Gas bearing rotor system and dynamic performance simulation analysis method thereof

Abstract

The invention discloses a gas bearing rotor system and a dynamic performance simulation analysis method thereof.The gas bearing rotor system comprises a shell and a rotor rotatably arranged in the shell, the rotor is rotatably supported in the shell through a dynamic pressure radial bearing, the two ends of the rotor extend outwards from an end cover and the shell respectively, and a driving mechanism is connected to the end of the rotor; the dynamic pressure radial bearing is used for providing radial bearing force for the rotor, a thrust plate is fixedly arranged on the rotor, axial thrust bearings are arranged on the two sides of the thrust plate respectively, and the axial thrust bearings are used for providing axial bearing force for the rotor. Compared with a numerical calculation method, the simulation analysis method has the advantages that a fluid domain and solid domain separation solution and bidirectional coupling method is adopted, the influence of solid structure deformation is fully considered, and the requirements for mathematical calculation and programming ability of designers are reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of dynamic characteristics research of gas bearing rotor systems, and in particular relates to a gas bearing rotor system and a dynamic performance simulation analysis method thereof. Background Art

[0002] As we all know, the simulation calculation of dynamic pressure foil gas bearings has formed a relatively systematic theoretical system, which mostly adopts numerical programming calculation methods. In order to obtain more accurate results, the fluid-solid coupling method is used. The process is generally divided into three steps: ①, build the theoretical models of the shaft and foil respectively, use the deformation theory to calculate the deformation of the foil under loading, perform numerical calculations to obtain the thickness of the air film at each location; ②, establish the air film thickness equation, and use the Reynolds equation for coupling solution to obtain the pressure distribution in the air film; ③, repeat the coupling iteration of processes ① and ② to obtain the air film pressure distribution of the bearing, and analyze the static and dynamic characteristics of the bearing through data processing.

[0003] In the relevant existing technologies, the shortcomings of the numerical calculation method are: the two-dimensional numerical calculation of the radial bearing under polar coordinates assumes that the gas film pressure and the foil deformation are evenly distributed along the axial direction, and does not consider the influence of the end gas leakage on the bearing capacity. During the numerical calculation, the gas lubrication equation established based on the gas motion equation, the gas mass flow continuity equation and the gas state equation ignores the influence of some tiny factors. However, ignoring the influence of these tiny factors will, to a certain extent, cause certain errors in the results of the numerical calculation, and the numerical modeling and solution process is cumbersome, requiring corresponding mathematical calculation and programming capabilities. Summary of the invention

[0004] The purpose of the present invention is to solve the above-mentioned problems existing in the prior art and to provide a method for simulating and analyzing the dynamic performance of a gas bearing rotor system. Compared with the numerical calculation method, this scheme adopts a method of separating and solving the fluid domain and the solid domain and then bidirectionally coupling them, which fully considers the influence of solid structure deformation and reduces the requirements for mathematical calculation and programming capabilities of designers.

[0005] One of the objects of the present invention is to provide a gas bearing rotor system, comprising a housing and a rotor arranged in the housing, wherein the rotor is rotatably supported in the housing by a hydrodynamic radial foil bearing, the two ends of the rotor respectively extend outward from an end cover and the housing, and at least one end of the rotor is connected to a driving mechanism; the hydrodynamic radial bearing is used to provide radial bearing capacity for the rotor, a thrust plate is fixedly provided on the rotor, axial thrust bearings are respectively provided on both sides of the thrust plate, and the axial thrust bearings are used to provide axial bearing capacity for the rotor.

[0006] As a preferred solution, the two ends of the rotor are supported in the housing by a first dynamic pressure radial foil bearing and a second dynamic pressure radial foil bearing, respectively. The first dynamic pressure radial foil bearing and the second dynamic pressure radial foil bearing are located on the same side of the thrust plate, and the first dynamic pressure radial foil bearing and the second dynamic pressure radial foil bearing are respectively installed in first bearing seats close to the two ends of the rotor, and the first bearing seats are fixedly connected to the housing.

[0007] As a preferred embodiment, a gap is formed at the connecting end of the end cover and the shell, and the gap is used to accommodate an axial thrust bearing and a thrust plate. A first dynamic pressure thrust bearing is arranged on the first end face side of the thrust plate, and the first dynamic pressure thrust bearing is fixedly connected to the end cover. A second dynamic pressure thrust bearing is arranged on the second end face side of the thrust plate, and the second dynamic pressure thrust bearing is fixedly connected to the shell.

[0008] As a preferred solution, the shell includes an upper shell and a lower shell, wherein the upper shell and the lower shell are butted together to form a cavity for installing the rotor, and the same end of the upper shell and the lower shell is fixed on the end cover.

[0009] As a preferred embodiment, the first dynamic pressure radial foil bearing and the second dynamic pressure radial foil bearing both include a bearing base, the bearing base has a cavity II for installing a foil assembly, and a slot for installing the foil assembly is axially arranged on the inner wall of the cavity II; the foil assembly includes a corrugated foil assembly located on the outer ring and a flat foil assembly located on the inner ring.

[0010] As a preferred embodiment, the flat foil assembly is surrounded by arc-shaped flat foils to form a cylindrical cavity for installing the rotor, and the wave foil assembly is surrounded by arc-shaped wave foils, and the arc-shaped wave foils are covered on the outer wall of the flat foil assembly. The arc-shaped wave foil is provided with a card plate I that cooperates with the slot, and the arc-shaped flat foil is provided with a card plate II that cooperates with the slot; the arc-shaped flat foil is located on the outer arc surface between the card plates I of two connected arc-shaped wave foils, and the card plates I and II are both correspondingly inserted into the slot.

[0011] As a preferred solution, the first dynamic pressure thrust bearing and the second dynamic pressure thrust bearing both include a bottom support, an intermediate corrugated foil and a top flat foil, and the bottom support, the intermediate corrugated foil and the top flat foil are coaxially arranged and sequentially connected.

[0012] As a preferred embodiment, a chuck is distributed on the end surface of the bottom support, the intermediate corrugated foil comprises an outer ring I and an inner ring I, the outer ring I and the inner ring I are divided into a plurality of sector-shaped areas by a support sheet I, each of the sector-shaped areas is provided with a plurality of corrugated foils distributed radially, one end of the corrugated foil is connected to the support sheet, and the other end is a free end, the top flat foil comprises an outer ring II and an inner ring II, the outer ring II and the inner ring II are divided into a plurality of sector-shaped areas by a support sheet II, each of the sector-shaped areas is provided with a flat foil, one side of the flat foil is connected to the support sheet II, and the other side is a free end, and the flat foil is provided in direct correspondence with the corrugated foil.

[0013] A second object of the present invention is to provide a simulation analysis method for a gas bearing rotor system, comprising the following steps:

[0014] Step 1: Establish an air film model of a dynamic pressure radial foil bearing based on Solidworks, import the established air film model into the Gambit platform, and mesh the fluid area;

[0015] Step 2: Combine the process simulation modules on the Ansys workbench platform;

[0016] Step 3: Import the meshed air film model into the pre-processing software ICEM CFD;

[0017] Step 4: Set the fluid properties, boundary conditions and dynamic mesh parameters in the fluid solver Fluent;

[0018] Step 5: First, set the gas bearing material properties in the solid solver Transient Structural, then mesh the flat foil and corrugated foil structures, and finally set the boundary conditions and solver parameters;

[0019] Step 6. In the System Coupling module, set the simulation time, step size, and number of steps in its settings, and associate the wall-out surface in the fluid solver with the Fluid Solid Interface surface in the solid solver to achieve the transmission of coupling data between the fluid solver and the solid solver.

