CN-121997655-A - Spiral groove gas film seal steady-state parameter optimization method based on flow field analysis

CN121997655ACN 121997655 ACN121997655 ACN 121997655ACN-121997655-A

Abstract

The invention discloses a steady-state parameter optimization method of a spiral groove gas film seal based on flow field analysis, which comprises the steps of establishing a three-dimensional model of a spiral groove gas film and a sealing ring through three-dimensional modeling software, dividing grids of the three-dimensional model, setting a gas film steady-state parameter calculation formula and a thermal steady-state energy calculation formula in simulation software, carrying out simulation analysis, determining gas film steady-state parameters of the sealing ring, such as gas film opening force, leakage amount, gas film rigidity and rigid-leak ratio, according to simulation results, so as to explore the sealing performance of a sealing assembly and the optimization direction of subsequent parameters, and finally determining the parameters of the sealing ring which is actually processed. According to the invention, through a simulation mode, the redundant workload of the air film sealing experiment can be effectively reduced, the experiment period is greatly shortened, and the high-efficiency and accurate technical support is provided for the design, parameter optimization and subsequent experiment of the spiral groove air film sealing, so that the method has remarkable engineering application value.

Inventors

ZHAI ZHAOYANG
LI XIUWEN
ZHANG DONGYA
ZHANG YANCHAO
DU CHUNHUA

Assignees

西安理工大学

Dates

Publication Date: 20260508
Application Date: 20260122

Claims (10)

1. The steady-state parameter optimization method for the spiral groove gas film seal based on flow field analysis is characterized by comprising the following steps: firstly, establishing a dynamic and static ring and air film three-dimensional model through three-dimensional modeling software, and introducing the model into finite element analysis software to set the boundary condition of an air film after assembly; Step two, importing the result of the step one into grid division software to carry out grid division to obtain a gas film grid model; step three, introducing the air film grid model into flow field simulation software to solve the air film flow field, obtaining the temperature distribution and pressure distribution of the air film, namely air film flow field data, and solving air film steady-state parameters for measuring the sealing performance, including leakage amount, air film opening force, air film rigidity and rigid-drain ratio; Setting boundary conditions of a dynamic ring and a static ring and a coupling surface of the dynamic ring and a gas film in a thermodynamic module of finite element simulation software, sharing gas film flow field data to the corresponding coupling surface, dividing the dynamic ring grid, setting relevant parameters of solid heat transfer, and carrying out thermodynamic calculation to obtain the distribution of a dynamic ring temperature field; setting boundary conditions of a dynamic ring and a static ring and a coupling surface of the dynamic ring and a gas film in a statics module of finite element simulation software, sharing the result of thermodynamic calculation in the fourth step and the gas film flow field data into the statics module until thermal-flow-solid coupling calculation is carried out, and finally analyzing stress strain and deformation of the dynamic ring and the static ring; Step six, post-processing the solved results, namely aiming at the cloud patterns of the gas film pressure generated in the step three and the cloud patterns of the stress strain and the deformation condition of the dynamic and static rings generated in the step four, intercepting the section cloud patterns of different axial interfaces by adjusting the space display view angles of the cloud patterns, and displaying the distribution form and gradient change characteristics of the gas film pressure in different areas of the sealing end face and the change of the deformation and the stress strain of the sealing ring; And step seven, optimizing the spiral groove parameters optimally according to simulation results, analyzing the air film steady state data after simulation convergence, determining the influence rule of the change of the single spiral groove parameters on the air film steady state characteristics, and determining the optimal value range of the parameters.
2. The steady-state parameter optimization method for the spiral groove gas film seal based on flow field analysis according to claim 1, wherein in the second step, the grid division adopts a method of dividing grids in a blocking manner, auxiliary points and auxiliary lines are constructed for a model, and the gas film model is grid-divided.
3. The optimization method of steady-state parameters of the spiral groove gas film seal based on flow field analysis as claimed in claim 1, wherein the calculation formula of the gas film opening force is as follows: Wherein F 0 is an opening force, N, p is the pressure of the air film on a certain point of the sealing end surface, pa, R 0 、R i is the inner diameter and the outer diameter of the end surface, mm, theta is the angle of a solution area, N g represents Zhou Xiangchong complex numbers, and R is a radial coordinate vector under a polar coordinate system, namely the radial distance from a certain point in the sealing end surface of the air film to the sealing center; The calculation formula of the leakage amount is as follows: θ is the angle of the solution area, δ is the film thickness, μm, Q is the leakage, kg.s -1 ;v r is the radial velocity component of the fluid at polar coordinates, m/s; The air film rigidity calculation formula is as follows: Wherein K is the air film rigidity, N.mu.m -1 , delta is the air film thickness, mu.m, F 0 is the opening force, N; The rigid-drain ratio calculation formula is as follows: Wherein, the N.s.kg -1 ·μm -1 is the rigid-drain ratio.
4. The steady-state parameter optimization method for the spiral groove gas film seal based on flow field analysis according to claim 1, wherein in the third step, the fluid calculation method in the flow field simulation software is set to be laminar flow model calculation, and a continuity equation, a momentum equation, an energy equation and a simple ec algorithm are adopted to solve by adjusting the inlet and outlet pressure and the rotation speed.
5. The method for optimizing steady-state parameters of a spiral groove gas film seal based on flow field analysis according to claim 1, wherein in the fourth step, the solid heat transfer related parameters include initial temperature, heat flux, and convective heat transfer coefficient.
6. The steady-state parameter optimization method for the spiral groove gas film seal based on flow field analysis according to claim 1, wherein in the fifth step, a solid conservation equation, a solid area energy transfer equation, a dynamic ring heat conduction equation, a static ring heat conduction equation and a fluid-solid coupling control equation are adopted for calculation of the heat-fluid-solid coupling.
7. The flow field analysis-based steady-state parameter optimization method for the spiral groove gas film seal of claim 6, wherein the solid conservation equation is as follows: Wherein, the Is solid density; Is the cauchy stress tensor; Local acceleration vectors for the solid domain; is the volumetric force vector.
8. The flow field analysis based steady state parameter optimization method of the spiral groove gas film seal according to claim 6, wherein the solid region energy transfer equation is: Wherein the left side of the equation represents convective energy transfer due to solid motion, the right side represents heat flow due to heat conduction and possible heat sources inside the solid, Is the absolute velocity vector of the solid; The sensible enthalpy is the sensible enthalpy of the solid, namely the heat energy carried by the solid in unit mass; is solid heat conductivity coefficient, W/(m.K); is a possible source of heat inside the solid; The mode length is the rate of change of temperature in this direction, which is the temperature gradient.
9. The flow field analysis-based steady-state parameter optimization method for the spiral groove gas film seal, as set forth in claim 6, wherein the moving ring heat conduction equation is as follows: Wherein K sr is the heat conductivity coefficient of the moving ring, W/(m.K), rho r moving ring density, kg/m 3 ;c r moving ring specific heat capacity, J/(kg.K), v sx moving ring speed in x direction, m/s, v sy moving ring speed in y direction, m/s, T r is moving ring temperature, K; The heat conduction equation of the stationary ring is as follows: Wherein K ss is the static ring heat conductivity coefficient, W/(m.K), T s is the static ring temperature, K.
10. The steady-state parameter optimization method for the spiral groove gas film seal based on flow field analysis as claimed in claim 6, wherein the fluid-solid coupling control equation is as follows: Where subscript f is fluid, subscript s is solid, q is heat flow, T is temperature, τ f is fluid force, τ s is solid stress, Z is displacement, n represents the unit normal vector of the fluid-solid interface, which is perpendicular to the fluid-solid interface.

