Aircraft dynamic sealing ring service life prediction method based on gap leakage analysis

Abstract

The application belongs to the technical field of rubber seal test, and relates to a method for predicting the service life of an aviation dynamic sealing ring based on gap leakage analysis, which comprises the following steps: S1, performing a service life pre-test of the aviation dynamic sealing ring, performing a sealing ring life investigation, and determining a sealing ring failure criterion; S2, performing a sealing ring life model correction test, and recording life correction parameters in the test process; S3, obtaining an aviation dynamic sealing ring wear variable according to Archard adhesive wear analysis and gap leakage analysis; S4, calculating the wear of the aviation dynamic sealing ring, establishing a sealing state judgment standard equation of the aviation dynamic sealing ring, and determining a working state; and S5, establishing an aging prediction model of the aviation dynamic sealing ring under a target working condition, and completing service life prediction and evaluation. The application replaces the traditional sealing ring size measurement with leakage to avoid complex disassembly and assembly of the sealing ring test, reduces non-experimental wear of the sealing ring, and establishes an accurate life prediction model.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of life prediction of aviation sealing rings, and particularly relates to a life prediction method for aviation dynamic sealing rings based on gap leakage analysis. BACKGROUND

[0002] In an aircraft hydraulic system, a sealing ring is often used as a common external dynamic sealing form and is often applied to an actuator of an aircraft actuating system. In a working process, due to the double effects of pre-compression and oil pressure, wear phenomena inevitably occur on the contact surface, and with the continuous loss of the sealing ring material, the sealing effect is reduced and the leakage is increased, and serious leakage can cause system failure and even affect flight safety. Therefore, the wear process of the sealing ring and the life prediction method for the wear of the sealing ring have important practical significance.

[0003] At present, the main failure criterion for the life prediction of the sealing ring is the wear amount of the sealing ring. This data acquisition needs to measure the size of the sealing ring. Due to the complexity of the sealing device, frequent disassembly and assembly of the sealing ring can increase the complexity of the test, affect the actual sealing performance, and the frequent disassembly and assembly operation can also cause additional tensile and compressive stress to the sealing ring, additional damage to the sealing ring, and thus increase the error of the test.

[0004] To solve the above problems, the application provides a dynamic sealing life prediction method considering leakage, which measures the leakage amount of hydraulic oil at different times, uses the leakage amount caused by pressure difference flow obtained by gap leakage analysis, reverses the mapping relationship between the leakage amount and the wear amount through the theory, obtains the wear amount of the sealing ring at each test time, corrects the wear modulus, establishes an Archard model, and predicts the life of the sealing ring according to the failure criterion. SUMMARY

[0005] In view of the deficiencies of the prior art, the application provides a life prediction method for aviation dynamic sealing rings based on gap leakage analysis, which replaces the traditional sealing ring size measurement with leakage to avoid complex disassembly and assembly experiments of the sealing ring, reduces the non-experimental wear of the sealing ring, establishes an accurate wear prediction model, and can accurately complete the life prediction within the acceptable error range. The wear prediction model has high accuracy and has positive significance for guiding product design, optimizing material selection and improving process.

[0006] To achieve the above purpose, the application discloses a life prediction method for aviation dynamic sealing rings based on gap leakage analysis, which comprises:

[0007] S1: performing a life prediction test of the aviation dynamic sealing ring, and determining a failure criterion of the sealing ring; the failure criterion of the life prediction test of the aviation dynamic sealing ring is determined according to the leakage amount of the sealing place per minute to determine the test time and the wear amount of the aviation dynamic sealing ring when the aviation dynamic sealing ring fails.

[0008] S2: Perform the aviation dynamic sealing ring life model correction test, record the life correction parameters during the test, including test leakage Q, test time T and dynamic sealing ring friction F f ;

[0009] S3: According to Archard adhesive wear analysis and gap leakage analysis, the wear variable of aviation dynamic sealing ring is obtained;

[0010] S31: According to Archard adhesive wear analysis, the total wear depth of aviation dynamic sealing ring is obtained by establishing the wear calculation model of aviation dynamic sealing ring in use:

[0011]

[0012] Wherein, H z is the total wear depth at any time; h i is the wear at the i th node t time; Δt is the wear time variable; n is the total number of measurement nodes of aviation dynamic sealing ring; i is the measurement node number of aviation dynamic sealing ring;

[0013] S32: According to the mapping relationship between leakage and wear determined by gap leakage analysis, the leakage of aviation dynamic sealing ring is calculated, and the wear variable of aviation dynamic sealing ring is obtained as:

