Seal-rotor and seal-rotor bearing system dynamic characteristic solving method

Abstract

The invention belongs to the technical field of rotating machinery, and particularly relates to a method for solving dynamic characteristics of seal-rotor and seal-rotor bearing systems. The method comprises the following steps: 1, solving four rotor dynamic coefficients under different rotating speeds and vortex frequencies by using a steady-state or transient computational fluid mechanics method; 2, establishing a sealed rotor dynamic coefficient database based on two-dimensional cubic polynomial interpolation; 3, setting a solved initial rotating speed, and giving an initial working condition; 4, the instantaneous vortex frequency of the rotor is calculated, the rotor dynamic coefficient of current sealing is found, and the sealing exciting force borne by the rotor is calculated; 5, establishing a dimensionless dynamic model required to be solved; 6, substituting the sealing exciting force obtained by solving in the step 4 into the kinetic equation established in the step 5, calculating by using a numerical method, judging whether a numerical solving result is converged or not, and if not, returning to the step 4; and 7, keeping a calculation convergence result, and judging whether the rotating speed at the moment is the upper limit of the solved rotating speed or not.

Description

Technical Field

[0001] The invention belongs to the technical field of rotating machinery, and in particular relates to a method for solving the dynamic characteristics of a seal-rotor and a seal-rotor bearing system. Background Art

[0002] Rotating machinery systems are generally composed of core components such as rotors, impellers, seals, and bearings. When calculating the dynamic characteristics of the rotor system, it is generally divided into a seal-rotor system that only considers the seal excitation force and the unbalanced eccentricity of the impeller, and a seal-rotor bearing system that considers both the seal excitation force and the nonlinear excitation force of the bearing oil film.

[0003] However, for the above two systems, in the process of model establishment and numerical solution, two sealing force models are generally used to describe the sealing excitation force, namely the Muszynska nonlinear sealing force model and the Black-Childs sealing force model with analytical form. Among them, the Muszynska nonlinear sealing force model can only describe the labyrinth seal that is continuous in the circumference of the sealing cavity, and the Black-Childs sealing force model can only describe the annular seal that is continuous in the circumference of the sealing cavity.

[0004] From the above background introduction, it can be seen that the existing solutions for the dynamic characteristics of seal-rotor and seal-rotor bearing systems can only consider the circumferentially continuous labyrinth seals and smooth annular seal structures in the seal cavity, and cannot calculate more damping seal structures with circumferentially discontinuous structures (such as partition labyrinth seals, honeycomb seals, hole-type seals, bag seals, etc.) and perforated partition labyrinth seal structures with circumferentially semi-continuous structures. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a solution method for calculating the dynamic characteristics of seals with circumferential discontinuous structures and circumferential semi-continuous structures in seal-rotor and seal-rotor bearing systems. The method uses computational fluid dynamics to calculate the dynamic coefficients of the seal rotor at different speeds and vortex frequencies, and uses an interpolation function to expand the obtained database, and applies the database to the solution of the dynamic characteristics of the seal-rotor and seal-rotor bearing system.

[0006] The technical solution adopted by the present invention is: a method for solving the dynamic characteristics of a seal-rotor and a seal-rotor bearing system, the method for solving the dynamic characteristics comprising the following steps: S1: Use steady-state or transient computational fluid dynamics methods to solve different speeds ω (unit: r / min) and vortex frequency Ω (unit: Hz) under the four rotor dynamic coefficients of the sealing structure. The four rotor dynamic coefficients are the direct stiffness coefficient K, the cross-coupling stiffness coefficient k, direct damping coefficient C and cross-coupling stiffness coefficient c .

[0007] S2: Establish a sealed rotor dynamic coefficient database based on two-dimensional cubic polynomial interpolation.

[0008] S3: Set the initial speed for the solution and give the initial operating conditions of the seal-rotor system and the seal-rotor bearing system.

