Local porous spiral groove gas thrust bearing and its static performance design method

Abstract

This invention discloses a locally porous helical groove gas thrust bearing and its static performance design method. The bearing includes a thrust disc, a thrust pad, a locally porous throttling device, helical grooves, a sleeve, and an end cap. The thrust pad or thrust disc is machined with pump-in helical grooves. The locally porous throttling device is made of porous material and is positioned in the groove area, platform area, or dam area of ​​the thrust pad, uniformly distributed circumferentially. The method includes: considering the inertial force of fluid flow inside the porous material, establishing a static model of the locally porous helical groove gas thrust bearing, dividing the flow field mesh, and proposing a numerical calculation method; static performance analysis of the locally porous helical groove gas thrust bearing; and static performance design of the locally porous helical groove gas thrust bearing to obtain the design variables corresponding to the maximum load capacity and static stiffness. This invention can increase the load capacity and static stiffness of the bearing at high speeds, eliminate frictional wear during start-up and shutdown, and improve the accuracy of the bearing's static performance design.

Description

Technical Field

[0001] This invention relates to the field of gas bearing technology, specifically to a locally porous helical groove gas thrust bearing and its static performance design method. Background Technology

[0002] Gas thrust bearings provide axial load support and are widely used in precision industries such as ultra-precision machine tools and high-speed rotating machinery due to their advantages of high precision, low friction, and no pollution. For pure hydrostatic gas thrust bearings, the throttling device is the core component, and its throttling characteristics have a significant impact on the bearing's static performance. Compared with traditional throttling devices, locally porous throttling devices exhibit better overall performance in terms of load-bearing capacity and static stiffness. However, pure hydrostatic gas thrust bearings cannot generate a dynamic pressure effect during high-speed operation, especially under centering conditions, thus limiting further improvement in bearing load-bearing capacity and failing to fully utilize available working conditions. On the other hand, although pure dynamic gas thrust bearings exhibit excellent static characteristics at high speeds, friction and wear problems are unavoidable during low-speed operation and start-up / shutdown phases. Therefore, it is necessary to design a new type of hydrostatic gas thrust bearing that can improve performance at high speeds while avoiding friction and wear problems during start-up / shutdown phases.

[0003] Currently, there are two main numerical methods for calculating the static performance of gas thrust bearings: the finite difference method and the finite element method. The finite difference method has the advantages of fast calculation speed and good convergence, but it struggles to handle irregular flow field structures and complex boundary conditions. The finite element method is mainly used to solve the classical Reynolds equations, but it is difficult to adapt to complex bearing models that consider the effects of inertial forces, rarefaction effects, and thermal effects. Therefore, for such hydrostatic and hydrodynamic gas thrust bearings with complex structures, it is necessary to establish a suitable mathematical model and propose accurate numerical calculation and performance design methods. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a locally porous helical groove gas thrust bearing and its static performance design method. The aim is to eliminate frictional wear during start-up and shutdown, while simultaneously improving the bearing's load-bearing capacity and static stiffness under high-speed operating conditions. Furthermore, considering the influence of the inertial force of fluid flow within the porous material, a lubrication model for the locally porous helical groove gas thrust bearing is established, and a static performance design method for this type of bearing is proposed, thereby improving the accuracy of bearing performance design.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A locally porous helical groove gas thrust bearing includes a thrust disc, a thrust bearing pad, a locally porous throttle, a helical groove, a sleeve, and an end cap.

[0006] Furthermore, the working surface of the thrust bearing or thrust plate is machined with several spiral grooves; the spiral grooves extend spirally from the outer circle of the bearing towards the inner circle, forming a pump-in structure, which generates a dynamic pressure effect to pump the lubricating gas from the outer circle of the bearing towards the inner circle.

[0007] Furthermore, the spiral groove is a logarithmic spiral shape, with several spiral grooves evenly distributed along the circumference, and all of them having the same groove parameters; the spiral groove divides the bearing working surface into three regions: the groove area, the platform area, and the dam area.

[0008] Furthermore, the locally porous throttling device is made of porous material and is plunger-shaped.

[0009] Furthermore, the local porous throttling device is mounted on the thrust bearing through a mounting hole, which fits tightly with the mounting hole to prevent lubricating gas from leaking through the outer cylindrical surface.

