Hydrodynamic effect of non-closed elliptical grooves of bi-directional rotation gas face seals

2019 ◽  
Vol 72 (3) ◽  
pp. 369-377 ◽  
Author(s):  
Jing Xie ◽  
Shaoxian Bai ◽  
Chunhong Ma
Keyword(s):  
Inclination Angle ◽  
Convergence Criterion ◽  
Hydrodynamic Effect ◽  
Face Seal ◽  
Content Type ◽  
Lubricating Film ◽  
Sealing Performance ◽  
Face Seals ◽  
Hydrodynamic Mechanism ◽  
Gas Face Seal

Purpose The purpose of this paper is to improve opening performance of bi-directional rotation gas face seals by investigating the hydrodynamic effect of non-closed elliptical grooves. Design/methodology/approach A model of non-closed elliptical groove bi-directional rotation gas face seal is developed. The distribution of lubricating film pressure is obtained by solving gas Reynolds equations with the finite difference method. The program iterates repeatedly until the convergence criterion on the opening force is satisfied, and the sealing performance is finally obtained. Findings Non-closed elliptical groove presents much stronger hydrodynamic effect than the closed groove because of drop of the gas resistance flowing into grooves. Besides, the non-closed elliptical groove presents significant hydrodynamic effect under bi-directional rotation conditions, and an increase of over 40 per cent is obtained for the opening force at seal pressure 4.5 MPa, as same level as the unidirectional spiral groove gas seal. In the case of bi-directional rotation, the value of the inclination angle is recommended to set as 90° presenting a structure symmetry so as to keep best opening performance for both positive and reverse rotation. Originality/value A model of non-closed elliptical groove bi-directional rotation gas face seal is established. The hydrodynamic mechanism of this gas seal is illustrated. Parametric investigation of inclination angle and integrity rate is presented for the non-closed elliptical groove bi-directional rotation gas face seal.

Thermoelastohydrodynamic characteristics of supercritical CO2 spiral groove face seals

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Delei Zhu ◽  
Shaoxian Bai
Keyword(s):  
Critical Temperature ◽  
Peer Review ◽  
Spiral Groove ◽  
Supercritical Regime ◽  
Content Type ◽  
Lubricating Film ◽  
Sealing Performance ◽  
Face Seals ◽  
The Face ◽  
Energy Equations

Purpose The purpose of this study is to determine the sealing performance of face seals by numerical analysis of thermoelastohydrodynamic characteristics of supercritical CO2 (S-CO2) spiral groove face seals in the supercritical regime. Design/methodology/approach The spiral groove face seal was used as the research object. The distribution of lubricating film pressure and temperature was analysed by solving the gas state, Reynolds and energy equations using the finite difference method. Furthermore, the influence law of sealing performance was obtained. Findings Close to the critical temperature of S-CO2, face distortions produced by increasing pressure lead to divergent clearance and resulted in reduced opening force. In the state of S-CO2, the face distortions generated by increasing seal temperature lead to convergent clearance, which enhances the opening force. In addition, near the critical temperature of S-CO2, the opening force may be reduced by 10%, and the leakage rate of the seal sharply increases by a factor of four. Originality/value The thermoelastohydrodynamic characteristics of supercritical CO2 face seals are illustrated considering the actual gas effect including compressibility, heat capacity and viscosity. Face distortions and sealing performance were calculated under different seal pressures and seal temperatures in the supercritical regime, as well as with N2 for comparison. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2020-0169/

A closed-form contact model for gas face seals during the opened operation

2018 ◽  
Vol 70 (6) ◽  
pp. 1110-1118 ◽  
Author(s):  
Songtao Hu ◽  
Noel Brunetiere ◽  
Weifeng Huang ◽  
Xi Shi ◽  
Zhike Peng ◽  
...  
Keyword(s):  
Closed Form ◽  
Rotor Dynamics ◽  
Contact Model ◽  
Strong Impact ◽  
Face Seal ◽  
Content Type ◽  
Face Seals ◽  
The Face ◽  
Nonparallel Plane ◽  
Gas Face Seal

