Design method of base of steam turbine generator with different rotating speed

Abstract

The application discloses a design method of a steam turbine generator base with different rotating speeds and relates to the technical field of steam turbine generator bases.The application comprises the following steps: establishing a finite element model of the steam turbine generator base with different rotating speeds; performing modal analysis on the steam turbine generator base with different rotating speeds; calculating disturbing force exciting frequency from modal frequency and different rotating speed ratios; performing steady-state analysis on the base by using the disturbing force exciting frequency; combining square sum and square root of the steady-state analysis result; drawing a disturbing force exciting point vibration response amplitude-frequency curve and a limit value curve; judging whether the result meets the limit value requirement; if the result does not meet the limit value requirement, adjusting the base shape and re-calculating; and if the result meets the limit value requirement, ending the base dynamic calculation.The application provides a design method of a steam turbine generator base with different rotating speeds, realizes the design of the steam turbine generator base with different rotating speeds by using steady-state analysis, and greatly improves the design efficiency of the steam turbine generator base with different rotating speeds.

Description

Technical Field

[0001] This invention relates to the field of steam turbine generator base technology, and in particular to a design method for steam turbine generator bases with different rotational speeds. Background Technology

[0002] As the foundation of power equipment, the power design analysis of the turbine generator base is essential. When the turbine and generator rotate at different speeds, under conventional steady-state analysis of disturbance conditions, the steady-state analysis frequencies for different speeds do not correspond, making it impossible to perform sum-of-squares (SRSS) data processing on the calculation results for each disturbance condition. Therefore, time-history analysis methods are often required for turbine generator bases with different speeds, which significantly increases the computational workload and analysis difficulty. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a design method for turbine generator bases with different rotational speeds, so as to realize the design of turbine generator bases with different rotational speeds using steady-state analysis, which greatly improves the design efficiency of turbine generator bases with different rotational speeds.

[0004] The technical solution adopted in this invention is as follows:

[0005] Establish finite element models of turbine generator bases at different speeds; perform modal analysis on turbine generator bases at different speeds; calculate the disturbance excitation frequency from the modal frequencies and different speed ratios; perform steady-state analysis of the base using the disturbance excitation frequency; combine the square and square root of the steady-state analysis results; plot the amplitude-frequency curve and limit curve of the vibration response at the disturbance excitation point; determine whether the results meet the limit requirements. If not, adjust the base shape and recalculate; if they meet the requirements, the dynamic calculation of the base ends.

[0006] Furthermore, the establishment of finite element models of the turbine generator base at different rotational speeds specifically includes:

[0007] The turbine and generator rotate at different speeds. The turbine rotor and generator rotor are connected by a gearbox. A finite element model is built using SAP2000 finite element software based on the dimensions of the turbine generator base.

[0008] Furthermore, the modal analysis of the turbine generator base at different rotational speeds specifically includes:

[0009] Modal analysis of the base was performed using the eigenvector method in SAP2000 finite element software. The modal cutoff frequency calculated by the modal analysis was taken as the larger of 1.4 times the rated operating frequency of the turbine and generator.

[0010] Furthermore, the calculation of the disturbance excitation frequency from the modal frequencies and different rotational speed ratios specifically includes:

[0011] Let the rated speed of the generator be n G The rated speed of the steam turbine is n T The generator's calculation range modal frequencies are The steam turbine's calculated modal frequencies are

[0012] Generator disturbance excitation frequency f G It consists of four parts: the generator calculation range and the modal frequency. Corresponding steam turbine calculation range modal frequencies Corresponding to the turbine's calculated smoothing point frequency (n) G / n T ):(n G / n T ):(n G / 60×1.4), generator rated frequency n G / 60; that is, the generator disturbance excitation frequency f G for And sort this set of disturbance excitation frequencies from smallest to largest while removing duplicate values;

[0013] Steam turbine disturbance excitation frequency f T It consists of 4 parts, namely: the corresponding generator calculation range modal frequency is Steam turbine calculation range modal frequencies Steam turbine calculation smoothing point frequency 1∶1∶(n T / 60×1.4), turbine rated frequency n T / 60; that is, the turbine disturbance excitation frequency f T Corresponding to Then, sort the excitation frequencies of this group of disturbance forces from smallest to largest and remove duplicate values.