[0009] S4: Calculate the instantaneous vortex frequency of the rotor in this state based on the operating condition information of the current system, find the rotor dynamics coefficient of the current seal in the rotor dynamics coefficient interpolation database built in S2, and calculate the sealing exciting force on the rotor.

[0010] S5: Establish the dimensionless dynamic model of the seal-rotor system and seal-rotor bearing system to be solved.

[0011] S6: Substitute the seal exciting force obtained by S4 into the dynamic equations of the seal-rotor system and the seal-rotor bearing system established by S5, use numerical methods to perform calculations, and determine whether the numerical solution results converge. If not, return to S4.

[0012] S7: retain the result when the calculation converges, and determine whether the speed at this time is the upper limit of the required speed. If it has not reached the upper limit of the required speed, set the speed to the current speed plus one speed step, and return to S4 to continue the calculation; if it reaches the upper limit of the required speed, it means that the solution of the dynamic characteristics of the seal-rotor system and the seal-rotor bearing system has been completed.

[0013] Furthermore, in S2, the four rotor dynamic coefficients calculated in S1 are interpolated using a two-dimensional cubic polynomial interpolation formula to obtain a rotor dynamic coefficient interpolation database within the required speed and vortex frequency range. The two-dimensional cubic polynomial interpolation formula is:

[0014] In the formula, a , b , c , d , e , f , g , h , i , j is the interpolation equation coefficient, which is obtained by the rotation speed-vortex frequency ( ω -Ω) space, each of the four adjacent groups of dynamic coefficients is fitted. P For K, k , C , c Any rotor dynamics coefficient in; The obtained rotor dynamics coefficient interpolation database is ω With Ω as independent variables, P is a set of two-dimensional coefficient surfaces for the dependent variable.

[0015] Furthermore, the initial operating condition in S3 is a set of displacements or velocities of the given rotor that are not initially zero.

[0016] Furthermore, the calculation method of the rotor instantaneous vortex frequency in S4 is:

[0017] In the formula, is the speed of the rotor in the x direction at any time, Y is the displacement of the rotor in the y direction at the same moment; the sealing excitation force on the current rotor is found in the rotor dynamics coefficient interpolation database, that is, the current speed and vortex frequency are used as parameters, and the corresponding values ​​are selected from a series of two-dimensional coefficient surfaces in S2 as the current sealed rotor dynamics coefficients.

[0018] Furthermore, in S5, the rotor centroid is established using dynamics. O D Displacement in perpendicular directions within the rotor section xoy ( X and Y ),speed( and )、Acceleration( and The dynamic equation between the rotor and the force. The force in the dynamic equation is the weight of the rotor. M D g in M D is the mass of the rotor, g is the acceleration due to gravity; the rotor has O G The periodic exciting force caused by the offset r relative to the centroid and , where t is the time parameter; the sealing excitation force brought by the sealing structure to the rotor system F x and F y , calculated from the sealed rotor dynamic coefficient. The dimensionless dynamic model of the seal-rotor system and the seal-rotor bearing system is obtained by selecting the dimensionless displacement ( x = X / c r， y = Y / c r ) and dimensionless time ( ) is dimensionless.

[0019] Furthermore, the numerical method in S6 is a numerical iterative method such as the fourth-order Runge-Kutta method and the Newmark-beta method; the method for judging whether the numerical solution result converges is: calculating whether the relative error of the dimensionless displacement of the rotor before and after the numerical solution is greater than 1e-6 and whether the absolute error is greater than 1e-8. If it is greater than the above values, the numerical solution has not converged, otherwise, it has reached convergence.

[0020] Furthermore, S7 retains the result when the calculation converges, that is, saves the rotor displacement and speed value calculated in the current state. The upper limit of the speed and the speed step length, that is, the maximum value of the speed range to be calculated, the speed step length is the value within the speed range that can divide the difference between the maximum value and the minimum value of the speed range.

