A method for calculating the life of a bearing-rotor system

Abstract

The present application relates to a bearing-rotor system life calculation method, which relates to the technical field of rotating systems and includes the following steps: obtaining radial force F by parameters r Step 1: Calculate the lubricating film pressure p if the bearing capacity ≥ radial force F r , using the Navier-Stokes equations for calculation, if the bearing capacity is less than the radial force F r , setting a lubricating oil groove on the shaft sleeve, calculated by formula #imgabs0#; calculating the wear distribution step, combining the Navier-Stokes equation or formula #imgabs1# to obtain the wear through formula #imgabs2#; calculating the wear amount step, obtaining the wear amount through formula #imgabs3#; judging step, judging whether the wear amount reaches a threshold. The present application has the advantage of being able to calculate the service life.

Description

Technical Field

[0001] The present application relates to the technical field of rotating systems, and in particular to a method for calculating the life of a bearing-rotor system. Background Art

[0002] The bearing-rotor system is one of the core technologies of rotating machinery and has a significant impact on the performance and reliability of rotating machinery. During the operation of rotating machinery, the dynamic reaction force of the liquid flowing out of the rotor components acts on the rotor to generate radial force, which may cause wear of the bearing-rotor system, thereby reducing its service life and seriously affecting the reliability and safety of the rotating machinery. Summary of the invention

[0003] In view of the shortcomings of the prior art, one of the purposes of the present application is to provide a method for calculating the life of a bearing-rotor system, which has the advantage of being able to calculate the service life.

[0004] The above-mentioned purpose of the present application is achieved through the following technical solutions:

[0005] A method for calculating the life of a bearing-rotor system comprises the following steps: a step of obtaining radial force by parameters, obtaining the radial force F of a rotating mechanical rotor r ; Calculate the lubricating film pressure p if the bearing capacity ≥ radial force F r , using the Navier-Stokes equation for calculation, if the bearing capacity is less than the radial force F r , a lubricating oil groove is set on the sleeve, and the lubricating film pressure can be expressed by the formula Calculation results: Where A is the effective contact area between the bearing and the rotor system; the steps for calculating the wear distribution are combined with the Navier-Stokes equation or formula By formula Get the wear, where V is the wear volume in mm 3 ; k is the wear coefficient; p is the lubricating film pressure, in N; A is the effective contact area between the bearing and the rotor system, in mm 2 ; v is the relative sliding velocity of the contact surface, in mm / s; t is the elapsed time, in s; H w is the Brinell hardness of the softer material in the contact component; the wear amount is calculated by the formula Obtaining the amount of wear; and determining whether the amount of wear reaches a threshold.

[0006] In a preferred example, the present application can be further configured as follows: the wear threshold is V 阈 , the calculation formula is , the bearing diameter is D b , bearing length is l b , the journal diameter is d j .

[0007] The present application has the following advantages: by calculating the wear amount to obtain the life span, it provides a guarantee for the safe and stable operation of the rotating machinery, and can achieve the effects of efficient management, scientific monitoring, and cost savings. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a schematic diagram of the cross-sectional structure of this application.

[0009] Figure 2 It is a schematic diagram of the bearing length structure of this application.

[0010] Figure 3 It is a schematic diagram of the bearing diameter structure of this application.

[0011] Figure 4 It is a schematic diagram of the radial force acting on the pump rotor in this application.

[0012] Figure 5 This is a diagram of the lubricating film pressure distribution between the rotor and the bearing of the present application.

[0013] Figure 6 It is a schematic diagram of the wear amount of the bearing-rotor system of this application.

[0014] Reference numeral: d j : Journal diameter, C: Radial clearance, D b : Bearing diameter, l b : Bearing length, l g : Circumferential groove length, d g : Circumferential groove diameter. DETAILED DESCRIPTION

[0015] The present application is further described in detail below in conjunction with the accompanying drawings.

[0016] Reference Figure 1-Figure 6 , is a bearing-rotor system life calculation method disclosed in the present application, comprising the following steps, wherein the numbers S1-S6 do not necessarily represent a certain order.

[0017] S1: Select the rotating machinery and bearing-rotor system, and obtain the basic parameters as follows: journal diameter d j , radial clearance C, bearing diameter D b , bearing length l b , circumferential groove length l g , circumferential groove diameter d g , the bearing is a sliding bearing;

[0018] S2: Use software to build a three-dimensional rotor model and obtain the radial force F of the rotating machinery rotor through computational fluid dynamics r , unit N;

[0019] S3: To calculate the lubricating film pressure distribution between the bearing and the rotor, the assumptions such as constant liquid density and constant lubricating film thickness along the axial direction are considered. If the bearing capacity ≥ radial force F r , using formulas (1) to (3) of the Navier-Stokes equation:

[0020] (1)

[0021] (2)

[0022]

[0023] If the bearing capacity is less than the radial force F r , in this case, a lubricating oil groove needs to be added, and the lubricating film pressure distribution can be calculated by formula (4):

[0024] (4)

[0025] Where A is the effective contact area between the bearing and rotor system.