[0010] Furthermore, the number of the local porous flow regulators is the same as the number of spiral grooves, and their positions can be set in the groove area, platform area or dam area, and they are evenly distributed along the circumference.

[0011] Furthermore, one end face of the local porous throttle is close to the non-working surface of the thrust bearing and serves as an inlet for lubricating gas, and each inlet is connected to the high-pressure gas supply device through an inlet ring groove and an inlet hole; the other end face of the local porous throttle is flush with the working surface of the thrust bearing and serves as an outlet for lubricating gas.

[0012] During the start-up and shutdown phases, the main shaft's weight is borne by the static pressure effect of the local porous throttling device, thus eliminating bearing friction and wear. As the rotational speed increases, the dynamic pressure effect generated by the spiral groove gradually strengthens, and the dynamic pressure effect works in conjunction with the static pressure effect. Under high-speed operating conditions, the external load is mainly borne by the dynamic pressure effect of the spiral groove, thereby significantly improving the bearing's load-bearing capacity and static stiffness.

[0013] A static performance design method for a locally porous helical groove gas thrust bearing, the method for the locally porous helical groove gas thrust bearing, includes the following steps: Step s1: Considering the inertial force of fluid flow inside the porous material, establish a local porous spiral groove gas thrust bearing static model, divide the flow field mesh, propose a numerical calculation method for the bearing static model, solve the gas film pressure distribution, and then obtain the bearing static performance parameters. Step s2: Based on the bearing static model and numerical calculation method established in s1, conduct static performance analysis of the locally porous helical groove gas thrust bearing; Step s3: Based on the analysis results of s2, conduct static performance design of the locally porous helical groove gas thrust bearing to obtain the design variables corresponding to the maximum load capacity and static stiffness.

[0014] Furthermore, s1 is achieved through the following four steps s11-s14: Step s11: Use 3D software to establish a local porous spiral groove gas thrust bearing flow field geometric model, and import the flow field geometric model into 3D mesh generation software; Step s12: Use the three-dimensional mesh generation software to mesh the air film region, groove region and porous region of the bearing flow field, and import the mesh model into ANSYS Fluent software; Step s13: In the ANSYS Fluent software, establish the continuity equation and NS equation for the gas flow in the film gas region: (1) (2) In equations (1) and (2): p It is the air film pressure; ρ τ is the gas density; τ is the viscous stress tensor. It is the velocity vector of the gas in the gas film; u , v and w These are the gases in the gas film along x , y and z The velocity component in the direction; In the ANSYS Fluent software, considering the influence of inertial forces on gas flow in porous regions, the continuity equation and Darcy-Forchheimer equation for gas flow in porous regions are established: (3) (4) In equations (3) and (4): p ′ is the gas pressure in the porous region; κ It is the permeability of porous materials; μ It is the viscosity of the gas; u ′、 v′ , w′ Gas along the porous region x , y and z velocity component in the direction; C I It is the inertial drag coefficient of gas flow in porous regions, which can be expressed as: (5) In formula (5): γ Porosity is the porosity of porous materials; In the ANSYS Fluent software, the equation of state for an ideal gas is: (6) In formula (6): R g It is the universal gas constant; T It is the absolute temperature of the gas; In the ANSYS Fluent software, tangential velocity slip at the interface between the film gas region and the porous region is ignored. The pressure and normal velocity components at the interface satisfy the continuity condition. z= 0) It has the following boundary conditions: (7) Step s14: In the ANSYS Fluent software, set the porous region, the permeability and porosity of the porous material, the inertial drag coefficient of the fluid flowing in the porous region, the fluid properties, the pressure boundary conditions, the rotational boundary conditions, the wall boundary conditions, the numerical calculation method, the convergence accuracy and the number of iterations, solve the equations (1)-(6) simultaneously, consider the boundary conditions (7), and obtain the gas film pressure distribution, thereby obtaining the static performance parameters of the bearing.

[0015] Furthermore, the static performance analysis of the locally porous helical groove gas thrust bearing in step s2 is based on the static model, mesh generation, and numerical calculation method of the locally porous helical groove gas thrust bearing established in s1, and systematically conducts a sensitivity analysis of the bearing's static performance to design variables.

[0016] Furthermore, the static performance design of the locally porous helical groove gas thrust bearing in s3 is based on the sensitivity analysis results of the static performance of the locally porous helical groove gas thrust bearing to the design variables obtained in s2, with the design variables corresponding to the maximum load capacity and static stiffness as the optimal values.

