Leakage judgment method for mechanical sealing interface
By obtaining the dynamic and static ring parameters of the mechanical seal and calculating the porosity and mechanical relationship of the sealing interface, the problem of inaccurate judgment of mechanical seal interface leakage in the prior art is solved, and the safety and reliability of the mechanical seal are improved.
Patent Information
- Application Number
- CN202511670308.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-14
- Publication Date
- 2026-02-13
AI Technical Summary
Existing technologies lack accurate methods for judging leakage at the mechanical seal interface and cannot effectively consider the effects of capillary forces and friction between the fluid and the wall, resulting in insufficient equipment safety and reliability.
By acquiring the morphology, material, interface, and operating parameters of the dynamic and static ring end faces of the mechanical seal, the actual contact area, porosity, and compression of the micro-protrusions at the sealing interface are calculated. Combined with wettability, capillary force, and differential pressure driving force, a mechanical relationship is established to determine leakage.
It enables accurate leakage prediction of the mechanical seal interface under certain operating conditions, avoids leakage caused by unreasonable design parameters, and improves the working safety of mechanical seals.
Smart Images
Figure CN121521709A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of mechanical seal technology, specifically relating to a method for judging leakage at the interface of a mechanical seal. Background Technology
[0002] Mechanical seals have undergone long-term development, resulting in significant improvements in service life and sealing performance, and are widely used in various fluid machinery and equipment. Mechanical face seals are used to prevent leakage between the power input shaft and the pump casing. Their performance is crucial to the normal operation and shutdown safety of the equipment. In some demanding environments, mechanical seals are even required to achieve a leak-free, zero-escape state during operation, such as the mechanical face seals used in nuclear main pumps. However, leakage between the sealing faces remains a major cause of seal failure.
[0003] For a long time, researchers have conducted a series of studies on the causes of mechanical seal leakage, such as Mayer's "fluid exchange flow theory" and Lebeak's "wavelength" theory, in order to accurately predict leakage at the sealing interface and formulate effective leak prevention measures to reduce waste caused by premature replacement of mechanical seals or material loss and environmental pollution caused by exceeding service life. However, since the actual sealing end face is on the micron scale, the influence of capillary force and friction between the fluid and the wall on leakage at the sealing interface cannot be ignored, but the leakage theories proposed in current research do not take this important factor into account. It can be seen that the lack of an accurate method for judging leakage at the sealing interface has seriously affected the safety of mechanical seal operation and made it impossible to avoid the risks of equipment downtime, failure, and even damage caused by leakage at the sealing interface. Summary of the Invention
[0004] To address the aforementioned shortcomings of existing technologies, this invention aims to provide a method for judging leakage at the mechanical seal interface, thereby solving the problem of the lack of existing methods for judging leakage at mechanical seal interfaces. This method enables accurate prediction of leakage at a given mechanical seal interface under specific operating conditions, avoiding mechanical seal leakage caused by unreasonable selection of design and operating parameters. The leakage judgment method includes the following steps:
[0005] S1. Obtain the end face morphology parameters, material parameters, interface parameters, operating condition parameters, and sealing surface width of the dynamic and static rings of the mechanical seal.
[0006] S2. Determine the actual contact area of the micro-protrusions at the sealing interface based on the end face morphology parameters, material parameters, and operating condition parameters of the dynamic and static rings.
[0007] S3. Determine the maximum height and initial porosity of the sealing interface gap between the dynamic and static rings based on the end face morphology parameters of the dynamic and static rings.
[0008] S4. Determine the compression amount of the sealing interface based on the actual contact area of the micro-protrusions at the sealing interface.
[0009] S5. Determine the loaded porosity of the sealing interface based on the initial porosity, the maximum height of the sealing interface gap, and the compression of the sealing interface.
[0010] S6. Determine the permeation state of the mechanical seal interface based on the loaded porosity.
[0011] When the loading porosity is <0.312, the sealing interface is in a non-permeable state, and there is no leakage at the mechanical seal interface.
[0012] When the loading porosity is ≥0.312, the sealing interface is in a percolation state, and a leakage channel exists at the sealing interface. The following steps are used to further determine the percolation state of the mechanical seal interface:
[0013] S61. Determine the wettability of the sealing interface of the dynamic and static rings based on the interface parameters of the sealing surfaces of the dynamic and static rings.