[0020] Step 7: Calculate the bearing capacity of the gas bearing;

[0021] Step 8: According to the monitoring results, determine whether the set residual convergence value is reached. If not, adjust the solution setting parameters of the fluid, solid and system coupling respectively until the set residual convergence value is reached; finally, output the bearing capacity and dynamic characteristic parameters of the air bearing;

[0022] Step 9: Arrange the bearing capacity and dynamic characteristic parameters of the gas bearing, and draw a trend chart of the bearing capacity and dynamic characteristic parameters changing with the rotation speed;

[0023] Step 10: Compare the simulation data with the experimental data and calculate the error value between the two.

[0024] As a preferred solution, the boundary conditions in step 4 are set as follows:

[0025] (41) Set the display ratio and size, and enable the energy equation;

[0026] (42) In the Material column, set the fluid to ideal gas, then in the Model Viscosity tab, set the parameters to k-epsilon, Realizable, and the wall function to standard wall function with compressible effect;

[0027] (43) In the boundary condition column, set the working pressure of inlet and outlet to 0, the gauge pressure to a standard atmospheric pressure, the wallin to the rotating wall, and the rotor eccentricity, and the speed through the rotor operating parameters;

[0028] (44) For the model with grids drawn in different areas, connect the area interfaces in the grid interface column;

[0029] (45) In the dynamic mesh column, the mesh method uses the layering and mesh reconstruction method. In the dynamic mesh area, set the inlet and outlet to Deform deformation surface, and the wallout to System Coupling system coupling surface;

[0030] (46) In the dynamic mesh column, open the 6DOF module, and in the Fluent user definition column, import the compiled UDF macro program into Fluent. This macro command can limit the six degrees of freedom of spatial motion and capture the motion path, velocity data, and force changes of the journal in each time step. Finally, according to the time series, the velocity and displacement data of the journal in the X and Y directions are stored in the Excel table for subsequent analysis.

[0031] (47) In the Fluent solver, the PISO calculation method is selected and the sub-relaxation factor parameters are set;

[0032] (48) Initialize the air film solution parameters and set the number of initial iterations.

[0033] Beneficial Effects

[0034] First, this solution simplifies the process of solving the dynamic performance parameters of the gas bearing to a certain extent by optimizing the simulation analysis method of the dynamic performance of the gas bearing rotor system, and can simulate the operation of the rotor more realistically. By simulating and analyzing the bearing capacity of the hydrodynamic radial foil bearing and the hydrodynamic thrust bearing, the bearing performance of the gas bearing rotor system is characterized, and the dynamic performance of the hydrodynamic radial and thrust gas bearings is simulated and analyzed, thereby characterizing the dynamic performance of the gas bearing rotor system. The relative error between the simulation analysis method of this solution and the theoretical calculation is within 10%, which effectively verifies the accuracy of this simulation method.

[0035] Secondly, the present invention optimizes the simulation analysis method, and through cooperation with the gas bearing rotor system of a specific structure, the load-bearing and dynamic performance analysis of the hydrodynamic radial foil bearing and the hydrodynamic thrust bearing is carried out on the Ansys simulation platform. The separation solution method is adopted, the solution parameters are set in the fluid domain Fluent and the solid domain Transient structure, and the data is exchanged through the system coupling System Coupling to realize the two-way fluid-solid coupling calculation. The 6DOF program is written to simulate the rotor motion through the dynamic mesh technology, and the macro program is introduced to simulate the steady-state and dynamic characteristics of the gas bearing. This method can use the embedded program in the simulation software to realize the modularization, efficiency and precision of the bearing load and dynamic parameter calculation process.

[0036] Third, the present invention also provides a gas bearing rotor system, including a dynamic pressure radial foil bearing and an axial thrust bearing. The dynamic performance simulation and analysis method of the present invention is combined with the gas bearing rotor system of the above-mentioned specific structure, wherein the simulation of the dynamic pressure radial foil bearing has higher accuracy, and the stable load-bearing capacity of the bearing is proportional to the axial length of the bearing. (In the relevant prior art, the numerical calculation assumes that the air film pressure and the foil deformation are evenly distributed along the axial direction and ignores the influence of the leakage at the end of the bearing. These factors affect the accuracy of the numerical calculation results; the method of using Fluent software to solve the fluid domain alone ignores the influence of the solid structure deformation.) This method uses a method of separating the fluid domain and the solid domain for solution and then bidirectionally coupling, which fully considers the influence of the solid structure deformation; based on the commercial fluid simulation software ANSYS Workbench platform, the calculation model and algorithm are all included in the software, which reduces the requirements for mathematical calculation and programming capabilities of designers. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0038] Figure 1 is a cross-sectional view of a gas bearing rotor system of the present invention;

[0039] Figure 2 An exploded view of the gas bearing rotor system of the present invention;

[0040] Figure 3 This is a diagram of a dynamic pressure radial foil bearing of the present invention;

[0041] Figure 4 This is a flat foil diagram of the dynamic pressure radial foil bearing of the present invention;

[0042] Figure 5 This is a complete flat foil diagram of the dynamic pressure radial foil bearing of the present invention;

[0043] Figure 6 This is a wave foil diagram of the dynamic pressure radial foil bearing of the present invention;

[0044] Figure 7 This is a complete wave foil diagram of the dynamic pressure radial foil bearing of the present invention;

[0045] Figure 8 A diagram of a dynamic pressure radial foil bearing seat of the present invention;

[0046] Fig. 9 A three-dimensional diagram of a dynamic pressure thrust bearing of the present invention from one viewing angle;

[0047] Fig.10 A three-dimensional diagram of the dynamic pressure axial thrust bearing of the present invention from another perspective;

[0048] Fig.11 This is a diagram of the base of the dynamic pressure axial thrust bearing of the present invention;

[0049] Fig.12 This is a wave foil diagram of the dynamic pressure axial thrust bearing of the present invention;

[0050] Fig.13 This is a flat foil diagram of the dynamic pressure axial thrust bearing of the present invention;

[0051] Fig.14 This is a structural diagram of a dynamic pressure axial thrust bearing chuck of the present invention;

[0052] Fig.15 It is a partial cross-sectional view of the dynamic pressure axial thrust bearing of the present invention;

[0053] Fig.16 It is a flow chart of the dynamic characteristic simulation of the present invention;

[0054] Fig.17 This is the mesh division diagram of the five-petal hydrodynamic radial foil bearing: fluid domain;

[0055] Fig.18This is the mesh division diagram of the five-petal hydrodynamic radial foil bearing: solid domain;

[0056] Fig.19 It is the ANSYS simulation combination module diagram;

[0057] Fig. 20 This is the simulation result diagram: deformation cloud diagram of flat foil and corrugated foil;

[0058] Fig.21 This is the simulation result diagram: air film pressure distribution cloud diagram;

