Oil-gas separation type suspension damping characteristic simulation analysis method based on liquid-solid-gas three-phase bidirectional coupling

Abstract

The invention discloses an oil-gas separation type suspension damping characteristic simulation analysis method based on liquid-solid-gas three-phase bidirectional coupling, and relates to the field of oil-gas suspension damping characteristic analysis methods. Aiming at the coupling relation among liquid, solid and gas of an oil-gas separation type suspension, interaction, influence and limitation among three physical fields are considered; in suspension liquid-solid-gas coupling simulation analysis, a liquid-solid coupling surface and a gas-solid coupling surface are utilized to realize transmission of force and displacement, the simulation precision of a multi-physics field coupling system is improved, a coupling solution algorithm-Coupled algorithm based on pressure is utilized to realize liquid-solid-gas three-phase bidirectional coupling analysis, the number of iterations is effectively reduced, the convergence speed is increased, and the simulation precision of a multi-physics field coupling system is improved. Robustness of coupling analysis is improved, the relation between the damping force and the speed of the oil-gas separation type suspension is solved based on liquid-solid-gas three-phase bidirectional coupling analysis, and the damping characteristic of the suspension is accurately predicted.

Description

Technical Field

[0001] The invention patent relates to the field of oil-gas suspension damping characteristic analysis methods, and in particular to an oil-gas separation suspension damping characteristic simulation analysis method based on liquid-solid-gas three-phase bidirectional coupling. Background Art

[0002] Hydro-pneumatic suspension is a suspension assembly that uses nitrogen as an elastic medium and oil to transmit pressure. It is a combination of elastic elements and shock absorbers. It is currently used in large-tonnage dump trucks, heavy-duty off-road vehicles or military vehicles. Hydro-pneumatic suspension has variable stiffness characteristics. Due to its good reliability and excellent stiffness and damping characteristics, it can make the vehicle have good ride comfort and handling stability, and can withstand very large loads. Even if the vehicle's driving road conditions and loading conditions are very bad, the use of hydro-pneumatic suspension can significantly mitigate the impact and reduce bumps, thereby improving the driver's working conditions and increasing the average vehicle speed. Hydro-pneumatic suspension is an important part of the vehicle chassis system. Its stiffness and damping characteristics have an important influence on the dynamic performance of the vehicle. Therefore, obtaining its accurate stiffness and damping characteristics is of great significance to the analysis and optimization of vehicle performance.

[0003] During the operation of the oil-gas suspension, the oil, nitrogen and solid parts are all in motion, which is the result of the joint action of multiple physical fields. The physical fields influence and restrict each other. If only the liquid-solid coupling motion between the oil and solid parts is considered to predict the damping characteristics of the suspension, the result cannot truly reflect its physical nature. Therefore, a more accurate analysis method is urgently needed to make up for this defect. Summary of the invention

[0004] The purpose of the present invention is to provide a simulation and analysis method for damping characteristics of oil-gas separation suspension based on liquid-solid-gas three-phase bidirectional coupling, which effectively makes up for the defect that liquid-solid coupling motion analysis cannot truly reflect the damping characteristics of suspension. Aiming at the coupling relationship between liquid, solid and gas of oil-gas separation suspension, the interaction, influence and restriction between the three physical fields are considered, and the liquid-solid coupling surface and gas-solid coupling surface are used in the suspension liquid-solid-gas coupling simulation analysis to realize the transmission of force and displacement, improve the simulation accuracy of the multi-physical field coupling system, and use the pressure-based coupling solution algorithm-Coupled algorithm to realize liquid-solid-gas three-phase bidirectional coupling analysis, effectively reduce the number of iterations, speed up the convergence speed, increase the robustness of the coupling analysis, solve the relationship between the damping force and speed of the oil-gas separation suspension based on the liquid-solid-gas three-phase bidirectional coupling analysis, and accurately predict the damping characteristics of the suspension.