[0014] Furthermore, the method of using the perturbation excitation frequency for base steady-state analysis specifically includes:

[0015] The disturbance forces at each excitation point of the base are applied under individual operating conditions, and the generator disturbance excitation point is at the generator disturbance excitation frequency f. G Steady-state analysis is performed, where the steady-state function corresponding to the generator disturbance is (f G / (n G / 60)) 2 The turbine disturbance excitation point adopts the turbine disturbance excitation frequency f. T Steady-state analysis is performed, where the steady-state function corresponding to the turbine disturbance force is (f T / (n T / 60)) 2 .

[0016] Furthermore, the steady-state analysis results are obtained by combining the square and the square root, specifically including: let the disturbance excitation point be i, the generator disturbance condition be j, the turbine disturbance condition be k, and the disturbance excitation frequency f corresponding to the generator disturbance excitation point. G The steady-state analysis results show that the response amplitude is U. ijG The turbine disturbance excitation point corresponds to the disturbance excitation frequency f. T The steady-state analysis results show that the response amplitude is U. ijT The disturbance condition will then be represented by a combination of the square and the square root of the sum of its squares, U. iSRSS for

[0017] Furthermore, the step of plotting the vibration response amplitude-frequency curve and limit curve at the disturbance excitation point specifically includes: using MATLAB to plot the amplitude-frequency U of the generator disturbance excitation point. iSRSS -f G The curve, and the limit curve is drawn using dashed lines, in [(0.75×n G / 60)~(1.25×n G The limit value is L (60) G , in [0~(0.75×n G The limit is 1.5 × L (60). G The amplitude and frequency U of the turbine's disturbance excitation point were plotted using MATLAB. iSRSS -f T The curve, and the limit curve is drawn using dashed lines, in [(0.75×n T / 60)~(1.25×n T The limit value is L (60) T , in [0~(0.75×n T The limit is 1.5 × L (60) T .

[0018] Furthermore, the judgment result is checked against the limit requirements. If the limit is not met, the base shape is adjusted and recalculated. If the limit is met, the base dynamic calculation ends. Specifically, this includes the combined value U of the disturbance excitation point. iSRSS If the value exceeds the corresponding limit, the base does not meet the dynamic design requirements, and the base shape should be adjusted and recalculated; the combined value of the disturbance excitation point U. iSRSS If all values ​​are less than their corresponding limits, then the base design meets the dynamic design requirements, and the base dynamic calculation ends.

[0019] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0020] 1. This invention is a design method for turbine generator bases with different rotational speeds. It solves the problem that conventional steady-state analysis cannot be used to perform dynamic calculations for turbine generator bases with different rotational speeds. Therefore, it is no longer necessary to perform dynamic time history analysis on turbine generator bases with different rotational speeds, which greatly reduces the amount of calculation and analysis difficulty for turbine generator bases with different rotational speeds.

[0021] 2. This invention is a design method for turbine generator bases with different rotational speeds. By calculating the disturbance excitation frequencies of the generator and the turbine during steady-state analysis, the calculation results of each disturbance excitation point of the turbine and generator under different disturbance conditions at different rotational speeds are made to correspond one-to-one in frequency. Thus, the steady-state analysis results can be directly processed using the SRSS method, enabling the design of turbine generator bases with different rotational speeds directly using the steady-state analysis method, which greatly improves the design efficiency of turbine generator bases with different rotational speeds.