[0014] S62. Determine the capillary force and maximum static friction force in the leakage channel of the sealing interface of the dynamic and static rings based on the interface parameters of the sealing surfaces of the dynamic and static rings.
[0015] S63. Determine the differential pressure driving force in the leakage channel of the sealing interface based on the maximum height of the sealing interface gap and the operating parameters of the dynamic and static rings.
[0016] S64. Based on the magnitude of wettability, capillary force, maximum static friction, and differential pressure driving force, establish the mechanical relationship within the leakage channel at the sealing interface of the dynamic and static rings to determine the leakage at the mechanical seal interface. In this application, "dynamic and static rings" is a general term for both the dynamic ring and the static ring.
[0017] Specifically, in step S1, the end-face morphology parameters include the fractal dimension of the moving ring D1, the fractal dimension of the stationary ring D2, the scale coefficient of the moving ring G1, the scale coefficient of the stationary ring G2, and the maximum height R of the moving ring surface profile. y1 Maximum height R of the stationary ring surface profile y2 ;
[0018] Material parameters include the elastic modulus E1 of the moving ring, the elastic modulus E2 of the stationary ring, the Poisson's ratio υ1 of the moving ring material, the Poisson's ratio υ2 of the stationary ring material, the yield strength σ1 of the moving ring, and the yield strength σ2 of the stationary ring.
[0019] The interface parameters of the sealing surface include the equivalent coefficient of friction μ. s Equivalent contact angle θ and equivalent surface tension coefficient τ;
[0020] Operating parameters include end face specific pressure p c and medium pressure p s .
[0021] Specifically, in step S2, the maximum height of the sealing interface gap is represented by h, and h is calculated using equation (1):
[0022] (1)
[0023] R y1 R is the maximum height of the moving ring surface profile. y2 This represents the maximum height of the stationary ring surface profile.
[0024] Initial porosity adopted express, The calculation is performed using equation (2):
[0025] (2)
[0026] Where D is the equivalent fractal dimension of the dynamic and static rings, a Lm denoted as , where is the base area of the largest micro-protrusion at the sealing interface, 'a' is the contact area of the micro-protrusion at the sealing interface, and 'l' is the diameter of the contour base of the largest micro-protrusion at the sealing interface.
[0027] D、a Lm The specific calculation of l is performed using formula (21):
[0028] (twenty one)
[0029] Where G is the equivalent scale coefficient of the dynamic and static rings, and G is calculated using equation (22):
[0030] (twenty two).
[0031] Specifically, in step S3, the actual contact area of the micro-protrusions at the sealing interface is measured using a. L It means, a L Solve using equation (3):
[0032] (3)
[0033] Where p c For end face specific pressure, a ec a is the critical contact area for elastic deformation of the micro-convex body. pc Let σ be the critical contact area for plastic deformation of the micro-convex body, E be the equivalent elastic modulus of the moving and stationary rings, and σ be the tangential elastic modulus. y σ² is the equivalent yield limit of the dynamic and static rings, G is the equivalent scale coefficient of the dynamic and static rings, e is the natural constant, l is the diameter of the profile base of the largest micro-protrusion at the sealing interface, D is the equivalent fractal dimension of the dynamic and static rings, and σ² is the yield limit of the static ring.
[0034] E, σ ySpecifically, the calculation is performed using equation (31):
[0035] (31)
[0036] a ec With a pc Specifically, the calculation is performed using equation (32):
[0037] (32).
[0038] Specifically, in step S4, the compression amount of the sealing interface is represented by δ, and δ is calculated using equation (4):
[0039] (4)
[0040] Where G is the equivalent scale coefficient of the moving and stationary rings, l is the diameter of the contour base of the largest micro-protrusion at the sealing interface, D is the equivalent fractal dimension, and a L This represents the actual contact area of the micro-protrusions at the sealing interface.
[0041] Specifically, in step S5, the loading porosity of the sealing interface is adopted. express, The calculation is performed using equation (5):
[0042] (5)
[0043] in denoted as the initial porosity, h as the maximum height of the gap at the sealing interface, and δ as the compression amount at the sealing interface.
[0044] Specifically, in step S61, the wettability of the sealing interface is determined using the following method:
[0045] When 0°≤θ≤90°, the sealing surface is hydrophilic; when 90°<θ≤180°, the sealing surface is hydrophobic, where θ is the equivalent contact angle.
