Method for determining an accelerated factor of a friction pair of a compressor pump body based on an accelerated wear model

Abstract

This invention provides a method for determining the acceleration factor of compressor pump body friction pairs based on an accelerated wear model, comprising: S1, collecting compressor rated operating conditions and structural parameters; S2, determining a first acceleration operating condition and a second acceleration operating condition, and respectively determining the intake pressure, exhaust pressure, and rotational frequency of the first acceleration operating condition and the second acceleration operating condition; S3, constructing the angle θ at which the cylinder compression chamber reaches the exhaust pressure. d i The calculation model is established and the compression index m is solved; S4, the angle at which the cylinder compression chamber reaches the exhaust pressure under the first and second acceleration conditions are calculated respectively; S5, an accelerated wear model of the compressor pump body friction pair is constructed and the acceleration index κ is calculated; S6, based on the rated operating condition and the experimental accelerated operating condition, the acceleration factor of the compressor pump body friction pair is calculated using the accelerated wear model determined in S5. This invention does not require a large number of experimental samples, and the calculation process is faster and more accurate. The determined acceleration factor can be applied in multiple scenarios.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of compressor pump body reliability accelerated experiment, and particularly relates to a method for determining an accelerated factor of a compressor pump body friction pair based on an accelerated wear model. BACKGROUND

[0002] One failure mode of a compressor product is the wear failure of a pump body friction pair, and the wear life thereof needs to be verified. In the product research and development process, the wear life of the product is generally verified through reliability experiments, but the experimental period is long, and reliability accelerated experiments often need to be carried out to improve the verification efficiency.

[0003] The key to carrying out reliability accelerated experiments is to establish an accelerated model based on the failure time results at multiple high stress levels and to calculate an accelerated factor to evaluate the failure time at a low stress level. The current method for calculating the accelerated factor mainly has two problems, one is that the required experimental sample size is too large, at least 3 stress levels need to be developed for experiments, and at least 4 samples are needed for each stress level, so at least 12 samples are needed; the second is that the accelerated model is fitted based on experimental data, and lacks a mechanistic explanation, and the applicability of the accelerated factor is limited.

[0004] Therefore, there is an urgent need to provide a new method for determining an accelerated factor of a compressor pump body friction pair to solve the problems of the prior art, such as too many experiments and limited applicability. SUMMARY

[0005] In order to solve the above problems of the prior art, the purpose of the present application is to provide a method for determining an accelerated factor of a compressor pump body friction pair based on an accelerated wear model, which can directly determine the accelerated factor of the compressor pump body friction pair through a mechanistic model by determining the relevant fitting parameters, which does not require a large number of experimental samples in the calculation, and the calculation process is more rapid and accurate, and the wear experiment is carried out to determine the accelerated index, and the accurate accelerated factor can be determined in multiple scenarios.

[0006] Specifically, the present application provides a method for determining an accelerated factor of a compressor pump body friction pair based on an accelerated wear model, which comprises the following steps:

[0007] S1, collecting the rated operating conditions and structural parameters of the compressor, wherein the rated operating conditions and structural parameters of the compressor include: rated operating condition suction pressure, rated operating condition discharge pressure, rated operating condition rotating frequency, cylinder inner radius, roller outer radius, cylinder depth, and the included angle between the suction port lower edge and the blade center line;

[0008] S2, determining a first accelerated operating condition and a second accelerated operating condition, and determining the suction pressure, discharge pressure and rotating frequency of the first accelerated operating condition and the second accelerated operating condition, respectively;

[0009] S3, build the angle θ of the cylinder compression chamber reaching the exhaust pressure d i The calculation model of and the solution of the compression index m, specifically including the following sub-steps:

[0010] S31, build the angle θ of the cylinder compression chamber reaching the exhaust pressure d i The calculation model of is:

[0011]

[0012] In the formula,

[0013]

[0014] Wherein, is the suction pressure of the i-th working condition, is the exhaust pressure of the i-th working condition, R is the radius of the cylinder, r is the outer radius of the roller, H is the depth of the cylinder, β is the included angle between the lower edge of the suction port and the center line of the blade, and m is the compression index;

[0015] S32, the calculation formula of the compression index m is as follows:

[0016]

[0017] S33, the angle of the cylinder compression chamber reaching the exhaust pressure is obtained by simulation analysis and brought into the calculation formula of step S31, and the value of the compression index m is obtained;