[0022] 3. This invention is a design method for turbine generator bases at different speeds. It includes a complete base design method, such as base model establishment, base modal analysis, calculation of disturbance excitation frequency, steady-state analysis calculation, post-processing of steady-state analysis results, plotting of amplitude-frequency curves and limit curves, and result judgment. It establishes a design process for turbine generator bases at different speeds using steady-state analysis, and forms a design system for modeling, analysis, and evaluation of turbine generator bases at different speeds, providing a complete design method for turbine generator bases at different speeds. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort, wherein:

[0024] Figure 1 A flowchart illustrating the design method for a turbine generator base with different rotational speeds;

[0025] Figure 2 This is a plan view of the turbine generator base.

[0026] Figure 3 This is an elevation layout diagram of the steam turbine generator base;

[0027] Figure 4 Finite element model of the turbine generator base;

[0028] Figure 5 The amplitude-frequency curve and limit curve of the vibration response at the generator's disturbance excitation point;

[0029] Figure 6 The amplitude-frequency curve and limit curve of the vibration response at the disturbance excitation point of the steam turbine.

[0030] Explanation of reference numerals: 1-I-axis column, 2-II-axis column, 3-III-axis column, 4-I-axis crossbeam of operating layer, 5-II-axis crossbeam of operating layer, 6-III-axis crossbeam of operating layer, 7-longitudinal beam of first operating layer, 8-longitudinal beam of second operating layer, 9-first intermediate layer platform, 10-second intermediate layer platform. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention; that is, the described embodiments are merely some embodiments of the invention, and not all embodiments. The components of the embodiments of the invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0032] It should be noted that the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0033] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0034] Example 1

[0035] Steam turbine generator base such as Figures 2-3 As shown, it includes a pair of I-axis posts 1, II-axis posts 2, and III-axis posts 3.

[0036] The following are respectively set up: the I-axis crossbeam 4 of the operating layer between the two I-axis columns 1, the II-axis crossbeam 5 of the operating layer between the two II-axis columns 2, and the III-axis crossbeam 6 of the operating layer between the two III-axis columns 3.

[0037] The first operating layer longitudinal beam 7 is connected between column 1 of axis I and column 2 of axis II, and the second operating layer longitudinal beam 8 is connected between column 2 of axis II and column 3 of axis III;

[0038] A first intermediate platform 9 is fixed between I-axis column 1 and II-axis column 2, and a second intermediate platform 10 is fixed on III-axis column 3.

[0039] like Figure 1 As shown, a design method for a turbine generator base with different rotational speeds is described, and the steps are as follows:

[0040] Step 1: Establish finite element models of the turbine generator base at different rotational speeds, such as... Figure 4 As shown, the specific details include: the turbine and generator have different speeds, with the turbine speed at 4684 rpm and the generator speed at 3000 rpm. The turbine rotor and generator rotor are connected through a gearbox. A finite element model is established using SAP2000 finite element software based on the dimensions of the turbine-generator base. The base adopts a cast-in-place reinforced concrete frame structure, with the operating floor elevation at 8.500m and the intermediate floor elevation at 4.500m. The outer dimensions of the operating floor are 19.55m x 9.2m. The beams and columns in the finite element model are simulated using rod elements, while the bottom plate and intermediate floor plates are simulated using shell elements.

[0041] Step 2 involves performing modal analysis on the turbine generator base at different speeds. Specifically, this includes using the eigenvector method in SAP2000 finite element software to perform modal analysis on the base. The modal cutoff frequency calculated is taken as the larger of 1.4 times the rated operating frequency of the turbine and generator. That is, the modal cutoff frequency calculated by the modal analysis is 1.4 × max(4684 / 60, 3000 / 60) = 109.29 Hz.