[0046] Specifically, in step S62, the capillary force is F. cap The maximum static friction force is expressed as f. s To represent; in step S63, the pressure difference driving force is represented by F comp Indicates; F cap f s and F comp Calculations are performed using equation (6):
[0047] (6)
[0048] Where τ is the equivalent surface tension coefficient, θ is the equivalent contact angle, r is the inner diameter of the leakage channel at the sealing interface, and p s For medium pressure, μs is the equivalent friction coefficient, h is the maximum height of the gap at the sealing interface, and b is the width of the sealing surface.
[0049] r is specifically calculated using equation (61):
[0050] (61).
[0051] Specifically, step S64 establishes the mechanical relationship between the dynamic and static ring sealing interfaces based on the wettability, capillary force, maximum static friction, and differential pressure driving force of the dynamic and static ring sealing interfaces. The specific method is as follows:
[0052] When the sealing surface is hydrophilic, when f s ≥F comp +F cap If there is no leakage at the sealing interface, then f s <F comp +F cap If so, there is leakage at the sealing interface;
[0053] When the sealing surface is hydrophobic, when F cap ≥F comp If the sealing interface is leak-free, then there is no leakage when F cap +f s ≥F comp Then there is no leakage at the sealed interface;
[0054] When F cap +f s <F comp If so, there will be leakage at the sealing interface.
[0055] When using this application to determine the leakage at the mechanical seal interface, the loading porosity of the sealing interface is first determined based on the end face morphology, material parameters, and operating conditions of the dynamic and static rings, thereby determining the permeation state of the sealing interface. Then, the wettability of the dynamic and static ring sealing interface is determined based on the interface parameters of the sealing surfaces. Finally, the mechanical relationship between capillary force, maximum static friction, and differential pressure driving force within the leakage channel of the dynamic and static ring sealing interface is established to determine the leakage at the mechanical seal interface. The successful implementation of this method effectively solves the problem of the lack of existing methods for judging mechanical seal interface leakage. It fully considers the influence of capillary force and the friction between the fluid and the wall on the leakage at the sealing interface, enabling accurate prediction of the leakage at a given mechanical seal interface under specific operating conditions. This avoids mechanical seal leakage caused by unreasonable selection of design and operating parameters, thus improving the operational safety of the mechanical seal. Attached Figure Description
[0056] Figure 1 This is a flowchart of the leakage detection method for the mechanical seal interface in this application. Detailed Implementation
[0057] To more clearly describe the above-mentioned features and advantages of the present invention, the specific embodiments of the present invention will be further described below.
[0058] like Figure 1 As shown, a method for determining leakage at a mechanical seal interface includes the following steps:
[0059] S1. Obtain the end face morphology parameters, material parameters, interface parameters, operating condition parameters, and sealing surface width of the dynamic and static rings of the mechanical seal. The dynamic and static rings are a collective term for both the dynamic and static rings.
[0060] The end-face morphology parameters of the moving and stationary rings include the fractal dimension D1 of the moving ring, the fractal dimension D2 of the stationary ring, the scale factor G1 of the moving ring, the scale factor G2 of the stationary ring, and the maximum height R of the moving ring surface profile. y1 Maximum height R of the stationary ring surface profile y2 ;
[0061] The material parameters of the dynamic and static rings include the elastic modulus E1 of the dynamic ring, the elastic modulus E2 of the static ring, the Poisson's ratio υ1 of the dynamic ring material, the Poisson's ratio υ2 of the static ring material, the yield strength σ1 of the dynamic ring, and the yield strength σ2 of the static ring.
[0062] The operating parameters of the dynamic and static rings include the end face specific pressure p. c and medium pressure p s ;
[0063] The interface parameters of the sealing surfaces of the dynamic and static rings include the equivalent friction coefficient μ. s The equivalent contact angle θ and the equivalent surface tension coefficient τ.
[0064] μ s The calculations of θ and τ are based on existing techniques, and the specific calculation formulas are as follows:
[0065] (1.1)
[0066] In the formula, μ1 is the friction coefficient of the moving ring; μ2 is the friction coefficient of the stationary ring.
[0067] (1.2)
[0068] In the formula, θ1 is the contact angle of the moving ring; θ2 is the contact angle of the stationary ring. The contact angles of the moving and stationary rings can be obtained according to the type of sealing medium and the materials of the moving and stationary rings.
[0069] (1.3)
[0070] In the formula, τ1 is the surface tension coefficient of the moving ring; τ2 is the surface tension coefficient of the stationary ring.