[0018] S4, the angle θ of the cylinder compression chamber reaching the exhaust pressure in the first acceleration working condition and the second acceleration working condition is calculated respectively by using the calculation model in step S3 d 1 And θ d 2 ;

[0019] S5, build the acceleration wear model of the compressor pump body friction pair and calculate the acceleration index κ, specifically including the following sub-steps:

[0020] S51, the acceleration wear model of the compressor pump body friction pair is:

[0021]

[0022] Wherein, F i , F j are the maximum gas forces borne by the friction pair under the i-th working condition and the j-th working condition, n i , n j are the rotation frequencies of the compressor pump body under the i-th working condition and the j-th working condition, and κ is the acceleration index;

[0023] S52, carry out wear experiment to determine acceleration index κ;

[0024] S6, based on the parameters of rated working condition and experimental acceleration working condition, calculate the compressor pump friction pair acceleration factor by using the compressor pump friction pair acceleration wear model determined in step S5.

[0025] Preferably, in step S51, the maximum gas force F i The calculation formula is:

[0026]

[0027] Where, P max i The maximum pressure of the cylinder compression chamber under i working condition, b is the fitting parameter.

[0028] Preferably, the maximum pressure P max i The calculation formula is:

[0029]

[0030] Preferably, the value of compression index m is 1.6, the value of b is 0.18, and the value of acceleration index κ is 9.67.

[0031] Preferably, in step S6, the calculation formula for calculating the compressor pump friction pair acceleration factor A PRE The calculation formula is:

[0032]

[0033] Where, F 实 , F 额 The maximum gas force on the friction pair under the experimental acceleration working condition and the rated working condition respectively, n 实 , n 额 The rotation frequency of the compressor pump under the experimental acceleration working condition and the rated working condition respectively.

[0034] Preferably, in step S2, the first acceleration working condition intake pressure is the minimum limit value, and the second acceleration working condition intake pressure is 1.05-1.1 times of the first acceleration working condition intake pressure;

[0035] The working frequency of the second acceleration working condition is the maximum limit value, and the working frequency of the first acceleration working condition is 0.75-0.8 times of the working frequency of the second acceleration working condition;

[0036] The first acceleration working condition exhaust pressure and the first acceleration working condition exhaust pressure are all taken as the maximum limit value.

[0037] Preferably, step S52 specifically includes the following sub-steps:

[0038] S521, respectively, in the first acceleration condition and the second acceleration condition, the compressor wear experiment is carried out, at least 3 samples are selected for each acceleration condition, when the performance of the compressor is more than 5% attenuation, the experiment is stopped, and the wear of each sample is tested after the experiment is completed;

[0039] S522, the wear pseudo-life of each sample is calculated;

[0040] S523, the wear life distribution of the friction pair under two acceleration conditions is determined respectively;

[0041] S524, the acceleration index κ is determined based on the wear life distribution of the friction pair under two acceleration conditions, and the calculation formula is as follows:

[0042] Ln(n i t i )=Ln(C)-κLn(F i )

[0043] Wherein, t i is the time required for the friction pair to reach the expected wear state under the current condition, F i is the maximum gas force on the friction pair under the i condition, and Ln(C) is the intercept.

[0044] Preferably, the maximum wear of the friction pair in the plurality of samples in step S522 is selected as the reference wear Based on the assumption that the wear amount is approximately linearly accumulated in the stable wear stage, the time for each friction pair of each experimental sample to reach the reference wear is calculated As the pseudo-failure life of the friction pair of each sample;

[0045] In step S523, based on the pseudo-failure life of each sample, the maximum likelihood estimation method is used to estimate the life distribution of the sample under two acceleration conditions, that is, the shape parameter and the scale parameter of the Weibull distribution are determined.

[0046] Preferably, in step S524, the friction pair reaches the same wear state under multiple conditions according to the accelerated wear model, and has:

[0047] (F 1 ) κ ×n×t0=(F 2 ) κ ×n ′ ×t ALT =C

[0048] Taking the logarithm of the expression (F i ) κ ×n i ×t i =C, we get:

[0049] Ln(n i t i )=Ln(C)-κLn(F i )。

[0050] Preferably, in step S5, the suction pressure, the exhaust pressure and the rotation frequency under the experimental accelerated working condition are obtained through experiments.

[0051] Compared with the prior art, the present application has the following advantages:

[0052] (1) The present application provides a compressor pump body friction pair acceleration factor determination method based on an accelerated wear model, which can directly calculate the compressor pump body friction pair acceleration factor through a calculation formula, and the acceleration index is obtained through simulation analysis, which does not require a large number of experimental samples, and the calculation process is more rapid and accurate, and the compressor pump body friction pair acceleration factor calculation formula considers the mechanism influence, and the determined acceleration factor can be applied in multiple scenarios.