[0017] Furthermore, the bearing static performance includes load capacity, static stiffness, and flow rate; the design variables include rotational speed, film thickness, gas supply pressure, location, length, and permeability of the local porous throttling device, and the helix angle and groove depth ratio of the helical groove.

[0018] The beneficial effects of this invention are: 1. The locally porous spiral groove gas thrust bearing provided by the present invention can not only overcome the unavoidable friction and wear problems of pure hydrodynamic spiral groove thrust bearings during start-up and shutdown and under low-speed conditions; but also exhibits superior static performance compared to pure hydrostatic locally porous throttling thrust bearings under high-speed conditions.

[0019] 2. The static performance design method for locally porous spiral groove gas thrust bearings provided by this invention considers the influence of the inertial force of fluid flow inside the porous material, and establishes a suitable static model and numerical calculation method for locally porous spiral groove gas thrust bearings. This not only provides an effective means for the static performance analysis and design of locally porous spiral groove gas thrust bearings with complex structures, but also greatly improves the accuracy of bearing static performance design.

[0020] 3. This invention can not only systematically conduct sensitivity analysis of the static performance (load capacity, static stiffness and flow rate) of thrust bearings on design variables (speed, film thickness, location, length and permeability of local porous throttling device, helix angle and groove depth ratio of helical groove), but also obtain the design variables corresponding to the maximum load capacity and static stiffness as the optimal values, thereby providing a theoretical basis for the performance design of such bearings. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a locally porous spiral groove gas thrust bearing structure.

[0022] Figure 2 This is a schematic diagram of the working surface structure of the thrust bearing.

[0023] Figure 3 These are the main steps and contents of the bearing static performance design method of the present invention.

[0024] Figure 4 This is a flowchart of the numerical calculation process for the static performance of bearings according to the present invention.

[0025] Figure 5 This refers to the flow field mesh generation and boundary condition setting during the static performance calculation of bearings.

[0026] Figure 6 These are the static performance curves of three types of bearings at a supply air pressure of 0.3 MPa, which vary with design variables: load capacity, static stiffness, and flow rate as a function of rotational speed and supply air pressure.

[0027] Figure 7 These are the static performance curves of three types of bearings at a supply air pressure of 0.5 MPa, which vary with design variables: load capacity, static stiffness, and flow rate as a function of rotational speed and supply air pressure.

[0028] Figure 8 These are the static performance curves of three types of bearings at a supply air pressure of 0.7 MPa, which vary with design variables: load capacity, static stiffness, and flow rate as a function of rotational speed and supply air pressure.

[0029] Figure 9 It shows the curves of the static performance of the bearing in the local porous throttling device as a function of design variables - the curves of the load-bearing capacity and static stiffness as a function of rotational speed.

[0030] Figure 10 The curves showing the variation of bearing static performance with design variables—load capacity, static stiffness, and rotational speed—are for a locally porous throttling device in the slot region.

[0031] Figure 11 It is a curve showing the change of bearing static performance with design variables - the change of bearing capacity and static stiffness with the permeability and film thickness of the local porous throttling device.

[0032] Figure 12 It is a curve showing the change of bearing static performance with design variables - the change of bearing capacity and static stiffness with the length and film thickness of the local porous throttling device.

[0033] Figure 13 These are curves showing the change of bearing static performance with design variables – curves showing the change of bearing capacity and static stiffness with the permeability of the local porous throttling device and the helical angle of the helical groove.

[0034] Figure 14 These are the curves showing the changes in the static performance of the bearing as a function of design variables—the curves showing the changes in load-bearing capacity, static stiffness, and flow rate as a function of the permeability of the local porous throttling device and the ratio of the spiral groove depth.

[0035] Figure 15 This is the detailed content of the geometric and operating parameters of the partially porous spiral groove gas thrust bearing in Table 1.

[0036] Explanation of reference numerals in the attached drawings: 1-thrust plate, 2-thrust bearing, 201-inlet ring groove, 202-partial porous throttling device, 203-spiral groove, 204-platform area, 205-groove area, 206-dam area, 207-mounting hole, 3-sleeve, 4-end cover, 401-inlet hole. Detailed Implementation

[0037] The following will be combined with the appendix Figure 1 and Figure 2 A locally porous spiral groove gas thrust bearing will be described in further detail, but this does not limit the invention to the scope of the embodiments.