[0005] The technical solution adopted by the present invention is as follows: a simulation analysis method of damping characteristics of oil-gas separation suspension based on liquid-solid-gas three-phase bidirectional coupling, comprising the following steps:

[0006] Step 1: Establish a liquid-solid-gas three-phase coupling analysis model for oil-gas separation suspension: First, import the simplified three-dimensional geometric model of the oil-gas separation suspension into the finite element analysis software, extract the internal fluid area, suppress other geometric bodies, obtain the gas domain, liquid domain and solid domain, and define their material properties, then perform structural mesh division and local refinement on the gas domain, liquid domain and solid domain, and finally set the boundary conditions and dynamic mesh settings for the gas domain, liquid domain and solid domain;

[0007] When setting the boundary conditions of the gas domain, fluid domain, and solid domain, the surface where the gas contacts the solid floating piston is named the gas-solid coupling surface, and the surface where the liquid contacts the solid floating piston is named the liquid-solid coupling surface. Then, in the dynamic mesh settings, it is defined that the motions of the gas-solid coupling surface and the liquid-solid coupling surface during the operation of the suspension are both system coupling motions.

[0008] Step 2: Establish a pressure-based suspension liquid-solid-gas three-phase bidirectional coupling simulation analysis method: First, set up the oil-gas separation suspension liquid-solid-gas three-phase bidirectional coupler, then share the shock absorber fluid domain and solid domain boundary conditions in the coupler, use the coupler to create a data transmission route, and finally select the pressure-based solution method-Coupled algorithm as the bidirectional coupling solution algorithm in the finite element analysis software;

[0009] Using a coupler to create a data transmission route means transferring the liquid-solid coupling solution results obtained during the suspension operation process to the gas through the liquid-solid coupling surface, and transferring the gas-solid coupling solution results to the liquid through the gas-solid coupling surface. Through continuous iteration of data, the bidirectional transmission of force and displacement is completed, and the liquid-solid-gas three-phase bidirectional coupling analysis is realized. The entire iterative process is completed in the coupler.

[0010] Step 3: Analyze the damping characteristics of the oil-gas separation suspension: Use the liquid-solid-gas three-phase bidirectional coupling simulation analysis method based on the Coupled algorithm to simulate and analyze the internal flow fields of the compression stroke and the extension stroke respectively, obtain the flow field velocity distribution and pressure distribution at any time under the set working conditions, and then calculate the relationship between the shock absorber damping force and speed.

[0011] When simulating and analyzing the internal flow field distribution during the compression and extension strokes of the suspension, the force generated by the liquid flow in the suspension oil cavity acts on the floating piston through the damping hole, the one-way valve, and the fluid-solid coupling surface, and then the force is transmitted to the gas in the suspension air chamber through the gas-solid coupling surface. The velocity cloud map and pressure cloud map of the longitudinal section flow field of the damping hole at different speeds are selected, and the relationship between the damping force and speed under the compression stroke and extension stroke is finally obtained through the flow field velocity distribution and pressure distribution.

[0012] The beneficial effects of the present invention are:

[0013] 1. The present invention takes into account the interaction, influence and limitation among the three physical fields of liquid, solid and gas during the operation of the oil-gas separation suspension, and utilizes the liquid-solid coupling surface and the gas-solid coupling surface in the suspension liquid-solid-gas coupling simulation analysis to realize the transmission of force and displacement, thereby improving the prediction accuracy of the suspension damping characteristics.

[0014] 2. The method proposed in the present invention adopts a coupling solution algorithm to transfer the liquid-solid coupling solution results obtained during the suspension operation process to the gas through the liquid-solid coupling surface, and the gas-solid coupling solution results are transferred to the liquid through the gas-solid coupling surface, completing the two-way transmission of force and displacement, realizing liquid-solid-gas three-phase two-way coupling analysis, and through continuous iteration of data, improving the simulation accuracy of multi-physical field coupling system simulation analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of a method for simulating and analyzing damping characteristics of an oil-gas separation suspension based on liquid-solid-gas three-phase bidirectional coupling according to an embodiment of the present invention;

[0016] Figure 2 Schematic diagram of liquid-solid-gas three-phase bidirectional coupling and schematic diagram of coupling analysis principle of an embodiment of the present invention;

[0017] Figure 3 is a schematic diagram of a three-dimensional geometric model of an oil-gas separation suspension according to an embodiment of the present invention;