[0053] (2) On the one hand, the present application determines the value of the compression index m based on simulation analysis, and through verification, it is found that the calculated start exhaust angle using the calculation model of the angle at which the cylinder compression chamber reaches the exhaust pressure is very close to the simulation obtained start exhaust angle, and there is almost no error, which can be accurately used in the subsequent calculation process. On the other hand, the acceleration index κ is determined through wear experiments, which ensures the accuracy of the accelerated wear model, thereby ensuring the accuracy of the acceleration factor value. BRIEF DESCRIPTION OF DRAWINGS

[0054] Figure 1 It is a flowchart of the compressor pump body friction pair acceleration factor determination method based on the accelerated wear model of the present application;

[0055] Figure 2 It is a compressor working cavity simulation model of the present application;

[0056] Figure 3 It is a compressor working cavity meshing diagram of the present application;

[0057] Figures 4a-4e It is a compressor working process simulation diagram of the present application;

[0058] Figure 5 It is a schematic diagram of the pressure change curve output by simulation;

[0059] Figure 6 It is a schematic diagram of extracting the pressure change curve in a single cycle;

[0060] Figure 7 It is a schematic diagram of the angle curve of the exhaust pressure under the first accelerated working condition obtained by simulation;

[0061] Figure 8 An angle curve diagram for simulating the exhaust pressure in the second acceleration condition is shown. DETAILED DESCRIPTION

[0062] Hereinafter, embodiments of the present application will be described with reference to the accompanying drawings.

[0063] Specifically, the present application provides a compressor pump body friction pair acceleration factor determination method based on an acceleration wear model, as shown in the formula (1), which comprises the following steps: Figure 1

[0064] S1, collecting compressor rated working conditions and structural parameters, wherein the compressor rated working conditions and structural parameters include rated working condition suction pressure, rated working condition exhaust pressure, rated working condition rotating frequency, cylinder inner radius, roller outer radius, cylinder depth, and the included angle between the suction port lower edge and the blade center line.

[0065] S2, determining the first acceleration condition and the second acceleration condition, and respectively determining the suction pressure, the exhaust pressure and the rotating frequency of the first acceleration condition and the second acceleration condition.

[0066] The parameters of the acceleration condition are generally between the rated condition and the limiting condition. In a specific embodiment, the first acceleration condition intake pressure is the minimum limit value, and the second acceleration condition intake pressure is slightly larger than the first acceleration condition, generally 5%-10% larger, i.e. 1.05-1.1 times the first acceleration condition intake pressure. The working frequency of the second acceleration condition is the maximum limit value, and the working frequency of the first acceleration condition is slightly lower than the working frequency of the second acceleration condition, generally reduced by 20%-25%, i.e. 0.75-0.8 times the working frequency of the second acceleration condition. The exhaust pressure of the two acceleration conditions is according to the limiting use condition / overload use condition, and the exhaust pressure is the maximum limit value.

[0067] S3, constructing the calculation model of the angle θ of the cylinder compression cavity reaching the exhaust pressure d i and solving the compression index m, specifically comprising the following sub-steps:

[0068] S31, constructing the calculation model of the angle θ of the cylinder compression cavity reaching the exhaust pressure d i

[0069]

[0070] In the formula, P is the exhaust pressure, P0 is the suction pressure, n is the rotating frequency, R is the cylinder inner radius, r is the roller outer radius, h is the cylinder depth, and θ is the angle of the cylinder compression cavity reaching the exhaust pressure.

[0071]

[0072] wherein, P0 is the suction pressure of the i-th working condition, ​​​is the exhaust pressure of the i th working condition, R is the radius of the cylinder, r is the outer radius of the rolling sleeve, H is the depth of the cylinder, β is the included angle between the lower edge of the air inlet and the center line of the blade, and m is the compression index. In the specific embodiment, the angle θ at which the cylinder compression chamber reaches the exhaust pressure under different working conditions can be solved based on the above formula d i , which can ensure the accuracy of the calculation results and greatly reduce the workload.

[0073] S32, the calculation formula of the compression index m is as follows:

[0074]

[0075] S33, the angle at which the cylinder compression chamber reaches the exhaust pressure is obtained by simulation analysis and is brought into the calculation formula of step S31 to obtain the value of the compression index m.