[0038] like Figure 1 and Figure 2As shown, this embodiment of a locally porous helical groove gas thrust bearing includes a thrust disc 1, a thrust pad 2, a locally porous throttling device 202, helical grooves 203, a sleeve 3, and an end cap 4. The thrust pad 2 is disposed inside the sleeve 3, and the non-working end face of the thrust pad 2 is tightly fitted with the end cap 4. An air inlet ring groove 201 is provided on the non-working surface of the thrust pad 2, and an air inlet hole 401 is provided inside the end cap 4. Seven helical grooves 203 are machined on the working surface of the thrust disc 1 or the thrust pad 2, which are evenly distributed circumferentially. The helical grooves 203 adopt a pump-in structure, extending spirally from the outer circle of the bearing towards the inner circle, which can generate a dynamic pressure effect to pump lubricating gas from the outer circle of the bearing towards the inner circle. The groove parameters of the seven helical grooves 203 are all the same and are logarithmic spiral lines, which divide the working surface of the bearing into three regions: groove area 205, platform area 204, and dam area 206. The thrust bearing 2 has an internal mounting hole 207. The locally porous throttling device 202 is made of porous material and is plunger-shaped. The locally porous throttling device 202 fits tightly with the mounting hole 207 to prevent lubricating gas leakage from its outer cylindrical surface. The number of locally porous throttling devices 202 is the same as the number of spiral grooves 203, and they are evenly distributed circumferentially. Depending on operational needs, the locally porous throttling devices 202 can be placed in the groove area 205, platform area 204, or dam area 206. One end face of the locally porous throttling device 202 is close to the non-working surface of the thrust bearing 2, serving as the inlet for lubricating gas, and is connected to an external high-pressure gas supply device through the inlet ring groove 201 and inlet hole 401. The other end face of the locally porous throttling device 202 is flush with the working surface of the thrust bearing 2, serving as the outlet for lubricating gas.

[0039] The bearing operates as follows: High-pressure gas from the outside enters through the inlet port 401, flows through the inlet ring groove 201, and finally enters the bearing clearance after being throttled by the local porous throttling device 202. During start-up, shutdown, or low-speed operation, the bearing primarily relies on the external air supply system and the throttling effect of the local porous throttling device 202 to generate a static pressure effect in the bearing clearance, suspending the thrust disc 1 and thus supporting the rotor's weight. This effectively prevents dry friction and wear in the bearing, at which point the static pressure effect is dominant. When the bearing operates at high or ultra-high speeds, the spiral groove 203 generates a strong dynamic pressure effect in the air film to support the external load, again at which point the dynamic pressure effect is dominant. When the bearing operates at medium to low speeds, if the air film pressure generated by the dynamic pressure effect of the spiral groove 203 alone is insufficient to support the entire external load, the static pressure effect can be enhanced by increasing the air supply pressure. This allows for a combined effect of dynamic and static pressure, creating a higher air film pressure to support the external load and ensure the normal operation of the bearing.

[0040] The following will be combined with the appendix Figure 1 , Figures 3 to 11A more detailed description of a static performance design method for a locally porous helical groove gas thrust bearing is provided, but this does not limit the invention to the scope of the embodiments.

[0041] like Figure 3 As shown, the specific content of the static performance design method for a locally porous helical groove gas thrust bearing according to this embodiment is given, which mainly includes the following steps: Step s1: Considering the inertial force of fluid flow inside the porous material, a local porous spiral groove gas thrust bearing static model is established, the flow field mesh is generated, a numerical calculation method for the bearing static model is proposed, the gas film pressure distribution is solved, and thus the bearing static performance parameters are obtained; such as Figure 4 As shown, the above process can be specifically divided into four steps: s11-s14. Step s11: Based on the bearing geometry and dimensional parameters, a local porous spiral groove gas thrust bearing flow field geometric model is established using SolidWorks. The bearing flow field is divided into three regions: the gas film region, the spiral groove region, and the porous region. The flow field geometric model is then imported into the software ANSYS Fluent.