[0018] Figure 4 It is a schematic diagram of a mesh model of a liquid domain and a gas domain of an oil-gas separation suspension according to an embodiment of the present invention;

[0019] Figure 5 is a schematic diagram of a solid domain mesh model of an oil-gas separation suspension according to an embodiment of the present invention;

[0020] Figure 6 Schematic diagram of setting solid domain boundary conditions of an oil-gas separation suspension according to an embodiment of the present invention;

[0021] Figure 7 1 is a schematic diagram of a setting flow of a liquid-solid-gas three-phase coupling analysis coupler according to an embodiment of the present invention;

[0022] Figure 8 is a velocity distribution cloud diagram of the compression stroke of the oil-gas separation suspension according to an embodiment of the present invention;

[0023] Fig. 9 is a pressure distribution cloud diagram of the compression stroke of the oil-gas separation suspension according to an embodiment of the present invention;

[0024] Fig.10 is a velocity distribution cloud diagram of the stretching stroke of the oil-gas separation suspension according to an embodiment of the present invention;

[0025] Fig.11is a pressure distribution cloud diagram of the stretching stroke of the oil-gas separation suspension according to an embodiment of the present invention;

[0026] Fig.12 It is a schematic diagram of the suspension damping characteristic curve. DETAILED DESCRIPTION

[0027] The present invention will be described in full below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] A simulation analysis method for damping characteristics of an oil-gas separation suspension based on liquid-solid-gas three-phase bidirectional coupling includes the following steps:

[0029] Step 1: Establish a liquid-solid-gas three-phase coupling analysis model for oil-gas separation suspension: First, import the simplified three-dimensional geometric model of the oil-gas separation suspension into the finite element analysis software, extract the internal fluid area, suppress other geometric bodies, obtain the gas domain, liquid domain and solid domain, and define their material properties, then perform structural mesh division and local refinement on the gas domain, liquid domain and solid domain, and finally set the boundary conditions and dynamic mesh settings for the gas domain, liquid domain and solid domain;

[0030] When setting the boundary conditions of the gas domain, fluid domain, and solid domain, the surface where the gas contacts the solid floating piston is named the gas-solid coupling surface, and the surface where the liquid contacts the solid floating piston is named the liquid-solid coupling surface. Then, in the dynamic mesh settings, it is defined that the motions of the gas-solid coupling surface and the liquid-solid coupling surface during the operation of the suspension are both system coupling motions.

[0031] Step 2: Establish a pressure-based suspension liquid-solid-gas three-phase bidirectional coupling simulation analysis method: First, set up the oil-gas separation suspension liquid-solid-gas three-phase bidirectional coupler, then share the shock absorber fluid domain and solid domain boundary conditions in the coupler, use the coupler to create a data transmission route, and finally select the pressure-based solution method-Coupled algorithm as the bidirectional coupling solution algorithm in the finite element analysis software;

[0032] Using a coupler to create a data transmission route means transferring the liquid-solid coupling solution results obtained during the suspension operation process to the gas through the liquid-solid coupling surface, and transferring the gas-solid coupling solution results to the liquid through the gas-solid coupling surface. Through continuous iteration of data, the bidirectional transmission of force and displacement is completed, and the liquid-solid-gas three-phase bidirectional coupling analysis is realized. The entire iterative process is completed in the coupler.

[0033] Step 3: Analyze the damping characteristics of the oil-gas separation suspension: Use the liquid-solid-gas three-phase bidirectional coupling simulation analysis method based on the Coupled algorithm to simulate and analyze the internal flow fields of the compression stroke and the extension stroke respectively, obtain the flow field velocity distribution and pressure distribution at any time under the set working conditions, and then calculate the relationship between the shock absorber damping force and speed.

[0034] When simulating and analyzing the internal flow field distribution of the suspension compression stroke and extension stroke, the force generated by the liquid flow in the suspension oil cavity acts on the floating piston through the damping hole, the one-way valve, and the fluid-solid coupling surface, and then the force is transmitted to the gas in the suspension air chamber through the gas-solid coupling surface. The velocity cloud map and pressure cloud map of the longitudinal section flow field of the damping hole at different speeds are selected, and the relationship between the damping force and the speed under the compression stroke and the extension stroke is finally obtained through the flow field velocity distribution and pressure distribution.

