Aviation gear pump tooth surface wear modeling method based on lubrication wear mechanism

Abstract

The invention discloses an aviation gear combustion pump tooth surface wear modeling method based on a lubrication wear mechanism, and the method is characterized in that the method comprises the following steps; the method comprises the following steps: 1, calculating the tangential speed, entrainment speed and comprehensive curvature radius of a meshing point at the current position; 2, calculating the contact stress of the current meshing point, the oil film pressure distribution and the elastic deformation distribution of the tooth surface, and carrying out mutual iteration until convergence; 3, calculating the tooth surface abrasion loss distribution of the current meshing point; 4, changing the position of the meshing point, repeating the step 1 to the step 3, calculating the abrasion condition of each position of the tooth surface when the meshing point passes through, and accumulating the abrasion condition; and step 5, outputting a result after calculation of each position of the tooth surface in the step 4 is completed, and finally realizing calculation of the abrasion loss distribution of the whole gear meshing surface.

Description

Technical Field

[0001] This invention relates to the field of performance modeling and simulation technology for aero-engine gear pumps, and in particular to a method for modeling wear on the tooth surface of aero-engine gear pumps based on lubrication and wear mechanisms. Background Technology

[0002] Aviation fuel gear pumps are core components of aero-engine fuel control systems, and their lifespan and reliability are crucial to the full performance of aero-engines. However, in existing technologies, gear surface wear has always been a key factor affecting the lifespan and reliability of aviation fuel gear pumps. Gear surface wear not only alters the meshing characteristics of the gear pair and reduces transmission accuracy, but may also lead to increased vibration and noise, and even trigger other failure modes.

[0003] Currently, there is limited research on methods for predicting lubrication and wear in aero-engine fuel gear pumps. The article "A Review of Key Technologies for Long-Life, High-Reliability Fuel Gear Pumps for Aero-engines" points out that the main failure modes of fuel gear pumps include fatigue wear of gears and splines, wear of radial sliding bearings, cavitation in the side plate area, and leakage caused by wear of sealing elements. Domestic research focuses on surface modification of traditional copper alloy materials, improving their wear resistance through surface texture and the addition of additives. However, these methods are still insufficient to meet the long-life and high-reliability requirements of aero-engine fuel gear pumps under conditions of frequent high and low temperature fluctuations. Furthermore, existing tooth surface wear modeling methods are mostly based on theoretical analysis, lacking in-depth research on the lubrication and wear mechanisms under actual operating conditions, making it difficult to accurately predict tooth surface wear patterns.

[0004] In summary, existing technologies for modeling wear on the gear surface of aviation fuel gear pumps and studying the lubrication-wear mechanism have the following shortcomings: First, existing models are difficult to adapt to wear prediction under complex operating conditions; second, traditional materials and surface modification technologies lack reliability under high temperature and alternating high and low temperature conditions; and third, there is a lack of systematic research on the lubrication-wear mechanism. Therefore, developing a modeling method for wear on the gear surface of aviation fuel gear pumps based on the lubrication-wear mechanism is of great significance for improving its performance and reliability. Summary of the Invention

[0005] To overcome the above technical problems, the purpose of this invention is to provide a method for modeling wear on the tooth surface of an aviation fuel gear pump based on the lubrication and wear mechanism, which is applicable to the high temperature and high pressure flow field of aviation fuel gear pumps.

[0006] The technical solution adopted in this invention is: A method for modeling wear on the tooth surface of an aero-engine fuel cell pump based on the lubrication and wear mechanism includes the following steps; Step 1: Calculate the tangential velocity, entrainment velocity, and combined radius of curvature at the current engagement point; Step 2: Calculate the contact stress at the current meshing point, the oil film pressure distribution, and the elastic deformation distribution of the tooth surface, and iterate them until convergence; Step 3: Calculate the wear distribution on the tooth surface at the current meshing point:

[0007] in, W This refers to the wear depth. k The Archard wear coefficient; H r The surface hardness of the material; u The relative linear velocity when the two contact surfaces are in contact; a constant. α , β , γ The selection is 1.

[0008] Step 4: Change the position of the meshing point and repeat steps 1 to 3. Calculate the wear of each position on the tooth surface when the meshing point is reached and accumulate the results. Step 5: After the calculation of each position on the tooth surface in Step 4 is completed, the result is output, and the wear distribution of the entire gear meshing surface is finally calculated.