[0042] Step s12: As Figure 5 As shown, in the software ANSYS Fluent, the mesh module is used to mesh the air film region, groove region, and porous region of the bearing flow field. Different meshing methods and the number of mesh layers are required for different regions. For the air film region, the sweep method is used to mesh, and the surface meshing method is used to divide it into 20 layers; for the more complex spiral groove region and porous region, the multizone method is used. Each wall and region is named: the inlet and outlet of the lubricating gas are named in and out, respectively; the porous region is named porous-film; the air film region is named air-film; and the rest are set as walls. A finer mesh is set in critical parts such as the air film region to ensure accurate capture of physical field details; while a coarser mesh can be used in non-critical areas to effectively control the total number of meshes. By combining local refinement with overall coordination, the computational resource consumption can be reasonably controlled while ensuring the calculation accuracy of the critical air film region, achieving an optimal balance between accuracy and efficiency.

[0043] Step s13: Establish as follows Figure 1 Using the Cartesian coordinate system shown, establish the continuity equation and Navier-Stokes equations for gas flow in the film gas region in ANSYS Fluent software: (1) (2) In equations (1) and (2): p It is the air film pressure; ρ τ is the gas density; τ is the viscous stress tensor. It is the velocity vector of the gas in the gas film; u , v and w These are the gases in the gas film along x , y and z The velocity component in the direction.

[0044] In ANSYS Fluent software, considering the influence of inertial forces on gas flow in porous regions, the continuity equation and Darcy-Forchheimer equation for gas flow in porous regions are established: (3) (4) In equations (3) and (4): p ′ is the gas pressure in the porous region; κ It is the permeability of porous materials; μ It is the viscosity of the gas; u ′、 v′ , w′ Gas along the porous region x , y and z velocity component in the direction; C I It is the inertial drag coefficient of gas flow in porous regions, which can be expressed as: (5) In formula (5): γ Porosity is the porosity of porous materials.

[0045] In ANSYS Fluent software, the equation of state for an ideal gas is: (6) In formula (6): R g It is the universal gas constant; T It is the absolute temperature of the gas.

[0046] In ANSYS Fluent software, tangential velocity slip at the interface between the film gas region and the porous region is ignored. The pressure and normal velocity components at the interface satisfy the continuity condition. z= 0) It has the following boundary conditions: (7) Step s14: In ANSYS Fluent software, set the porous zone to Porous Zone; set the viscous resistance coefficient of the porous property parameter to the reciprocal of the permeability, set the porosity value, and set the inertial resistance coefficient value according to the calculation results of equation (5); set the mathematical model to laminar flow model, and the fluid property to ideal gas; set the solver algorithm, set the pressure-velocity coupling mode to simple mode (SIMPLEC), the pressure variable to standard discretization, and the momentum to first-order upwind discretization; set the convergence residual in the Residual Monitors panel, and set the convergence threshold of the continuity equation and the velocity equations (x / y / z-velocity) in the three directions to 10. -6 In the RunCalculation panel, set the Number of Iterations to 1000. Inlet and outlet boundary conditions include pressure inlet, pressure outlet, and periodic boundary conditions; set the inlet and outlet boundary conditions, rotational boundary conditions, and wall functions according to the actual operating conditions of the bearing.

[0047] Using ANSYS Fluent software, equations (1)-(6) are solved simultaneously, and boundary condition (7) is considered to calculate the pressure distribution on the bearing working surface. The bearing capacity is calculated by integrating the gas film pressure on the working surface. (8) In equation (8): W is the bearing capacity; A0 is the working surface area.

[0048] Based on the load-bearing capacity on the working surface, the static stiffness of the bearing is calculated using the center difference method: (9) In equation (9): S is the static stiffness; h It refers to the thickness of the air film.

[0049] Flow rate through all local porous flow regulators: (10) In formula (10): Q It is the flow rate through all the local porous flow regulators, and A1 is the cross-sectional area of ​​the local porous flow regulator.

[0050] Step s2: Static performance analysis of locally porous spiral groove gas thrust bearing: like Figure 12As shown in Table 1, the geometric and operating parameters of the locally porous helical groove gas thrust bearing are listed. When determining the influence of a certain design variable on the static performance of the bearing, all other variables remain constant. Based on the static model, flow field mesh generation, and numerical calculation method of the locally porous helical groove gas thrust bearing established in s1, the influence of design variables such as rotational speed, film thickness, gas supply pressure, position, length, and permeability of the locally porous throttle, and the helix angle and groove depth ratio of the helical groove on the static performance of the bearing is systematically analyzed. The calculation results are shown in Table 1. Figures 6-11 As shown.