[0076] The specific simulation process is as follows:

[0077] The fluid simulation uses Simerics PumpLinx software, and a CAD model of the structure fluid is established according to the structure size and working principle as shown in Figure 2 .

[0078] First, the fluid region and the fluid boundary are divided according to the fluid inlet, the fluid outlet, the exhaust valve, the rotor, the inner wall of the cylinder and other parts, and the CAD model is divided into different blocks according to different types, and the fluid and dynamic mesh are set for different types of fluid and boundary regions, as shown in Figure 3 .

[0079] In the model, working parameters are set respectively, including suction pressure, exhaust pressure, speed, gas parameters, clearance and the like. After the working parameter setting is completed, fluid solving parameter setting is performed. Since the gas flow in the clearance and the compression chamber belongs to turbulent flow during rotation, a two-parameter turbulent equation needs to be introduced in the simulation, and the difference format is first-order upwind format.

[0080] After all the parameters are set, the solving can be performed. The solving process is consistent with the actual working process, and a rotation around the inner wall is completed in one cycle to complete a compression and exhaust, and the whole process is shown in Figures 4a-4e .

[0081] The pressure change curve output by the simulation is shown in Figure 5 , and the compression chamber pressure change curve in a single cycle is shown in Figure 6 . Based on the above curve, the exhaust start angle θ dThe angle at which the pressure reaches the specified exhaust pressure is substituted into the formula for solving the compression index m, and the value of the compression index m is solved. In one embodiment, the final value of m is 1.6, which is also the optimal value in specific applications.

[0082] S4, calculating the angle θ at which the cylinder compression chamber reaches the exhaust pressure under the first and second acceleration conditions respectively using the calculation model in step S3 d 1 and θ d 2 .

[0083] S5, constructing an acceleration wear model of the compressor pump body friction pair and calculating an acceleration index κ, specifically including the following sub-steps:

[0084] S51, constructing the acceleration wear model of the compressor pump body friction pair is:

[0085]

[0086] wherein, F i , F j are the maximum gas forces received by the friction pair under the i-th condition and the j-th condition, n i , n j are the rotation frequencies of the compressor pump body under the i-th condition and the j-th condition, and κ is the acceleration index.

[0087] The calculation formula of the maximum gas force F i received by the friction pair under the i-th condition is:

[0088]

[0089] wherein, P max i is the maximum pressure of the cylinder compression chamber under the i-th condition, and b is a fitting parameter, and in one embodiment, the value of b is 0.18.

[0090] wherein, P max i is the maximum pressure of the cylinder compression chamber under the i-th condition.

[0091]

[0092] The construction process of the acceleration wear model is:

[0093] The general relationship between the wear amount of the friction surface generated per unit distance of sliding and the contact pressure is:

[0094] I=QP κ

[0095] In the formula, Q is a wear coefficient, which is related to structural parameters such as material hardness, surface roughness, lubrication state and working conditions, and P is a surface contact pressure, which is determined by external load conditions; κ is related to the structure of the part and is generally determined through experiments.

[0096] Taking the same total wear amount as the equivalent basis of the accelerated experiment, there is:

[0097]

[0098] In the formula, Q ALT and Q0 represent the wear coefficients under the accelerated working condition and the conventional working condition respectively; and P0 represent the unit contact pressures under the accelerated working condition and the conventional working condition respectively; S represents the relative sliding displacement of the friction pair in one rotation of the pump body; t ALT and t0 represent the time required to reach the same wear amount under the accelerated working condition and the conventional working condition respectively.

[0099] In the accelerated experiment, by restricting the range of pressure and temperature, the wear mechanism and the lubrication state of the friction pair are ensured to be similar, so it can be considered that Q ALT = Q0, and S is only related to the structural size and is not related to the working condition, so there is:

[0100]

[0101] That is:

[0102]

[0103] S52, the wear experiment is carried out to determine the acceleration index κ, which specifically includes the following sub-steps:

[0104] S521, the compressor wear experiment is carried out under the first accelerated working condition and the second accelerated working condition respectively, at least three samples are selected for each accelerated working condition, the experiment is stopped when any performance of the compressor decays by more than 5%, and the wear amount of the friction pair of each sample is tested after the experiment is completed.

[0105] S522, the wear pseudo-life of the friction pair of each sample is calculated: the maximum wear amount of the friction pair in multiple samples is selected as the reference wear amount Based on the assumption that the wear amount in the stable wear stage is approximately linearly accumulated, the time for each experimental sample to reach the reference wear amount of each friction pair is calculated as the pseudo-failure life of the friction pair of each sample.