[0059] Fig. 22 This is a graph showing the variation of the load-bearing performance of a five-petal pressed radial foil bearing with the speed;

[0060] Fig.23 This is the trend diagram of the dynamic characteristic coefficient of the five-petal dynamic pressure radial foil bearing changing with the speed: stiffness coefficient;

[0061] Fig.24 This is the trend diagram of the dynamic characteristic coefficient of the five-petal dynamic pressure radial foil bearing changing with the speed: damping coefficient;

[0062] Fig.25 This is a comparison chart of the simulation results and test results of the five-petal dynamic pressure radial foil bearing: stiffness coefficient;

[0063] Fig.26 This is a comparison chart of the simulation results and test results of the five-petal dynamic pressure radial foil bearing: damping coefficient;

[0064] Fig. 27 It is the trend diagram of the load-bearing performance of the dynamic pressure axial thrust bearing changing with the speed;

[0065] Fig.28 It is the trend diagram of the dynamic characteristic coefficient of the hydrodynamic axial thrust bearing with the speed: stiffness coefficient;

[0066] Fig.29 It is the trend diagram of the dynamic characteristic coefficient of the hydrodynamic axial thrust bearing changing with the speed: damping coefficient;

[0067] Markings in the figure: 1, turbine Ⅰ, 2, end cover, 3, first dynamic pressure thrust bearing, 31, bottom support, 311, chuck, 312, strip groove, 311, mounting hole Ⅰ, 32, middle corrugated foil, 321, outer ring Ⅰ, 322, inner ring Ⅰ, 323, support sheet Ⅰ, 324, corrugated foil, 325, mounting hole Ⅱ, 33, top flat foil, 331, outer ring Ⅱ, 332, inner ring Ⅱ, 333, support sheet Ⅱ, 334, flat foil, 335, mounting hole Ⅲ, 336, inclined plate , 337, fan-shaped plate, 4, thrust plate, 5, second dynamic pressure thrust bearing, 6, first bearing seat, 7, first dynamic pressure radial foil bearing, 71, bearing base, 72, cavity II, 721, slot, 73, wave foil assembly, 731, arc wave foil, 732, card plate I, 74, flat foil assembly, 741, arc flat foil, 742, card plate II, 8, upper shell, 9, lower shell, 10, rotor, 11, second bearing seat, 12, second dynamic pressure radial foil bearing, 13, turbine II. DETAILED DESCRIPTION

[0068] The present invention is described in detail below by means of exemplary embodiments. However, it should be understood that, without further description, elements, structures and features in one embodiment may also be beneficially combined in other embodiments.

[0069] It should be noted that, unless otherwise defined, the technical terms or scientific terms used herein shall have the usual meanings understood by persons with ordinary skills in the field to which the invention belongs. The words "one", "an" or "the" and the like used in the patent application specification and claims of the present invention do not express quantitative limitations, but indicate the existence of at least one. Words such as "include" or "comprise" indicate that the elements or objects appearing before "include" or "comprises" include the elements or objects listed after "include" or "comprises" and their equivalents, but do not exclude other elements or objects with the same function.

[0070] like Figure 1 , 2 As shown, this embodiment provides a gas bearing rotor system, including an impeller Ⅰ1, an end cover 2, a first dynamic pressure thrust bearing 3, a thrust plate 4, a second dynamic pressure thrust bearing 5, a first bearing seat 6, a first dynamic pressure radial foil bearing 7, an upper shell 8, a lower shell 9, a rotor 10, a second bearing seat 11, a second dynamic pressure radial foil bearing 12 and an impeller Ⅱ13.

[0071] like Figure 1 , 2As shown, the shell is formed by docking an upper shell 8 and a lower shell 9. Specifically, the upper and lower shells 8 and 9 are connected by lifting ears and bolts, and the connecting flange at the end of the shell has a through hole in the circumferential direction. The shell is bolted to the end cover 2 through the connecting flange. The rotor 10 is rotatably arranged inside the cavity I of the shell through two dynamic pressure radial foil bearings. The two ends of the rotor 10 extend outward from the two ends of the shell respectively. The end of the rotor 10 is connected to a driving mechanism. The dynamic pressure radial foil bearing is used to provide radial bearing force for the rotor 10. The dynamic pressure radial foil bearing includes a first dynamic pressure radial foil bearing 7 and a second dynamic pressure radial foil bearing 12. The first dynamic pressure radial foil bearing 7 and the second dynamic pressure radial foil bearing 12 are respectively fixed inside the two first bearing seats 6. The two first bearing seats 6 are arranged opposite to each other, and the two first bearing seats 6 are respectively fixedly connected to the two ends of the shell by bolts. The first end of the rotor 10 sequentially passes through the first dynamic pressure radial foil bearing 7, the second dynamic pressure thrust bearing 5, the thrust plate 4, the first dynamic pressure thrust bearing 3 and the end cover 2 and then extends outward, and a turbine I1 is fixedly arranged on the end of the rotor 10 after the extension, and the second end of the rotor 10 passes through the second dynamic pressure radial foil bearing 12 and then extends outward from the housing, and a turbine II 13 is fixedly arranged on the extended part of the end of the rotor 10. The two ends of the rotor 10 are respectively fixedly connected with the turbine I1 and the turbine II 13 by threading, and the turbine I1 and the turbine II 13 are used to provide driving force for the rotor 10 to realize the rotation of the rotor 10.

[0072] In this solution, the same end of the upper shell 8 and the lower shell 9 is fixed on the end cover 2. A gap is formed between the end cover 2 and one end of the shell, and the gap is used to accommodate the dynamic pressure axial thrust bearing and the thrust plate 4. The first end face side of the thrust plate 4 is provided with a first dynamic pressure thrust bearing 3, and the first dynamic pressure thrust bearing 3 is fixedly installed on the inner end face of the end cover 2 by bolts. The second end face side of the thrust plate 4 is provided with a second dynamic pressure thrust bearing 5, and the second dynamic pressure thrust bearing 5 is fixed on the first bearing seat 6 by bolts, and the thrust plate 4 is provided between the first dynamic pressure thrust bearing 3 and the second dynamic pressure thrust bearing 5, and the thrust plate 4 is fixedly connected to the rotor 10 by interference fit.

[0073] The structure of the dynamic pressure radial foil bearing is described below; taking the first dynamic pressure radial foil bearing 7 as an example, the first dynamic pressure radial foil bearing 7 includes a bearing base 71, and the bearing base 71 has a cavity Ⅱ72 for installing the foil assembly; a plurality of slots 721 are opened on the inner wall of the cavity Ⅱ72 along the circumferential direction; the slots 721 are axial through-slot structures, and the length direction is arranged along the axial direction of the entire cavity Ⅱ72. Preferably, 5 slots 721 are arranged on the inner wall of the cavity Ⅱ72, and the cross-section of each slot 721 is L-shaped. The slots 721 are arranged through along the axial direction of the entire cavity Ⅱ72. The foil assembly includes a corrugated foil assembly 73 and a flat foil assembly 74, wherein the corrugated foil assembly 73 is located on the outer ring, and the flat foil assembly 74 is located on the inner ring. The component 74 is surrounded by an arc-shaped flat foil 741 to form a cylindrical cavity for installing the rotor 10, and the wave foil assembly 73 is surrounded by an arc-shaped wave foil 731. The surface of the arc-shaped wave foil 731 is provided with a plurality of circular protrusions, and the arc-shaped wave foil 731 is divided into five petals along the circumferential direction and overlapped and distributed; the arc-shaped wave foil 731 is covered on the outer wall of the flat foil assembly 74, and a clamping plate I 732 matching with the slot 721 is provided on the arc-shaped flat foil 731, and a clamping plate II 742 matching with the slot 721 is provided on the arc-shaped flat foil 741; the clamping plate I 732 passes through the gap between adjacent arc-shaped wave foils 731 outwardly and is inserted into the slot 721, and the clamping plate II 742 is inserted into the slot 721, and the clamping plate I 732 fits with the clamping plate II 742.

