A method for dynamic design of a gas turbine rotor with simultaneous front and rear power output

Abstract

The application belongs to the technical field of engine design, and particularly relates to a gas turbine rotor dynamics design method with simultaneous front and rear power output. The method comprises the following steps: S1, converting the working speed of a double-rotor system into an input parameter of dynamics design; S2, determining an outer transmission shaft system based on the connection mode of the two rotor systems of the double-rotor system, and giving the value range of the influence parameter of dynamics design; S3, establishing a simulation analysis model; S4, determining the critical speed of the double-rotor system, rotor strain energy, outer transmission shaft system strain energy and outer transmission shaft system support point strain energy based on the simulation analysis model; and S5, optimizing the simulation analysis model of step S3 based on the threshold values of the parameters. The application establishes the shaft system structure such as an output coupling and a speed reducer in the simulation model, so that the rotor dynamics design contains the influence of the power output shaft system on the vibration characteristics of the gas turbine.

Description

Technical Field

[0001] This application belongs to the field of engine design technology, specifically relating to a method for designing the dynamics of a gas turbine rotor that can output power simultaneously from both the front and rear ends. Background Technology

[0002] With the increasing variety of applications for aero-derivative gas turbines in recent years (including marine, power generation, and combined propulsion), there are more requirements for their power output configuration. Besides the conventional rear-output (exhaust-end output) and front-output (intake-end output) configurations, a simultaneous front-to-rear output configuration has become more demanding in recent years. This means a single gas turbine can simultaneously power multiple devices at both ends, and the power distribution can be adjusted arbitrarily according to the load. This type of gas turbine is characterized by long spans, small shaft diameters, multiple couplings, and multiple support points, which brings greater challenges to rotor dynamics design, necessitating the development of targeted rotor dynamics design methods.

[0003] Vibration of aero-derivative gas turbines directly affects their lifespan and safety. Statistics show that over 90% of structural strength failures are caused by or related to vibration. Therefore, ensuring good vibration characteristics of the gas turbine is crucial. Existing rotor dynamics design technology for aero-derivative gas turbines mainly relies on aircraft design methods. It cannot fully cover the key factors of rotor dynamics design for this type of gas turbine from both structural characteristics and usage requirements. Structurally, current assessments primarily focus on the gas turbine's own structure, while insufficiently considering the impact of power output shafts such as output couplings and reducers on the gas turbine's vibration characteristics. Furthermore, strain energy distribution does not differentiate between flexible compensation components (flexible connections). From a usage perspective, the same model of gas turbine generally corresponds to multiple operating environments, including at least bench testing and field use. The corresponding operating speeds, output shaft systems, and mounting base conditions all differ, and current design methods have not yet differentiated between these environments. Summary of the Invention

[0004] To address one of the aforementioned problems, this application provides a gas turbine rotor dynamics design method for simultaneous power output from both ends. This method is applied to a dual-rotor system comprising a gas generator rotor and a power turbine rotor. The front and rear ends of the dual-rotor system are connected to the load via external transmission shafts including flexible connection structures. The design method includes:

[0005] Step S1: Convert the operating speed of the dual-rotor system into input parameters for dynamic design;

[0006] Step S2: Determine the external transmission shaft system based on the connection method of the two rotor systems of the dual rotor system, and give the value range of the influence parameters of the dynamic design based on the support method of the external transmission shaft system.

[0007] Step S3: Establish a simulation analysis model based on the input parameters of the dynamic design of the dual rotor system and the value range of the influence parameters of the dynamic design;

[0008] Step S4: Based on the simulation analysis model, determine the critical speed of the dual rotor system, and the rotor strain energy, external transmission shaft strain energy, and external transmission shaft support point strain energy at the corresponding critical speed.

[0009] Step S5: Optimize the simulation analysis model of step S3 based on the critical speed threshold, rotor strain energy threshold, external transmission shaft strain energy threshold, and external transmission shaft support point strain energy threshold.

[0010] Preferably, step S1 further includes:

[0011] For a dual-rotor system with two independent rotor systems, each rotor system corresponds to its own rotational speed. For a dual-rotor system with two coupled rotor systems, the rotational speed relationship between the two rotor systems is determined based on the matching range of the rotational speeds of each rotor system.