[0106] S523, the wear life distribution of the friction pair under two accelerated working conditions is determined respectively: based on the pseudo-failure life of each sample, the maximum likelihood estimation method is used to estimate the life distribution of the sample under two accelerated working condition levels, that is, the shape parameter and the scale parameter of the Weibull distribution are determined.

[0107] S524, determine the acceleration index K based on the characteristic life under two acceleration conditions, and the friction pair reaches the same wear state under multiple working conditions according to the acceleration wear model, which has:

[0108] (F 1 ) κ ×n×t0=(F 2 ) κ ×n′×t ALT =C。

[0109] Taking the logarithm of both sides of the expression (F i ) κ ×n i ×t i =C, we get:

[0110] Ln(n i t i )=Ln(C)-κLn(F i )。

[0111] Where t i is the time required for the friction pair to reach the expected wear state under the current working condition.

[0112] In one embodiment, the acceleration index K is solved as 9.67, which is also the optimal value in specific applications.

[0113] S6, based on the parameters of the rated working condition and the experimental acceleration working condition, calculate the acceleration factor of the compressor pump body friction pair using the acceleration wear model of the compressor pump body friction pair determined in step S5.

[0114] The calculation formula of the acceleration factor A PRE of the compressor pump body friction pair in step S6 is specifically:

[0115]

[0116] Where F 实 , F 额 are the maximum gas forces on the friction pair under the experimental acceleration working condition and the rated working condition respectively, n 实 , n 额 are the rotation frequencies of the compressor pump body under the experimental acceleration working condition and the rated working condition respectively.

[0117] In specific embodiments, the suction pressure, discharge pressure and rotation frequency under the experimental acceleration working condition are obtained through experiments. Specific embodiment 1

[0119] S1, collect the compressor rated working condition and structure information as shown in Table 1.

[0120] Table 1

[0121]

[0122] S2, determine two acceleration conditions and parameters of the two acceleration conditions as shown in Table 2.

[0123] Table 2

[0124] Operating Condition Number Suction Pressure Discharge Pressure Frequency (Hz) 1 0.75 4.8 85 2 0.8 4.8 110

[0125] S3, construct the angle θ of the cylinder compression chamber reaching the exhaust pressure d i The calculation model and solve the compression index m, specifically including the following sub-steps:

[0126] S31, construct the calculation model of the angle θ of the cylinder compression chamber reaching the exhaust pressure d i .

[0127] S32, substitute the simulation obtained exhaust starting angle into the formula for solving the compression process index m:

[0128]

[0129] The compression index m is 1.6.

[0130] The simulation data is shown in Table 3:

[0131]

[0132] The angle curve of the exhaust pressure of the two working conditions obtained by simulation is shown in Figure 7 and Figure 8 , wherein, Figure 7 is the angle curve of the exhaust pressure of the first acceleration condition obtained by simulation; Figure 8 is the angle curve of the exhaust pressure of the second acceleration condition obtained by simulation.

[0133] S4, calculate the angle θ of the cylinder compression chamber reaching the exhaust pressure d 1 and θ d 2 in the first and second acceleration conditions using the calculation model in step S3. The theoretical value of the exhaust angle is shown in Table 4.

[0134] Table 4 Theoretical value of exhaust angle

[0135]

[0136] From the table, it can be seen that the angle θ of the cylinder compression chamber reaching the exhaust pressure d iThe calculated start exhaust angle is very close to the simulated start exhaust angle, with almost no error, and can be accurately used in subsequent calculation process.

[0137] S5, constructing a compressor pump body friction pair accelerated wear model and calculating an acceleration index κ, specifically including the following sub-steps:

[0138] S51, constructing a compressor pump body friction pair accelerated wear model is:

[0139]

[0140] Where, F i , F j are the maximum gas forces received by the friction pair under the i-th working condition and the j-th working condition, n i , n j are the rotation frequencies of the compressor pump body under the i-th working condition and the j-th working condition, and κ is the acceleration index.

[0141] The specific construction process is as follows:

[0142] Firstly, the general equation of the compressor pump body friction pair accelerated wear model is constructed based on the adhesive wear failure mechanism model.

[0143] The general relationship between the wear amount generated by the friction surface per unit sliding distance and the contact pressure is:

[0144] I=QP κ

[0145] In the formula, Q is the wear coefficient, which is related to structural parameters such as material hardness, surface roughness, lubrication state and working condition; P is the surface contact pressure, which is determined by external load conditions; κ is related to the structure of the part, and is generally determined by experiment.

