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.

Numerical Modelling of High Pressure Gas Face Seals

2005 ◽  
Author(s):  
Se´bastien Thomas ◽  
Noe¨l Brunetie`re ◽  
Bernard Tournerie
Keyword(s):  
High Pressure ◽  
Thermal Effects ◽  
Operating Conditions ◽  
Compressible Fluids ◽  
Face Seal ◽  
Choked Flow ◽  
Exit Boundary ◽  
Face Seals ◽  
Gas Face Seal ◽  
Comparison With Experimental Data

A numerical model of face seals operating with compressible fluids at high pressure is presented. Inertia terms are included using an averaged method and thermal effects are considered. The real behaviour of gases at high pressure is taken into account. An original exit boundary condition is used to deal with choked flow. The model is validated by comparison with experimental data and analytical solutions. Finally, the influence of the operating conditions on the performance of a high-pressure gas face seal is analysed.

Numerical Modelling of High Pressure Gas Face Seals

2005 ◽  
Vol 128 (2) ◽  
pp. 396-405 ◽  
Author(s):  
Sébastien Thomas ◽  
Noël Brunetière ◽  
Bernard Tournerie
Keyword(s):  
High Pressure ◽  
Thermal Effects ◽  
Operating Conditions ◽  
Compressible Fluids ◽  
Face Seal ◽  
Choked Flow ◽  
Exit Boundary ◽  
Face Seals ◽  
Real Behavior ◽  
Gas Face Seal

An axisymetric numerical model of face seals operating with compressible fluids at high pressure is presented. Inertia terms are included using an averaged method and thermal effects are considered. The real behavior of gases at high pressure is taken into account. An original exit boundary condition is used to deal with choked flow. The model is validated by comparison with experimental data and analytical solutions. Finally, the influence of the operating conditions on the performance of a high-pressure gas face seal is analyzed. It is shown that when the flow is choked, the mass flow rate is reduced and the behavior of the seal becomes unstable.

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 Heat transfer study of mechanical face seal and fin by analytical method

2018 ◽  
Vol 21 (3) ◽  
pp. 380-388 ◽  
Author(s):  
M. Mosavat ◽  
R. Moradi ◽  
M. Rahimi Takami ◽  
M. Barzegar Gerdroodbary ◽  
D.D. Ganji
Keyword(s):  
Heat Transfer ◽  
Analytical Method ◽  
Face Seal ◽  
Mechanical Face Seal ◽  
Transfer Study

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.

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.

The Parameter Variation in Pressure Vessel during Loading Operation by Considering Heat Transfer Impact Based on Real Gas Model

2012 ◽  
Vol 516-517 ◽  
pp. 467-470
Author(s):  
Wei Qing Wang ◽  
Li Yang ◽  
Shi Gui Lv
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Pressure Vessel ◽  
Simulation Method ◽  
Ideal Gas ◽  
Molecular Volume ◽  
Real Gas ◽  
The Real ◽  
Ideal Gas Model ◽  
The Ideal

Since the molecular force and the molecular volume were ignored in the ideal gas model, and it was less accurate when the ideal gas model was used to depict characteristics of real gas under high pressure, so the real gas model was adopted and the heat transfer was considered, the dynamic variation model was set up for internal gas in the pressure vessel during loading operation. The model was solved by using the numerical simulation method of Runge-Kutta. Comparison was made between the ideal gas model and the real gas model under adiabatic and non-adiabatic conditions, it showed that under low pressure the results obtained by the two models were in good agreement, but under high pressure the deviation was enlarged, the real gas model with considering the heat transfer influenced would be more coincident with the reality.

Parametric Study of the Behavior of a Mechanical Face Seal Operating in Mixed and TEHD Lubrication Regimes

2012 ◽  
Author(s):  
André Parfait Nyemeck ◽  
Noël Brunetière ◽  
Bernard Tournerie
Keyword(s):  
Heat Transfer ◽  
Friction Coefficient ◽  
Mixed Lubrication ◽  
Operating Conditions ◽  
Fluid Viscosity ◽  
Face Seal ◽  
Lubrication Regimes ◽  
Lubrication Regime ◽  
Mechanical Face Seal ◽  
Mixed Lubrication Regime

In this paper, the behavior of a mechanical face seal is analyzed for different operating conditions and designs. For that, a theoretical model including a multiscale approach of the mixed lubrication regime, heat transfer and deformation of the seal rings is used. It has been possible to clearly identify the three different lubrication regimes of a mechanical seal: the mixed lubrication where the friction coefficient decreases, the rough hydrodynamic regime corresponding to an increasing friction and then the thermo-elasto-hydrodynamic (TEHD) regime for which the coefficient of friction is approximately constant. In this work, the influence of the fluid pressure, the seal roughness height, the balance ratio, the rings materials, the dry friction coefficient and viscosity are respectively examined. Generally speaking, the variation of these parameters affects the location of the optimum value of the friction coefficient in the mixed lubrication regime. In the TEHD regime, the temperature is mainly influenced by the materials and the fluid viscosity, which control the amplitude of deformation and heat transfer. A dimensionless parametric analysis has been carried out in order to perform an overall discussion of the results. It is shown that the mixed and rough hydrodynamic lubrication regimes are controlled by the modified duty parameter, while the TEHD regime is controlled by the sealing parameter.

Thermoelastohydrodynamic Behavior of Gas Spiral Groove Face Seals Operating at High Pressure and Speed

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Shaoxian Bai ◽  
Chunhong Ma ◽  
Xudong Peng ◽  
Shizhu Wen
Keyword(s):  
High Pressure ◽  
Fluid Film ◽  
Temperature Fields ◽  
Thermal Distortion ◽  
Face Seal ◽  
Spiral Groove ◽  
Effect Analysis ◽  
Choked Flow ◽  
Film Forming ◽  
Elastic Distortion

A numerical modeling of thermoelastohydrodynamic gas spiral groove face seal behavior is presented. Temperature fields of the fluid film and the seal rings are computed, as they are the elastic and thermal distortions of the rings. Numerical analysis is carried out on a gas spiral groove face seal taking into account of choked flow effect. Analysis results show that both elastic and thermal distortions induce strong influence on the geometry of the fluid film, forming obvious divergent clearance which leads to significant decrease of minimum equilibrium clearance, exceeding 50% in degree. Thermal distortion may induce the same influence degree as elastic distortion on the minimum equilibrium clearance in high pressure cases, but the rotation speed has no obvious influence on the minimum clearance when both elastic and thermal distortions are considered. The thermal distortion as well as elastic distortion should be concerned in high pressure analysis.

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