[0071] S2. Determine the maximum height and initial porosity of the sealing interface gap between the dynamic and static rings based on the end face morphology parameters of the dynamic and static rings.
[0072] The maximum height of the sealing interface gap is represented by h, which is calculated using equation (1):
[0073] (1)
[0074] Initial porosity adopted express, The calculation is performed using equation (2):
[0075] (2)
[0076] Where D is the equivalent fractal dimension of the dynamic and static rings, a Lm denoted as , where is the base area of the largest micro-protrusion at the sealing interface, 'a' is the contact area of the micro-protrusion at the sealing interface, and 'l' is the diameter of the contour base of the largest micro-protrusion at the sealing interface.
[0077] D、a Lm The specific calculation of l is performed using formula (21):
[0078] (twenty one)
[0079] Where G is the equivalent scale coefficient of the dynamic and static rings, and G is calculated using equation (22):
[0080] (twenty two).
[0081] S3. Determine the actual contact area of the micro-protrusions at the sealing interface based on the end face morphology parameters, material parameters, and operating condition parameters of the dynamic and static rings.
[0082] Among them, the actual contact area of the micro-protrusions at the sealing interface is a L It means, a L Solve using equation (3):
[0083] (3)
[0084] Where p c For end face specific pressure, a ec a is the critical contact area for elastic deformation of the micro-convex body. pc Let σ be the critical contact area for plastic deformation of the micro-convex body, E be the equivalent elastic modulus of the moving and stationary rings, and σ be the tangential elastic modulus. y σ² is the equivalent yield limit of the dynamic and static rings, G is the equivalent scale coefficient of the dynamic and static rings, e is the natural constant, l is the diameter of the profile base of the largest micro-protrusion at the sealing interface, and σ² is the yield limit of the static ring.
[0085] E, σ ySpecifically, the calculation is performed using equation (31):
[0086] (31)
[0087] a ec With a pc Specifically, the calculation is performed using equation (32):
[0088] (32).
[0089] S4. Determine the compression amount of the sealing interface based on the actual contact area of the micro-protrusions at the sealing interface.
[0090] The compression amount at the sealing interface is represented by δ, which is calculated using equation (4):
[0091] (4)
[0092] Where G is the equivalent scale coefficient of the moving and stationary rings, l is the diameter of the contour base of the largest micro-protrusion at the sealing interface, D is the equivalent fractal dimension, and a L This represents the actual contact area of the micro-protrusions at the sealing interface.
[0093] S5. Determine the loaded porosity of the sealing interface based on the initial porosity, the maximum height of the sealing interface gap, and the compression of the sealing interface.
[0094] Among them, the loading porosity of the sealing interface is adopted. express, The calculation is performed using equation (5):
[0095] (5).
[0096] in denoted as the initial porosity, h as the maximum height of the gap at the sealing interface, and δ as the compression amount at the sealing interface.
[0097] S6. Determine the permeation state of the mechanical seal interface based on the loaded porosity.
[0098] When the loaded porosity is less than 0.312, the sealing interface is in a non-permeable state, and there is no leakage at the sealing interface.
[0099] When the loaded porosity is greater than or equal to 0.312, the sealing interface is in a permeable state, and there is a leakage channel at the sealing interface. Therefore, there may be leakage at the sealing interface, and further judgment is needed on the leakage situation of the mechanical seal interface. The specific steps are as follows:
[0100] S61. Determine the wettability of the sealing interface between the dynamic and static rings based on the interface parameters of their sealing surfaces. The wettability of the sealing interface is determined as follows: when 0°≤θ≤90°, the sealing surface is hydrophilic; when 90°<θ≤180°, the sealing surface is hydrophobic, where θ is the equivalent contact angle.
[0101] S62. Determine the capillary force and maximum static friction force in the leakage channel of the sealing interface of the dynamic and static rings based on the interface parameters of the sealing surfaces of the dynamic and static rings.
[0102] S63. Determine the differential pressure driving force in the leakage channel of the sealing interface based on the maximum height of the sealing interface gap and the operating parameters of the dynamic and static rings.