[0146] Secondly, taking the same total wear amount as the equivalent basis of the accelerated experiment, then:

[0147]

[0148] In the formula, Q ALT , Q0 respectively represent the wear coefficients under the accelerated working condition and the conventional working condition; respectively represent the unit contact pressure under the accelerated working condition and the conventional working condition; S represents the relative sliding displacement of the friction pair in one rotation of the pump body; t ALT , t0 respectively represent the time required to reach the same wear amount under the accelerated working condition and the conventional working condition.

[0149] Finally, in the accelerated experiment, by restricting the range of pressure and temperature, the wear mechanism and lubrication state of the friction pair are approximately ensured, so it can be considered that Q ALT= Q0, while S is only related to the structure size and is independent of the working condition, then we have:

[0150]

[0151] i.e.:

[0152]

[0153] Based on the above formula, the accelerated wear model of the compressor pump body friction pair can be obtained.

[0154] S52, the power index κ of the accelerated wear model is determined by conducting a wear experiment, specifically including the following steps:

[0155] S521, the compressor wear experiment is conducted under two accelerated working conditions respectively, and at least three samples are used for each working condition. The experiment is stopped when any performance of the compressor decays by more than 5%. After the experiment is completed, the wear amount of the friction pair of each sample is tested:

[0156] (1) Observe the wear area and find the wear edge.

[0157] (2) Observe the wear edge under the super-depth microscope, find the height step formed by wear on the surface, and take the height difference as the wear amount of the current position. For the wear edge that is not obvious, take the height difference in the width direction of the wear area as the wear amount.

[0158] (3) Take 3-4 points along the wear edge, select the test points as shown in Table 5, and determine the average wear amount of the friction pair. The wear amount test is shown in Table 6.

[0159] Table 5

[0160] Test Point 1 Test Point 2 Test Point 3 Test Point 4 Average Value 1.589 6.769 7.883 4.509 5.188

[0161] Table 6

[0162]

[0163]

[0164] S522, the pseudo-life of the friction pair of each sample is calculated:

[0165] Select the maximum wear amount of the friction pair in multiple samples as the reference wear amount Based on the assumption that the wear amount is approximately linearly accumulated in the stable wear stage, the time for each friction pair of each experimental sample to reach the reference wear amount is extrapolated and calculated As the pseudo-failure life of the friction pair of each sample, it is specifically shown in Table 7.

[0166] Table 7

[0167]

[0168] S523, respectively determine the friction pair wear life distribution under two acceleration conditions:

[0169] Based on historical data, the wear life distribution obeys Weibull distribution, based on the pseudo-life data of each sample, the maximum likelihood estimation method is used to estimate the life distribution of the sample under two acceleration conditions, that is, to determine the shape parameter and scale parameter of Weibull distribution. The working condition and characteristic life of the two acceleration conditions are shown in Table 8.

[0170] Table 8

[0171]

[0172]

[0173] Specifically, Van Montfort test method is used to test whether the life distribution obeys Weibull distribution based on the r data. First, the null hypothesis is established:

[0174] H0: The life of the product obeys Weibull distribution.

[0175] W(β,η)

[0176] Let

[0177]

[0178] They are order statistics of extreme value distribution and standard extreme value distribution respectively, where μ = lnη, σ = 1 / β are unknown parameters. Van Montfort statistic is constructed:

[0179]

[0180] Under the condition that the null hypothesis H0 is established, G i Asymptotically independent and asymptotically obey standard exponential distribution, that is, χ 2 Distribution with 2 degrees of freedom, G i Divide into two groups, then the statistic:

[0181]

[0182] Asymptotically obey F distribution with degrees of freedom 2(r-r'-1), 2r', where For a given significance level α, if:

[0183] F 1-α / 2 (2(r-r'-1), 2r') < F < F α / 2 (2(r-r'-1), 2r').

[0184] The original hypothesis H0 is considered to be true, and the truncated sample is from a Weibull distribution, where F α (f1,f2) is the alpha quantile of the F distribution with degrees of freedom f1,f2, and the values can be found in the F distribution critical value table for alpha = 0.1, 0.05, 0.01. The test results of each friction pair are shown in Table 9.

[0185] Table 9

[0186]

[0187] S524, determine the wear life distribution of the friction pair under two acceleration conditions.