[0035] For the analysis process in step 3, the following theories and formulas are specifically applied:

[0036] 1. Liquid-solid coupling analysis

[0037] There is liquid-solid coupling between the oil in the liquid cavity of the oil-gas suspension and its internal floating piston, which essentially involves the analysis of both solid and liquid. By calculating the characteristics of liquid and solid structures at the same time, liquid-solid coupling analysis can significantly reduce the time and cost required for analysis, making the results closer to actual physical laws. The basic theory of liquid-solid coupling needs to start from two branches of mechanics.

[0038] (1) Fluid mechanics equations

[0039] As a type of fluid, the flow of liquid must obey the laws of physical conservation, including the law of conservation of mass, the law of conservation of momentum, and the law of conservation of energy.

[0040] The mass conservation equation is:

[0041]

[0042] The momentum conservation equation is:

[0043]

[0044] Where t is time, ρ f is the fluid density, v is the fluid velocity vector, f f is the body force vector, τ f is the transverse stress tensor, τ f It can be expressed as:

[0045]

[0046] Where p is the fluid pressure, μ is the dynamic viscosity of the fluid, and e is the velocity stress tensor. e can be calculated using the formula

[0047] It is expressed as:

[0048]

[0049] The energy conservation equation is:

[0050]

[0051] In the formula, h tot is the sum of enthalpy in thermodynamics, λ is the energy transfer parameter, S E It is a function of energy.

[0052] (2) Mechanical equations

[0053] The mechanical equations can be derived from Newton's second law:

[0054]

[0055] In the formula, ρ s is the density of the solid, d s ″ is the Cauchy stress tensor, σ s is the body force vector, f s ″ is the local acceleration vector of the solid domain, and the thermal deformation term caused by temperature is

[0056]

[0057] In the formula, α T is the coefficient of thermal expansion of the liquid in thermodynamics.

[0058] (3) Liquid-solid coupling theory

[0059] The conservation principle of fluid-solid coupling must be followed at the liquid-solid coupling interface, that is, the conservation relationship between the fluid and the solid, such as stress, displacement, heat flow and temperature, should satisfy the following four equations:

[0060] τ f ·n f =τ s ·n s

[0061] d f =d s

[0062] q f =q s

[0063] T f =T s (8)

[0064] Where τ is stress, d is displacement, q is heat flow, T is temperature, scalars with subscript f represent fluid properties, and variables with subscript s represent solid properties.

[0065] 2. Gas-Solid Coupling Analysis

[0066] The interaction between the gas in the air cavity of the oil-gas suspension and its internal floating piston belongs to the gas-solid coupling problem. When analyzing and processing the gas-solid coupling problem, in order to reduce the complexity of the analysis model, the following assumptions are usually made about the gas:

[0067] ① Assume that the gas is an ideal gas. Since the research focus is on the interaction between gas and solid, the interaction between molecules inside the gas is considered to be negligible. Therefore, the gas in the container can be simplified as an ideal gas for treatment.

[0068] ② Assume that the gas is compressible. The compressibility of a gas refers to the degree of change in unit volume under a certain pressure, which is expressed by the elastic modulus E and is defined as the ratio of the pressure change to the relative change in unit mass of gas volume, that is,

[0069]

[0070] Among them, dV is the change in volume per unit mass of gas, and dp is the change in pressure of gas.

[0071] The volume of the air cavity changes under the action of the floating piston, so the gas is regarded as compressible gas.

[0072] ③ Assume that the gas movement is an unsteady flow. In general, the motion characteristics of a particle include its velocity, pressure and density in all directions. If the derivatives of these parameters with respect to time are not zero, then this type of flow is called an unsteady flow. Considering that the movement of the gas in the air cavity is affected by a floating piston, causing the volume of the air cavity to change continuously, and thus causing the velocity, pressure and density of the gas in the cavity to change accordingly, we can classify the movement of the gas in a closed cavity as an unsteady flow.

[0073] Based on the above assumptions, the continuity equation and momentum equation of the gas in the air cavity can be written as

[0074] Continuity equation:

[0075]

[0076] Momentum equation:

[0077]

[0078] Based on the basic assumption of gas, ignoring the gas's own gravity, the momentum equation is simplified as follows:

[0079]

[0080] where u, v, and w represent the fluid velocity components in the x, y, and z directions, respectively.