[0103] Among them, the capillary force in the leakage channel at the dynamic and static ring sealing interface is F. cap The maximum static friction force is expressed as f. s The pressure differential driving force within the leakage channel at the sealed interface is represented by F. comp Indicates; F cap f s and F comp It can be calculated using equation (6):
[0104] (6)
[0105] Where τ is the equivalent surface tension coefficient, θ is the equivalent contact angle, r is the inner diameter of the leakage channel at the sealing interface, and p s For medium pressure, μ s is the equivalent friction coefficient, h is the maximum height of the gap at the sealing interface, and b is the width of the sealing surface.
[0106] r is specifically calculated using equation (61):
[0107] (61).
[0108] S64. Based on the wettability, capillary force, maximum static friction force, and differential pressure driving force of the dynamic and static ring sealing interface, establish the mechanical relationship within the leakage channel of the dynamic and static ring sealing interface, and judge the leakage of the mechanical seal interface.
[0109] The specific method for establishing the mechanical relationship between the dynamic and static ring sealing interfaces based on the wettability, capillary force, maximum static friction, and differential pressure driving force of the dynamic and static ring sealing interfaces is as follows:
[0110] The sealing surface is hydrophilic.
[0111] When the sealing surface is hydrophilic, when f s ≥F comp +F cap If there is no leakage at the sealing interface, then f s<F comp +F cap If so, there is leakage at the sealing interface;
[0112] When the sealing surface is hydrophobic, when F cap ≥F comp If the sealing interface is leak-free, then there is no leakage when F cap +f s ≥F comp Then there is no leakage at the sealed interface;
[0113] When F cap +f s <F comp If so, there will be leakage at the sealing interface.
[0114] The following specific embodiment further illustrates the leakage determination method in this application. The specific steps are as follows:
[0115] S1. Obtain the end face morphology parameters, material parameters, interface parameters, operating parameters, and sealing surface width of the dynamic and static rings of the mechanical seal. The end face morphology parameters and material parameters of the dynamic and static rings of the mechanical seal are shown in Table 1. The interface parameters of the sealing surfaces of the dynamic and static rings of the mechanical seal are shown in Table 2. The operating parameters and sealing surface width of the dynamic and static rings of the mechanical seal are shown in Table 3.
[0116] Table 1. End face morphology and material parameters of the dynamic and static rings of the mechanical seal.
[0117]
[0118] Table 2. Corresponding parameters of the sealing surface interfaces between the dynamic ring and the stationary ring.
[0119]
[0120] The interface parameters of the sealing surfaces of the dynamic and static rings are obtained using equations (1.1), (1.2), (1.3) and the data in Table 2, as shown in Table 2.1 below.
[0121] Table 2.1 Interface parameters of the sealing surfaces of the dynamic and static rings
[0122]
[0123] Table 3 Operating parameters and sealing surface width of the dynamic and static rings of the mechanical seal
[0124]
[0125] S2. Determine the maximum height and initial porosity of the sealing interface gap between the dynamic and static rings based on the end face morphology parameters of the dynamic and static rings.
[0126] The maximum height R of the dynamic ring surface profile in Table 1 is... y1=0.28, Maximum height R of the stationary ring surface profile y2 =2.13 Substituted into equation (1):
[0127] (1)
[0128] The maximum height of the sealing interface gap between the dynamic and static rings was obtained as h = 1.79786 μm;
[0129] initial porosity The calculation is performed using equation (2):
[0130] (2)
[0131] Where D is the equivalent fractal dimension of the dynamic and static rings, a Lm D is the base area of the largest micro-protrusion at the sealing interface, a is the contact area of the micro-protrusion at the sealing interface, l is the diameter of the contour base of the largest micro-protrusion at the sealing interface, and D, a Lm And l can be calculated using equation (21):
[0132] (twenty one)
[0133] Where G is the equivalent scale coefficient of the dynamic and static rings, and G is calculated using equation (22):
[0134] (twenty two)
[0135] Substituting the dimensional coefficients G1 and G2 of the moving ring end face from Table 1 into Equation (22), we obtain the equivalent dimensional coefficients G of the moving and stationary rings; substituting the fractal dimensions D1 and D2 of the moving ring end face from Table 1 into Equation (21), we obtain the equivalent fractal dimensions D of the moving and stationary rings; substituting the equivalent fractal dimensions D of the moving and stationary rings, the equivalent dimensional coefficients G of the moving and stationary rings, and the maximum height h of the sealing interface gap of the moving and stationary rings into Equation (21), we obtain the contour base diameter l of the maximum micro-protrusion of the sealing interface; substituting the contour base diameter l of the maximum micro-protrusion of the sealing interface into Equation (21), we obtain the base area a of the maximum micro-protrusion of the sealing interface. Lm .
