor gap support;

[0007] Step SS2: construct a rotor clearance support test bench;

[0008] Step SS3: Conduct rotor dynamics tests under different clearance conditions to obtain the influence of different clearances on rotor dynamics characteristics;

[0009] Step SS4: Identify the stiffness and damping parameters of the gap support based on the model simulation and test results.

[0010] As a preferred embodiment, the step SS1 specifically includes:

[0011] The dynamic equation of the nonlinear model of the rotor clearance support structure is:

[0012]

[0013] Among them, F nl is the radial pressure F n and tangential friction f t The superposition of:

[0014] F nl =F n cosθ+f t sinθ (2)

[0015] Radial pressure F n for:

[0016]

[0017] Tangential friction force f t :

[0018]

[0019] In the nonlinear dynamic equation of the rotor gap support structure, the nonlinear parameters include contact stiffness k bn , contact damping c bn , friction coefficient μ, and further analyze the influence of the change of nonlinear parameters on the dynamic characteristics of the rotor clearance support structure.

[0020] As a preferred embodiment, the step SS2 specifically includes: installing the gap support structure on the test device to build a rotor dynamics test platform with gap support.

[0021] As a preferred embodiment, the step SS4 specifically includes: after discretizing the rotor support structure into a one-dimensional model, its dynamic equation is:

[0022]

[0023] Where M, K, C are the mass, stiffness, and damping matrices of the rotor, and G is the rotor gyroscopic torque matrix. These parameters are considered fixed when the rotor structure and material are determined. K b , C b To support the stiffness and damping matrix, these parameters cannot be obtained by direct measurement and calculation, so support stiffness and damping parameter identification is required.

[0024] As a preferred embodiment, the step SS4 specifically includes: using the transfer function to identify the support parameters, the unbalanced force F applied to the test shaft in the test test o , and the response x of the rotor structure, perform Fourier transform on them, and then divide them to get the transfer function X(ω) / F(ω), which can be sorted out as follows:

[0025]

[0026] According to the X(ω) / F(ω) test value and the known M, K, C, and G, the K to be identified can be calculated by numerical method. b , C b .

[0027] The present invention also proposes a testing device for a rotor gap support structure, comprising a front support and a rear support distributed front and rear, and a rotating shaft located between the front support and the rear support, the front support being provided with a front supporting casing, the rear support being provided with a rear supporting casing, the front and rear parts of the rotating shaft being respectively cooperated with and installed with a front bearing and a test bearing, the front end of the rotating shaft being cooperated with a driving end, and the test bearing being cooperated with an SFD component.

[0028] As a preferred embodiment, the rotating shaft is made of 30CrMnSi.

[0029] As a preferred embodiment, the front support casing is made of 7074 aluminum alloy.

[0030] As a preferred embodiment, the front support and the rear support are made of 45 steel.

[0031] The beneficial effects achieved by the present invention are as follows: First, the present invention aims at solving the technical requirements of how to simulate the installation conditions of the gap support structure and realize the rapid installation of the gap support device, and proposes a test device for the rotor gap support structure. In the test, the front bearing has a larger support stiffness and is a rigid support, the rear bearing is an elastic support, and there is a certain gap between the inner ring of the rear bearing and the end of the rotor. When the rotor rotates at high speed, the journal part collides with the inner ring of the rear bearing, generating nonlinear force to simulate the installation conditions and realize the rapid installation of the gap support structure; second, a rigid rotor is used to simplify the rotor characteristics and reduce the influencing factors of the parameter identification results; third, the present invention aims at solving the problem of how to accurately identify the stiffness and damping of the rotor gap support structure based on model simulation and experimental test data. Parameters, provide a reference for the rotor dynamics design of the gap support structure, improve the technical demand for design efficiency, propose a parameter identification method for the rotor gap support structure, use the finite element method to establish the rotor dynamics model composed of the rotor disk, shaft, rigid front support and gap rear support, and construct the nonlinear structural dynamics equation of the rotor gap support; build a rotor gap support test bench; carry out rotor dynamics tests under different gap conditions to obtain the influence of different gaps on the rotor dynamics characteristics; identify the stiffness and damping parameters of the gap support based on model simulation and experimental results, and combine model simulation and experimental test data to accurately identify the stiffness and damping parameters of the rotor gap support structure, providing support for the rotor dynamics design of the gap support structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a structural schematic diagram of the rotor gap support structure testing device of the present invention.

[0033] Figure 2 It is a schematic diagram of a test scheme for an embodiment of the rotor gap support structure of the present invention.

[0034] Figure 3 It is a schematic diagram of a finite element model of the rotor gap support structure of the present invention.