[0021] The beneficial effects of the present invention are as follows: a method for solving the dynamic characteristics of a seal-rotor and a seal-rotor bearing system is provided. The method uses computational fluid dynamics to calculate the dynamic coefficients of the seal rotor at different rotation speeds and turbulence frequencies, and uses an interpolation function to expand the obtained database, and applies the database to the solution of the dynamic characteristics of the seal-rotor and the seal-rotor bearing system. Since the results obtained by computational fluid dynamics are used as the basic data of the database in the process of solving the dynamic characteristics of the seal-rotor and the seal-rotor bearing system, the type of sealing structure considered is not limited. The dynamic characteristics of circumferential discontinuous seals and circumferential semi-continuous seal structures in the seal-rotor and the seal-rotor bearing system can be solved, which provides a new idea for the analysis of the dynamic behavior of the rotary mechanical seal-rotor and the seal-rotor bearing system. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a flow chart of the method for solving the dynamic characteristics of the seal-rotor and seal-rotor bearing system; Figure 2 is a schematic diagram of the main structure of the seal-rotor system in the second embodiment; Figure 3 Schematic diagram of the side view structure of the seal-rotor system in the second embodiment Figure 4 It is a schematic diagram of the database construction method in Example 2; Figure 5 is a schematic diagram of the structure of a traditional labyrinth seal considered in calculation (1) of Example 2; Figure 6 is a comparison diagram of bifurcation results obtained by using the traditional Muszynska nonlinear force model and the dynamic characteristics solution method in calculation (1) of Example 2; Figure 7is a comparison chart of the dimensionless maximum amplitude results obtained by using the traditional Muszynska nonlinear force model and the dynamic characteristic solution method in the calculation (1) of the second embodiment; Figure 8 It is a schematic diagram of the structure of the circumferential discontinuous seal-diaphragm labyrinth seal considered in calculation (2) of Example 2 and Example 3; Fig. 9 is a schematic diagram of the structure of the circumferential semi-continuous seal-perforated partition labyrinth seal considered in the calculation (2) of the second embodiment; Fig.10 is the seal-rotor system bifurcation diagram obtained by solving the diaphragm labyrinth seal in calculation (2) of Example 2; Fig.11 is the seal-rotor system bifurcation diagram obtained by solving the perforated baffle labyrinth seal in calculation (2) of Example 2; Fig.12 is a schematic structural diagram of a seal-rotor bearing system of Embodiment 3; Fig.13 This is the seal-rotor bearing system bifurcation diagram obtained by solving the partition labyrinth seal in Example 3. DETAILED DESCRIPTION Example

[0023] like Figure 1 As shown, the method for solving the dynamic characteristics of the seal-rotor and seal-rotor bearing system includes the following steps: S1: Use steady-state or transient computational fluid dynamics methods to solve different speeds ω (unit: r / min) and vortex frequency Ω (unit: Hz) under the four rotor dynamic coefficients of the sealing structure. The four rotor dynamic coefficients are the direct stiffness coefficient K, the cross-coupling stiffness coefficient k , direct damping coefficient C and cross-coupling stiffness coefficient c .

[0024] S2: Establish a sealed rotor dynamic coefficient database based on two-dimensional cubic polynomial interpolation; use the two-dimensional cubic polynomial interpolation formula to interpolate the four rotor dynamic coefficients calculated in S1 to obtain the rotor dynamic coefficient interpolation database within the required speed and vortex frequency range. The two-dimensional cubic polynomial interpolation formula is:

[0025] In the formula, a , b , c , d , e , f , g , h , i ,j is the interpolation equation coefficient, which is obtained by the rotation speed-vortex frequency ( ω -Ω) space, each of the four adjacent groups of dynamic coefficients is fitted. P For K, k , C , c Any rotor dynamics coefficient in; The obtained rotor dynamics coefficient interpolation database is ω With Ω as independent variables, P is a set of two-dimensional coefficient surfaces for the dependent variable.

[0026] S3: Set the initial speed of the solution and give the initial working conditions of the seal-rotor system and the seal-rotor bearing system. The initial working conditions are a set of displacements or speeds of the given rotor that are not zero initially.