[0014]

[0015] Wherein, ΔH is the wear variable of aviation dynamic sealing ring; H i is the wear depth at t time; H i-1 is the wear depth at t last time; μ j is the dynamic viscosity of fluid; L is the length of gap sealing; Q is the leakage of aviation dynamic sealing ring; D is the diameter of cylindrical surface; Δp is the pressure difference between the two ends of the gap;

[0016] S4: Calculate the wear of aviation dynamic sealing ring, establish the standard equation of aviation dynamic sealing ring sealing state judgment, and determine the working state of aviation dynamic sealing ring;

[0017] S41: Map the relationship between the total wear depth of aviation dynamic sealing ring in step S31 and the wear variable of aviation dynamic sealing ring in step S32, calculate the wear modulus of aviation dynamic sealing ring, and obtain the wear of aviation dynamic sealing ring as:

[0018]

[0019] Wherein, is the wear prediction of aviation dynamic sealing ring; is the wear modulus weighted sum; p cis the sealing rough contact pressure; v is the average speed of a single stroke; T is the aviation dynamic sealing ring test time; I(t i ) is the wear modulus of the dynamic sealing ring; t i is the time of the ith measurement node;

[0020] S42: According to the aviation dynamic sealing ring wear H in step S31, the aviation dynamic sealing ring sealing state judgment standard equation is established based on the demand threshold, and the working state S i of the aviation dynamic sealing ring is determined.

[0021] S5: Establishing an aviation dynamic sealing ring aging prediction model for the target working condition, and completing the service life prediction evaluation;

[0022] When the working state of the aviation dynamic sealing ring in step S42 is the normal sealing state S i =1, the aviation dynamic sealing ring service life prediction result based on the wear is obtained according to the aviation dynamic sealing ring aging prediction model under the target working condition calculated in step S31:

[0023]

[0024] Wherein, T0 is the aviation dynamic sealing ring service life prediction result; H0 is the aviation dynamic sealing ring demand judgment threshold.

[0025] Preferably, the aviation dynamic sealing ring service life prediction test is performed in step S1, specifically: a group of aviation dynamic sealing rings are installed, and when one of the sealing rings in the test device reaches the standard of the failure criterion, the test is stopped, and the time when the test is performed is recorded.

[0026] Preferably, the aviation dynamic sealing ring service life model correction test is performed in step S2, specifically:

[0027] S21: A group of aviation dynamic sealing rings are installed; the aviation dynamic sealing rings are opened and placed in the installation slot of the test tool, so that the aviation dynamic sealing rings are placed reasonably, without twisting and turning, and the installation state is consistent;

[0028] S22: The oil temperature in the aviation dynamic sealing ring is raised to the test temperature, and the friction force is measured and recorded under the stable medium pressure for 1 hour;

[0029] S23: The wear life test is performed according to the test speed, oil pressure and test temperature corresponding to the test group, the sensor real-time collects and stores the friction force and oil leakage, and the leakage is observed and recorded every 2 hours.

[0030] Preferably, the wear depth of the wear surface is obtained according to Archard adhesive wear analysis in step S31, specifically:

[0031] According to the Archard adhesive wear analysis, the volume wear rate of the aero dynamic seal ring in t time is determined as:

[0032]

[0033] Wherein, V is the wear volume; t is the wear time; K is the wear coefficient; F is the normal contact load of the seal; H d is the material hardness of the aero dynamic seal ring;

[0034] The wear modulus I of the aero dynamic seal ring is K / H d The wear volume of the aero dynamic seal ring is:

[0035] dV = IFVdt

[0036] Divide both sides of the above formula by the wear area S, then the wear depth of the aero dynamic seal ring is:

[0037] dh = Ip(t) Vdt

[0038] Wherein, h is the wear depth of the aero dynamic seal ring; p(t) is the contact pressure at t time;

[0039] When the wear modulus I and the single stroke average speed v are determined, the wear amount of the seal ring is positively correlated with the contact pressure of the sealing contact surface; the wear depth of the i-th measurement node on the contact surface of the aero dynamic seal ring at t time is:

[0040]

[0041] Due to the mutual influence between the wear amount and the contact pressure of the sealing contact surface, according to the calculated contact pressure at t time, the total wear depth of the aero dynamic seal ring is:

[0042] h = I V∫p(t)dt

[0043] According to the actual test data collection time, the wear amount needs to be discretized as:

[0044]

[0045] Wherein, p(t i ) is the contact pressure at t i time; Δt is the test time interval.