[0136] Finally, the equivalent fractal dimension D of the moving and stationary rings and the base area a of the largest micro-protrusion at the sealing interface are calculated. Lm Substituting the diameter l of the substrate of the maximum micro-protrusion at the sealing interface into equation (3), the initial porosity is obtained. =0.83.
[0137] S3. Determine the contact area of the micro-protrusions at the sealing interface based on the material parameters and operating conditions of the dynamic and static rings.
[0138] The actual contact area a of the micro-protrusion LSolve using equation (3):
[0139] (3)
[0140] Where p c For end face specific pressure, a ec a is the critical contact area for elastic deformation of the micro-convex body. pc Let σ be the critical contact area for plastic deformation of the micro-convex body, E be the equivalent elastic modulus of the moving and stationary rings, and σ be the tangential elastic modulus. y σ² is the equivalent yield limit of the dynamic and static rings, G is the equivalent scale coefficient of the dynamic and static rings, e is the natural constant, l is the diameter of the profile base of the largest micro-protrusion at the sealing interface, and σ² is the yield limit of the static ring.
[0141] E, σ y Specifically, the calculation is performed using equation (31):
[0142] (31)
[0143] a ec With a pc Specifically, the calculation is performed using equation (32):
[0144] (32)
[0145] Substituting the elastic modulus E1 of the moving ring, the elastic modulus E2 of the stationary ring, the Poisson's ratio υ1 of the moving ring, the Poisson's ratio υ2 of the stationary ring, the yield limit σ1 of the moving ring, and the yield limit σ2 of the stationary ring into equation (31), we obtain the equivalent elastic modulus E and the equivalent yield limit σ of the moving and stationary rings. y The equivalent yield limit σ of the moving and stationary rings y Substituting the equivalent elastic modulus E of the moving and stationary rings, the equivalent scale coefficient G of the moving and stationary rings, the equivalent fractal dimension D of the moving and stationary rings, and the diameter l of the contour base of the largest micro-protrusion at the sealing interface into equation (32) yields the critical contact area a of the micro-protrusion's elastic deformation. ec The critical contact area a for plastic deformation of micro-protrusions pc ;
[0146] Finally, the end face specific pressure p in Table 1 is... c The equivalent elastic modulus E of the moving and stationary rings, the equivalent scale factor G of the moving and stationary rings, the equivalent fractal dimension D of the moving and stationary rings, the profile base diameter l of the largest micro-protrusion at the sealing interface, and the equivalent yield strength σ of the moving and stationary rings. y σ2, yield limit of static ring, critical contact area a for elastic deformation of micro-convex body ec The critical contact area a for plastic deformation of micro-protrusions pc Substituting into equation (3), the actual contact area a of the micro-protrusion is obtained. L =4.12832×10 -6 m 2.
[0147] S4. Determine the compression amount of the sealing interface based on the actual contact area of the micro-protrusions at the sealing interface.
[0148] The compression amount δ at the sealing interface is calculated using equation (4):
[0149] (4)
[0150] The equivalent scale factor G of the moving and stationary rings, the equivalent fractal dimension D of the moving and stationary rings, the contour base diameter l of the largest micro-protrusion at the sealing interface, and the actual contact area a of the micro-protrusion at the sealing interface are used. L Substituting into equation (4), we obtain the compression amount at the sealing interface δ = 6.771 × 10⁻⁶. -7 m.
[0151] S5. Determine the loading porosity based on the initial porosity of the sealing interface, the maximum height of the gap between the sealing interfaces, and the compression of the sealing interface.
[0152] Loading porosity The calculation is performed using equation (5):
[0153] (5)
[0154] Substituting the maximum height h of the sealing interface gap, the initial porosity φ0, and the sealing interface compression δ into equation (5), the loaded porosity of the sealing interface is obtained. =0.727.
[0155] S6. Determine the permeation state of the sealing interface based on the applied porosity. Because the applied porosity... =0.727>0.312, therefore, the sealing interface is in a permeable state at this time, and there is a leakage channel at the sealing interface. Therefore, there may be leakage at the sealing interface, and further judgment is needed on the leakage situation of the mechanical seal interface. The specific steps are as follows:
[0156] S61. Determine the wettability of the sealing interface between the dynamic and static rings based on the interface parameters of the sealing surfaces of the dynamic and static rings.