[0051] Calculation results show that, within a specific speed range, the load-bearing capacity and static stiffness of the locally porous helical groove gas thrust bearing are superior to those of both pure hydrostatic and pure dynamic pressure porous gas thrust bearings. However, at considerably higher speeds, due to backflow phenomena occurring in the locally porous throttling device, the performance of the locally porous helical groove gas thrust bearing may be inferior to that of the pure dynamic pressure helical groove gas thrust bearing. The optimal installation position of the locally porous throttling device corresponding to the maximum load-bearing capacity and static stiffness is located in the middle or outer region of the thrust bearing 2, depending on the operating speed of the bearing; the optimal helix angle and groove depth ratio are related to the permeability of the locally porous throttling device.

[0052] Step s3: Based on the analysis results of s2, conduct static performance design of the locally porous helical groove gas thrust bearing to obtain the design variables corresponding to the maximum load capacity and static stiffness.

[0053] Based on the calculation results of s2, the following design criteria are derived: For maximum load capacity, the optimal values ​​of the helix angle and groove depth ratio for a locally porous helical groove gas thrust bearing are related to the permeability of the porous throttling device; however, for maximum static stiffness, the optimal values ​​of the helix angle and groove depth ratio are independent of permeability. The optimal values ​​of the helix angle and groove depth ratio corresponding to maximum static stiffness are 15 degrees and 1.5-2.0, respectively.

[0054] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations will be apparent to those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the basic spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A locally porous helical groove gas thrust bearing, characterized in that: It includes a thrust plate (1), a thrust bearing (2), a local porous throttling device (202), a spiral groove (203), a sleeve (3), and an end cap (4); wherein, the working surface of the thrust bearing (2) or the thrust plate (1) is machined with a number of spiral grooves (203); the local porous throttling device (202) is installed on the thrust bearing (2) through a mounting hole (207), and it fits tightly with the mounting hole (207) to prevent lubricating gas from leaking through the outer cylindrical surface.

2. The locally porous helical groove gas thrust bearing according to claim 1, characterized in that: The spiral groove (203) extends spirally from the outer circle of the bearing towards the inner circle, and is a pump-in structure; the spiral groove (203) is a logarithmic spiral line, and several spiral grooves (203) are evenly distributed along the circumference, and their groove parameters are all the same; the spiral groove (203) divides the bearing working surface into three areas: groove area (205), platform area (204) and dam area (206).

3. The locally porous helical groove gas thrust bearing according to claim 1, characterized in that: The local porous throttling device (202) is made of porous material and is plunger-shaped; the number of local porous throttling devices (202) is the same as the number of spiral grooves (203), and their positions can be set in the groove area (205), platform area (204) or dam area (206), and are evenly distributed along the circumference.

4. A method for designing the static performance of a locally porous helical groove gas thrust bearing, characterized in that: It includes the following three steps: Step s1: Considering the inertial force of fluid flow inside the porous material, establish a local porous spiral groove gas thrust bearing static model, divide the flow field mesh, propose a numerical calculation method for the bearing static model, solve the gas film pressure distribution, and then obtain the bearing static performance parameters. Step s2: Based on the bearing static model and numerical calculation method established in s1, conduct static performance analysis of the locally porous helical groove gas thrust bearing; Step s3: Based on the analysis results of s2, conduct static performance design of the locally porous helical groove gas thrust bearing to obtain the design variables corresponding to the maximum load capacity and static stiffness.