[0081] 3. Liquid-solid-gas coupling analysis

[0082] During the compression and extension process of the oil-gas suspension, the analysis that considers the changes of the internal liquid, gas and solid at the same time is called liquid-solid-gas coupling analysis. Liquid-solid-gas multi-field coupling refers to the combination of liquid-solid coupling and gas-solid coupling. The specific process is: the pressure of the liquid transmits force and displacement to the solid through the liquid-solid coupling surface, and the solid receives force and displacement and transmits it to the gas through the gas-solid coupling surface, thereby changing the gas pressure. Figure 2 As shown. Liquid and gas can indirectly conduct force and transfer displacement through movable and deformable solids. The interaction between liquid, gas and solid constitutes liquid-solid-gas three-phase coupling.

[0083] Bidirectional fluid-solid coupling analysis means that data exchange is bidirectional, that is, the results of fluid analysis are transmitted to solid structure analysis, and the results of solid structure analysis are transmitted back to fluid analysis. This type of analysis is mostly used in situations where the density ratio of fluid and solid medium is not much different or under high speed and high pressure, the solid deformation is very obvious and its effect on fluid flow is significant. The liquid-solid-gas three-phase coupling of the oil-gas suspension proposed in the present invention refers to the combination of liquid-solid coupling and gas-solid coupling. The specific working principle is as follows Figure 3 shown.

[0084] 4. Solution of damping characteristics of oil-gas suspension based on coupling analysis

[0085] Through the multi-field coupling simulation of the oil-gas suspension, the flow field velocity and pressure distribution at any time under specific working conditions can be obtained, and the pressure value at any time in the rod cavity and the rodless cavity can be obtained, so as to calculate the damping force. Assuming that the lubrication between the oil-gas suspension cylinder and the piston rod is good, the external output force F can be calculated by the following formula:

[0086] F=P1A1-P2A2 (17)

[0087] Among them, P1 and P2 are the pressures of the rodless cavity and the rod cavity respectively, and A1 and A2 are the cross-sectional areas of the rodless cavity and the rod cavity respectively. The pressure difference between the upper cavity and the lower cavity is:

[0088] ΔP=P1-P2 (18) Therefore, the external output force F can be deduced as:

[0089] F=P1(A1-A2)+(P1-P2)A2=P1(A1-A2)+ΔP·A2 (19)

[0090] Embodiment 1:

[0091] The specific application experiment example execution process of obtaining relevant data by using the technical solution of the present invention is as follows:

[0092] (1) Establish a liquid-solid-gas three-phase coupling analysis model for oil-gas separation suspension.

[0093] The basic parameters used in the oil-gas separation suspension coupling simulation analysis model in this embodiment are shown in Table 1:

[0094] Table 1: Basic parameters of the oil-gas separation suspension coupling simulation analysis model

[0095]

[0096]

[0097] The three-dimensional geometric model of the oil-gas separation suspension is imported into the finite element analysis software, the internal fluid area is extracted, other geometric bodies are suppressed, the gas domain, liquid domain and solid domain are obtained, and their material properties are defined. Then, the gas domain, liquid domain and solid domain are structurally meshed and locally refined. Finally, the boundary conditions of the gas domain, liquid domain and solid domain and the dynamic mesh setting are performed.

[0098] The mesh division of the gas domain, liquid domain and solid domain of the three-dimensional geometric model of the oil-gas separation suspension adopts a global 2mm tetrahedral mesh and performs local refinement, such as Figure 4 and Figure 5 After the meshing is completed, the continuity, repeatability, normal direction and other contents related to the unit quality of the mesh unit should be checked to determine the rationality of the meshing. The evaluation parameters of the meshing quality mainly include skewness, aspect ratio, orthogonal quality, Jacob ratio, etc.