[0046] Preferably, in step S32, the leakage amount Q of the aero dynamic seal ring is due to the reciprocating motion of the piston rod of the aero dynamic seal ring, forming a leakage channel on the sealing surface, performing life prediction modeling and calculation, and setting the initial leakage change of the hydraulic rod seal to zero through conversion, so that the leakage amount Q of the aero dynamic seal ring is:

[0047] Q = Q0 - q

[0048] Wherein, Q0 is the actual measured piston seal leakage; q is the initial leakage of the seal work.

[0049] Preferably, in step S32, the mapping relationship between the leakage and the wear is determined according to the gap leakage analysis, and the leakage of the aviation dynamic seal ring is calculated, specifically:

[0050] Since the differential pressure flow will cause the leakage of the aviation dynamic seal ring, the mapping relationship between the leakage and the wear is deduced through the gap leakage analysis, and the leakage of the aviation dynamic seal ring under the differential pressure flow is obtained as:

[0051]

[0052] Wherein, Q1 is the leakage of the aviation dynamic seal ring under the differential pressure flow; D is the diameter of the cylindrical surface; h is the wear depth; μ j is the fluid dynamic viscosity; Δp is the pressure difference between the two ends of the gap; μ0 is the relative speed of the inner and outer cylinders;

[0053] When the relative speed of the inner and outer cylinders of the aviation dynamic seal ring μ0 = 0, that is, there is no relative movement between the piston and the cylinder wall, the concentric ring gap flow is:

[0054]

[0055] Wherein, Q2 is the leakage of the aviation dynamic seal ring under the differential pressure flow without relative speed;

[0056] Due to the increase of the reciprocating motion times between the piston and the cylinder wall, the aviation dynamic seal ring is worn during reciprocation, and the sealing wear depth h changes; the sealing gap of the aviation dynamic seal ring after wear is equivalent to the concentric annular gap, and the leakage of the aviation dynamic seal ring under the sealing wear depth h is:

[0057]

[0058] Preferably, in step S41, the wear modulus of the aviation dynamic seal ring is:

[0059]

[0060] Wherein, I(t i ) is the wear modulus of the aviation dynamic seal ring; p(t i ) is the contact pressure at time t i .

[0061] In order to ensure the accuracy of the calculation of the wear modulus of the seal ring, the average wear modulus of the seal ring in a wear time period is used to calculate the wear modulus.

[0062] Preferably, the t i Time contact pressure p(t i )for:

[0063]

[0064] Among them, F f (t i ) is t i The friction force over time; μ is the coefficient of kinetic friction.

[0065] Preferably, in step S42, a standard equation for determining the sealing state of the aviation dynamic seal ring is established based on the required threshold, specifically:

[0066]

[0067] Among them, H0 is the threshold for determining the demand for aviation dynamic seals; S i For the working state of aviation dynamic seal ring, S i =1 is the normal sealing state, S i =0 is the seal failure state. When the wear depth of the aviation dynamic seal ring exceeds the judgment threshold, it means that the seal has failed and a new aviation dynamic seal ring needs to be replaced.

[0068] Compared with the prior art, the present invention has the following beneficial effects:

[0069] (1) The present invention avoids the complicated experimental steps of disassembling and assembling the sealing ring by measuring the leakage amount instead of the traditional sealing ring size measurement, reduces the non-experimental wear and performance change of the sealing ring, and increases the service life of the dynamic sealing ring.

[0070] (2) The present invention corrects the wear modulus based on the calculated wear amount of the dynamic seal ring and establishes the Archard model, thereby realizing the prediction of the seal life of the dynamic seal ring. This is of great significance for guiding the design of dynamic seal ring products, optimizing the selection of dynamic seal ring materials and improving the dynamic seal ring production and manufacturing process.

[0071] (3) The wear prediction model established by the dynamic seal life prediction method considering leakage proposed in the present invention has high accuracy and can accurately complete the life prediction of the dynamic seal ring within the acceptable error range. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] Figure 1 This is a flow chart of the method for predicting the service life of an aviation dynamic seal ring based on gap leakage analysis of the present invention;

[0073] Figure 2 This is a flow chart of the dynamic seal life prediction test of the present invention;

[0074] Figure 3A geometric size diagram of a nitrile sealing ring used for a test of the application;

[0075] Figure 4 A test process data diagram of a dynamic sealing life prediction test of the application;

[0076] Figure 5 An effect diagram of a dynamic sealing life prediction model verification of the application. DETAILED DESCRIPTION

[0077] Exemplary embodiments, features and aspects of the application will be described in detail below with reference to the accompanying drawings. The same reference numerals in the drawings represent functionally the same or similar elements. Although various aspects of the embodiments are shown in the drawings, the drawings are not necessarily drawn to scale unless specifically indicated.