[0035] Figure 4 It is a schematic flow chart of the rotor clearance support structure parameter identification method of the present invention.

[0036] The meaning of the marks in the figure: 1-drive end, 2-front bearing, 3-front support casing, 4-front support, 5-rotating shaft, 6-rear support, 7-rear support casing, 8-test bearing, 9-SFD assembly. DETAILED DESCRIPTION

[0037] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0038] Example 1: Figure 1 , Figure 2 and Figure 3 As shown, the present invention also proposes a test device for a rotor gap support structure, comprising a front support 4 and a rear support 6 distributed front and rear, and a rotating shaft 5 located between the front support 4 and the rear support 6, the front support 4 is provided with a front support casing 3, the rear support 6 is provided with a rear support casing 7, the front and rear parts of the rotating shaft 5 are respectively equipped with a front bearing 2 and a test bearing 8, the front end of the rotating shaft 5 is equipped with a driving end 1, and the test bearing 8 is equipped with an SFD component 9.

[0039] The rotating shaft 5 is made of 30CrMnSi, the front supporting casing 3 is made of 7074 aluminum alloy, and the front support 4 and the rear support 6 are made of 45# steel.

[0040] A set of clearance support tester was designed for the rear support structure of a certain type of turbine engine, and the dynamic characteristics of the test shaft clearance support structure were analyzed. In the test, the front bearing support stiffness is large and is a rigid support, while the rear bearing is an elastic support. There is a certain gap between the inner ring of the rear bearing and the end of the rotor. When the rotor rotates at high speed, the journal part collides with the inner ring of the rear bearing, generating nonlinear force.

[0041] The rotor tester consists of a main body and auxiliary systems, including a drive system, oil supply and return equipment, and a test collection system.

[0042] Drive system: The maximum speed of the object under study is 36000r / min, so a motor spindle with a maximum speed of 50000r / min and a torque of 2N·m is selected. In addition, the additional device solves the problems of bearing lubrication of the electric spindle and cooling of the magnetic coil.

[0043] Lubricating oil supply and return equipment: The bearings used in the test rotor work under high speed conditions, and special lubricating oil is required to cool the bearings to ensure stable operation of the bearings. At the same time, the squeeze film damper in the gap support structure also requires lubricating oil of a certain pressure to achieve a vibration reduction effect. The oil supply station can provide lubricating oil with a certain pressure to meet the test requirements. The maximum oil supply pressure of the oil supply station can reach 14MPa.

[0044] Select an oil supply pump with sufficient power to ensure the oil supply pressure and oil supply volume for bearing cooling and squeeze film damper operation; the pressure and flow rate can be displayed and adjusted; and the oil supply and return routes should be arranged reasonably.

[0045] Test acquisition system: The test system arranges sensors at two measuring points. The collected signals are filtered, de-noised, and converted to analog-to-digital before entering the computer. Eddy current sensors are used to measure rotor speed and rotor vibration displacement signals. Test plan: Figure 3 shown.

[0046] Example 2: Figure 4 As shown, the present invention also proposes a parameter identification method of a rotor gap support structure, comprising the following steps:

[0047] Step SS1: using the finite element method to establish a rotor dynamics model consisting of a rotor disk, a shaft, a rigid front support, and a gap rear support, and constructing a nonlinear structural dynamics equation of the rotor gap support;

[0048] Step SS2: construct a rotor clearance support test bench;

[0049] Step SS3: Conduct rotor dynamics tests under different clearance conditions to obtain the influence of different clearances on rotor dynamics characteristics;

[0050] Step SS4: Identify the stiffness and damping parameters of the gap support based on the model simulation and test results.

[0051] The step SS1 specifically includes:

[0052] The dynamic equation of the nonlinear model of the rotor clearance support structure is:

[0053]

[0054] where F nl is the radial pressure F n and tangential friction f t The superposition of:

[0055] F nl =F n cosθ+f t sinθ (2)

[0056] Radial pressure F n for:

[0057]

[0058] Tangential friction force f t :

[0059]

[0060] In the nonlinear dynamic equation of the rotor gap support structure, the nonlinear parameters include contact stiffness k bn , contact damping c bn , friction coefficient μ, and further analyze the influence of the change of nonlinear parameters on the dynamic characteristics of the rotor clearance support structure.

[0061] The step SS2 specifically includes: installing the gap support structure on the test device to build a rotor dynamics test platform with gap support.