5. The static performance design method for a locally porous helical groove gas thrust bearing according to claim 4, characterized in that: The s1 includes the following four steps: Step s11: Based on the bearing geometry and dimensional parameters, a local porous spiral groove gas thrust bearing flow field geometric model is established using SolidWorks. The bearing flow field is divided into three regions: the gas film region, the spiral groove region, and the porous region. The flow field geometric model is then imported into the software ANSYS Fluent. Step s12: In the software ANSYS Fluent, the mesh module is used to mesh the air film region, groove region, and porous region of the bearing flow field. Different meshing methods and the number of mesh layers are required for different regions. For the air film region, the sweep method is used to mesh, and the surface meshing method is used to divide it into 20 layers. For the more complex spiral groove region and porous region, the multizone method is used to mesh. Each wall and region is named: the inlet and outlet of the lubricating gas are named in and out, respectively; the porous region is named porous-film; the air film region is named air-film; and the rest are set as walls. A finer mesh is set in key parts such as the air film region to ensure accurate capture of physical field details; while a coarser mesh can be used in non-critical areas to effectively control the total number of meshes. By combining local refinement with overall coordination, the computational resource consumption can be reasonably controlled while ensuring the calculation accuracy of the key air film region, thus achieving an optimized balance between accuracy and efficiency. Step s13: In ANSYS Fluent software, establish the continuity equation and Navier-Stokes equation for gas flow in the film gas region: (1) (2) In equations (1) and (2): p It is the air film pressure; ρ τ is the gas density; τ is the viscous stress tensor. It is the velocity vector of the gas in the gas film; u , v and w These are the gases in the gas film along x , y and z The velocity component in the direction; In ANSYS Fluent software, considering the influence of inertial forces on gas flow in porous regions, the continuity equation and Darcy-Forchheimer equation for gas flow in porous regions are established: (3) (4) In equations (3) and (4): p ′ is the gas pressure in the porous region; κ It is the permeability of porous materials; μ It is the viscosity of the gas; u ′、 v′ , w′ Gas along the porous region x , y and z velocity component in the direction; C I It is the inertial drag coefficient of gas flow in porous regions, which can be expressed as: (5) In formula (5): γ Porosity is the porosity of porous materials; In ANSYS Fluent software, the equation of state for an ideal gas is: (6) In formula (6): R g It is the universal gas constant; T It is the absolute temperature of the gas. In ANSYS Fluent software, tangential velocity slip at the interface between the film gas region and the porous region is ignored. The pressure and normal velocity components at the interface satisfy the continuity condition. z= 0) It has the following boundary conditions: (7) Step s14: In ANSYS Fluent software, set the porous zone to Porous Zone; set the viscous resistance coefficient of the porous property parameter to the reciprocal of the permeability, set the porosity value, and set the inertial resistance coefficient value according to the calculation results of equation (5); set the mathematical model to laminar flow model, and the fluid property to ideal gas; set the solver algorithm, set the pressure-velocity coupling mode to simple mode (SIMPLEC), the pressure variable to standard discretization, and the momentum to first order upwind discretization; set the convergence residual in the Residual Monitors panel, and set the convergence threshold of the continuity equation and the velocity equations (x / y / z-velocity) in the three directions to 10. -6 In the RunCalculation panel, set the number of iterations to 1000; the inlet and outlet boundary conditions include pressure inlet, pressure outlet, and periodic boundary conditions; set the inlet and outlet boundary conditions, rotational boundary conditions, and wall functions according to the actual operating conditions of the bearing. Using ANSYS Fluent software, equations (1)-(6) are solved simultaneously, and boundary condition (7) is considered to calculate the pressure distribution on the bearing working surface. The bearing capacity is calculated by integrating the gas film pressure on the working surface. (8) In equation (8): W is the bearing capacity; A0 is the working surface area; Based on the load-bearing capacity on the working surface, the static stiffness of the bearing is calculated using the center difference method: (9) In equation (9): S is the static stiffness; h It refers to the thickness of the air film; Flow rate through all local porous flow regulators: (10) In formula (10): Q It is the flow rate through all the local porous flow regulators, and A1 is the cross-sectional area of ​​the local porous flow regulator.

6. The static performance design method for a locally porous helical groove gas thrust bearing according to claim 4, characterized in that: The static performance analysis of the locally porous helical groove gas thrust bearing in step s2 is based on the static model, mesh generation, and numerical calculation method of the locally porous helical groove gas thrust bearing established in s1. It systematically conducts a sensitivity analysis of the bearing's static performance to design variables. The bearing's static performance includes load capacity, static stiffness, and flow rate. The design variables include rotational speed, film thickness, gas supply pressure, the position, length, and permeability of the locally porous throttling device, and the helix angle and groove depth ratio of the helical groove.

7. The static performance design method for a locally porous helical groove gas thrust bearing according to claim 4, characterized in that: The static performance design of the locally porous helical groove gas thrust bearing in s3 is based on the sensitivity analysis results of the static performance of the locally porous helical groove gas thrust bearing to the design variables obtained in s2, with the design variables corresponding to the maximum load capacity and static stiffness as the optimal values.

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