[0078] The embodiment of the application provides a kind of aviation dynamic sealing ring service life prediction method based on gap leakage analysis, as shown in Figure 1 As shown in the figure, aviation dynamic sealing ring service life pretest is carried out, sealing ring life is probed, and sealing ring failure criterion is determined;Aviation dynamic sealing ring life model correction test is carried out, and life correction parameters in test process are recorded;According to Archard adhesion wear analysis and gap leakage analysis, the wear amount variable of aviation dynamic sealing ring is obtained;The wear amount of aviation dynamic sealing ring is calculated, the equation of aviation dynamic sealing ring sealing state judgment standard is established, and working state is determined;The aging prediction model of target working condition aviation dynamic sealing ring is established, and service life prediction evaluation is completed;It includes:

[0079] The material of the aviation dynamic sealing ring of the embodiment of the application is nitrile rubber, the inner diameter of the sealing ring is 28.2mm, the cross-sectional diameter is 1.78mm, the material's Mooney-Revlin model coefficient is C_10=-0.12MPa, C_01=1.41MPa, as shown in Figure 3 The geometric size diagram of the nitrile sealing ring used for the test of the application is shown in the figure. The elastic modulus of the polytetrafluoroethylene sealing ring is 225.15MPa, the surface roughness is 0.8607μm, the friction coefficient is 0.285, the wear modulus is 1.2×10^(-5)mm^3 / N·m, the test oil is No.15 aviation hydraulic oil, the density at room temperature is 839.3〖kg / m〗^3, and the viscosity is 9.6435m^2 / s. For example, the wear amount prediction model is established, the product life is predicted, the accelerated life prediction evaluation and the test of failure consistency are verified. In order to verify the accuracy of the wear model, the piston rod speed is 20mm / s, and the stroke is 50mm.

[0080] Step S1: aviation dynamic sealing ring service life pretest is carried out, sealing ring life is probed, and sealing ring failure criterion is determined.

[0081] First, the sealing ring life determination test is carried out, according to the failure criterion of the test: the leakage at the sealing place is 0.05g per minute, when reaching this state, the test time is recorded, the sealing ring life is determined, and the size of the dynamic sealing ring at failure is obtained, the wear amount is calculated, and the specific performance parameter data is shown in Table 1.

[0082] Table 1: Failure performance parameter table of aviation dynamic sealing ring

[0083] Time (h) Failure size (mm) Wear amount (mm) Wear rate 1095 1.0101 0.7698 43.2％

[0084] As Figure 2 shown is a dynamic sealing life pretest flowchart of the application; the aviation dynamic sealing ring service life pretest is carried out, a group of aviation dynamic sealing rings are installed, when one of the sealing rings in the test device reaches the standard of the failure criterion, the test is stopped, and the time of the test is recorded. The failure criterion of the aviation dynamic sealing ring life pretest is set as: the leakage at the sealing place is 0.05g per minute, the test time and the wear amount of the aviation dynamic sealing ring at failure are obtained.

[0085] Step S2: aviation dynamic sealing ring life model correction test is carried out, specifically:

[0086] Step S21: a group of aviation dynamic sealing rings are installed; the aviation dynamic sealing rings are opened and placed in the installation groove of the test tool, so that the aviation dynamic sealing rings are placed reasonably, without twisting and turning, and the installation state is consistent.

[0087] Step S22: the oil temperature in the aviation dynamic sealing ring is raised to the test temperature, and the friction force is measured and recorded under the stable medium pressure for 1 hour.

[0088] Step S23: the wear life test is carried out according to the test speed, oil pressure and test temperature corresponding to the test, the sensor collects and stores the friction force and oil leakage in real time, and the leakage needs to be observed and recorded every 2 hours. The life correction parameters in the test process are recorded, including: test leakage Q, test time T and dynamic sealing ring friction force F f . The wear test data is shown in Table 2.

[0089] Table 2: Part of the friction force and leakage data of the sealing ring wear test

[0090]

[0091]

[0092] Step S3: according to the Archard adhesive wear analysis and gap leakage analysis, the aviation dynamic sealing ring wear amount variable is obtained.