[0042] Step 3: Calculate the excitation frequency of the disturbance force based on the modal frequencies and different speed ratios. Specifically, this includes: the generator's rated speed is n. G =3000rpm, the rated speed of the steam turbine is n T =4684rpm, generator calculation range modal frequency is The steam turbine's calculated modal frequencies are

[0043] Generator disturbance excitation frequency f G It consists of four parts: the generator calculation range and the modal frequency. Corresponding steam turbine calculation range modal frequencies The corresponding turbine calculated smoothing point frequency is (3000 / 4684): (3000 / 4684): (3000 / 60×1.4), and the generator rated frequency is 3000 / 60; that is, the generator disturbance excitation frequency f. G for And sort this set of disturbance excitation frequencies from smallest to largest while removing duplicate values;

[0044] Steam turbine disturbance excitation frequency f T It consists of 4 parts, namely: the corresponding generator calculation range modal frequency is Steam turbine calculation range modal frequencies The calculated smoothing point frequency of the steam turbine is 1:1:(4684 / 60×1.4), and the rated frequency of the steam turbine is 4684 / 60; that is, the disturbance excitation frequency f of the steam turbine. TCorresponding to Then, sort the excitation frequencies of this group of disturbance forces from smallest to largest and remove duplicate values.

[0045] Step 4: Perform steady-state analysis of the base using the disturbance excitation frequency. Specifically, this includes: applying disturbance forces at each disturbance excitation point of the base under individual operating conditions, and applying the generator disturbance excitation frequency f at the generator disturbance excitation point. G Steady-state analysis is performed, where the steady-state function corresponding to the generator disturbance is (f G / (3000 / 60)) 2 The turbine disturbance excitation point adopts the turbine disturbance excitation frequency f. T Steady-state analysis is performed, where the steady-state function corresponding to the turbine disturbance force is (f T / (4684 / 60)) 2 .

[0046] Step 5: Apply a combination of squares and square roots to the steady-state analysis results. Specifically, this includes: setting the disturbance excitation point as i, the generator disturbance condition as j, the turbine disturbance condition as k, and the disturbance excitation frequency f corresponding to the generator disturbance excitation point. G The steady-state analysis results show that the response amplitude is U. ijG The turbine disturbance excitation point corresponds to the disturbance excitation frequency f. T The steady-state analysis results show that the response amplitude is U. ijT The disturbance condition will then be represented by a combination of the square and the square root of the sum of its squares, U. iSRSS for

[0047] Step 6: Plot the vibration response amplitude-frequency curve and limit curve at the disturbance excitation point. Specifically, this includes: using displacement control for the generator, plotting the amplitude-frequency U at the generator disturbance excitation point using MATLAB. iSRSS -f G The curve is drawn using a dashed line to represent the limit curve. The limit is 20 μm in the range [(0.75×3000 / 60)~(1.25×3000 / 60)] and 30 μm in the range [0~(0.75×3000 / 60)]. Figure 5 As shown;

[0048] The steam turbine employs speed control. MATLAB is used to plot the amplitude and frequency U of the turbine's disturbance excitation point. iSRSS -f T The curve is drawn using a dashed line to represent the limit curve. The limit is 5 mm / s in the range [(0.75×4684 / 60)~(1.25×4684 / 60)] and 7.5 mm / s in the range [0~(0.75×4684 / 60)]. Figure 6 As shown.

[0049] Step 7: Determine if the result meets the limit requirements. If not, adjust the base shape and recalculate. If it meets the requirements, the base dynamic calculation ends. The combined value of the disturbance excitation point U is... iSRSS All are less than their corresponding limits, i.e. Figure 5 and Figure 6 In the calculation, the amplitude-frequency curves do not exceed the amplitude limit, the base design meets the dynamic design requirements, and the base dynamic calculation is completed.