[0026] S4: Based on the lubricating film pressure p calculated in step S3, taking into account and , due to the existence of bearing capacity ≥ radial force F r and bearing capacity < radial force F r Therefore, according to the situation, the wear distribution of the bearing-rotor system can be calculated by combining formulas (1) to (3) or (4), which can be expressed as formula (5):

[0027] (5)

[0028] Where V is the wear volume in mm 3 ; k is the wear coefficient; p is the lubricating film pressure, in N; A is the effective contact area between the bearing and the rotor system, in mm 2 ; v is the relative sliding velocity of the contact surface, in mm / s; t is the elapsed time, in s; H w It is the Brinell hardness of the softer material in the contact component. For example, if the hardness of the rotor is greater than that of the bearing, then the Brinell hardness is the hardness of the bearing.

[0029] S5: Further, by integrating formula (5) with respect to time and space, the wear amount within a certain period of time can be obtained, which can be expressed as formula (6):

[0030] (6)

[0031] S6: According to step S5, the wear amount of the bearing-rotor system can be calculated and combined with its wear threshold V阈 The wear time can be derived and the service life can be predicted.

[0032] (7)

[0033] Where V 阈 is the allowable wear of the bearing-rotor system, which can be expressed by the formula It is calculated that T is the life of the bearing-rotor system.

[0034] For example, the speed of a shielded pump is 5500r / min, the design flow rate is 135L / min, the design head is 7.5m, the lubricant medium is 20℃ water, and the density is 998.2kg / m 3 , dynamic viscosity 0.001Pa·s. Consider the case where the bearing capacity is greater than the radial force.

[0035] S1: journal diameter d j =8mm, radial clearance C=0.03mm, bearing diameter D b =8.06mm, bearing length l b =42mm, circumferential groove length l g =16mm, circumferential groove diameter d g =7.8mm;

[0036] S2: Use software to build a three-dimensional rotor model and obtain the radial force F of the rotor of the canned pump through numerical solution r ,like Figure 4 shown.

[0037] S3: To calculate the lubricating film pressure distribution between the bearing and the rotor, the assumptions such as constant liquid density and constant lubricating film thickness along the axial direction are considered. If the bearing capacity is ≥ radial force, the Navier-Stokes equations (1) to (3) are used:

[0038] (1)

[0039] (2)

[0040]

[0041] Get as Figure 5 The lubricating film pressure distribution between the rotor and the bearing is shown.

[0042] S4: Based on the lubricating film pressure p calculated in step S3, taking into account and , combined with formula (1), the wear distribution of the bearing-rotor system can be calculated and expressed as formula (4):

[0043] (4)

[0044] S5: Further, by integrating formula (4) with respect to time and space, the wear amount within a certain period of time can be obtained, which can be expressed as formula (5):

[0045] (5)

[0046] Where V is the wear volume in mm 3 ; k is the wear coefficient, k=10 -6 ; Wear surface sliding speed v=0.001mm / s; Brinell hardness H w = 600. After calculation, we get Figure 6 The amount of wear on the bearing-rotor system is shown.

[0047] S6: Based on the wear amount of the bearing-rotor system calculated in step S5, combined with its wear threshold V 阈 The wear time can be derived and the service life can be predicted.

[0048] Among them, according to Figure 5 The maximum wear of the bearing-rotor system is calculated to be , allowable wear of bearing-rotor system , then the bearing-rotor system life can be calculated as:

[0049] (6)

[0050] Therefore, the predicted life expectancy is 9 years.

[0051] The implementation principle of this embodiment is: by calculating the wear and life of the bearing-rotor system, a guarantee is provided for the safe and stable operation of the rotating machinery, and the effects of efficient management, scientific monitoring and cost saving can be achieved.

[0052] The embodiments of this specific implementation method are all preferred embodiments of the present application, and are not intended to limit the protection scope of the present application. Therefore, all equivalent changes made based on the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method for calculating the life of a bearing-rotor system, relating to the technical field of rotating systems, characterized in that: The following steps are included: a step of obtaining radial force parameters, obtaining the radial force F of the rotating machinery rotor r ; Calculate the lubricating film pressure p if the bearing capacity ≥ radial force F r , using the Navier-Stokes equation for calculation, if the bearing capacity is less than the radial force F r , a lubricating oil groove is set on the sleeve, and the lubricating film pressure can be expressed by the formula Calculation results: Where A is the effective contact area between the bearing and the rotor system; the steps for calculating the wear distribution are combined with the Navier-Stokes equation or formula By formula Get the wear, where V is the wear volume in mm 3 ; k is the wear coefficient; p is the lubricating film pressure, in N; A is the effective contact area between the bearing and the rotor system, in mm 2 ; v is the relative sliding velocity of the contact surface, in mm / s; t is the elapsed time, in s; H w is the Brinell hardness of the softer material in the contact component; Calculate the wear step by formula Obtaining the amount of wear; and determining whether the amount of wear reaches a threshold.

2. A bearing-rotor system life calculation method according to claim 1, characterized in that: The wear threshold is V 阈 , the calculation formula is , the bearing diameter is D b , bearing length is l b , the journal diameter is d j .

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