[0074] More specifically, the flat foil assembly 74 is a cylindrical structure surrounded by five arc-shaped flat foils. The arc-shaped flat foil 74 includes a flat foil and a clamping plate Ⅰ732 arranged at one end of the flat foil (the arc-shaped flat foil has the end where the clamping plate Ⅰ732 is arranged as the head end). The clamping plate Ⅰ732 is an L-shaped bending structure. A boss 733 is arranged in the middle section of the flat foil. The boss 733 is arranged along the width direction of the arc-shaped flat foil 74. The head end of the arc-shaped flat foil 74 abuts against the boss 733 on the outer arc surface of the adjacent arc-shaped flat foil 74, and the tail end of the arc-shaped flat foil 74 is fitted on the inner arc surface of another adjacent arc-shaped flat foil 74. There are five arc-shaped wave foils 731, and they are respectively located on the outer arc surface between the card plates I 732 of two adjacent arc-shaped flat foils 74. The arc-shaped wave foil 731 includes a wave foil and a card plate II 742 arranged at one end of the wave foil. The card plate II 742 is an L-shaped bending structure, that is, the card plate I 732 passes through the gap between adjacent arc-shaped wave foils 731 and is inserted into the slot 721. Similarly, the card plate II 742 is inserted into the slot 721. The outer arc surface of the arc-shaped wave foil 731 and the inner wall surface of the cavity II 72 serve as a set of opposing surfaces facing inside and outside. The arc-shaped corrugated foil 731 is arranged on the inner wall surface of the bearing base 71, and the arc-shaped flat foil 741 is arranged on the inner wall surface of the arc-shaped corrugated foil 731. The radial dynamic pressure foil bearing connection method is a slot connection. The arc-shaped corrugated foil 731 and the arc-shaped flat foil 741 are both installed on the inner wall surface of the bearing base 71 through an L-shaped groove at one end, and the other end is a free end extending circumferentially.

[0075] In this solution, the first dynamic pressure thrust bearing 3 and the second dynamic pressure thrust bearing 5 each include a bottom support 31, an intermediate wave foil 32 and a top flat foil 33 which are stacked in three layers in sequence, and a plurality of mounting holes Ⅰ313 are provided on the outer edge of the bottom support 31; a chuck 311 is distributed on the end surface of the bottom support 31; the positions of the chuck 311, the support sheet Ⅰ323 and the support sheet Ⅱ333 correspond to each other, and a strip groove 312 is provided in the space between adjacent chucks 311; the intermediate wave foil 32 includes an outer ring Ⅰ321 and an inner ring Ⅰ322 which are concentrically arranged, wherein the outer ring Ⅰ321 and the inner ring Ⅰ322 are separated into a plurality of fan-shaped notch areas by the support sheet Ⅰ323, and the support sheet Ⅰ323 is arranged corresponding to the position of the chuck 311 and the strip groove 312. A plurality of radially distributed bump foils 324 are provided in each of the fan-shaped slot areas, one end of the bump foil 324 is connected to the support plate 323, and the other end is a free end, and a gap is formed between the free end and the adjacent support plate I323, and the chuck 311 can pass through the gap, a plurality of mounting holes II325 are circumferentially arranged on the outer edge of the middle bump foil 32, and an arc gap is formed between two adjacent bump foils 324 in the same fan-shaped slot area.

[0076] In this solution, the top flat foil 33 includes an outer ring II331 and an inner ring II332 arranged concentrically, the outer ring II331 and the inner ring II332 are divided into a plurality of fan-shaped notch areas by a support sheet II333, a mounting hole III335 is arranged at the edge of the outer ring II331, and a flat foil 334 is arranged in each of the fan-shaped notch areas, one side of the flat foil 334 is connected to the support sheet II333, and the other side is a free end, a gap is formed between the free end of the flat foil 33 and the adjacent support sheet II333, and the chuck 311 can pass through the gap and be exposed outward, and the function of setting the chuck 311 is to realize the relative position fixing of the bottom support 31, the middle wave foil 32 and the top flat foil 33, that is, to prevent the three from rotating relative to each other, and the flat foil 33 is arranged corresponding to the wave foil 324. At the same time, the chuck 311 can stop and limit the top flat foil 33 in the axial direction, thereby limiting the relative position of the three. The flat foil 334 includes an inclined plate 336 and a fan-shaped plate 337, one side of the fan-shaped plate 337 is connected to the support plate II 333 through the inclined plate 336, wherein the outer ring II 331, the inner ring II 332 and the support plate II 333 are in the same plane, while the fan-shaped plate 337 is parallel to the plane and not in the plane, and the inclined plate 336 and the fan-shaped plate 337 form a certain obtuse angle. The middle wave foil 32 corresponds to the fan-shaped notch area of ​​the top flat foil 33, that is, the flat foil 33 and the wave foil 324 are arranged opposite to each other. In this scheme, the mounting hole I 313, the mounting hole II 325 and the mounting hole III 335 are arranged correspondingly and fixed on the end cover 2 or the first bearing seat 6 through a series connection, and the top flat foils 33 of the first dynamic pressure thrust bearing 3 and the second dynamic pressure thrust bearing 5 on both sides are arranged facing the end surface of the thrust plate 4.

[0077] The principle of the gas bearing rotor system of this scheme is as follows: the air supply machine provides power, and when high-pressure gas is supplied into the air wheel Ⅰ1 and the air wheel Ⅱ13, the high-pressure gas will generate impact force on the blades when it flows through the blades, pushing the air wheel Ⅰ1 and the air wheel Ⅱ13 to rotate, thereby driving the rotor 10 to work; when the rotor 10 rotates, it drives the thrust plate 4 to rotate, and the thrust plate 4 and the flat foil of the dynamic pressure thrust bearings 3 and 5 produce relative movement. Due to the existence of the wedge-shaped gap, an air film is formed between the thrust plate 4 and the first dynamic pressure thrust bearing 3 and the second dynamic pressure thrust bearing 5, and a dynamic pressure effect is generated, so that the first dynamic pressure thrust bearing 3 and the second dynamic pressure thrust bearing The thrust bearing 5 generates an axial bearing force to offset the axial load and prevent the rotor 10 from generating end face friction due to large axial offset during operation; since the deadweight of the rotor 10 will generate eccentricity with the first dynamic pressure radial foil bearing 7 and the second dynamic pressure radial foil bearing 12, a convergent gap is formed between the flat foil below the bearing and the contact surface of the rotor 10. When the rotor 10 rotates, the gap generates a dynamic pressure effect, and a pressure difference is generated above and below the contact surface of the rotor 10, so that the first dynamic pressure radial foil bearing 7 and the second dynamic pressure radial foil bearing 12 provide radial bearing force for the rotor 10, thereby realizing radial support for the rotor 10.