[0012] Preferably, in step S2, the influencing parameters include mass parameters and stiffness parameters.

[0013] Preferably, step S5 includes:

[0014] If the critical speed is greater than the critical speed threshold, the rotor strain energy is less than the rotor strain energy threshold, the strain energy of the external transmission shaft system is less than the external transmission shaft system strain energy threshold, and the strain energy of the external transmission shaft system support point is less than the external transmission shaft system support point strain energy threshold, then the dual rotor system meets the design criteria; otherwise, return to step S3 to modify the design parameters.

[0015] Preferably, for a dual-rotor system in which two rotor systems are coupled to each other, the critical speed threshold is set outside a margin range formed by a predetermined proportion based on the common operating speed range of the two rotor systems.

[0016] Preferably, the rotor strain energy threshold is designed to be less than the strain energy threshold of the external transmission shaft system.

[0017] Preferably, in step S2, the range of values ​​for the influence parameters of the external transmission shaft system differs for dual-rotor systems used for different purposes.

[0018] This application ensures that the rotor dynamics design includes the influence of the power output shaft system on the vibration characteristics of the gas turbine by establishing shaft systems such as the output coupling and reducer in the simulation model. During the dynamics analysis, the strain energy of the flexible components in the rotor is differentiated when extracting rotor strain energy, and the strain energy requirements for the flexible components are appropriately relaxed, improving the accuracy of rotor dynamics evaluation and the feasibility of optimized design. Furthermore, the non-fixed rotational speed relationship between the two rotors of the gas turbine is considered during rotor dynamics calculations and standard comparisons, and different designs are implemented for different applications of the gas turbine, improving the accuracy and environmental adaptability of the gas turbine rotor dynamics design. Attached Figure Description

[0019] Figure 1 This is a flowchart of a preferred embodiment of the gas turbine rotor dynamics design method for simultaneously outputting power before and after this application.

[0020] Figure 2 This is a diagram showing the operating speed relationship of a certain twin-rotor gas turbine.

[0021] Figure 3 This is a schematic diagram of a gas turbine with front and rear outputs and its output shaft system.

[0022] Among them, 1-reducer rotor, 2-front output coupling, 3-gas generator rotor, 4-power turbine rotor, 5-rear output coupling, 6-torque. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are only some, not all, of the embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0024] This application provides a gas turbine rotor dynamics design method for simultaneous power output from both the front and rear ends. It is applied to a dual-rotor system including a gas generator rotor and a power turbine rotor. The front and rear ends of the dual-rotor system are connected to the load via external transmission shafts including flexible connection structures. Figure 1 As shown, the design method includes:

[0025] Step S1: Convert the operating speed of the dual-rotor system into input parameters for dynamic design.

[0026] In this step, when designing a dual-rotor system, the dynamic input parameters of each rotor system are converted into expressions using the rotational speed of each rotor system.

[0027] In some alternative implementations, step S1 further includes:

[0028] For a dual-rotor system with two independent rotor systems, each rotor system corresponds to its own rotational speed. For a dual-rotor system with two coupled rotor systems, the rotational speed relationship between the two rotor systems is determined based on the matching range of the rotational speeds of each rotor system.

[0029] In this embodiment, the gas turbine operating speed is specified based on operating conditions. During rotor dynamics design, it needs to be converted into a usable speed expression using calculation methods and software. The speed conversion varies depending on the type of rotor support system. For a dual-rotor independent system, the dynamics design of the two rotors is performed separately, with the speed corresponding to the rotor. For a dual-rotor coupled system, considering the non-fixed relationship between the two rotor speeds, it is necessary to clarify the speed relationship or define the matching range of rotor speeds. A typical matching range for dual rotor speeds is expressed as follows: Figure 2 As shown, Figure 2 In the diagram, region A represents the range of speeds that can be matched between the two rotors, i.e., the operating speed range. Region B is a larger range formed by considering a certain percentage of margin. It should also be noted that when the same gas turbine is used for multiple purposes, the operating ranges of the gas turbines for different purposes need to be distinguished.

