scholarly journals Effects of the shape of surface micropores on the performance of a face seal

1970 ◽  
Vol 38 ◽  
pp. 25-31 ◽  
Author(s):  
M Mahbubur Razzaque ◽  
M Tanvir Rahman Faisal
Keyword(s):  
Pore Size ◽  
Hydrodynamic Pressure ◽  
Control Area ◽  
Friction Torque ◽  
Face Seal ◽  
Cylindrical Pores ◽  
Face Seals ◽  
Mechanical Face Seal ◽  
Performance Surface ◽  
Pore Depth

 A mathematical model is developed for the prediction of performance of a mechanical face seal with regular microstructure on its surface in the form of pores. Pores of right circular cylindrical, hemispherical and exponential profiles have been considered. A two dimensional steady state Reynolds equation is solved to get the hydrodynamic pressure distribution on an imaginary control area around a single pore. Consequently, the seal performance parameters such as seal clearance, friction torque and leakage across the seal are calculated. A parametric analysis is done for right circular cylindrical pores for a range of sealed pressure, pore size and pore ratio. Increase of pore ratio improves the seal performance up to a pore ratio of 12%, beyond which no improvement of the seal performance is possible. The optimum pore size depends on the sealed pressure as well as on the pore profile. Through a comparison of the performance of face seals with different pore profiles hemispherical pores are recommended for enhancement of performance. For any pore profile, the seal performance improves with the increase of pore depth as long as the depth is less than 1.5 times of the pore radius. Keywords: Face seal, seal performance, surface micropore, pore profile, pore ratio.DOI: 10.3329/jme.v38i0.897 Journal of Mechanical Engineering Vol.38 Dec. 2007 pp.25-31  

Thermoelastohydrodynamic Behavior of Mechanical Gas Face Seals Operating at High Pressure

2007 ◽  
Vol 129 (4) ◽  
pp. 841-850 ◽  
Author(s):  
Sébastien Thomas ◽  
Noël Brunetière ◽  
Bernard Tournerie
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Numerical Modeling ◽  
Face Seal ◽  
Inertia Effects ◽  
Real Gas ◽  
Choked Flow ◽  
Face Seals ◽  
Mechanical Face Seal ◽  
Gas Expansion

A numerical modeling of thermoelastohydrodynamic mechanical face seal behavior is presented. The model is an axisymmetric one and it is confined to high pressure compressible flow. It takes into account the behavior of a real gas and includes thermal and inertia effects, as well as a choked flow condition. In addition, heat transfer between the fluid film and the seal faces is computed, as are the elastic and thermal distortions of the rings. In the first part of this paper, the influence of the coning angle on mechanical face seal characteristics is studied. In the second part, the influence of the solid distortions is analyzed. It is shown that face distortions strongly modify both the gap geometry and the mechanical face seal’s performance. The mechanical distortions lead to a converging gap, while the gas expansion, by cooling the fluid, creates a diverging gap.

scholarly journals Lubrication and Wear Characteristics of Mechanical Face Seals under Random Vibration Loading

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1285
Author(s):  
Wentao He ◽  
Shaoping Wang ◽  
Chao Zhang ◽  
Xi Wang ◽  
Di Liu
Keyword(s):  
Dynamic Model ◽  
Random Vibration ◽  
Experimental Studies ◽  
Lumped Parameter Model ◽  
Axial Stiffness ◽  
Face Seal ◽  
Wear Characteristics ◽  
Vibration Loading ◽  
Face Seals ◽  
Mechanical Face Seal

The service life of mechanical face seals is related to the lubrication and wear characteristics. The stable analytical methods are commonly used, but they cannot address effects of random vibration loading, which, according to experimental studies, are important factors for lubrication and wear of mechanical face seals used in air and space vehicles. Hence, a dynamic model for mechanical face seals is proposed, with a focus on the effects of random vibration loading. The mechanical face seal in the axial direction is described as a mass-spring-damping system. Spectrum analysis specified for random vibration is then performed numerically to obtain the response power spectral density (PSD) of the mechanical face seal and calculate the root mean square (RMS) values under random vibration conditions. A lumped parameter model is then developed to examine how dynamic parameters such as stiffness and damping affect the lubrication regimes of mechanical face seals. Based on the dynamic model and Archard wear equation, a numerical wear simulation method is proposed. The results elucidated that the increase of input acceleration PSDs, the decrease of axial damping, and the increase of axial stiffness lead to the probability of the mechanical face seal operating under full film lubrication regime increase and finally the decrease of wear. This research provides a guideline for improving the adaptability of mechanical face seals under random vibration environments.