[0157] As shown in Table 2.1, the equivalent contact angle θ of the dynamic and static ring sealing interface is 120°. Therefore, the equivalent contact angle θ satisfies 90°<θ≤180°, indicating that the sealing surface is hydrophobic.
[0158] S62. Determine the capillary force and maximum static friction force in the leakage channel of the sealing interface of the dynamic and static rings based on the interface parameters of the sealing surfaces of the dynamic and static rings.
[0159] Capillary force F cap and maximum static friction force f s The calculation is performed using equation (6):
[0160] (6);
[0161] Where r is the inner diameter of the leakage channel at the sealing interface, and b is the width of the sealing surface;
[0162] The inner diameter r of the leakage channel at the sealing interface, the maximum height h of the sealing interface gap, the equivalent surface tension coefficient τ, the equivalent contact angle θ, and the equivalent friction coefficient μ of the dynamic and static ring sealing interfaces in Table 2.1 are used to determine these parameters. s Substituting the sealing surface width b from Table 3 into equation (6), we obtain the capillary force F. cap =5.6452 ×10 -2 N, maximum static friction force f s =1.50719×10 -5 N.
[0163] S63. Determine the differential pressure driving force in the leakage channel of the sealing interface based on the maximum height of the sealing interface gap and the operating parameters of the dynamic and static rings.
[0164] Pressure differential driving force F in the leakage channel of the sealed interface comp The calculation is performed using equation (6):
[0165] (6)
[0166] The inner diameter r of the leakage channel at the sealing interface and the medium pressure p in Table 3 are specified. s Substituting into equation (6), we obtain the pressure difference driving force F. comp =3.88215×10 -6 N.
[0167] S64. Based on the wettability, capillary force, maximum static friction force, and differential pressure driving force of the dynamic and static ring sealing interface, establish the mechanical relationship within the leakage channel of the dynamic and static ring sealing interface to determine the leakage of the mechanical seal interface.
[0168] As shown in Table 2.1, the equivalent contact angle θ of the dynamic and static ring sealing interface is 120°. Therefore, the equivalent contact angle θ satisfies 90° < θ ≤ 180°, indicating that the sealing surface is hydrophobic and the capillary force F cap =5.6452 ×10 -2 N, F comp =3.88215×10 -6 N, satisfying F cap ≥F comp Therefore, there is no leakage at the sealed interface.
Claims
1. A method for determining leakage at a mechanical seal interface, characterized in that, Includes the following steps: S1. Obtain the end face morphology parameters, material parameters, interface parameters, operating condition parameters, and sealing surface width of the dynamic and static rings of the mechanical seal. S2. Determine the maximum height and initial porosity of the sealing interface gap between the dynamic and static rings based on the end face morphology parameters of the dynamic and static rings. S3. Determine the actual contact area of the micro-protrusions at the sealing interface based on the end face morphology parameters, material parameters, and operating condition parameters of the dynamic and static rings. S4. Determine the compression amount of the sealing interface based on the actual contact area of the micro-protrusions at the sealing interface. S5. Determine the loaded porosity of the sealing interface based on the initial porosity, the maximum height of the sealing interface gap, and the compression of the sealing interface. S6. Determine the permeation state of the mechanical seal interface based on the loaded porosity. When the loading porosity is <0.312, the sealing interface is in a non-permeable state, and there is no leakage at the mechanical seal interface. When the loading porosity is ≥0.312, the sealing interface is in a percolation state, and a leakage channel exists at the sealing interface. The following steps are used to further determine the percolation state of the mechanical seal interface: S61. Determine the wettability of the sealing interface of the dynamic and static rings based on the interface parameters of the sealing surfaces of the dynamic and static rings. S62. Determine the capillary force and maximum static friction force in the leakage channel of the sealing interface of the dynamic and static rings based on the interface parameters of the sealing surfaces of the dynamic and static rings. S63. Determine the differential pressure driving force in the leakage channel of the sealing interface based on the maximum height of the sealing interface gap and the operating parameters of the dynamic and static rings. S64. Based on the magnitude of wettability, capillary force, maximum static friction force, and differential pressure driving force, establish the mechanical relationship within the leakage channel of the sealing interface of the dynamic and static rings, and judge the leakage of the mechanical seal interface.