[0030] Step S2: Determine the external transmission shaft system based on the connection method of the two rotor systems of the dual rotor system, and give the value range of the influence parameters of the dynamic design based on the support method of the external transmission shaft system.

[0031] The dynamic design of a gas turbine rotor needs to consider the influence of the power output shaft system, such as the output coupling and the reducer. Therefore, identifying which structures affect the dynamics of the gas turbine is the key point of this step. Generally speaking, the output coupling is a must-consider component and is also the structure with the greatest and most direct impact. The output coupling is an unsupported rotor with flexible compensation structures at both ends. Therefore, for the coupling, such as... Figure 3As shown, the gas generator rotor 3 and the power turbine rotor 4 form a dual-rotor system, coupled to each other. The front end of the gas generator rotor 3 is connected to the reducer rotor 1 via a front output coupling 2, used to output power to the front load. The power turbine rotor 4 is connected to the torque 6 via a rear output coupling 5, used to output power to the rear load. Since the coupling is connected to the gas turbine end (gas generator rotor 3 and power turbine rotor 4), the gas turbine end itself provides support for one end of the coupling, while the other end of the coupling needs to be supported by other support components. Therefore, the support structure of the coupling needs to be clearly defined. In addition to the coupling, the external transmission shaft system of this application usually includes structures such as reducers. Based on the dynamic design and optimization results, restrictions or suggestions should also be made on the key influencing parameters of the external transmission shaft system. In some optional embodiments, the influencing parameters include mass parameters, stiffness parameters, etc.

[0032] Step S3: Establish a simulation analysis model based on the input parameters of the dynamic design of the dual rotor system and the range of values ​​of the influence parameters of the dynamic design.

[0033] Step S4: Based on the simulation analysis model, determine the critical speed of the dual-rotor system, and the rotor strain energy, external transmission shaft strain energy, and external transmission shaft support point strain energy at the corresponding critical speed.

[0034] In this embodiment, in addition to extracting the strain energy of the support and the rotor separately according to the existing rotor dynamics design technology, it is also necessary to extract the strain energy of the flexible connection structure on the rotor used for flexible compensation separately. The table of extracted data is shown in Table 1.

[0035] Table 1 Parameter Extraction Table

[0036] Critical speed (r / min) - - Rotor strain energy % - - Flexible component rotor strain energy % - - Pivot 1 strain energy % - - Pivot 2 strain energy % - - Pivot 3 strain energy % - - 。。。 - -

[0037] Step S5: Optimize the simulation analysis model of step S3 based on the critical speed threshold, rotor strain energy threshold, external transmission shaft strain energy threshold, and external transmission shaft support point strain energy threshold.

[0038] In some alternative implementations, step S5 includes:

[0039] If the critical speed is greater than the critical speed threshold, the rotor strain energy is less than the rotor strain energy threshold, the strain energy of the external transmission shaft system is less than the external transmission shaft system strain energy threshold, and the strain energy of the external transmission shaft system support point is less than the external transmission shaft system support point strain energy threshold, then the dual rotor system meets the design criteria; otherwise, return to step S3 to modify the design parameters.

[0040] In some alternative implementations, for a dual-rotor system in which two rotor systems are coupled to each other, the critical speed threshold is set outside a margin range formed by a predetermined proportion based on the common operating speed range of the two rotor systems.

[0041] In some alternative implementations, the rotor strain energy threshold is designed to be less than the external transmission shaft strain energy threshold.

[0042] The rotor dynamics design standard is the goal of optimization design. The design standard focuses on two parameters: the critical speed and the rotor dynamics design standard. The critical speed should not be near the operating speed for long periods of time, meaning that a certain margin must be maintained. Figure 2 The first requirement is that bending-type critical speeds are not allowed in both regions A and B. The second requirement is rotor strain energy. For critical speeds that are not near the long-term operating speed but need to be passed, the rotor strain energy should be kept at a low level to ensure smooth passage. However, the requirements for the strain energy of flexible rotor components can be relaxed. Appropriately relaxing the strain energy of flexible rotor components can effectively improve the accuracy of rotor dynamics assessment and the feasibility of optimization design while ensuring the reliability of the gas turbine.