Description

Spiral groove gas film seal steady-state parameter optimization method based on flow field analysis Technical Field The invention belongs to the technical field of gas film seal flow field simulation methods, and particularly relates to a steady-state parameter optimization method for spiral groove gas film seals based on flow field analysis. Background The gas film sealing is a non-contact mechanical sealing technology using gas as a sealing medium, and a stable gas film is formed by the fluid dynamic pressure effect generated by the miniature groove of the sealing end face, so that the gas sealing of the end face of the rotating shaft is realized. The working process of the spiral groove air film seal is divided into three stages along with the change of the rotating speed of equipment, and the core logic is that the dynamic pressure effect generates opening force, and the air film enters a stable state after balancing the closing force. When the device is not started, the pretightening force of the elastic element pushes the stationary ring to be in contact with the movable ring, the sealing end face is tightly attached, and the wear-resistant coating prepared on the end face can play a protective role in a dry contact stage at the moment of starting and stopping. When the shaft drives the movable ring to rotate, the spiral groove on the end face of the movable ring generates a pumping effect, gas is grabbed by the spiral surface of the groove from the low pressure side of the sealing ring and flows to the high pressure side along the spiral direction of the groove, the volume of the gas is compressed when flowing in the groove due to the blocking of the sealing dam in the spiral groove, when the opening force generated by pressure rise is larger than the closing force, the static ring is jacked up, the dynamic ring and the static ring are separated to generate a uniform gas film with the thickness of 1-10 mu m, and the sealing enters a non-contact state at the moment. The sealing ring has become a key component of equipment such as compressors, turbines and the like in the fields of petrochemical industry, energy power and aerospace. The air film sealing experiment needs to frequently replace various parameters, so that the influence rule of different conditions on the sealing performance can be comprehensively explored. The parameters to be adjusted in the experiment cover two main core dimensions, namely, structural parameters of the spiral groove, such as groove depth (5-20 mu m), groove width occupation ratio (30-70%), lead (5-20 mm) and groove angle (30-60 degree progressive test), and operating condition parameters, including air film thickness, medium pressure and rotating speed. And each time a group of parameters are replaced, the test piece is required to be reassembled, the pressure sensor and the torque measuring instrument are calibrated, the stable and consistent experimental working conditions are ensured, and the time for single parameter adjustment and preparation is long. In summary, the processing and testing of the spiral groove air film sealing sleeve has the remarkable challenges that the processing technology is complex, the requirements on the environment are severe, the processing difficulty is high, and the problems of long processing period and high consumable cost exist. And when the spiral groove parameter optimization experiment is carried out on the basis, a large amount of manpower and material resources are required to be input, and the overall consumption is large. Disclosure of Invention The invention aims to provide a steady-state parameter optimization experiment method for a spiral groove gas film seal based on flow field analysis, which solves the problems of large experimental quantity and long period caused by frequent replacement of various parameters in the gas film seal experiment in the prior art by calculating steady-state parameters of the seal spiral groove and guaranteeing the accuracy of the gas film seal, and defines the parameter optimization direction for subsequent experiments and supports the improvement of parameters according to target performance requirements. The technical scheme adopted by the invention is that the steady-state parameter optimization experiment method for the spiral groove gas film seal based on flow field analysis comprises the following steps: step one, a dynamic and static ring and air film three-dimensional model which accords with the actual size is established through three-dimensional modeling software, and the model is assembled. The assembly of the gas film and the dynamic and static rings is introduced into finite element analysis software to set the boundary conditions of the gas film (the dynamic and static ring models in the assembly are suppressed). Step two, importing the air film three-dimensional model file with the boundary condition set in the step one into grid division software to carry out grid division to