[0093] Step S31: According to Archard adhesive wear analysis, an aviation dynamic seal ring wear calculation model is established; according to Archard adhesive wear analysis, the wear depth of the wear surface is obtained, and the volume wear change rate of the aviation dynamic seal ring in t time is determined as:

[0094]

[0095] Wherein, V is the wear volume; t is the wear time; K is the wear coefficient; F is the normal contact load of the seal; H d is the material hardness of the aviation dynamic seal ring.

[0096] The wear modulus I of the aviation dynamic seal ring is K / H d , and the wear volume of the aviation dynamic seal ring is:

[0097] dV=IFνdt;

[0098] Divide both sides of the above formula by the wear area S, and the wear depth of the aviation dynamic seal ring is:

[0099] dh=Ip(t)νdt;

[0100] Wherein, h is the wear depth of the aviation dynamic seal ring; p(t) is the contact pressure at t time.

[0101] When the wear modulus I and the single stroke average speed v are determined, the wear amount of the seal ring is positively correlated with the contact pressure of the seal contact surface; the wear depth of the i th measurement node on the contact surface of the aviation dynamic seal ring at t time is:

[0102]

[0103] Due to the mutual influence between the wear amount and the contact pressure of the seal contact surface, according to the calculated contact pressure at t time, the total wear depth of the aviation dynamic seal ring is:

[0104] h=Iν∫p(t)dt

[0105] Due to the limitation of real physical test conditions, the step size cannot be infinitely reduced like simulation test, so according to the actual test data collection time, the wear amount needs to be discretized as:

[0106]

[0107] Wherein, p(t i ) is the contact pressure at t i time; Δt is the test time interval.

[0108] The total wear depth of the aviation dynamic seal ring is:

[0109]

[0110] wherein H z is the total wear depth at any time; h i is the wear amount of the i-th node at time t; Δt is the wear time variable; n is the total number of measurement nodes of the aero dynamic seal ring; i is the measurement node number of the aero dynamic seal ring.

[0111] Step S32: determining the mapping relationship between the leakage amount and the wear amount according to the gap leakage analysis, and calculating the leakage amount of the aero dynamic seal ring, specifically:

[0112] Since the pressure difference flow will cause the leakage amount of the aero dynamic seal ring, the mapping relationship between the leakage amount and the wear amount is deduced by gap leakage analysis, and the leakage amount of the aero dynamic seal ring under the pressure difference flow is obtained as:

[0113]

[0114] wherein Q1 is the leakage amount of the aero dynamic seal ring under the pressure difference flow; D is the diameter of the cylindrical surface; h is the wear depth; μ j is the fluid dynamic viscosity; Δp is the pressure difference between the two ends of the gap; μ0 is the relative speed between the inner and outer cylinders.

[0115] When the relative speed between the inner and outer cylinders of the aero dynamic seal ring μ0 = 0, i.e. the concentric circular ring gap flow when there is no relative movement between the piston and the cylinder wall is:

[0116]

[0117] wherein Q2 is the leakage amount of the aero dynamic seal ring under the pressure difference flow when there is no relative speed.

[0118] Since the number of reciprocating movements between the piston and the cylinder wall increases, the aero dynamic seal ring wears during reciprocation, and the sealing wear depth h changes; the sealing gap of the aero dynamic seal ring after wear is equivalent to the concentric annular gap, and the leakage amount of the aero dynamic seal ring under the sealing wear depth h is:

[0119]

[0120] The wear amount variable of the aero dynamic seal ring is obtained as:

[0121]

[0122] wherein ΔH is the wear amount variable of the aero dynamic seal ring; H i is the wear depth at time t; H i-1 is the wear depth at the previous time t; μ jis the fluid dynamic viscosity; L is the length of the gap seal; Q is the leakage of the aero dynamic seal ring; D is the diameter of the cylindrical surface; and Δp is the pressure difference between the two ends of the gap.

[0123] The leakage Q of the aero dynamic seal ring is due to the reciprocating movement of the piston rod of the aero dynamic seal ring, and a leakage channel is formed on the sealing surface. The life prediction modeling and calculation are carried out, the initial leakage change of the hydraulic rod seal is set to zero through conversion, and the leakage Q of the aero dynamic seal ring is obtained as follows:

[0124] Q = Q0 - q;

[0125] wherein Q0 is the actually measured piston seal leakage; and q is the leakage at the initial stage of the sealing work.