Experimental Evaluation of a Mixed Friction Hydrostatic Mechanical Face Seal Model Considering Radial Taper, Thermal Taper, and Wear

1982 ◽  
Vol 104 (4) ◽  
pp. 439-447 ◽  
Author(s):  
L. A. Young ◽  
A. O. Lebeck
Keyword(s):  
Surface Roughness ◽  
Radial Profile ◽  
Surface Characteristics ◽  
Experimental Investigations ◽  
Test Duration ◽  
Face Seal ◽  
Mixed Friction ◽  
Face Seals ◽  
Water Test ◽  
Mechanical Face Seal

In this paper the results of experimental investigations of the effects of radial taper on mechanical face seals are presented and compared to theory. The previously published theory considers the effects of thermal taper caused by a temperature gradient in the seal rings; mixed friction in the case where load support is shared between hydrostatic support and partial contact of the seal faces; surface roughness, which affects both load sharing and leakage; and wear, which alters the radial profile. Fifteen tests were run using a 100 mm diameter carbon versus tungsten carbide seal at 1800 rpm and 3.45 MPa in water. Test duration was up to 100 hr. Varying amounts of radial taper were used. Tests were run at balance ratios of 1.00 and 0.75. Initial and final surface profiles were recorded. Seal torque, leakage, and face temperatures were recorded as functions of time. Results show that theory predicts initial torque and leakage as functions of initial taper quite well, given knowledge of seal surface characteristics. Predicted equilibrium thermal taper as a function of torque for a balance ratio of 1.0 is good. For a seal having a balance ratio of 0.75, predicted equilibrium thermal rotation shows some agreement but more experimental data are needed. The results of 1.00 balance ratio tests suggest that after a long period of operation, any initial taper will be worn away and the seal would continue to operate as a parallel face seal. Results from long-term tests indicate that the wear coefficient is not a constant. While the experimental results support the basic concepts of the model, the results show where further work must be done to better understand the role of surface roughness and wear processes in mechanical face seals.

scholarly journals Experimental and numerical study of wavy mechanical face seals operating under pressure inversions

2019 ◽  
Vol 234 (2) ◽  
pp. 247-260 ◽  
Author(s):  
Jérémy Cochain ◽  
Noël Brunetière ◽  
Andrew Parry ◽  
Henri Denoix ◽  
Abdelghani Maoui
Keyword(s):  
Numerical Model ◽  
Numerical Study ◽  
Hydrodynamic Pressure ◽  
Poor Performance ◽  
Force Balance ◽  
Face Seal ◽  
Spring Force ◽  
Face Seals ◽  
The Face ◽  
The Impact

This paper investigates the impact of the face waviness and pressure inversions on the leakage and on the outer fluid entry of mechanical face seals using a numerical model and an experimental setup. The numerical model couples a transient Reynolds equation, an analytical contact model, a force balance solver, and a solver for the thermo-mechanical deformations. The experimental tests on a face seal with low waviness and on a face seal with high waviness provide leakage and outer fluid entry data, which are reproduced by the model. Contrary to the face seal with low waviness, the face seal with high waviness has poor performance and the pressure inversions increase significantly the ingression of outer fluid. The parametric study shows a decrease of leakage with increasing spring force, and an increase of leakage and outer fluid entry with increasing values of waviness amplitude. The higher leakage observed for wavy seals is shown to be due to the higher average film thickness, and to some extent due to the mechanisms associated with waviness: hydrodynamic pressure generation, film squeeze and stretching.

scholarly journals Dynamic Response to Rotating-Seat Runout in Noncontacting Face Seals

1981 ◽  
Vol 103 (4) ◽  
pp. 587-592 ◽  
Author(s):  
I. Etsion
Keyword(s):  
Dynamic Response ◽  
Dynamic Characteristics ◽  
Operating Conditions ◽  
Face Seal ◽  
Small Perturbations ◽  
Good Insight ◽  
Face Seals ◽  
Tracking Ability ◽  
Mechanical Face Seal ◽  
Insight Into

The dynamic response of a flexibly-mounted ring to runout of the rotating seat in mechanical face seal is analyzed assuming small perturbations. It is found that tracking ability of the stator depends only on its dynamic characteristics and operating conditions and is not affected by the amount of runout. Three different modes of dynamic response are shown and the condition for parallel tracking is presented. The present analysis is limited to flat-faced seals with no secondary seal damping. Nevertheless it provides a good insight into the dynamic behavior of noncontacting face seals.

scholarly journals Semi Salix Leaf Textured Gas Mechanical Face Seal with Enhanced Opening Performance