[0099] The gas domain and liquid domain boundary condition settings include solver type settings, turbulence type settings and dynamic mesh model settings. The solver type setting uses Fluent in the finite element analysis software as the target solver, selects the pressure-based solver, sets the velocity format to absolute, and the time to transient. The turbulence model setting selects the Realizable k-ε turbulence model in Fluent, and selects the standard wall function to simulate and analyze the internal flow field of the oil-gas suspension. The dynamic mesh model setting uses spring smoothing and mesh reconstruction to update the moving boundary. The dynamic mesh motion is defined using the UDF macro provided by Fluent. The motion explored is within 0-0.1S, and the moving wall velocity is a uniformly accelerated motion of 0-1m / s.

[0100] The solid domain boundary condition setting uses Mechanical in the finite element analysis software as the target solver. Because the floating piston is passively moved by the liquid and gas pressure, it is necessary to add a remote displacement, set the Y component to free, and set the other components to 0. At the same time, set the liquid-solid coupling surface and the gas-solid coupling surface, such as Figure 6 shown.

[0101] (2) Establish a pressure-based suspension liquid-solid-gas three-phase bidirectional coupling simulation analysis method

[0102] The liquid-solid-gas three-phase bidirectional coupling simulation analysis method for the oil-gas separation suspension described in this embodiment first shares the liquid domain and gas domain models set in Fluent and the solid domain model set in Mechanical to the system coupling solver, such as Figure 7 As shown, data transmission is then created in the coupler between the gas-solid coupling surface in the gas domain, the liquid-solid coupling surface in the liquid domain, and the gas-solid coupling surface and liquid-solid coupling surface in the solid domain to complete the bidirectional transmission of force and displacement. Finally, the suspension liquid-solid-gas three-phase bidirectional coupling simulation analysis software is set up in the coupling solver.

[0103] The suspension liquid-solid-gas three-phase bidirectional coupling simulation analysis software setting in the coupling solver refers to the setting of the solution method, and the specific settings are shown in Table 2:

[0104] Table 2: Liquid-solid-gas three-phase two-way coupling simulation analysis software settings

[0105]

[0106] (3) Analysis of damping characteristics of oil-gas separation suspension

[0107] The analysis of the damping characteristics of the oil-gas separation suspension described in this embodiment utilizes a liquid-solid-gas three-phase bidirectional coupling simulation analysis method based on the Coupled algorithm to perform internal flow field simulations of the compression stroke and the tension stroke respectively, to obtain the flow field velocity distribution and pressure distribution at any time under a certain working condition, and then complete the calculation of the relationship between the suspension damping force and the speed.

[0108] The internal flow field simulation of the compression stroke is to perform liquid-solid coupling solution and gas-solid coupling solution simultaneously in the coupling solver, and transfer the respective solution results to each other as conditions, that is, the result obtained by the liquid-solid coupling solution is transferred to the gas through the fluid-solid coupling surface, and the result obtained by the gas-solid coupling solution is also transferred to the liquid through the gas-solid coupling surface, completing the two-way transmission of simulation data, and finally realizing the liquid-solid-gas coupling simulation of the internal flow field through continuous iterative calculation. The internal flow field simulation of the stretching stroke is exactly the same as the internal flow field simulation process of the compression stroke.

[0109] The flow field distribution and pressure distribution at any time during the compression stroke described in this embodiment are as follows: Figure 8-11 As shown, Figure 8 The figure shows the fluid velocity distribution of the internal flow field when the piston movement speed during the compression stroke is 0.25m / s, 0.5m / s, 0.75m / s, and 1m / s. Fig. 9 The figure shows the pressure distribution of the internal flow field when the piston moves at 0.25m / s, 0.5m / s, 0.75m / s, and 1m / s during the compression stroke. Fig.10 The figure shows the fluid velocity distribution of the internal flow field when the piston movement speed during the stretching stroke is 0.25m / s, 0.5m / s, 0.75m / s, and 1m / s. Fig.11 Shown is the pressure distribution of the internal flow field when the piston movement speed during the stretching stroke is 0.25m / s, 0.5m / s, 0.75m / s, and 1m / s.