[0009] The first step is specifically as follows: (1.1) Calculate the distance from the meshing point to the node on the actual meshing line segment. L Pt : in, r 1 represents the pitch circle radius of the driving wheel; r 2 is the pitch circle radius of the driven gear; r c This is the distance from the current engagement point to the center of the driving wheel; α For the gear pressure angle; (1.2) According to L Pt Calculate the tangential sliding velocity at the meshing point V Sucking speed U and combined radius of curvature R E : First, calculate the relative velocity of the two tooth surfaces at the meshing point. V 1 and V 2: in, n 1. n 2. The speeds of the master and driven wheels; r 2 is the pitch circle radius of the driven wheel; substituting it into the following formula, we obtain the tangential sliding speed. V and entrainment speed U : And the combined radius of curvatureR E for: in, R E1 and R E2 Let be the radius of curvature of the driving and driven gears.

[0010] Step two specifically involves: This step specifically involves: (2.1) Calculating the contact stress at the current meshing point: First, calculate the total contact force. F nc : in, K This is the load distribution factor when the meshing point is located in the double-tooth meshing zone. K When the value is 0.5, it is located in the single-tooth meshing zone. K Take 1; Z 1 and Z 2 represents the module of the driving and driven gears; According to Hertz's contact theory, the average contact stress between tooth surfaces... The formula is: in, B For tooth width; Poisson's ratio for the materials of the driving and driven gears; The Young's modulus of the materials for the driving and driven gears; (2.2) Calculate the oil film pressure distribution at the current engagement point: The fluid element at each node follows the Reynolds equations for oil film lubrication in sliding bearings: in, h For oil film thickness, p For oil film pressure, For the viscosity of the medium, The suction speed is the speed at which the suction is drawn in. R E To account for the radius of curvature, all variables are in international standard units, and the oil film thickness follows the Dowson-Higginson minimum film thickness formula: In the formula, ψ This refers to the viscosity-pressure coefficient of the lubricating oil. This refers to the dynamic viscosity of lubricating oil under normal pressure. E W The comprehensive elastic modulus of the material; (2.3) Calculate the elastic deformation distribution of the tooth surface at the current meshing point: Based on Winkler's spring model: in, L b This refers to the thickness of the elastic layer.

[0011] Step four specifically involves: [removing / completing] the steps from step one... r c Add one more person as selected. Make L Pt This becomes the distance on the actual meshing line segment that reacts to the next meshing point, and then steps one through three are repeated, increasing the distance each time. The wear depths are accumulated to obtain the total wear depth for the entire meshing process.

[0012] Step five specifically involves: As step four continuously increases r c When the wear depth is increased to the tip circle radius, it is considered as one meshing process is completed. At this time, the wear depth at each moment is accumulated as the total wear depth of the entire meshing process, thus realizing the calculation of the wear distribution of the entire gear meshing surface.

[0013] The beneficial effects of this invention are: This invention can more accurately simulate the wear process of aviation fuel cell pump tooth surfaces under complex operating conditions. By incorporating fluid pressure into the model in step two, the accuracy of wear prediction is significantly improved. Furthermore, the total wear distribution during the meshing process in step five can quickly identify weak points in tooth surface wear. For example, the wear at the tooth root is greater than that at the tooth tip, thus providing a scientific basis for optimized design and condition-based maintenance, effectively improving the reliability and service life of aviation fuel cell pumps.

[0014] Furthermore, this method, through simulation modeling, reduces reliance on experiments, lowers R&D costs and time, and improves R&D efficiency. It provides important support for the design optimization and reliability improvement of aero-engine fuel pumps, and has significant practical value and broad application prospects. Attached Figure Description

[0015] Figure 1 Flowchart of a simulation method for lubrication and wear of gear pump teeth in aviation fuel.

[0016] Figure 2 This is a schematic diagram of the simulation results at the engagement point.

[0017] Figure 3 This is a schematic diagram of the wear distribution on the tooth surface after 1000 hours of wear. Detailed Implementation

[0018] 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, and 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.

[0019] The main technology employed in this invention is a simulation method for lubrication and wear of aviation fuel gear pump tooth surfaces that takes into account elastic deformation. Its basic principle is summarized as follows: To achieve the above objectives, the present invention provides the following technical approach: Step 1: Calculate the tangential velocity, entrainment velocity, and combined radius of curvature at the current engagement point; The first step is specifically as follows: (1.1) Calculate the distance from the meshing point to the node on the actual meshing line segment. L Pt : in, r 1 represents the pitch circle radius of the driving wheel; r 2 is the pitch circle radius of the driven gear; r c This is the distance from the current engagement point to the center of the driving wheel; α For the gear pressure angle; (1.2) According to L Pt Calculate the tangential sliding velocity at the meshing point V Sucking speed U and combined radius of curvature R E : First, calculate the relative velocity of the two tooth surfaces at the meshing point. V 1 and V 2: in, n 1. n 2. The speeds of the master and driven wheels; r 2 is the pitch circle radius of the driven wheel; substituting it into the following formula, we obtain the tangential sliding speed. V and entrainment speed U : And the combined radius of curvature R E for: in, R E1 and R E2 Let be the radius of curvature of the driving and driven gears.