[0027] S4: Calculate the instantaneous vortex frequency of the rotor in this state based on the working condition information of the current system, find the rotor dynamic coefficient of the current seal in the rotor dynamic coefficient interpolation database built in S2, and calculate the sealing exciting force on the rotor; the calculation method of the rotor instantaneous vortex frequency is:

[0028] In the formula, is the speed of the rotor in the x direction at any time, Y is the displacement of the rotor in the y direction at the same moment; the sealing excitation force on the current rotor is found in the rotor dynamics coefficient interpolation database, that is, the current speed and vortex frequency are used as parameters, and the corresponding values ​​are selected from a series of two-dimensional coefficient surfaces in S2 as the current sealed rotor dynamics coefficients.

[0029] S5: Establish dimensionless dynamic models of the seal-rotor system and seal-rotor bearing system to be solved; use dynamic methods to establish the rotor centroid O D Displacement in perpendicular directions within the rotor section xoy ( X and Y ),speed( and )、Acceleration( and ) and the dynamic equation between the forces; the forces in the dynamic equation are the weight of the rotor M D g in M D is the mass of the rotor, g is the acceleration due to gravity; the rotor has O G The periodic exciting force caused by the offset r relative to the centroid and , where t is the time parameter; the sealing excitation force brought by the sealing structure to the rotor system F x and F y , calculated from the sealed rotor dynamic coefficient; the dimensionless dynamic model of the seal-rotor system and the seal-rotor bearing system is obtained by selecting the dimensionless displacement ( x = X / c r， y = Y / c r ) and dimensionless time ( ) is dimensionless.

[0030] S6: Substitute the seal exciting force solved by S4 into the dynamic equations of the seal-rotor system and the seal-rotor bearing system established by S5, use numerical methods to calculate, and judge whether the numerical solution results converge. If not, return to S4; the numerical method is a numerical iterative method such as the fourth-order Runge-Kutta method and the Newmark-beta method; the method for judging whether the numerical solution results converge is: calculate whether the relative error of the dimensionless displacement of the rotor before and after the numerical solution is greater than 1e-6, and whether the absolute error is greater than 1e-8. If it is greater than the above values, the numerical solution has not converged. If it is less than the above values, it has reached convergence.

[0031] S7: retain the result when the calculation converges, and determine whether the speed at this time is the upper limit of the required speed. If the upper limit of the required speed has not been reached, set the speed to the current speed plus one speed step, and return to S4 to continue the calculation; if the upper limit of the required speed is reached, it means that the solution of the dynamic characteristics of the seal-rotor system and the seal-rotor bearing system has been completed; retain the result when the calculation converges, that is, save the rotor displacement and speed values ​​calculated in the current state; the upper limit of the speed and the speed step, that is, the maximum value of the speed range to be calculated, the speed step is the value that can divide the difference between the maximum value and the minimum value of the speed range within the speed range. Example

[0032] like Figure 2 and Figure 3 A seal-rotor system is shown, wherein the rotor shaft length l 0 =1m, shaft radius R Sh =0.015m, roulette length l D =0.05m, radius of the wheel R D=0.03m, the Young's modulus of the rotor is 206 GPa, and the rotor density is 7850 kg / m 3 , equivalent unbalanced eccentricity of the wheel r =0.00001m. Considering the equivalent unbalanced eccentricity of the wheel of the seal-rotor system and the gravity received, the dynamic equation of the system can be obtained:

[0033] Where: X, Y are the rotor displacements (m, m); D d 、K D They are the structural damping (N﹒s / m) and structural stiffness (N / m) of the rotor respectively; F x 、F y is the component of the sealing force along the vertical direction of the cross section (N, N), which is given by K, k , C , c Calculated; M D is the mass of the roulette wheel (kg); g is the gravitational acceleration ( g = 9.8m / s 2 ); ω is the rotor speed (displayed in r / min, calculated in rad / s); t r is the real time (s).