[0062] The step SS4 specifically includes: after discretizing the rotor support structure into a one-dimensional model, its dynamic equation is:

[0063]

[0064] Where M, K, C are the mass, stiffness, and damping matrices of the rotor, and G is the rotor gyroscopic torque matrix. These parameters are considered fixed when the rotor structure and material are determined. K b , C b For the support stiffness and damping matrix, these parameters cannot be obtained by direct measurement and calculation, so it is necessary to identify the support stiffness and damping parameters. The support parameters can be identified by combining experimental testing and simulation calculation based on the rotor dynamic characteristics obtained by experimental testing and the mechanical model of the rotor structure.

[0065] There are many kinds of dynamic characteristic data used in the identification process, such as modal parameters, dynamic response, transfer function, etc., which can be used as the basis for identification, thus forming different types of methods. Taking the use of transfer function to identify support parameters as an example, the unbalanced force F applied to the test shaft in the test test is o , and the response x of the rotor structure, perform Fourier transform on them, and then divide them to get the transfer function X(ω) / F(ω), which can be sorted out as follows:

[0066]

[0067] According to the X(ω) / F(ω) test value and the known M, K, C, and G, the K to be identified can be calculated by numerical method. b , C b .

[0068] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0069] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 These computer program instructions can also be stored in a computer-readable memory that can guide a computer or other programmable data processing device to work in a specific way, so that the instructions stored in the computer-readable memory produce a product including an instruction device, which implements the functions specified in the process. Figure 1 A process or multiple processes and / or boxes Figure 1 These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable device provide for implementing the process in the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for identifying parameters of a rotor gap support structure, characterized in that: The steps include: Step SS1: using the finite element method to establish a rotor dynamics model consisting of a rotor disk, a shaft, a rigid front support, and a gap rear support, and constructing a nonlinear structural dynamics equation of the rotor gap support; Step SS2: construct a rotor clearance support test bench; Step SS3: Conduct rotor dynamics tests under different clearance conditions to obtain the influence of different clearances on rotor dynamics characteristics; Step SS4: Identify the stiffness and damping parameters of the gap support based on the model simulation and test results.

2. The method for identifying parameters of a rotor gap support structure according to claim 1, characterized in that: The step SS1 specifically includes: The dynamic equation of the nonlinear model of the rotor clearance support structure is: where F nl is the radial pressure F n and tangential friction f t The superposition of: F nl =F n cosθ+f t sinθ (2) Radial pressure F n for: Tangential friction force f t : In the nonlinear dynamic equation of the rotor gap support structure, the nonlinear parameters include contact stiffness k bn , contact damping c bn , friction coefficient μ, and further analyze the influence of the change of nonlinear parameters on the dynamic characteristics of the rotor clearance support structure.

3. The parameter identification method of a rotor gap support structure according to claim 1, characterized in that: The step SS2 specifically includes: installing the gap support structure on the test device to build a rotor dynamics test platform with gap support.

4. The method for identifying parameters of a rotor gap support structure according to claim 2, characterized in that: The step SS4 specifically includes: after discretizing the rotor support structure into a one-dimensional model, its dynamic equation is: Where M, K, C are the mass, stiffness, and damping matrices of the rotor, and G is the rotor gyroscopic torque matrix. These parameters are considered fixed when the rotor structure and material are determined. K b , C b To support the stiffness and damping matrix, these parameters cannot be obtained by direct measurement and calculation, so support stiffness and damping parameter identification is required.

5. A method for identifying parameters of a rotor gap support structure according to claim 4, characterized in that: The step SS4 specifically includes: using the transfer function to identify the support parameters, and applying the unbalanced force F on the test shaft in the test test. o , and the response x of the rotor structure, perform Fourier transform on them, and then divide them to get the transfer function X(ω) / F(ω), which can be sorted out as follows: According to the X(ω) / F(ω) test value and the known M, K, C, and G, the K to be identified can be calculated by numerical method. b , C b .

6. A testing device based on the parameter identification method of the rotor gap support structure according to claim 1, characterized in that: The invention comprises a front support (4) and a rear support (6) which are distributed front and rear, and a rotating shaft (5) located between the front support (4) and the rear support (6); the front support (4) is provided with a front support casing (3); the rear support (6) is provided with a rear support casing (7); the front and rear parts of the rotating shaft (5) are respectively equipped with a front bearing (2) and a test bearing (8); the front end of the rotating shaft (5) is equipped with a driving end (1); and the test bearing (8) is equipped with an SFD component (9).

7. A testing device for a rotor gap support structure according to claim 6, characterized in that: The rotating shaft (5) is made of 30CrMnSi.

8. A testing device for a rotor gap support structure according to claim 6, characterized in that: The front support casing (3) is made of 7074 aluminum alloy.

9. A testing device for a rotor gap support structure according to claim 6, characterized in that: The front support (4) and the rear support (6) are made of No. 45 steel.

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