[0078] This embodiment provides a method for simulating and analyzing the dynamic performance of a gas bearing rotor system. The bearing capacity of a dynamic pressure radial and thrust gas bearings is simulated and analyzed, thereby characterizing the bearing performance of the gas bearing rotor system. The dynamic performance of a dynamic pressure radial foil bearing and a dynamic pressure axial thrust bearing is simulated and analyzed, thereby characterizing the dynamic performance of the gas bearing rotor system.

[0079] The dynamic performance simulation analysis method of the present invention comprises the following steps:

[0080] S1: A three-dimensional structural model of the dynamic pressure radial foil bearing air film of the gas bearing rotor system was established based on Solidworks.

[0081] S2: Import the established air film model into the meshing software Gambit platform, mesh the fluid area, and name the external surface, internal surface, and pressure inlet and outlet surfaces as wallout, wallin, inlet, and outlet, respectively.

[0082] S3: On the Ansys workbench platform, the process simulation modules are combined, including the Geometry processing module, the ICEM CFD mesh quality inspection module, the Fluent fluid solver module, the TransientStranctural solid solver module and the System Coupling system coupling module.

[0083] S4: Import the meshed air film model into the pre-processing software ICEM CFD and check the mesh quality. A mesh quality of 0.4 or above can obtain better simulation results.

[0084] S5: Set the fluid properties, boundary conditions, and dynamic mesh parameters in the fluid solver Fluent. The settings of each boundary condition are as follows:

[0085] (51) Set the display ratio and size, and enable the energy equation.

[0086] (52) In the Material column, set the fluid to ideal gas, and then in the Model Viscosity tab, set the parameters to k-epsilon, Realizable, and the wall function to standard wall function with compressible effect.

[0087] (53) In the boundary condition column, set the working pressure of the inlet and outlet working conditions to 0, the gauge pressure to a standard atmospheric pressure, the wallin to the rotating wall, and the rotor eccentricity, and set its speed through the rotor operating parameters.

[0088] (54) For the model with partitioned grids, connect the regional interfaces in the grid interface column.

[0089] (55) In the dynamic mesh column, the mesh method uses the layering and mesh reconstruction method. In the dynamic mesh area, set the inlet and outlet to Deform deformation surfaces, and the wallout to System Coupling system coupling surface.

[0090] (56) In the dynamic mesh column, open the 6DOF module, and in the Fluent user definition column, import the compiled UDF macro program into Fluent. This macro command can limit the six degrees of freedom of spatial motion and capture the motion path, velocity data, and force changes of the journal in each time step. Finally, according to the time series, the velocity and displacement data of the journal in the X and Y directions are stored in Excel for subsequent analysis.

[0091] (57) In the Fluent solver, the PISO calculation method is selected and the sub-relaxation factor parameter is set to 0.3.

[0092] (58) Initialize the air film solution parameters and set the number of initial iterations to 200.

[0093] S6: In the solid solver Transient Structural, first set the gas bearing material properties, then mesh the flat foil and corrugated foil structures, and finally set the boundary conditions and solver parameters;

[0094] (61) Setting of foil material: Create the material properties of the foil in the Transient Structural module engineering data, set the density of the foil material to 8250kg / m3, the elastic modulus to 1.99E+11Pa, and the Poisson's ratio to 0.3.

[0095] (62) In the Geometry setting column, first suppress the fluid, and then select the materials of the flat foil and corrugated foil as the materials set in step (61).

[0096] (63) Solid meshing: In mesh, the sweep method is used to sweep the flat foil, the mesh is a tetrahedral mesh, and the sizing method is used to perform regional meshing on the edge line of the flat foil. Then, the corrugated foil is divided according to the regional size by selecting the volume, and finally the solid domain mesh is generated.

[0097] (64) Contact settings: In Transient Structural, set the contact type between the foils and between the foils and the bearing shell to fixed support, and keep the calculation equations as default.

[0098] (65) Add constraints, set the bearing shell as a rigid body, do not perform meshing, and set the connection ends of the flat foil and corrugated foil to the bearing shell as fixed supports.

[0099] (66) Apply a standard atmospheric pressure to the outside of the flat foil.

[0100] (67) Turn off the automatic time step, select sub-step calculation, and set the calculation time.

[0101] (68) Setting the fluid-solid coupling surface: setting the inner side of the flat foil as the fluid-solid coupling surface.

[0102] S7: In the System Coupling module, set the simulation time to 0.0015s, the step size to 0.0001, and the number of steps to 15 in the analysis settings, and associate the wall-out surface in the fluid solver with the Fluid Solid Interface surface in the solid solver to achieve the transmission of coupling data between the fluid solver and the solid solver.

[0103] S8: Calculate and solve the gas bearing capacity.

[0104] S9: According to the monitoring results, determine whether the set residual convergence value is reached. If not, adjust the solution setting parameters of fluid, solid and system coupling respectively until the set residual convergence value is reached. Finally, output the bearing capacity and dynamic characteristic parameters of the air bearing.

[0105] S10: Arrange the bearing capacity and dynamic characteristic parameters of the gas bearing, and draw a trend diagram of the bearing capacity and dynamic characteristic parameters changing with the rotation speed;

[0106] S11: Compare the simulation data with the theoretical calculation data and the experimental data, and calculate the error value between the two to illustrate the feasibility of the simulation method.

[0107] The following is further described by specific examples:

[0108] like Fig.16 The figure shows the simulation flow chart of the dynamic pressure radial foil bearing with a five-petal structure. The eccentricity of the gas bearing is set to 0.8, and the rotor speed is adjusted to simulate the load-bearing capacity.

[0109] S1: The structural parameters of the dynamic pressure radial foil bearing of the gas bearing rotor system used in this scheme are as follows:

[0110] Table 1 Foil bearing structure parameters

[0111]

[0112]

[0113] S2: Based on Solidworks, the air film model of the dynamic pressure radial foil bearing is established, and the established air film is imported into the Gambit platform. The fluid area is meshed, and the external surface, internal surface, and pressure inlet and outlet surfaces are named wallout, wallin, inlet, and outlet, respectively. Fig.17 shown.

[0114] S3: On the Ansys workbench platform, the process simulation module is combined. The simulation module includes the Geometry processing module, the ICEM CFD mesh quality inspection module, the Fluent fluid solver module, the Transient Stranctural solid solver module and the System Coupling system coupling module. Fig.19 shown.

[0115] S4: Import the meshed air film model into the pre-processing software ICEM CFD and check the mesh quality. A mesh quality of 0.4 or above can obtain better simulation results.

[0116] S5: Set the fluid properties, boundary conditions, and dynamic mesh parameters in the fluid solver Fluent. The settings of each boundary condition are as follows:

[0117] (51) Set the display ratio and size, and enable the energy equation.

[0118] (52) In the Material column, set the fluid to ideal gas, and then in the Model Viscosity tab, set the parameters to k-epsilon, Realizable, and the wall function to standard wall function with compressible effect.