[0034] The structural damping of the rotor is calculated using Rayleigh damping, i.e.

[0035] in, k 1 and k 2 are two Rayleigh factors. According to Rayleigh's method, the Rayleigh factors k 1 and k 2 Can be expanded to: ; Where: ω n1 ,ω n2 are the first and second order natural frequencies of the rotor respectively; ξ 1、 ξ2 is the damping ratio of the first two modes, with values ​​of ξ1=0.02, ξ2=0.04, ξ1=0.02, ξ2=0.04.

[0036] Select Dimensionless Displacement x = X / c r， y = Y / c r and dimensionless time To simplify the calculation process, the fourth-order Runge-Kutta numerical algorithm is used to solve the dimensionless state equation.

[0037] like Figure 4 As shown, the cross-coupling stiffness coefficient of the labyrinth seal is k As an example, the process of using this method to expand the 6×7 total 42 initial data obtained by computational fluid dynamics into 101×30001 total 3030101 sets of databases is shown. In the process of applying this solution method, for each type of seal, K, k , C , c The four sets of data are expanded and then used in the subsequent calculation process.

[0038] In Example 2, two sets of calculations are compared to verify that: , by applying the Muszynska nonlinear force model and the seal-rotor and seal-rotor bearing system dynamic characteristics solution method (referred to as the "solution method") to the seal-rotor system using the traditional labyrinth seal, Figure 2 The bifurcation diagram of the seal-rotor system in the speed range of 1000 r / min to 10000 r / min is shown to verify the accuracy of the solution method; in, Figure 5 The structural parameters of the traditional labyrinth seal are shown, where the rotor radius is 30 mm and the sealing gap c r It is 0.2mm, the sealing cavity height h is 3.5mm, the sealing tooth gap l1 is 3.8mm, the sealing tooth width t is 0.25mm, and the cavity width l2 is 2.3mm.

[0039] Figure 6 The Muszynska nonlinear force model and the proposed dynamic characteristics solution method are shown. Figure 2The bifurcation diagram shown in the figure is obtained after the dynamic calculation of the seal-rotor system. From the content in the figure, it can be found that the ability of this dynamic characteristic solution method to solve the dynamic characteristics of the seal-rotor system at different speeds has reached the level of using the traditional Muszynska nonlinear force model. In the speed range of 100~1100 r / min, the description of the dynamic behavior of the seal-rotor system by this dynamic characteristic solution method is clearer than that using the traditional Muszynska nonlinear force model.

[0040] Figure 7 The dimensionless maximum amplitude diagram calculated using the Muszynska nonlinear force model and the present dynamic characteristic solution method is shown. From the content in the diagram, it can be found that the rotational speed at which the maximum amplitude of the seal-rotor system is obtained by the present dynamic characteristic solution method is consistent with that calculated using the traditional Muszynska nonlinear force model, with only a slight difference in the numerical value of the dimensionless maximum amplitude.

[0041] comprehensive Figure 6 and Figure 7 The comparison results show that the method for solving the dynamic characteristics of the seal-rotor and seal-rotor bearing system has sufficient accuracy for solving the dynamic characteristics of the seal-rotor system.

[0042] , by solving the dynamic characteristics of the seal-rotor system using different types of seals, including traditional labyrinth seals (circumferentially continuous seals), partition labyrinth seals (circumferentially discontinuous seals) and perforated partition labyrinth seals (circumferentially semi-continuous seals), the research object of the seal-rotor system dynamics is transformed from circumferentially continuous seals to circumferentially discontinuous seals and circumferentially semi-continuous seals, to verify the innovativeness and technical effect of this dynamic characteristic solution method.

[0043] in, Figure 8 The structure of a circumferential discontinuous seal - a partition labyrinth seal is shown. Φ The size of the labyrinth part of the partition labyrinth seal is Figure 5 The traditional labyrinth seal shown is consistent with the four additional sets of partitions using circumferential angles θ To represent, the value is 2°.

