A simulation method for friction and lubrication performance of plane surface texture

Abstract

The present application belongs to the field of aero-engine fuel control, and relates to a planar surface texture friction and lubrication performance simulation method. The method comprises: obtaining the basic parameters of a friction pair and a lubricant, and the fixed constraint of a texture; generating a PV value matrix according to the basic parameters; determining a texture parameter search range for each PV value in the PV value matrix based on the fixed constraint of the texture; wherein one PV value represents one PV working condition, and under one PV working condition, the friction coefficient μ is calculated for different parameters in the texture parameter search range, a simplified multi-physical field friction model is constructed, the total friction coefficient of the friction pair is obtained, and the smallest total friction coefficient is taken as the optimal total friction coefficient.

Description

Technical Field

[0001] This invention belongs to the field of aero-engine fuel control and relates to a method for simulating the friction and lubrication performance of planar surface texture. Background Technology

[0002] The fuel control unit of an aero-engine contains various friction pairs. In order to reduce the load on the friction pairs, surface texture technology has been introduced to improve the relevant loads, so that the friction pairs can still work normally in a high PV value environment. However, it is difficult to carry out the three-dimensional simulation of surface texture at present. It relies on experiments and empirical formulas, and the relevant physical models are incomplete and cannot take into account the influence of surface roughness. The computational workload for realizing the multi-physics coupling effect and screening key surface texture parameters is huge. Summary of the Invention

[0003] Purpose of the invention: To address the aforementioned pain points, the purpose of this invention is to overcome the shortcomings of existing technologies and provide a simplified method for determining the main parameters of surface texture based on multi-physics coupling and physical-guided optimization. This method can quickly and accurately determine the optimal texture parameters under different working conditions, avoiding the enormous workload of 3D mesh modeling and simulation of complex structures.

[0004] Technical solution: A method for simulating the friction and lubrication performance of planar surface textures is provided, including: Obtain the basic parameters of the friction kinematic pairs and lubricant, and the fixed constraints of the texture; Generate a PV value matrix based on the basic parameters; Based on the fixed constraints of texture, the search range of texture parameters is determined for each PV value in the PV value matrix; where each PV value represents a PV working condition. Under a PV condition, the friction coefficient μ is calculated for different parameters within the search range of texture parameters. A simplified multiphysics friction model is constructed to obtain the total friction coefficient of the friction pair. The minimum total friction coefficient is taken as the optimal total friction coefficient.

[0005] Furthermore, the basic parameters include: multiple contact pressures P in array form, relative motion speeds V in array form, and the ambient viscosity of the lubricant used to lubricate the frictional moving pairs. η 0. Compressibility coefficient α, material parameters, including composite roughness Rq and hardness H of the softer material; the fixed constraint of the texture is a fixed texture width w.

[0006] Furthermore, a PV value matrix is ​​generated based on the basic parameters, including: Calculate the PV values ​​for all pressure and velocity combinations to obtain the PV value matrix PV_vals, which will be used for subsequent traversal.

[0007] Furthermore, the search range for texture parameters is the search range for the texture area ratio ρ. Based on the fixed constraints of texture, the search range for texture parameters is determined for each PV value in the PV value matrix, including: Based on the one-dimensional Reynolds equation, the theoretical oil film thickness of the lubricant is estimated. h 0; Based on the physical principle that "optimal depth = oil film thickness", the depth range is limited, and M points are uniformly selected within the depth range for subsequent calculation of the optimal total friction coefficient. Based on the different PV values ​​in the PV value matrix, the search range of ρ is determined, and N points are uniformly selected within each search range for subsequent calculation of the optimal total friction coefficient.

[0008] Furthermore, under a PV condition, the friction coefficient μ is calculated for different parameters within the texture parameter search range. A simplified multiphysics friction model is constructed to obtain the total friction coefficient of the friction pair, including: Under PV conditions, a point is selected within the search range of ρ. The geometric spacing s is calculated based on this point and the texture width w. Based on the basic parameters and geometric spacing s, the texture dynamic pressure effect, i.e., the pressure increase ΔP_text, is calculated, and the theoretical oil film thickness is corrected using ΔP_text. h 0, to obtain the actual oil film thickness. h min Thus, the total friction coefficient μ is obtained.