[0043] In some alternative implementations, in step S2, the range of values ​​for the influence parameters of the external transmission shaft system varies for dual-rotor systems used for different purposes.

[0044] It should be noted that the same gas turbine model generally corresponds to multiple applications, including bench testing, power generation, and ship propulsion. The output shaft system and operating speed differ for different applications, so rotor dynamics design must be carried out separately for different applications, and restrictions must be imposed on key influencing factors.

[0045] This application ensures that the rotor dynamics design includes the influence of the power output shaft system on the vibration characteristics of the gas turbine by establishing shaft systems such as the output coupling and reducer in the simulation model. During the dynamics analysis, the strain energy of the flexible components in the rotor is differentiated when extracting rotor strain energy, and the strain energy requirements for the flexible components are appropriately relaxed, improving the accuracy of rotor dynamics evaluation and the feasibility of optimized design. Furthermore, the non-fixed rotational speed relationship between the two rotors of the gas turbine is considered during rotor dynamics calculations and standard comparisons, and different designs are implemented for different applications of the gas turbine, improving the accuracy and environmental adaptability of the gas turbine rotor dynamics design.

[0046] Although this application has been described in detail above with general descriptions and specific embodiments, some modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, such modifications or improvements made without departing from the spirit of this application are all within the scope of protection claimed in this application.

Claims

1. A method for designing the dynamics of a gas turbine rotor that outputs power simultaneously from both ends, applied to a dual-rotor system including a gas generator rotor and a power turbine rotor, wherein the front and rear ends of the dual-rotor system are connected to the load via external transmission shafts including flexible connection structures, characterized in that... The design method includes: Step S1: Convert the operating speed of the dual-rotor system into input parameters for dynamic design; Step S2: Determine the external transmission shaft system based on the connection method of the two rotor systems of the dual rotor system, and give the value range of the influence parameters of the dynamic design based on the support method of the external transmission shaft system. Step S3: Establish a simulation analysis model based on the input parameters of the dynamic design of the dual rotor system and the value range of the influence parameters of the dynamic design; Step S4: Based on the simulation analysis model, determine the critical speed of the dual rotor system, and the rotor strain energy, external transmission shaft strain energy, and external transmission shaft support point strain energy at the corresponding critical speed. Step S5: Optimize the simulation analysis model of step S3 based on the critical speed threshold, rotor strain energy threshold, external transmission shaft strain energy threshold, and external transmission shaft support point strain energy threshold.

2. The gas turbine rotor dynamics design method for simultaneous front and rear power output as described in claim 1, characterized in that, Step S1 further includes: For a dual-rotor system with two independent rotor systems, each rotor system corresponds to its own rotational speed. For a dual-rotor system with two coupled rotor systems, the rotational speed relationship between the two rotor systems is determined based on the matching range of the rotational speeds of each rotor system.

3. The gas turbine rotor dynamics design method for simultaneous front and rear power output as described in claim 1, characterized in that, In step S2, the influencing parameters include mass parameters and stiffness parameters.

4. The gas turbine rotor dynamics design method for simultaneous front and rear power output as described in claim 1, characterized in that, Step S5 includes: If the critical speed is greater than the critical speed threshold, the rotor strain energy is less than the rotor strain energy threshold, the strain energy of the external transmission shaft system is less than the external transmission shaft system strain energy threshold, and the strain energy of the external transmission shaft system support point is less than the external transmission shaft system support point strain energy threshold, then the dual rotor system meets the design criteria; otherwise, return to step S3 to modify the design parameters.

5. The gas turbine rotor dynamics design method for simultaneous front and rear power output as described in claim 4, characterized in that, For a dual-rotor system in which two rotor systems are coupled to each other, the critical speed threshold is set outside a margin range formed by a predetermined proportion based on the common operating speed range of the two rotor systems.

6. The gas turbine rotor dynamics design method for simultaneous front and rear power output as described in claim 4, characterized in that, The rotor strain energy threshold is designed to be less than the strain energy threshold of the external transmission shaft system.

7. The gas turbine rotor dynamics design method for simultaneous front and rear power output as described in claim 1, characterized in that, In step S2, the range of values ​​for the influence parameters of the external transmission shaft system differs for dual-rotor systems used for different purposes.

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