[0188] From the acceleration equation, when the friction pair reaches the same wear state under multiple conditions, we have:

[0189] (F 1 ) κ ×n×t0=(F 2 ) κ ×n′×t ALT =C

[0190] Taking the logarithm of both sides of the expression (F i ) κ ×n i ×t i =C, we get:

[0191] Ln(n i t i )=Ln(C)-κLn(F i ).

[0192] Therefore, the accelerated wear model is a linear function in the double logarithmic coordinate, and the slope κ and the intercept Ln(C) are unknown variables. At this time, we have obtained the time t i required for the friction pair to reach the same wear state under at least two conditions based on experimental data, and we know the contact force F i and the rotation frequency n i of the friction pair under each condition, which can be substituted into the expression to determine the acceleration index κ = 9.67.

[0193] S6, calculate the acceleration factor. The specific steps of this embodiment are as follows:

[0194] Collect the compressor rated operating conditions and structural parameters, wherein the compressor rated operating conditions and structural parameters

[0195] include: rated operating condition suction pressure, rated operating condition discharge pressure, rated operating condition rotation frequency, cylinder inner radius, roller outer radius, cylinder depth, and the included angle between the lower edge of the suction port and the center line of the blade. In this embodiment, the collected compressor rated operating conditions and structural parameters are shown in Table 10.

[0196] Table 10

[0197]

[0198]

[0199] Using the following formula, substitute the rated working condition suction pressure P b = 0.7Mpa, rated working condition exhaust pressure P d = 4.2Mpa, working frequency 85Hz, and the structural parameters of the values R=0.024m, r=0.018m, H=0.015m, β=28°. With the help of Matlab and other computing tools to solve θ d = 217.4°.

[0200]

[0201] The maximum pressure P max of the cylinder compression chamber under the rated working condition is calculated using the following formula in this embodiment, resulting in P max = 7.5Mpa:

[0202]

[0203] The maximum gas force F 额 (N) on the friction pair under the rated working condition is calculated using the following formula:

[0204]

[0205] The experimental acceleration working condition parameters are determined, specifically including: acceleration working condition suction pressure P b ', unit: Mpa, in this embodiment, according to the limited use condition / overload use condition, the suction pressure is taken as the minimum limit value under the condition that the pressure ratio does not exceed the allowable value, which is 0.5Mpa in this embodiment.

[0206] Acceleration working condition exhaust pressure P d ', unit: Mpa, in this embodiment, according to the limited use condition / overload use condition, the exhaust pressure is taken as the maximum limit value, which is 4.2Mpa in this embodiment.

[0207] Acceleration working condition rotation frequency n', unit: Hz, in this embodiment, the working frequency is taken as the maximum limit value, which is 110Hz in this embodiment.

[0208] The angle θ d ' of the cylinder compression chamber reaching the exhaust pressure under the acceleration working condition is calculated.

[0209] The maximum pressure P max ' of the cylinder compression chamber under the acceleration working condition is calculated.

[0210]

[0211] Calculate the maximum gas force F experienced by the compressor pump body friction pair under acceleration conditions. 实 :

[0212]

[0213] The acceleration factor A of the pump body friction pair is calculated using the following formula. PRE :

[0214]

[0215] As can be seen from the above embodiments, the present invention directly calculates the acceleration factor of the compressor pump body friction pair through a calculation formula. The acceleration index is obtained through simulation analysis, which does not require a large number of experimental samples and the calculation process is faster and more accurate. Furthermore, the calculation formula for the acceleration factor of the compressor pump body friction pair takes into account the mechanism influence, and the determined acceleration factor can be applied in multiple scenarios.