[0009] Furthermore, the minimum total friction coefficient is taken as the optimal total friction coefficient, including: Within the search range of ρ under this PV condition, multiple total friction coefficients μ are obtained; The minimum total friction coefficient μ is selected as the optimal total friction coefficient under the PV working condition, and the optimal texture area ratio, optimal actual oil film thickness, and optimal geometric spacing under the PV working condition are then derived.

[0010] Furthermore, based on the one-dimensional Reynolds equation, the theoretical oil film thickness of the lubricant is estimated. h 0, including: Calculate the effective viscosity under the compressive viscosity effect: ; Estimate theoretical oil film thickness: L = 1 × 10 - ³m.

[0011] Furthermore, h min The calculation formula is: ;

[0012] β=hi / s ; in, β Aspect ratio, h i Let be the i-th point uniformly selected within the depth range, and P be the static pressure of the texture; h min , h , s The unit for all of them is m.

[0013] Furthermore, the formula for calculating μ is: ; ; ; ; ; τ fluid For fluid shear stress, τ asperity For rough contact stress, A real This is the actual contact area ratio. A ratio It is the theoretical contact area ratio.

[0014] Beneficial effects: This method embeds a complete mathematical and physical model within the process framework of S1 to S6: It estimates the theoretical oil film thickness based on the one-dimensional Reynolds equation; determines the search interval for the texture area ratio based on PV value partitioning; calculates the friction coefficient using the dynamic pressure enhancement formula, the oil film thickness correction formula, and the improved Greenwood-Williamson contact model; and finally obtains the optimal texture depth, spacing, and area ratio corresponding to the minimum friction coefficient through a two-layer grid search. This invention solves the problems of low efficiency, insufficient physical coupling, and lack of adaptability to operating conditions in existing optimization methods, significantly improving the accuracy of texture design and its engineering practicality.

[0015] This invention can quickly and accurately determine the optimal surface texture parameters under different working conditions, significantly improving optimization efficiency and prediction accuracy. It is applicable to the texture optimization design of various friction pairs. The methods and analysis are derived from summaries of various cases. Any improvements or modifications made without deviating from the basis of this invention are within the scope of protection claimed by this invention. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a flowchart of a simulation method for the friction and lubrication performance of planar surface texture.

[0018] Figure 2 Detail the flowchart for the method process.

[0019] Figure 3 This is a diagram showing the combination of PV values ​​under various operating conditions.

[0020] Figure 4 A simplified diagram of the key logic for optimizing search. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] The features and illustrative embodiments of various aspects of the present invention will now be described in detail. Numerous specific details are set forth in the following detailed description to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention. The invention is by no means limited to any specific setups and methods set forth below, but covers any improvements, substitutions, and modifications to structures, methods, and devices without departing from the spirit of the invention. Well-known structures and techniques are not shown in the drawings and the following description to avoid unnecessarily obscuring the invention.

[0023] In the description of this invention, it should be noted that the directions or positional relationships indicated by terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing and simplifying the invention, and should not be construed as limiting the invention. Furthermore, the use of ordinal numbers (e.g., "first and second," etc.) is for distinguishing objects and is not limited to this order, and should not be construed as indicating or implying relative importance.

[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly, encompassing both direct connection and indirect connection via an intermediate medium. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0025] It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other, and the various embodiments can be referenced and cited in each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0026] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0027] This invention aims to provide a textured surface lubrication optimization method based on multi-physics coupling and physics-guided search, capable of handling arbitrary input conditions (pressure P, velocity V, lubricant viscosity). η 0) Quickly output the optimal texture depth, spacing, and area ratio to minimize the coefficient of friction.

[0028] This invention aims to provide a textured surface lubrication optimization method based on multi-physics coupling and physics-guided search, capable of handling arbitrary input conditions (pressure P, velocity V, lubricant viscosity). η 0) Quickly output the optimal texture depth, spacing, and area ratio to minimize the coefficient of friction.

[0029] This method has the following innovations: First, it constructs a simple multiphysics coupled surface texture simulation process, enabling rapid acquisition of key parameters; second, it integrates some practical engineering experimental experience into the simulation process. For example... Figure 1-2 As shown, the main steps are as follows: Step S1: Input basic parameters and fixed constraints: Contact pressure array P (unit: MPa), relative motion velocity array V (unit: m / s); lubricant ambient viscosity η 0 (unit: Pa·s); compressive viscosity coefficient α (unit: 1 / Pa), commonly used value 2.2 × 10⁻⁶ -8Material parameters: composite roughness Rq (unit: m), softer material hardness H (unit: Pa); fixed texture width w (unit: mm), for striped texture, w = 0.01 mm in this embodiment.