[0119] (53) In the boundary condition column, set the working pressure of the inlet and outlet working conditions to 0, the gauge pressure to a standard atmospheric pressure, the wallin to the rotating wall, and the rotor eccentricity to 0.024 mm. Set the speed through the rotor operating parameters.

[0120] (54) For the model with partitioned grids, connect the regional interfaces in the grid interface column.

[0121] (55) In the dynamic mesh column, the mesh method uses the layering and mesh reconstruction method. In the dynamic mesh area, set the inlet and outlet to Deform deformation surfaces, and the wallout to System Coupling system coupling surface.

[0122] (56) In the dynamic mesh column, open the 6DOF module, and in the Fluent user definition column, import the compiled UDF macro program into Fluent. This macro command can limit the six degrees of freedom of spatial motion and capture the motion path, velocity data, and force changes of the journal in each time step. Finally, according to the time series, the velocity and displacement data of the journal in the X and Y directions are stored in Excel for subsequent analysis.

[0123] (57) In the Fluent solver, the PISO calculation method is selected and the sub-relaxation factor parameter is set to 0.3.

[0124] (58) Initialize the air film solution parameters and set the number of initial iterations to 200.

[0125] S6: In the solid solver Transient Structural, first set the gas bearing material properties, then mesh the flat foil component and corrugated foil component structure, and finally set the boundary conditions and solver parameters, such as Fig.18 As shown;

[0126] (61) Setting of foil material: Create the material properties of the foil in the Transient Structural module engineering data, set the density of the foil material to 8250kg / m3, the elastic modulus to 1.99E+11Pa, and the Poisson's ratio to 0.3.

[0127] (62) In the Geometry setting column, first suppress the fluid, and then select the material of the flat foil component and the corrugated foil component as the material set in step (61).

[0128] (63) Solid meshing: In mesh, the sweep method is used to sweep the flat foil component, and the mesh is a tetrahedral mesh. Then the sizing method is used to perform regional meshing on the edge line of the flat foil component. Then, the corrugated foil component is divided according to the regional size by selecting the volume, and finally the solid domain mesh is generated.

[0129] (64) Contact settings: In Transient Structural, set the contact type between the foils and between the foils and the bearing shell to fixed support, and keep the calculation equations as default.

[0130] (65) Add constraints, set the bearing shell as a rigid body, do not perform meshing, set the connection ends of the flat foil assembly and the corrugated foil assembly to the bearing base as fixed supports, and set the outer side of the bearing shell to be connected to the ground.

[0131] (66) Apply a standard atmospheric pressure to the outside of the flat foil assembly (the side where the flat foil assembly and the corrugated foil assembly are in contact).

[0132] (67) Turn off the automatic time step, select sub-step calculation, and set the calculation time to 1s.

[0133] (68) Setting a fluid-solid coupling surface: the inner side of the flat foil assembly (the side where the flat foil assembly contacts the rotor) is set as the fluid-solid coupling surface.

[0134] S7: In the System Coupling module, set the simulation time to 0.0015s, the step size to 0.0001, and the number of steps to 15 in the analysis settings, and associate the wall-out surface in the fluid solver with the Fluid Solid Interface surface in the solid solver to achieve the transmission of coupling data between the fluid solver and the solid solver.

[0135] S8: Calculate and solve the gas bearing capacity.

[0136] S9: According to the monitoring results, determine whether the set residual convergence value is reached. If not, adjust the solution setting parameters of fluid, solid and system coupling respectively until the set residual convergence value is reached. Finally, output the bearing capacity and dynamic characteristic parameters of the air bearing.

[0137] S10: When the journal is subjected to a small disturbance, the journal will deviate a small distance in the static equilibrium position. The ratio of the increment of the air film bearing capacity to the small disturbance distance is called stiffness. In the analysis and calculation, the small offset is decomposed into components along the X and Y directions of the coordinate axis, and the increment of the air film force is also decomposed into components along the X and Y directions. Differential calculations are performed on them respectively to obtain four stiffness coefficients. According to the output parameters, the force and displacement components of the air film in the X and Y directions are processed, and the force and displacement data obtained by simulation are saved in Excel. According to the formula:

[0138]

[0139] Where K xx , K yy is the main stiffness coefficient, K xy , K yx is the cross stiffness coefficient, ΔF dxx , ΔF dxy , ΔF dyy , ΔF dyx is the change of the air film force in the X and Y directions, and Δx and Δy are the decomposition of the displacement change in the X and Y directions.

[0140] The dynamic stiffness coefficient of the gas bearing is solved. The finite difference method is used and a Matlab rolling iterative calculation program is written to solve the initial dynamic stiffness coefficient. After screening the results, the average value is taken to obtain the stiffness coefficient, and then the dynamic performance of the bearing is analyzed.

[0141] S11: When the journal is subjected to a small disturbance, the journal will obtain a small disturbance velocity at the static equilibrium position. The ratio of the increment of the air film damping force to the disturbance velocity is called damping. In the analysis and calculation, the disturbance velocity is decomposed into components along the X and Y directions of the coordinate axis, and the increment of the air film force is also decomposed into components along the X and Y directions. Differential calculations are performed on them respectively to obtain four damping coefficients. According to the output parameters, the force and velocity components of the air film in the X and Y directions are processed, and the force and velocity components obtained by simulation are saved in Excel. According to the formula:

[0142]

[0143] Where C xx , C yy is the main damping coefficient, C xy , C yx is the cross damping coefficient, ΔF vxx , ΔFvxy , ΔF vyy , ΔF vyx is the change value of the air film damping force in the X and Y directions, It is the decomposition of the velocity change value in the X and Y directions.

[0144] The dynamic damping coefficient of the gas bearing is solved. The finite difference method is used and a Matlab rolling iterative calculation program is written to solve the initial dynamic damping coefficient. After screening the results, the average value is taken to obtain the damping coefficient, and then the dynamic performance of the bearing is analyzed.

[0145] S12: Arrange the bearing capacity and dynamic characteristic parameters of the gas bearing, and draw a trend chart of the bearing capacity and dynamic characteristic parameters changing with the speed, such as Fig. 22 , 23 , as shown in 24;

[0146] S13: Compare the simulation data with the experimental data, e.g. Fig.25 , 26 , calculate the relative error value between the two to illustrate the feasibility of the simulation method.

[0147] S14: In this scheme, when the speed of the dynamic pressure radial foil bearing is 40000r / min, the simulation results are compared with the theoretical calculation and test data, and the relative error of the bearing capacity is as follows:

[0148] Table 2 Bearing capacity comparison analysis table (N)

[0149]

[0150] S15: In this scheme, when the speed of the dynamic pressure radial foil bearing is 40000r / min, the simulation results are compared with the theoretical calculation and test data. The relative error of the dynamic characteristic coefficient (positive or negative is only related to the preset direction) is as follows:

[0151] Table 3 Comparative analysis of dynamic characteristic coefficients (10 6 N / m)

[0152]

[0153] In this embodiment, the simulation flow chart of the dynamic pressure axial thrust bearing is as follows: Fig.16 , adjust the rotation speed of rotor 10 to simulate and solve the load-bearing capacity and dynamic characteristic coefficient.