[0110] The calculation method of the relationship between the suspension damping force and the speed is as follows: in the simulation analysis result module, according to the flow velocity and pressure distribution of the internal flow field in the compression stroke and the extension stroke, a plane is established in the center of the gas domain, the upper chamber oil, and the lower chamber oil, and the average pressure and time relationship curve in any period of time is obtained on the plane, and then the corresponding relationship between the average pressure of the fluid and the piston movement speed is finally obtained by combining the piston movement speed and time relationship curve. On this basis, the relationship between the suspension damping force and the piston movement speed can be calculated using formulas (17), (18), and (19) (as shown in Table 3), and a fifth-order polynomial fitting is performed using a Gaussian function to obtain the suspension damping characteristic curve, as shown in Fig.12 shown.

[0111] Table 3 Relationship between suspension damping force and piston movement speed

[0112]

[0113] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and the embodiments. It can be fully applied to various fields suitable for the present invention, and for those familiar with the art, additional modifications can be easily realized. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to the specific details and the illustrations shown and described here.

Claims

1. A simulation analysis method for damping characteristics of oil-gas separation suspension based on liquid-solid-gas three-phase bidirectional coupling, characterized in that: The steps include: Step 1: Establish a liquid-solid-gas three-phase coupling analysis model for oil-gas separation suspension: First, import the simplified three-dimensional geometric model of the oil-gas separation suspension into the finite element analysis software, extract the internal fluid area, suppress other geometric bodies, obtain the gas domain, liquid domain and solid domain, and define their material properties, then perform structural mesh division and local refinement on the gas domain, liquid domain and solid domain, and finally set the boundary conditions and dynamic mesh settings for the gas domain, liquid domain and solid domain; Step 2: Establish a pressure-based suspension liquid-solid-gas three-phase bidirectional coupling simulation analysis method: First, set up the oil-gas separation suspension liquid-solid-gas three-phase bidirectional coupler, then share the shock absorber fluid domain and solid domain boundary conditions in the coupler, use the coupler to create a data transmission route, and finally select the pressure-based solution method-Coupled algorithm as the bidirectional coupling solution algorithm in the finite element analysis software; Step 3: Analyze the damping characteristics of the oil-gas separation suspension: Use the liquid-solid-gas three-phase bidirectional coupling simulation analysis method based on the Coupled algorithm to simulate and analyze the internal flow fields of the compression stroke and the extension stroke respectively, obtain the flow field velocity distribution and pressure distribution at any time under the set working conditions, and then calculate the relationship between the shock absorber damping force and speed.

2. The simulation analysis method of damping characteristics of oil-gas separation suspension based on liquid-solid-gas three-phase bidirectional coupling according to claim 1 is characterized by: In the step 1, when setting the boundary conditions of the gas domain, fluid domain and solid domain, the surface where the gas contacts the solid floating piston is named the gas-solid coupling surface, and the surface where the liquid contacts the solid floating piston is named the liquid-solid coupling surface. Then, in the dynamic mesh setting, it is defined that the movements of the gas-solid coupling surface and the liquid-solid coupling surface during the operation of the suspension are both system coupling movements.

3. The simulation analysis method of damping characteristics of oil-gas separation suspension based on liquid-solid-gas three-phase bidirectional coupling according to claim 1 is characterized in that: In the step 2, using a coupler to create a data transmission route means transferring the liquid-solid coupling solution results obtained during the suspension operation process to the gas through the liquid-solid coupling surface, and transferring the gas-solid coupling solution results to the liquid through the gas-solid coupling surface. Through continuous iteration of data, the bidirectional transmission of force and displacement is completed, and the liquid-solid-gas three-phase bidirectional coupling analysis is realized. The entire iterative process is completed in the coupler.

4. The simulation analysis method of damping characteristics of oil-gas separation suspension based on liquid-solid-gas three-phase bidirectional coupling according to claim 1 is characterized in that: In the step three, when simulating and analyzing the internal flow field distribution during the compression stroke and extension stroke of the suspension, the force generated by the liquid flow in the suspension oil cavity acts on the floating piston through the damping hole, the one-way valve, and the fluid-solid coupling surface, and then the force is transmitted to the gas in the suspension air chamber through the gas-solid coupling surface. The velocity cloud map and pressure cloud map of the longitudinal section flow field of the damping hole at different speeds are selected, and the relationship between the damping force and the speed under the compression stroke and the extension stroke are finally obtained through the flow field velocity distribution and pressure distribution.

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