[0044] Fig. 9 The structure of a circumferential semi-continuous seal - a perforated partition labyrinth seal is shown, in which the basic dimensions of the perforated partition labyrinth seal are Figure 8 The labyrinth seal of the partition shown is consistent with that of the above, and the additional four sets of circumferential perforations use apertures of Φ To represent, the value is 1 mm.

[0045] Using this dynamic characteristic solution method, the following calculations are performed when using a partition labyrinth seal and a perforated partition labyrinth seal. Figure 2 The bifurcation diagram of the seal-rotor system in the speed range of 1000 r / min to 10000 r / min is shown in FIG. Fig.10 The bifurcation diagram of the seal-rotor system using the diaphragm labyrinth seal shown in FIG. Fig.11 The bifurcation diagram of the seal-rotor system using a perforated diaphragm labyrinth seal is shown. The dynamic characteristics of the seal-rotor system at a specific speed are shown as labeled in the figure.

[0046] pass Fig.10 , Fig.11 The results show that this method for solving dynamic characteristics can solve the circumferential discontinuous seal and circumferential semi-continuous seal in the seal-rotor system dynamics problem. Example

[0047] Fig.12 A seal-rotor bearing system is shown in the figure. The numbers represent the shaft segment numbers. The 4th, 6th, 8th and 10th shaft segments are equivalent to the compressor wheels, and the 12th and 14th shaft segments are equivalent to the turbine wheels. The bearing oil film force acts on the 2nd and 16th shaft segments. This embodiment adopts the Capone oil film force model. The seal excitation force acts on all the above 6 wheels. The seal type is selected Figure 8 The partition labyrinth seal structure shown.

[0048] The dynamic characteristics of the seal-rotor bearing system were calculated using the dynamic characteristics solution method, and the following results were obtained: Fig.13 The bifurcation diagram of the seal-rotor bearing system as the speed changes is shown. The types of dynamic behavior of the system at different speeds are marked in the figure, and the Poincare mapping results when the system is in a partial motion state are shown on the right.

[0049] In the disclosure of this solution, various aspects of the technical solution are described with reference to the accompanying drawings, in which many illustrative embodiments are shown. The embodiments of the technical solution are not necessarily intended to include all aspects of the technical solution. It should be understood that the various concepts and embodiments introduced above, as well as those described in more detail below, can be implemented in any of many ways, because the concepts and embodiments disclosed by the technical solution are not limited to any implementation. In addition, some aspects disclosed by the technical solution can be used alone, or in any appropriate combination with other aspects disclosed by the technical solution.

[0050] Although the technical solution has been disclosed as a preferred embodiment, it is not intended to limit the technical solution. Those with ordinary knowledge in the technical field to which the technical solution belongs can make various changes and modifications without departing from the spirit and scope of the technical solution. Therefore, the protection scope of the technical solution shall be determined by the definition of the claims.

Claims

1. A method for solving the dynamic characteristics of a seal-rotor and seal-rotor bearing system, characterized in that: The dynamic characteristics solution method includes the following steps: S1: Use steady-state or transient computational fluid dynamics methods to solve different speeds ω And the four rotor dynamic coefficients of the sealing structure under the vortex frequency Ω, the four rotor dynamic coefficients are the direct stiffness coefficient K, the cross-coupling stiffness coefficient k , direct damping coefficient C and cross-coupling stiffness coefficient c ; S2: Establish a sealed rotor dynamic coefficient database based on two-dimensional cubic polynomial interpolation; S3: Set the initial speed of the solution and give the initial working conditions of the seal-rotor system and the seal-rotor bearing system; S4: Calculate the instantaneous vortex frequency of the rotor in this state based on the working condition information of the current system, find the rotor dynamics coefficient of the current seal in the rotor dynamics coefficient interpolation database built in S2, and calculate the sealing exciting force on the rotor; S5: Establish dimensionless dynamic models of the seal-rotor system and seal-rotor bearing system to be solved; S6: Substitute the seal exciting force obtained by S4 into the dynamic equations of the seal-rotor system and the seal-rotor bearing system established by S5, use the numerical method to calculate, and judge whether the numerical solution results converge. If not, return to S4; S7: retain the result when the calculation converges, and determine whether the speed at this time is the upper limit of the required speed. If it has not reached the upper limit of the required speed, set the speed to the current speed plus one speed step, and return to S4 to continue the calculation; if it reaches the upper limit of the required speed, it means that the solution of the dynamic characteristics of the seal-rotor system and the seal-rotor bearing system has been completed.