[0030] Step S2: Generate the PV value matrix and construct the main loop process: Calculate the PV value for all pressure and velocity combinations: ……………………(1) Generate a grid matrix PV_vals for subsequent traversal.

[0031] Step S3: For each PV value, intelligently determine the search range for texture parameters: (A) Estimation of theoretical oil film thickness h0 (based on one-dimensional Reynolds equation) Given the current pressure P (Pa) and velocity V (m / s), first calculate the effective viscosity under the compressive viscosity effect: …………………………(2) (B) Search range of texture depth h (unit: mm) Based on the physical principle that "optimal depth ≈ oil film thickness", the depth range is limited to: ………………(4) Here, ×1000 converts meters to millimeters, and the depth search vector depth_vec uniformly selects M points within this interval (usually M=20).

[0032] (C) Search range for texture area ratio ρ (based on PV value partitioning) Define the area percentage ρ = w / (w+s), with a range of 0 < ρ < 1.

[0033] The search interval is determined according to the PV value (unit: MPa·m / s) as shown in Table 1: Table 1

[0034] The ρ search vector rho_vec uniformly selects N points (usually N=20) within the corresponding interval. This zoning pattern stems from the fact that high PV requires a greater texture density to improve load-bearing capacity and oil storage.

[0035] Step S4: Double-layer mesh search, calculate the friction coefficient μ for each (h,ρ) combination, and construct a simplified multiphysics friction model: (A) Calculate the geometric spacing from the area ratio Given a fixed texture width w (mm), then: ………………………………(5) At this point, the unit of s is mm. The depth h and spacing s need to be converted to meters for subsequent fluid calculations.

[0036] (B) Calculate the dynamic pressure effect of texture (pressure increase ΔP_text) Define aspect ratio β = h i / s ( h i (where s is in meters), then the dynamic pressure increase is: ………………(6) The first term in the formula is the classic slider dynamic pressure term, the second term is the aspect ratio correction, and the third term is the area ratio enhancement factor (the larger the area ratio, the stronger the dynamic pressure).

[0037] Effective pressure: …………………………(7) (C) Correcting the actual oil film thickness h min Considering that increased dynamic pressure will thicken the oil film, the actual minimum oil film thickness is: ……………………(8) (D) Fluid shear stress ……………………………(9) (E) Rough contact stress (based on GW model and coupled with area ratio) This model assumes a Gaussian distribution, and the nominal contact area ratio is approximated by an exponential decay function: ……………………………(10) Considering the oil storage effect of texture and the fact that textured regions do not undertake actual contact, the actual contact area ratio is: ………………(11) Rough contact stress: ………………………(12) Where H is the hardness (Pa) of the softer material, and the coefficient 0.15 is an empirical value of the friction coefficient.

[0038] (F) Total coefficient of friction ……………………………(13) Record the μ corresponding to the current (h, ρ). If μ is less than the current optimal value, update the optimal solution.

[0039] Step S5: Select and store the optimal parameters for this PV operating condition, and determine the parameter range: For all (h, ρ) combinations currently being processed, select the combination with the smallest friction coefficient and record it: Optimal depth h_opt (mm) Optimal area proportion ρ_opt Corresponding spacing s_opt=w(1 / ρ_opt) 1) (mm) Minimum friction coefficient μ_min Auxiliary outputs: actual oil film thickness hmin, pressure increase ΔP_text Step S6: Output the optimization results for all PV operating conditions: Summarize the optimal parameters for each operating condition and generate the results. Simultaneously, draw the following relationship diagram: PV value vs. optimal depth PV value vs. optimal area ratio / spacing PV value vs. minimum coefficient of friction Depth / oil film thickness ratio distribution (validation and optimization criteria) Example The specific implementation process is carried out using a case study as an example. For instance, the surface texture optimization of a graphite ring-steel plane friction pair is performed. The main input parameters are: viscosity η = 0.08 Pa·s, pressure P = [0.5, 1, 2, 5] MPa, velocity V = [0.1, 0.5, 1, 2] m / s, and texture width = 0.01 mm. This completes step S1. Based on step S2, various working condition combinations are generated, such as Figure 3 As shown, more combinations of working conditions can certainly be generated; Based on step S3, construct the grid search optimization iterative process; see the relevant logic below. Figure 4 ; Based on step S4, a simplified multiphysics friction model is constructed. The simplified model needs to consider key sub-models such as the calculation of base oil film thickness, the calculation of texture dynamic pressure effect, the calculation of effective viscosity, fluid shear pressure, and rough contact stress. The calculations were performed according to steps S5 and S6, and the relevant results were obtained, as shown in Table 2.