2. The leakage detection method according to claim 1, characterized in that, In step S1, the end-face morphology parameters include the fractal dimension D1 of the moving ring, the fractal dimension D2 of the stationary ring, the scale factor G1 of the moving ring, the scale factor G2 of the stationary ring, and the maximum height R of the moving ring surface profile. y1 Maximum height R of the stationary ring surface profile y2 ; Material parameters include the elastic modulus E1 of the moving ring, the elastic modulus E2 of the stationary ring, the Poisson's ratio υ1 of the moving ring material, the Poisson's ratio υ2 of the stationary ring material, the yield strength σ1 of the moving ring, and the yield strength σ2 of the stationary ring. The interface parameters of the sealing surface include the equivalent coefficient of friction μ. s Equivalent contact angle θ and equivalent surface tension coefficient τ; Operating parameters include end face specific pressure p c and medium pressure p s .
3. The leakage detection method according to claim 1, characterized in that, In step S2, the maximum height of the sealing interface gap is represented by h, which is calculated using equation (1): （1） R y1 R is the maximum height of the moving ring surface profile. y2 This represents the maximum height of the stationary ring surface profile. Initial porosity adopted express, The calculation is performed using equation (2): （2） Where D is the equivalent fractal dimension of the dynamic and static rings, a Lm Let be the base area of the largest micro-protrusion at the sealing interface, and 'a' be the contact area of the micro-protrusion at the sealing interface. l The diameter of the base profile of the largest micro-protrusion at the sealing interface.
4. The leakage detection method according to claim 1, characterized in that, In step S3, the actual contact area of the micro-protrusions at the sealing interface is measured using a. L It means, a L Solve using equation (3): （3） Where p c For end face specific pressure, a ec a is the critical contact area for elastic deformation of the micro-convex body. pc Let σ be the critical contact area for plastic deformation of the micro-convex body, E be the equivalent elastic modulus of the moving and stationary rings, and σ be the tangential elastic modulus. y Let G be the equivalent yield limit of the dynamic and static rings, G be the equivalent scale coefficient of the dynamic and static rings, and e be the natural constant. l σ² is the diameter of the profile base of the largest micro-protrusion at the sealing interface, D is the equivalent fractal dimension of the moving and stationary rings, and σ² is the yield limit of the stationary ring.
5. The leakage detection method according to claim 1, characterized in that, In step S4, the compression of the sealing interface is represented by δ, and δ is calculated using equation (4): （4） Where G is the equivalent scale coefficient of the dynamic and static loops. l Where D is the diameter of the base profile of the largest micro-protrusion at the sealing interface, and a is the equivalent fractal dimension. L This represents the actual contact area of the micro-protrusions at the sealing interface.
6. The leakage detection method according to claim 1, characterized in that, In step S5, the loading porosity of the sealing interface is adopted. express, The calculation is performed using equation (5): （5） in denoted as the initial porosity, h as the maximum height of the gap at the sealing interface, and δ as the compression amount at the sealing interface.
7. The leakage detection method according to claim 1, characterized in that, In step S61, the wettability of the sealing interface is determined using the following method: When 0°≤θ≤90°, the sealing surface is hydrophilic; when 90°<θ≤180°, the sealing surface is hydrophobic. θ is the equivalent contact angle.
8. The leakage detection method according to claim 1, characterized in that, In step S62, the capillary force is F. cap The maximum static friction force is expressed as f. s To represent; in step S63, the pressure difference driving force is represented by F comp Indicates; F cap f s and F comp Calculations are performed using equation (6): (6)； Where τ is the equivalent surface tension coefficient, θ is the equivalent contact angle, r is the inner diameter of the leakage channel at the sealing interface, and p s For medium pressure, μ s is the equivalent friction coefficient, h is the maximum height of the gap at the sealing interface, and b is the width of the sealing surface.
9. The leakage detection method according to claim 8, characterized in that, In step S64, the mechanical relationship between the sealing interfaces of the dynamic and static rings is as follows: When the sealing surface is hydrophilic, when f s ≥F comp +F cap If there is no leakage at the sealing interface, then f s <F comp +F cap If so, there is leakage at the sealing interface; When the sealing surface is hydrophobic, when F cap ≥F comp If the sealing interface is leak-free, then there is no leakage when F cap +f s ≥F comp Then there is no leakage at the sealed interface; When F cap +f s <F comp If so, there will be leakage at the sealing interface.