[0154] S1: The structural parameters of the hydrodynamic axial thrust bearing of the gas bearing rotor system proposed in this scheme are as follows:

[0155] Table 4 Foil bearing structure parameters

[0156]

[0157]

[0158] S2: An air film model of a hydrodynamic thrust bearing is established based on Solidworks, and the established air film model is imported into the Gambit platform. The fluid area is meshed, and the external surface, internal surface, and pressure inlet and outlet surfaces are named wallout, wallin, inlet, and outlet, respectively.

[0159] S3: On the Ansys workbench platform, the process simulation modules are combined, including the Geometry processing module, ICEM CFD mesh quality inspection module, Fluent fluid solver module, Transient Stranctural solid solver module and System Coupling system coupling module.

[0160] S4: Import the meshed air film model into the pre-processing software ICEM CFD and check the mesh quality. A mesh quality of 0.4 or above can obtain better simulation results.

[0161] S5: Set the fluid properties, boundary conditions, and dynamic mesh parameters in the fluid solver Fluent. The settings of each boundary condition are as follows:

[0162] (51) Set the display ratio and size, and enable the energy equation.

[0163] (52) In the Material column, set the fluid to ideal gas, and then in the Model Viscosity tab, set the parameters to k-epsilon, Realizable, and the wall function to standard wall function with compressible effect.

[0164] (53) In the boundary condition column, set the working pressure of inlet and outlet to 0, the gauge pressure to a standard atmospheric pressure, the wallin to the rotating wall, and the speed of rotor 10 to the operating parameters.

[0165] (54) For a model with partitioned grids, connect the regional interfaces in the grid interface column.

[0166] (55) In the dynamic mesh column, the mesh method uses the layering and mesh reconstruction method. In the dynamic mesh area, set the inlet and outlet to Deform deformation surfaces, and the wallout to System Coupling system coupling surface.

[0167] (56) In the dynamic mesh column, open the 6DOF module, and in the Fluent user definition column, import the compiled UDF macro program into Fluent. This macro command can limit the six degrees of freedom of spatial motion and capture the motion path, velocity data, and force changes of the journal in each time step. Finally, according to the time series, the velocity and displacement data of the journal in the Z direction and other parameter values ​​are stored in the Excel table for subsequent analysis.

[0168] (57) In the Fluent solver, the PISO calculation method is selected and the sub-relaxation factor parameter is set to 0.3.

[0169] (58) Initialize the air film solution parameters and set the number of initial iterations to 200.

[0170] S6: In the solid solver Transient Structural, first set the gas bearing material properties, then mesh the bottom support, top flat foil, and middle corrugated foil structures, and finally set the boundary conditions and solver parameters;

[0171] (61) Setting of foil material: Create the material properties of the foil in the Transient Structural module engineering data and set the density of the foil material to 8250 kg / m 3 , elastic modulus is 1.99E+11Pa, and Poisson's ratio is 0.3.

[0172] (62) In the Geometry setting column, first suppress the fluid, and then select the materials of the bottom support, top flat foil and middle corrugated foil as the materials set in (61).

[0173] (63) Solid meshing: In the mesh, the sweep method is used to sweep the bottom support and the top flat foil. The mesh is a tetrahedral mesh. The sizing method is then used to perform regional meshing on the bottom support and the top flat foil edge line. Then, the intermediate wave foil is divided according to the regional size by selecting the body, and finally the solid domain mesh is generated.

[0174] (64) Contact settings: In Transient Structural, set the contact type between the foils (top flat foil and middle corrugated foil) and between the foil and the bottom support to fixed support, and keep the calculation equations as default.

[0175] (65) Apply a standard atmospheric pressure to the outside of the top flat foil (the side where the top flat foil contacts the middle corrugated foil).

[0176] (66) Turn off the automatic time step, select sub-step calculation, and set the calculation time to 1s.

[0177] (67) Setting the fluid-solid coupling surface: the inner side of the top flat foil (the contact surface between the top flat foil and the thrust plate) is set as the fluid-solid coupling surface.

[0178] S7: In the System Coupling module, set the simulation time to 0.0015s, the step size to 0.0001, and the number of steps to 15 in the analysis settings, and associate the wallout surface in the fluid solver with the Fluid Solid Interface surface in the solid solver to achieve the transmission of coupling data between the fluid solver and the solid solver.

[0179] S8: Calculate and solve the gas bearing capacity.

[0180] S9: According to the monitoring results, determine whether the set residual convergence value is reached. If not, adjust the solution setting parameters of fluid, solid and system coupling respectively until the set residual convergence value is reached. Finally, output the bearing capacity and dynamic characteristic parameters of the air bearing.

[0181] S10: When the journal is subjected to a small disturbance, the journal will deviate a small distance in the static equilibrium position. The ratio of the increment of the air film bearing capacity to the small disturbance distance is called stiffness. In the analysis and calculation, the small offset is decomposed into components along the Z direction of the coordinate axis, and the increment of the air film force is decomposed into components along the Z direction. Differential calculations are performed on them respectively to obtain the axial stiffness coefficient. According to the output parameters, the component force and displacement of the air film in the Z direction are processed, and the component force and displacement data obtained by simulation are saved in Excel. According to the formula:

[0182]

[0183] Where K zz is the axial stiffness coefficient, ΔF dzz is the change of the air film force in the Z direction, and Δz is the decomposition of the displacement change in the Z direction.

[0184] The dynamic stiffness coefficient of the gas bearing is solved. The finite difference method is used and a Matlab rolling iterative calculation program is written to solve the initial dynamic stiffness coefficient. After screening the results, the average value is taken to obtain the axial stiffness coefficient, and then the dynamic performance of the bearing is analyzed.

[0185] S11: When the journal is subjected to a small disturbance, the journal will obtain a small disturbance velocity at the static equilibrium position. The ratio of the increment of the air film damping force to the disturbance velocity is called damping. In the analysis and calculation, the disturbance velocity is decomposed into components along the Z direction of the coordinate axis, and the increment of the air film force is decomposed into components along the Z direction. The differential calculation is performed on them respectively to obtain the axial damping coefficient. According to the output parameters, the force and velocity components of the air film in the Z direction are processed, and the force and velocity component data obtained by simulation are saved in Excel. According to the formula:

[0186]

[0187] Where C zz is the axial damping coefficient, ΔF vzz is the change of air film damping force in the Z direction, It is the decomposition of the velocity change value in the Z direction.

[0188] The dynamic damping coefficient of the gas bearing is solved. The finite difference method is used and a Matlab rolling iterative calculation program is written to solve the initial dynamic damping coefficient. After screening the results, the average value is taken to obtain the damping coefficient, and then the dynamic performance of the bearing is analyzed.

[0189] S12: Arrange the bearing capacity and dynamic characteristic parameters of the gas bearing, and draw a trend chart of the bearing capacity and dynamic characteristic parameters changing with the speed, such as Fig. 27 , 28 , as shown in Figure 29.