[0126] As Figure 4 shown in the dynamic seal life prediction test experiment process data graph of the present application; the relationship between the wear and the leakage is derived according to the foregoing content, and the wear depth change of the seal ring within 200 hours is obtained according to the experimental data as shown in Table 3.

[0127] Table 3 Partial calculation results of the seal ring wear

[0128]

[0129] Step S4: Calculate the wear of the aero dynamic seal ring, establish the seal state judgment standard equation of the aero dynamic seal ring, and determine the working state of the aero dynamic seal ring.

[0130] Step S41: Map the relationship between the total wear depth of the aero dynamic seal ring in step S31 and the wear variable of the aero dynamic seal ring in step S32, and calculate the wear modulus of the aero dynamic seal ring,

[0131] The wear of the aero dynamic seal ring is obtained as follows:

[0132]

[0133] wherein H is the wear of the aero dynamic seal ring; is the wear modulus weighted sum; p c is the sealing rough contact pressure; v is the average speed of a single stroke; T is the test time of the aero dynamic seal ring; I(t i ) is the wear modulus of the dynamic seal ring; t i is the time of the i-th measurement node;

[0134] The wear modulus of the aero dynamic seal ring is:

[0135]

[0136] wherein I(t i ) is the wear modulus of the aero dynamic seal ring; p(ti ) is t i Time contact pressure.

[0137] t i Time contact pressure p(t i )for:

[0138]

[0139] Among them, F f (t i ) is t i The friction force over time; μ is the coefficient of kinetic friction.

[0140] The calculated instantaneous value of the seal ring wear modulus within 200 hours is shown in Table 4.

[0141] Table 4 Partial data table for calculation of seal ring wear modulus

[0142]

[0143] The average wear modulus in the first 200 hours is -1.385×10 -8 According to the Archard wear prediction model, the wear amount of the aviation dynamic seal ring is obtained as follows:

[0144] H=-1.555×10 -8 p c νT;

[0145] Step S42: Based on the wear amount H of the aviation dynamic seal ring in step S31, a standard equation for judging the sealing state of the aviation dynamic seal ring is established based on the required threshold value, specifically:

[0146]

[0147] Among them, H0 is the threshold for determining the demand for aviation dynamic seals; S i For the working state of aviation dynamic seal ring, S i =1 is the normal sealing state, S i =0 is the seal failure state. When the wear depth of the aviation dynamic seal ring exceeds the judgment threshold, it means that the seal has failed and a new aviation dynamic seal ring needs to be replaced.

[0148] Step S5: Establishing an aging prediction model for the aviation dynamic seal ring under target working conditions to complete service life prediction and evaluation;

[0149] When the working state of the aviation dynamic seal ring in step S42 is the normal sealing state S i =1, the aging prediction model of the aviation dynamic seal ring under the target working condition is obtained according to the calculation in step S31, and the service life prediction result of the aviation dynamic seal ring is obtained based on the wear amount:

[0150]

[0151] Wherein, T0 is the aviation dynamic sealing ring service life prediction result; H0 is the aviation dynamic sealing ring demand judgment threshold.

[0152] As Figure 5 The dynamic sealing life prediction model verification effect diagram of the present application is shown, according to the sealing ring life determination test, taking the wear amount = 0.77mm as the failure threshold, it is calculated that the sealing ring life is: 980h when the piston rod speed is 20mm / s, the stroke is 50mm, the friction coefficient is 0.285 and the friction force is 200N. According to the experimental data, the model verification can be carried out, it is found that the model accuracy reaches 89.50%, and the specific results are shown in Table 5:

[0153] Table 5 aviation dynamic sealing ring service life prediction result table

[0154] Predicted life / h Actual life / h Accuracy / % 980 1095 89.50

[0155] The beneficial effects of the present application are that the present application provides an aviation dynamic sealing ring service life prediction method based on gap leakage analysis, the present application replaces the traditional sealing ring size measurement by measuring the leakage amount, avoids the complex disassembly and assembly experiment steps of the sealing ring, reduces the non-experimental wear and performance change of the sealing ring, according to the calculated wear amount, the wear modulus is corrected, the archard model is established, the dynamic sealing life prediction is realized, the wear prediction model established has an accuracy of 89.5%, the life prediction is accurately completed within the acceptance error range, which has important significance for guiding product design, optimizing material selection and improving process.

[0156] The above-described embodiments are only preferred embodiments of the present application, and do not limit the scope of the present application, and various modifications and improvements to the technical solutions of the present application made by those skilled in the art without departing from the design spirit of the present application shall fall within the protection scope of the present application determined by the claims.