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7522
Author(s):  
Linqing Bai ◽  
Pengcheng Zhang ◽  
Zulfiqar Ahmad Khan
Keyword(s):  
Friction Torque ◽  
Contact Friction ◽  
Textured Surface ◽  
Face Seal ◽  
Textured Surfaces ◽  
Positive Effects ◽  
Mechanical Face Seal ◽  
Gas Face Seal ◽  
Hydrodynamic Effects ◽  
The Impact

Seal performance of a novel gas mechanical face seal with semi salix leaf textures was introduced and theoretically investigated with the purpose of enhancing hydrostatic and hydrodynamic opening performance. First, a theoretical model of a laser surface textured gas mechanical face seal with semi salix leaf textures was developed. Second, the impact of operating and texturing parameters on open force, leakage, and friction torque was numerically investigated and has been discussed based on gas lubrication theory. Numerical results demonstrate that the semi salix leaf textured gas face seal has larger hydrostatic and hydrodynamic effects than the semi ellipse textured seal because of the effect of the inlet groove. All semi salix leaf textured surfaces had better open performance than the semi ellipse textured surface, which means that the inlet groove plays an important role in improving open performance and consequently decreasing contact friction during the start-up stage. Texturing parameters also influenced the seal performance of thee semi salix leaf textured gas face seal. When the inclination angle was 50°, the radial proportion of the inlet groove was 0.8, the dimple number was 9, and the open force resulted in the maximum value. This research has demonstrated the positive effects of the applications of a semi salix leaf textured gas mechanical face seal that combines the excellent hydrostatic and hydrodynamic effects of groove texture and the excellent wear resistance of microporous textures.

Impact Phenomena in a Noncontacting Mechanical Face Seal

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Philip Varney ◽  
Itzhak Green
Keyword(s):  
Rough Surface ◽  
Vibration Monitoring ◽  
Face Seal ◽  
Frequency Spectra ◽  
Face Seals ◽  
Surface Contact ◽  
Mechanical Face Seal ◽  
Impact Phenomena ◽  
Rough Surface Contact ◽  
First Time

Noncontacting mechanical face seals are often described as unpredictable machine elements, gaining this moniker from numerous instances of premature and unexpected failure. Machine faults such as misalignment or imbalance exacerbate seal vibration, leading to undesirable and unforeseen contact between the seal faces. A hypothesis explaining the high probability of failure in noncontacting mechanical face seals is this undesired seal face contact. However, research supporting this hypothesis is heuristic and experiential and lacks the rigor provided by robust simulation incorporating contact into the seal dynamics. Here, recent developments in modeling rotor–stator rub using rough surface contact are employed to simulate impact phenomena in a flexibly mounted stator (FMS) mechanical face seal designed to operate in a noncontacting regime. Specifically, the elastoplastic Jackson–Green rough surface contact model is used to quantify the contact forces using real and measurable surface and material parameters. This method also ensures that the seal face clearance remains positive, thus allowing one to calculate fluid-film forces. The seal equations of motion are simulated to indicate several modes of contacting operation, where contact is identified using waveforms, frequency spectra, and contact force calculations. Interestingly, and for the first time, certain parameters generating contact are shown to induce aperiodic mechanical face seal vibration, which is a useful machine vibration monitoring symptom. Also for the first time, this work analytically shows a mechanism where severe contact precipitates seal failure, which was previously known only through intuition and/or experience. The utility of seal face contact diagnostics is discussed along with directions for future work.

Numerical Analysis of Dry Gas Face Seals With Spiral Groove and Inner Annular Groove

2008 ◽  
Author(s):  
Xu-Dong Peng ◽  
Li-Li Tan ◽  
Ji-Yun Li ◽  
Song-En Sheng ◽  
Shao-Xian Bai
Keyword(s):  
Reynolds Equation ◽  
Geometric Parameters ◽  
Axial Stiffness ◽  
Face Seal ◽  
Optimization Principle ◽  
Face Seals ◽  
The Face ◽  
Gas Face Seal ◽  
Film Stiffness ◽  
Spiral Grooves

A two-dimensional Reynolds equation was established for isothermal compressible gas between the two faces of a dry gas face seal with both spiral grooves and an inner annular groove onto the hard face. The opening force, the leakage rate, the axial film stiffness and the film stiffness to leakage ratio were calculated by finite element method. The comparisons with the sealing performances of a typical gas face seal only with spiral grooves onto its hard face were made. The effects of the face geometric parameters on the static behavior of such a seal were analyzed. The optimization principle for geometric parameters of a dry gas face seals with spiral grooves and an inner annular groove was presented. The recommended geometric parameters of spiral grooves and circular groove presented by optimization can ensure larger axial stiffness while lower leakage rates.

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