[0020] Step 2: Calculate the contact stress at the current meshing point, the oil film pressure distribution, and the elastic deformation distribution of the tooth surface, and iterate them until convergence. This step specifically involves: (2.1) Calculating the contact stress at the current meshing point: First, calculate the total contact force. F nc : in, K This is the load distribution factor when the meshing point is located in the double-tooth meshing zone. K When the value is 0.5, it is located in the single-tooth meshing zone. K Take 1; Z 1 and Z 2 represents the module of the driving and driven gears.

[0021] According to Hertz's contact theory, the average contact stress between tooth surfaces... The formula is: in, B For tooth width; Poisson's ratio for the materials of the driving and driven gears; The Young's modulus of the materials for the driving and driven gears.

[0022] (2.2) Calculate the oil film pressure distribution at the current engagement point: The fluid element at each node follows the Reynolds equations for oil film lubrication in sliding bearings: in, h For oil film thickness, p For oil film pressure, For the viscosity of the medium, The suction speed is the speed at which the suction is drawn in. R E To account for the radius of curvature, all variables are in international standard units, and the oil film thickness follows the Dowson-Higginson minimum film thickness formula: In the formula, ψ This refers to the viscosity-pressure coefficient of the lubricating oil. This refers to the dynamic viscosity of lubricating oil under normal pressure. E W This refers to the overall elastic modulus of the material.

[0023] (2.3) Calculate the elastic deformation distribution of the tooth surface at the current meshing point: Based on Winkler's spring model: in, L b This refers to the thickness of the elastic layer.

[0024] Step 3: Calculate the wear distribution on the tooth surface at the current meshing point:

[0025] in, W This refers to the wear depth. k The Archard wear coefficient; H r The surface hardness of the material; u The relative linear velocity when the two contact surfaces are in contact; a constant. α , β , γ The selection is 1.

[0026] Step 4: Change the position of the meshing point and repeat steps 1 to 3. Calculate the wear of each position on the tooth surface when the meshing point is reached and accumulate the results. Step 5: Output the results after the calculations for each position on the tooth surface have been completed.

[0027] Experimental Example: The advantages of this invention can be further illustrated by the following simulation experiments: 1. Simulation parameters To demonstrate the accuracy and reliability of the simulation predictions of the lubrication and wear simulation model in this invention, a set of fuel gear pump lubrication and wear test results under a specific load spectrum are selected for comparison with the simulation results. The basic parameters of a certain type of gear pump targeted in this study are shown in Table 1, and the working medium is RP-3 aviation fuel.

[0028] Table 1 Main parameters of aviation fuel gear pump When aviation fuel gear pumps are operating normally under service conditions, their inlet and outlet pressures, speeds, and other operating parameters will change to varying degrees. To ensure that the life prediction closely matches the actual operating conditions of aviation fuel gear pumps, this study selects the rated operating condition of the gear pump as the simulation input condition and conducts a 1000-hour simulation of lubrication wear failure.

[0029] 2. Simulation Results Substitute the parameters from Table 1 into Figure 1 The calculation process involves calculating the wear amount of a single tooth surface across all positions during a single meshing process, and then calculating the number of meshing cycles over 1000 hours to obtain the tooth surface wear distribution over 1000 hours. The results are as follows: Figure 2 , 3 As shown.

[0030] 3. Results Analysis Conclusion 1: Through Figure 2The simulation results show that the pressure distribution of the oil film in the aviation fuel gear pump is on the same order of magnitude as the contact stress during gear meshing. Both provide support and induce elastic deformation. This means that the lubrication and wear mechanism of the aviation fuel gear pump is different from the usual gear meshing lubrication and wear mechanism, which proves the innovation of this invention.

[0031] Conclusion 2: The study found that, Figure 3 The wear distribution on the tooth surface of aviation fuel gear pumps is uneven, with wear generally occurring greater at the tooth root than at the tooth tip. Therefore, in actual operation, inter-tooth seal failures tend to occur near the tooth root, necessitating special treatment of the tooth root surface. This means that the tooth surface lubrication and wear mechanism modeling method proposed in this invention can quickly identify the weak points of aviation fuel gear pumps, facilitating optimized design and condition-based maintenance.