Claims

1. A method for predicting the service life of an aviation dynamic seal ring based on gap leakage analysis, characterized in that: It includes: S1: Conduct preliminary service life test of aviation dynamic seals to determine the failure criteria of the seals; The failure criterion of the life pre-test of the aviation dynamic seal ring is to determine the test time and wear amount when the aviation dynamic seal ring fails based on the leakage rate of the seal per minute; S2: Conduct life model correction test of aviation dynamic seal ring and record the life correction parameters during the test, including test leakage Q, test time T and dynamic seal ring friction F f ; S3: Based on Archard adhesive wear analysis and gap leakage analysis, the wear variables of aviation dynamic seals are obtained; S31: Based on Archard adhesive wear analysis, a wear calculation model for aviation dynamic seals is established, and the total wear depth of aviation dynamic seals is obtained as follows: Among them, H z is the total wear depth at any time; h i is the wear amount of the i-th node at time t; Δt is the wear time variable; n is the total number of measurement nodes of the aviation dynamic seal ring; i is the measurement node number of the aviation dynamic seal ring; S32: Determine the mapping relationship between leakage and wear based on gap leakage analysis, calculate the leakage of the aviation dynamic seal ring, and obtain the wear variable of the aviation dynamic seal ring as: Among them, ΔH is the wear variable of aviation dynamic seal ring; H i is the wear depth at time t; H i-1 is the wear depth at time t; μ j is the fluid dynamic viscosity; L is the gap sealing length; Q is the leakage of the aviation dynamic seal ring; D is the diameter of the cylinder; Δp is the pressure difference at both ends of the gap; S4: Calculate the wear of the aviation dynamic seal ring, establish the standard equation for judging the sealing state of the aviation dynamic seal ring, and determine the working state of the aviation dynamic seal ring; S41: Map the relationship between the total wear depth of the aviation dynamic seal ring in step S31 and the wear amount variable of the aviation dynamic seal ring in step S32, calculate the wear modulus of the aviation dynamic seal ring, and obtain the wear amount of the aviation dynamic seal ring as: in, Predict wear of aviation dynamic seals; is the weighted sum of wear modulus; p c is the sealing roughness contact pressure; ν is the average speed of a single stroke; T is the test time of the aviation dynamic seal ring; I(t i ) is the wear modulus of the dynamic seal ring; t i is the time of the i-th measurement node; S42: Based on the wear amount H of the aviation dynamic seal ring in step S31, a standard equation for judging the sealing state of the aviation dynamic seal ring is established based on the required threshold value to determine the working state S of the aviation dynamic seal ring. i ; S5: Establish an aging prediction model for aviation dynamic seals under target working conditions and complete service life prediction and evaluation; When the working state of the aviation dynamic seal ring in step S42 is the normal sealing state S i =1, the aging prediction model of the aviation dynamic seal ring under the target working condition is obtained according to the calculation in step S31, and the service life prediction result of the aviation dynamic seal ring is obtained based on the wear amount: Among them, T0 is the service life prediction result of aviation dynamic sealing ring; H0 is the demand judgment threshold of aviation dynamic sealing ring.

2. The method for predicting the service life of an aviation dynamic seal ring based on gap leakage analysis according to claim 1 is characterized in that: In step S1, a preliminary test of the service life of an aviation dynamic sealing ring is performed, specifically: a group of aviation dynamic sealing rings are installed, the test is stopped when one of the sealing rings in the test device reaches the failure criterion standard, and the test time at this time is recorded.

3. The method for predicting the service life of an aviation dynamic seal ring based on gap leakage analysis according to claim 1, characterized in that: In step S2, a life model correction test of an aviation dynamic seal ring is performed, specifically: S21: Install a set of aviation dynamic seals; expand the aviation dynamic seals and place them into the installation slots of the test fixture, ensuring that the aviation dynamic seals are properly placed, not twisted or flipped, and in a consistent installation state; S22: Raise the oil temperature in the aviation dynamic seal to the test temperature, operate it for 1 hour under a stable medium pressure, and measure and record the friction force; S23: Wear life test is carried out according to the test speed, oil pressure and test temperature corresponding to this group of tests. The sensor collects and stores the friction force and oil leakage in real time. At the same time, the leakage volume needs to be observed and recorded every 2 hours.