[0216] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for determining an accelerated factor of a compressor pump body friction pair based on an accelerated wear model, the method comprising: It comprises the following steps: ​ S1, collecting compressor rated operating conditions and structural parameters, wherein the compressor rated operating conditions and structural parameters include: rated operating condition suction pressure, rated operating condition discharge pressure, rated operating condition rotating frequency, cylinder inner radius, roller outer radius, cylinder depth, and the included angle between the lower edge of the suction port and the blade center line; S2, determining a first acceleration operating condition and a second acceleration operating condition, and respectively determining the suction pressure, discharge pressure and rotating frequency of the first acceleration operating condition and the second acceleration operating condition; S3, Constructing the cylinder compression chamber at the angle θ to achieve exhaust pressure. d i The calculation model is used to solve for the compression index m, specifically including the following sub-steps: S31, constructing the angle θ at which the compression chamber of the cylinder reaches the exhaust pressure d i The calculation model is: In the formula, wherein, is the intake pressure for the i-th operating condition, is the exhaust pressure for the i-th operating condition, R is the radius of the cylinder, r is the outer radius of the roller, H is the depth of the cylinder, β is the angle between the lower edge of the intake port and the center line of the blade, and m is the compression exponent. S32, the calculation formula of the compression index m is as follows: S33, the angle at which the cylinder compression chamber reaches the discharge pressure is obtained through simulation analysis and is brought into the calculation formula of step S31 to obtain the value of the compression index m; S4, calculating the angle θ at which the compression chamber reaches the exhaust pressure under the first and second acceleration conditions respectively using the calculation model in step S3 d 1 and θ d 2 ; S5, constructing a compressor pump body friction pair accelerated wear model and calculating an acceleration index κ, specifically comprising the following sub-steps: S51, the compressor pump body friction pair accelerated wear model is constructed as follows: wherein F i , F j are the maximum gas forces on the friction pair in the i-th and j-th operating conditions, respectively, j being an operating condition different from i, n i , n j are the rotational frequencies of the compressor pump body in the i-th and j-th operating conditions, respectively, and k is an acceleration exponent. S52, wear experiment is carried out to determine the acceleration index κ; S6, based on the rated operating condition and the experimental acceleration operating condition, the compressor pump body friction pair accelerated wear model determined in step S5 is used to calculate the compressor pump body friction pair acceleration factor.

2. The method of claim 1, wherein: The maximum gas force F received by the friction pair in the i working condition in step S51 i The calculation formula is: where P max i is the maximum cylinder pressure under i operating conditions, and b is a fitting parameter.

3. The method of claim 2, wherein: The maximum cylinder compression chamber pressure P under the i operating condition max i The calculation formula is:

4. The method of claim 1, wherein: The value of the compression index m is 1.6, the value of b is 0.18, and the value of the acceleration index κ is 9.

67.

5. The method of claim 1, wherein: In step S6, the acceleration factor A of the compressor pump body friction pair is calculated. PRE The specific calculation formula is as follows: wherein F 实 , F 额 are the maximum gas forces received by the friction pair under the experimental acceleration operating condition and the rated operating condition, respectively, n 实 , n 额 are the rotational frequencies of the compressor pump body under the experimental acceleration operating condition and the rated operating condition, respectively.

6. The method of claim 1, wherein: In step S2, the first acceleration operating condition suction pressure is the minimum limit value, and the second acceleration operating condition suction pressure is 1.05-1.1 times the first acceleration operating condition suction pressure; The second acceleration operating condition working frequency is the maximum limit value, and the first acceleration operating condition working frequency is 0.75-0.8 times the second acceleration operating condition working frequency; The first acceleration operating condition discharge pressure and the first acceleration operating condition discharge pressure are both taken as the maximum limit value.

7. The method of claim 1, wherein: Step S52 specifically comprises the following sub-steps: S521, respectively under the first acceleration operating condition and the second acceleration operating condition, compressor wear experiments are carried out, at least 3 samples are selected for each acceleration operating condition, the experiment is stopped when any performance of the compressor decays by more than 5%, and after the experiment is completed, the friction pair wear amount of each sample is tested; S522, the friction pair wear pseudo-life of each sample is calculated; S523, the friction pair wear life distribution under the two acceleration operating conditions is respectively determined; S524, the acceleration index κ is determined based on the friction pair wear life distribution under the two acceleration operating conditions, and the calculation formula is as follows: Ln(n i t i ) = Ln(C) - κLn(F i ) wherein t i is the time required for the friction pair to reach the expected wear state under the current operating condition, F i is the maximum gas force to which the friction pair is subjected under the i operating condition, C is a characteristic constant, and Ln(C) is the logarithm of the characteristic constant C.

8. The method of claim 1, wherein: In step S522, the maximum wear amount of the friction pair in the plurality of samples is selected as the reference wear amount Based on the assumption that the wear amount approximately linearly accumulates in the stable wear stage, the time for each friction pair of each experimental sample to reach the reference wear amount is calculated The pseudo failure life of the friction pair of each sample In step S523, based on the pseudo-failure life of each sample, the maximum likelihood estimation method is used to estimate the life distribution of the sample under the two acceleration operating condition levels.

9. The method of claim 5, wherein: In step S6, the suction pressure, discharge pressure and rotating frequency under the experimental acceleration operating condition are obtained through experiments.

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