[0190] By comparing the gas bearing data in Tables 2 and 3 above, it can be seen that the commercial simulation software ANSYS Workbench uses a two-way fluid-solid coupling method for simulation, which fully considers the impact of factors such as end leakage and solid domain deformation on bearing performance, reduces the tedious calculation process of numerical simulation, and improves the solution speed. Due to the influence of various factors in the experiment, the relative error between the bearing capacity and dynamic characteristic coefficient of the five-petal dynamic pressure gas bearing and the simulation data is large, while the relative error between the simulation data and the theoretical calculation is within 10%, which verifies the accuracy of this simulation method.

[0191] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A gas bearing rotor system, characterized in that: It includes a shell and a rotor arranged in the shell, the rotor is rotatably supported in the shell by a dynamic pressure radial foil bearing, the two ends of the rotor extend outward from the end cover and the shell respectively, and at least one end of the rotor is connected to a driving mechanism; the dynamic pressure radial bearing is used to provide radial bearing capacity for the rotor, a thrust plate is fixedly arranged on the rotor, and dynamic pressure axial thrust bearings are respectively arranged on both sides of the thrust plate, and the dynamic pressure axial thrust bearings are used to provide axial bearing capacity for the rotor.

2. A gas bearing rotor system according to claim 1, characterized in that: The two ends of the rotor are supported in the housing by a first dynamic pressure radial foil bearing and a second dynamic pressure radial foil bearing, respectively. The first dynamic pressure radial foil bearing and the second dynamic pressure radial foil bearing are located on the same side of the thrust plate, and the first dynamic pressure radial foil bearing and the second dynamic pressure radial foil bearing are respectively installed in first bearing seats close to the two ends of the rotor, and the first bearing seats are fixedly connected to the housing.

3. A gas bearing rotor system according to claim 1, characterized in that: A gap is formed at the connecting end of the end cover and the shell, and the gap is used to accommodate a dynamic pressure axial thrust bearing and a thrust plate. A first dynamic pressure thrust bearing is arranged on the first end face side of the thrust plate, and the first dynamic pressure thrust bearing is fixedly connected to the end cover. A second dynamic pressure thrust bearing is arranged on the second end face side of the thrust plate, and the second dynamic pressure thrust bearing is fixedly connected to the shell.

4. A gas bearing rotor system according to claim 1, characterized in that: The shell comprises an upper shell and a lower shell, wherein the upper shell and the lower shell are butted together to form a cavity I for installing the rotor, and the same end of the upper shell and the lower shell is fixed on the end cover.

5. A gas bearing rotor system according to claim 1, characterized in that: The first dynamic pressure radial foil bearing and the second dynamic pressure radial foil bearing both include a bearing base, the bearing base has a cavity II for installing a foil assembly, and a slot for installing the foil assembly is axially arranged on the inner wall of the cavity II; the foil assembly includes a corrugated foil assembly located on the outer ring and a flat foil assembly located on the inner ring.

6. A gas bearing rotor system according to claim 5, characterized in that: The flat foil assembly is surrounded by arc-shaped flat foils to form a cylindrical cavity for installing the rotor, and the wave foil assembly is surrounded by arc-shaped wave foils. The arc-shaped wave foils are covered on the outer wall of the flat foil assembly, and the arc-shaped wave foils are provided with a card plate I that cooperates with the slot, and the arc-shaped flat foil is provided with a card plate II that cooperates with the slot; the arc-shaped flat foil is located on the outer arc surface between the card plates I of two connected arc-shaped wave foils, and the card plates I and II are correspondingly inserted into the slot.

7. A gas bearing rotor system according to claim 1, characterized in that: The first dynamic pressure thrust bearing and the second dynamic pressure thrust bearing both include a bottom support, an intermediate corrugated foil and a top flat foil, and the bottom support, the intermediate corrugated foil and the top flat foil are coaxially arranged and sequentially connected.

8. A gas bearing rotor system according to claim 7, characterized in that: A chuck is distributed on the end surface of the bottom support, the middle corrugated foil comprises an outer ring I and an inner ring I, the outer ring I and the inner ring I are divided into a plurality of sector-shaped areas by a support sheet I, each of the sector-shaped areas is provided with a plurality of corrugated foils distributed radially, one end of the corrugated foil is connected to the support sheet, and the other end is a free end, the top flat foil comprises an outer ring II and an inner ring II, the outer ring II and the inner ring II are divided into a plurality of sector-shaped areas by a support sheet II, each of the sector-shaped areas is provided with a flat foil, one side of the flat foil is connected to the support sheet II, and the other side is a free end, and the flat foil is provided in direct correspondence with the corrugated foil.

9. A simulation analysis method for a gas bearing rotor system, characterized in that: The steps include: Step 1: Establish an air film model of a dynamic pressure radial foil bearing based on Solidworks, import the established air film model into the Gambit platform, and mesh the fluid area; Step 2: Combine the process simulation modules on the Ansys workbench platform; Step 3: Import the meshed air film model into the pre-processing software ICEM CFD; Step 4: Set the fluid properties, boundary conditions and dynamic mesh parameters in the fluid solver Fluent; Step 5: First, set the gas bearing material properties in the solid solver Transient Structural, then mesh the flat foil and corrugated foil structures, and finally set the boundary conditions and solver parameters; Step 6. In the System Coupling module, set the simulation time, step size, and number of steps in its settings, and associate the wall-out surface in the fluid solver with the Fluid Solid Interface surface in the solid solver to achieve the transmission of coupling data between the fluid solver and the solid solver. Step 7: Calculate the bearing capacity of the gas bearing; Step 8: According to the monitoring results, determine whether the set residual convergence value is reached. If not, adjust the solution setting parameters of the fluid, solid and system coupling respectively until the set residual convergence value is reached; finally, output the bearing capacity and dynamic characteristic parameters of the air bearing; Step 9: Arrange the bearing capacity and dynamic characteristic parameters of the gas bearing, and draw a trend chart of the bearing capacity and dynamic characteristic parameters changing with the rotation speed; Step 10: Compare the simulation data with the experimental data and calculate the error value between the two.

10. The simulation analysis method of the gas bearing rotor system according to claim 9, characterized in that: The boundary conditions of step 4 are set as follows: (41) Set the display ratio and size, and enable the energy equation; (42) In the Material column, set the fluid to ideal gas, then in the Model Viscosity tab, set the parameters to k-epsilon, Realizable, and the wall function to standard wall function with compressible effect; (43) In the Boundary Conditions column, set the working pressure of the inlet and outlet to 0, the gauge pressure to a standard atmospheric pressure, the wallin to the rotating wall, and the rotor eccentricity, and the speed through the rotor operating parameters; (44) For the model with gridded partitions, connect the regional interfaces in the grid interface column; (45) In the dynamic mesh column, the mesh method uses the layering and mesh reconstruction method. In the dynamic mesh area, set the inlet and outlet to Deform deformation surfaces, and the wallout to System Coupling system coupling surface; (46) In the dynamic mesh column, open the 6DOF module, and in the Fluent user definition column, import the compiled UDF macro program into Fluent. This macro command can limit the six degrees of freedom of spatial motion and capture the motion path, velocity data, and force changes of the journal in each time step. Finally, according to the time series, the velocity and displacement data of the journal in the X and Y directions are stored in the Excel table for subsequent analysis. (47) In the Fluent solver, the PISO calculation method is selected and the sub-relaxation factor parameters are set; (48) Initialize the air film solution parameters and set the number of initial iterations.

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