4. The method for predicting the service life of an aviation dynamic seal ring based on gap leakage analysis according to claim 1, characterized in that: In step S31, the wear depth of the wear surface is obtained according to Archard adhesive wear analysis, specifically: According to Archard adhesive wear analysis, the volume wear change rate of the aviation dynamic seal ring within time t is determined as: Where V is the wear volume; t is the wear time; K is the wear coefficient; F is the seal normal contact load; H d The material hardness of the aviation dynamic seal ring; Wear modulus of aviation dynamic seal ring I = K / H d , then the wear volume of the aviation dynamic seal is: dV=IFνdt Divide both sides of the above equation by the wear area S, and the wear depth of the aviation dynamic seal ring is: dh=Ip(t)νdt Where h is the wear depth of the aviation dynamic seal; p(t) is the contact pressure at time t; When the wear modulus I and the average speed v of a single stroke are determined, the wear amount of the seal ring is positively correlated with the contact pressure of the seal contact surface; the wear depth of the i-th measurement node on the contact surface of the aviation dynamic seal ring at time t is: Due to the mutual influence between the wear amount and the contact pressure of the sealing contact surface, according to the calculated contact pressure at time t, the total wear depth of the aviation dynamic seal ring is obtained as: h=Iν∫p(t)dt According to the actual test data collection time, the wear amount needs to be discretized as follows: Among them, p(t i ) is t i The contact pressure over time; Δt is the test time interval.

5. The method for predicting the service life of an aviation dynamic seal ring based on gap leakage analysis according to claim 1, characterized in that: In step S32, the leakage amount Q of the aviation dynamic seal ring is formed on the sealing surface due to the reciprocating motion of the piston rod of the aviation dynamic seal ring. The life prediction modeling and calculation are performed. The initial leakage change of the hydraulic rod seal is set to zero through conversion, and the leakage amount Q of the aviation dynamic seal ring is obtained as: Q=Q0-q Among them, Q0 is the actual measured piston seal leakage; q is the leakage at the initial stage of sealing operation.

6. The method for predicting the service life of an aviation dynamic seal ring based on gap leakage analysis according to claim 1, characterized in that: In step S32, the mapping relationship between leakage and wear is determined based on the gap leakage analysis, and the leakage of the aviation dynamic seal ring is calculated, specifically: Since differential pressure flow can cause leakage of aviation dynamic seals, the mapping relationship between leakage and wear can be deduced through gap leakage analysis, and the leakage of aviation dynamic seals under differential pressure flow is obtained as follows: Where Q1 is the leakage of the aviation dynamic seal ring under pressure differential flow; D is the diameter of the cylinder; h is the wear depth; μ j is the dynamic viscosity of the fluid; Δp is the pressure difference at both ends of the gap; μ0 is the relative velocity of the inner and outer cylinders; When the relative speed of the inner and outer cylinders of the aviation dynamic seal is μ0=0, that is, when there is no relative motion between the piston and the cylinder wall, the flow rate of the concentric ring gap is: Among them, Q2 is the leakage of aviation dynamic seal ring under pressure differential flow without relative velocity; Due to the increase in the number of reciprocating motions between the piston and the cylinder wall, the aviation dynamic seal ring wears during the reciprocating process, and the seal wear depth h changes. The sealing gap of the aviation dynamic seal ring after wear is equivalent to the concentric annular gap. The leakage of the aviation dynamic seal ring at the seal wear depth h is:

7. The method for predicting the service life of an aviation dynamic seal ring based on gap leakage analysis according to claim 1, characterized in that: The wear modulus of the aviation dynamic seal ring in step S41 is: Among them, I(t i ) is the wear modulus of aviation dynamic seal; p(t i ) is t i contact pressure of time; In order to ensure the accuracy of the calculation of the wear modulus of the sealing ring, the average wear modulus of the sealing ring within a wear period is used to calculate its wear modulus.

8. The method for predicting the service life of an aviation dynamic seal ring based on gap leakage analysis according to claim 7, characterized in that: The t i Time contact pressure p(t i )for: Among them, F f (t i ) is t i The friction force over time; μ is the coefficient of kinetic friction.

9. The method for predicting the service life of an aviation dynamic seal ring based on gap leakage analysis according to claim 1, characterized in that: In step S42, a standard equation for determining the sealing state of the aviation dynamic seal ring is established based on the required threshold, specifically: Among them, H0 is the threshold for determining the demand for aviation dynamic seals; S i For the working state of aviation dynamic seal ring, S i =1 is the normal sealing state, S i =0 is the seal failure state. When the wear depth of the aviation dynamic seal ring exceeds the judgment threshold, it means that the seal has failed and a new aviation dynamic seal ring needs to be replaced.

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