[0040] Table 2

[0041] The above detailed embodiments are a description of the present invention. It should not be considered that the specific embodiments of the present invention are limited to these descriptions. For those skilled in the art, several simple deductions and substitutions can be made without departing from the concept of the present invention, and all of these should be considered to fall within the protection scope of the present invention.

Claims

1. A method for simulating the friction and lubrication performance of planar surface textures, characterized in that, include: Obtain the basic parameters of the friction kinematic pairs and lubricant, and the fixed constraints of the texture; Generate a PV value matrix based on the basic parameters; Based on the fixed constraints of texture, the search range of texture parameters is determined for each PV value in the PV value matrix; where each PV value represents a PV working condition. Under a PV condition, the friction coefficient μ is calculated for different parameters within the search range of texture parameters. A simplified multiphysics friction model is constructed to obtain the total friction coefficient of the friction pair. The minimum total friction coefficient is taken as the optimal total friction coefficient.

2. The method according to claim 1, characterized in that, The basic parameters include: multiple contact pressures P in array form, relative motion speeds V in array form, and the ambient viscosity of the lubricant used to lubricate the moving friction pairs. η 0. Compressibility coefficient α, material parameters, including composite roughness Rq and hardness H of the softer material; the fixed constraint of the texture is a fixed texture width w.

3. The method according to claim 2, characterized in that, Generate a PV value matrix based on the basic parameters, including: Calculate the PV values ​​for all pressure and velocity combinations to obtain the PV value matrix PV_vals, which will be used for subsequent traversal.

4. The method according to claim 2, characterized in that, The search range for texture parameters is the search range for the texture area ratio ρ. Based on the fixed constraints of texture, the search range for texture parameters is determined for each PV value in the PV value matrix, including: Based on the one-dimensional Reynolds equation, the theoretical oil film thickness of the lubricant is estimated. h 0; Based on the physical principle that "optimal depth = oil film thickness", the depth range is limited, and M points are uniformly selected within the depth range for subsequent calculation of the optimal total friction coefficient. Based on the different PV values ​​in the PV value matrix, the search range of ρ is determined, and N points are uniformly selected within each search range for subsequent calculation of the optimal total friction coefficient.

5. The method according to claim 4, characterized in that, Under a PV condition, the friction coefficient μ is calculated for different parameters within the texture parameter search range. A simplified multiphysics friction model is constructed to obtain the total friction coefficient of the friction pair, including: Under PV conditions, a point is selected within the search range of ρ. The geometric spacing s is calculated based on this point and the texture width w. Based on the basic parameters and geometric spacing s, the texture dynamic pressure effect, i.e., the pressure increase ΔP_text, is calculated, and the theoretical oil film thickness is corrected using ΔP_text. h 0, to obtain the actual oil film thickness. h min Thus, the total friction coefficient μ is obtained.

6. The method according to claim 5, characterized in that, The minimum total friction coefficient is taken as the optimal total friction coefficient, including: Within the search range of ρ under this PV condition, multiple total friction coefficients μ are obtained; The minimum total friction coefficient μ is selected as the optimal total friction coefficient under the PV working condition, and the optimal texture area ratio, optimal actual oil film thickness, and optimal geometric spacing under the PV working condition are then derived.

7. The method according to claim 5, characterized in that, Based on the one-dimensional Reynolds equation, the theoretical oil film thickness of the lubricant is estimated. h 0, including: Calculate the effective viscosity under the compressive viscosity effect: ; Estimate theoretical oil film thickness: L = 1 × 10 - ³m.

8. The method according to claim 7, characterized in that, h min The calculation formula is: ； β=hi / s ； in, β Aspect ratio, h i Let be the i-th point uniformly selected within the depth range, and P be the static pressure of the texture; h min , h , s The unit for all of them is m.

9. The method according to claim 8, characterized in that, The formula for calculating μ is: ； ； ； ； ； τ fluid For fluid shear stress, τ asperity For rough contact stress, A real This is the actual contact area ratio. A ratio It is the theoretical contact area ratio.

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