[0050] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be conceived by those skilled in the art within the technical scope disclosed in the present invention without creative effort should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A design method for a turbine generator base with different rotational speeds, characterized in that, Includes the following steps: Establish finite element models of turbine generator bases at different rotational speeds; Modal analysis was performed on the turbine generator base at different rotational speeds; The excitation frequency of the disturbance force is calculated from the modal frequencies and different rotational speed ratios; Steady-state analysis of the base was performed using the perturbation excitation frequency. The steady-state analysis results were combined with the square and square root; the amplitude-frequency curve and limit curve of the vibration response at the excitation point were plotted. Determine whether the result meets the limit requirements. If not, adjust the base shape and recalculate. If it meets the requirements, the base dynamic calculation ends. The establishment of finite element models of turbine generator bases at different rotational speeds specifically includes: The turbine and generator rotate at different speeds. The turbine rotor and generator rotor are connected by a gearbox. A finite element model is built using SAP2000 finite element software based on the dimensions of the turbine generator base. The modal analysis of the turbine generator base at different rotational speeds specifically includes: In SAP2000 finite element software, the eigenvector method is used to perform modal analysis on the base. The modal cutoff frequency calculated by the modal analysis is taken as the larger value of 1.4 times the rated operating frequency of the steam turbine and the generator. The calculation of the excitation frequency based on the modal frequency and different rotational speed ratios specifically includes: Let the rated speed of the generator be The rated speed of the steam turbine is The generator's calculation range modal frequencies are The calculated modal frequencies of the steam turbine are , Generator disturbance excitation frequency It consists of four parts: the generator calculation range and the modal frequency. Corresponding to the modal frequencies within the calculation range of the steam turbine. The corresponding smoothing point frequency of the steam turbine. : : Generator rated frequency That is, the generator disturbance excitation frequency. for[ , , : : , The excitation frequencies of this group of disturbance forces are sorted from smallest to largest, and duplicate values ​​are removed. Steam turbine disturbance excitation frequency It consists of 4 parts, namely: the corresponding generator calculation range modal frequency is Steam turbine calculation range modal frequencies The turbine's calculated smoothing point frequency is 1:1: Steam turbine rated frequency That is, the turbine disturbance excitation frequency. Corresponding to [ , , 1:1: , The excitation frequencies of this group of disturbance forces are sorted from smallest to largest, and duplicate values ​​are removed. The method of using the perturbation excitation frequency for base steady-state analysis specifically includes: The disturbance forces at each excitation point of the base are applied under individual operating conditions, and the generator disturbance excitation point uses the generator disturbance excitation frequency. Steady-state analysis is performed, where the steady-state function corresponding to the generator disturbance is: The turbine disturbance excitation point adopts the turbine disturbance excitation frequency. Steady-state analysis is performed, where the steady-state function corresponding to the turbine disturbance is: .

2. The design method for a turbine generator base with different rotational speeds according to claim 1, characterized in that, The steady-state analysis results are analyzed using a combination of squares and square roots, specifically including: Let the excitation point of the disturbance force be The generator disturbance condition is The turbine disturbance condition is The generator disturbance excitation point corresponds to the disturbance excitation frequency. The steady-state analysis results show that the response amplitude is The turbine disturbance excitation point corresponds to the disturbance excitation frequency. The steady-state analysis results show that the response amplitude is The disturbance condition will then be represented by a combination of the square and the square root of the sum. for .

3. The design method for a turbine generator base with different rotational speeds according to claim 2, characterized in that, The plotting of the vibration response amplitude-frequency curve and limit curve at the disturbance excitation point specifically includes: Plotting the amplitude and frequency of the generator's disturbance excitation point using MATLAB - The curve, and the limit curve is drawn using dashed lines, in [ The limit is ,exist[ The limit is The amplitude and frequency of the turbine's disturbance excitation point were plotted using MATLAB. - The curve, and the limit curve is drawn using dashed lines, in [ The limit is ,exist[ The limit is .

4. The design method for a turbine generator base with different rotational speeds according to claim 3, characterized in that, If the judgment result meets the limit requirements, the base shape is adjusted and recalculated if not, and the base dynamic calculation ends if it meets the requirements. This specifically includes: the combined value of the disturbance excitation point. If the value exceeds the corresponding limit, the base does not meet the dynamic design requirements, and the base shape should be adjusted and recalculated; combined value of disturbance excitation points. If all values ​​are less than their corresponding limits, then the base design meets the dynamic design requirements, and the base dynamic calculation ends.

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