2. The method for solving the dynamic characteristics of the seal-rotor and seal-rotor bearing system according to claim 1, characterized in that: In S2, the four rotor dynamic coefficients calculated in S1 are interpolated using a two-dimensional cubic polynomial interpolation formula to obtain a rotor dynamic coefficient interpolation database within the required speed and vortex frequency range. The two-dimensional cubic polynomial interpolation formula is: In the formula, a , b , c , d , e , f , g , h , i , j is the interpolation equation coefficient, which is obtained by fitting every 4 groups of adjacent dynamic coefficients in the speed-vortex frequency space. P For K, k , C , c Any rotor dynamic coefficient in ; The obtained rotor dynamic coefficient interpolation database is as follows: ω With Ω as independent variables, P is a set of two-dimensional coefficient surfaces for the dependent variable.

3. The method for solving the dynamic characteristics of a seal-rotor and a seal-rotor bearing system according to claim 1, characterized in that: The initial operating condition in S3 is a set of displacements or speeds of the given rotor that are not initially zero.

4. The method for solving the dynamic characteristics of a seal-rotor and a seal-rotor bearing system according to claim 1, characterized in that: The calculation method of the rotor instantaneous vortex frequency in S4 is: In the formula, is the speed of the rotor in the x direction at any time, Y is the displacement of the rotor in the y direction at the same moment; the sealing excitation force on the current rotor is found in the rotor dynamics coefficient interpolation database, that is, the current speed and vortex frequency are used as parameters, and the corresponding values ​​are selected from a series of two-dimensional coefficient surfaces in S2 as the current sealed rotor dynamics coefficients.

5. The method for solving the dynamic characteristics of a seal-rotor and a seal-rotor bearing system according to claim 1, characterized in that: In S5, the rotor centroid is established by using dynamics. O D The dynamic equations between displacement, velocity, acceleration and force in mutually perpendicular directions within the rotor section xoy; The force in the dynamic equation is the weight of the rotor M D g in M D is the mass of the rotor, g is the acceleration due to gravity; the rotor has O G The periodic exciting force caused by the offset r relative to the centroid and , where t is the time parameter; the sealing excitation force brought by the sealing structure to the rotor system F x and F y , calculated from the rotor dynamic coefficient of the seal; The dimensionless dynamic model of the seal-rotor system and the seal-rotor bearing system is obtained by selecting dimensionless displacement and dimensionless time from the dynamic model of the seal-rotor system and the seal-rotor bearing system and performing dimensionless transformation.

6. The method for solving the dynamic characteristics of a seal-rotor and a seal-rotor bearing system according to claim 1, characterized in that: The numerical method in S6 is the fourth-order Runge-Kutta and Newmark-beta numerical iteration method; The method to determine whether the numerical solution results have converged is: calculate whether the relative error of the dimensionless displacement of the rotor before and after the numerical solution is greater than 1e-6, and whether the absolute error is greater than 1e-8. If it is greater than the above values, the numerical solution has not converged. If it is less than the above values, it has reached convergence.

7. The method for solving the dynamic characteristics of a seal-rotor and a seal-rotor bearing system according to claim 1, characterized in that: The result of the calculation convergence is retained in S7, that is, the rotor displacement and speed value calculated in the current state are saved; the upper limit of the speed and the speed step, that is, the maximum value of the speed range to be calculated, and the speed step is the value within the speed range that can divide the difference between the maximum value and the minimum value of the speed range.

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