[0032] Conclusion 3: Through Figure 3 The simulation results were compared with the actual experimental results, and it was found that the average wear amount obtained by simulation at each sample point was 22.330 mm, which is consistent with the experimental results. The accuracy of the lubrication wear mechanism model was verified, and the feasibility and effectiveness of the method proposed in this invention were verified.

Claims

1. A method for modeling the wear of the tooth surface of an aviation gear pump based on the lubrication wear mechanism, characterized in that, The method comprises the following steps; Step one: calculate the tangential velocity, entrainment velocity and comprehensive curvature radius of the current position engagement point; Step two: calculate the contact stress, oil film pressure distribution and elastic deformation distribution of the current engagement point, and iterate each other until convergence; Step three: calculate the tooth surface wear distribution of the current engagement point: wherein, W is the wear depth; k is the Archard wear coefficient; H r is the material surface hardness; u is the relative linear velocity of the two contacting surfaces when in contact; Step four: change the engagement point position and repeat steps one to three to calculate the wear of each position of the tooth surface when the engagement point passes through and accumulate; Step five: output the result when each position of the tooth surface in step four is calculated, and finally realize the calculation of the wear distribution of the entire gear engagement surface.

2. The method of claim 1, wherein the method is characterized by, The step one is specifically: (1.1) calculating the distance from the engagement point to the node on the actual engagement line segment L Pt : where, r 1 is the pitch circle radius of the driving wheel; r 2 is the pitch circle radius of the driven wheel; r c is the distance of the current position of the meshing point to the center of the driving wheel; α is the pressure angle of the gear; (1.2) according to L Pt Calculate the tangential sliding speed of the meshing point V , the entrainment speed U and the comprehensive curvature radius R E : First, the relative velocity of the two tooth surfaces at the meshing point is calculated V 1 and V 2: wherein, n 1、 n 2 is the rotational speed of the driving and driven wheels; r 2 is the pitch radius of the driven wheel; introducing this into the following equation gives the tangential sliding velocity V and the entrainment velocity U : And the integrated radius of curvature R E is: wherein, R E1 and R E2 Ri and R2 are the radii of curvature of the driving and driven gears.

3. The method of claim 1, wherein the method is characterized by: The step two is specifically: This step is specifically: (2.1) Calculate the contact stress of the current engagement point: First, the total contact force is calculated F nc : wherein, K is a load distribution coefficient, when the point of engagement is in the double toothed engagement region K is taken as 0.5, when the point of engagement is in the single toothed engagement region K is taken as 1 ; Z 1 and Z 2 are the module numbers of the driving and driven gears; Then, according to the Hertz contact theory, the average contact stress between tooth surfaces The formula is: wherein, B is the tooth width; is the material Poisson's ratio of the driving and driven gears; is the material Young's modulus of the driving and driven gears; (2.2) Calculate the oil film pressure distribution of the current engagement point: Each node fluid element follows the Reynolds equation for sliding bearing oil film lubrication: where, h is the oil film thickness, p is the oil film pressure, is the medium viscosity, is the entrainment velocity, R E is the resultant radius of curvature, all variables are in international standard units, the oil film thickness follows the Dowson-Higginson minimum film thickness formula: wherein Ψ is the barus pressure coefficient of the lubricating oil; is the dynamic viscosity of the lubricating oil at atmospheric pressure; E W is the composite modulus of elasticity of the material; (2.3) Calculate the elastic deformation distribution of the tooth surface of the current engagement point: According to the Winkler spring model: wherein, L b is the thickness of the elastic layer.

4. The method for modeling the wear of the tooth surface of an aviation gear pump based on the lubrication wear mechanism according to claim 1, characterized in that, The step four is specifically: The distance between the actual engagement line segment of the next engagement point of the reaction and the previous engagement line segment of the previous engagement point of the reaction is calculated. r c The number of persons is increased by one for the selected The distance between the actual engagement line segment of the next engagement point of the reaction and the previous engagement line segment of the previous engagement point of the reaction is calculated. L Pt The distance between the actual engagement line segment of the next engagement point of the reaction and the previous engagement line segment of the previous engagement point of the reaction is calculated. The wear depth is accumulated in advance as the total wear depth of the entire engagement process.

5. The method of claim 1, wherein, The step five is specifically: When the increasing in step four r c When the increasing in step four When the increasing in step four

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