Purpose Face contact has a strong impact on the service life of non-contacting gas face seals; the current research which mainly focuses on the face contact had appeared during the startup or shutdown operation. This paper aims to present a closed-form contact model of a gas face seal during the opened operation. Design/methodology/approach Referring to the axial rub-impact model of rotor dynamics, a closed-form contact model is developed under a nonparallel plane contact condition that corresponds to the local face contact of sealing rings arising from some disturbances during the opened operation. The closed-form contact model and a direct numerical contact model are performed on Gaussian surfaces to compare the contact behavior. Findings The closed-form contact model is in a good agreement with the direct numerical contact model. However, the closed-form contact model cannot involve the influence of grooves on the sealing ends. The error is eliminated in some other types of gas face seals such as coned gas face seals. Besides non-contacting face seals, the closed-form model can be applied to the axial rub impact of rotor dynamics. Originality value A closed-form contact model of a gas face seal is established during the opened operation. The closed-form contact model is validated by a direct numerical contact model. The closed-form contact model also suits for axial rub-impact of rotor dynamics.

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.

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.

Parameter optimization of sealing performance for packer rubber

2019 ◽  
Vol 71 (5) ◽  
pp. 664-671
Author(s):  
Fuying Zhang ◽  
Hao Che Shui ◽  
Yufei Zhang
Keyword(s):  
Finite Element ◽  
Friction Coefficient ◽  
Response Surface ◽  
Inclination Angle ◽  
Rubber Tube ◽  
Test Results ◽  
Element Analysis ◽  
Content Type ◽  
Sealing Performance ◽  
Maximum Contact

Purpose The purpose of this paper is based on the response surface method, the authors determined the conditions for achieving the optimum rubber-sealing performance by using the maximum contact stress as the response value. Design/methodology/approach A two-dimensional model of a compression packer rubber was established by finite-element analysis software. Under the single axial load of 53.85 MPa, the four single factors of the end-face inclination angle, subthickness, height of rubber and friction coefficient of the rubber were analyzed. Findings Results show that the optimum sealing performance of the rubber tube is achieved when the end-face angle is equal to 45º and the thickness of the rubber tube is 9 mm. The response surface designed by Box–Behnken shows that the sealing performance of the rubber tube is the optimum when the end-face inclination angle is 48.1818°, the subthickness is 9 mm, the height of rubber is 90 mm and the friction coefficient is 0.1. Verification test results show that the model is reliable and effective. Originality/value Packer operations are performed downhole, and research on real experiments is limited. In this work, the feasibility of such experiments is determined by comparing finite-element modeling with actual experiments, and the results have guiding significance for actual downhole operations.

A Face Seal With Circumferential Pumping Grooves and Rayleigh-Steps

1988 ◽  
Vol 110 (2) ◽  
pp. 313-317 ◽  
Author(s):  
K. Ikeuchi ◽  
H. Mori ◽  
T. Nishida
Keyword(s):  
High Pressure ◽  
Experimental Results ◽  
Pressure Side ◽  
Face Seal ◽  
Shaft Speed ◽  
High Stiffness ◽  
Lubricating Film ◽  
Limit Value ◽  
Sealing Performance ◽  
Theoretical Predictions

This paper presents an analysis of a new noncontacting pumping seal. A hydrodynamic lubricating film is maintained due to Rayleigh-steps. If the low pressure side of the seal is filled with a fluid, the fluid can be pumped into the high pressure side by pumping grooves until the shaft speed reaches a limit value. The experimental results confirm the theoretical predictions for lubrication and sealing performance. Due to the high pumping ability in addition to the high stiffness of its hydrodynamic film, the seal can operate without wear and leakage for a high pressure fluid.

Evolution of bi-Gaussian surface parameters and sealing performance for a gas face seal under a low-speed condition

2018 ◽  
Vol 120 ◽  
pp. 317-329 ◽  
Author(s):  
Songtao Hu ◽  
Weifeng Huang ◽  
Xi Shi ◽  
Zhike Peng ◽  
Xiangfeng Liu ◽  
...  
Keyword(s):  
Face Seal ◽  
Surface Parameters ◽  
Low Speed ◽  
Speed Condition ◽  
Sealing Performance ◽  
Gas Face Seal ◽  
Gaussian Surface

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.

Experimental study on the water lubrication of non-contacting face seals for turbopumps

2014 ◽  
Vol 66 (2) ◽  
pp. 314-321 ◽  
Author(s):  
Zhang Guo-yuan ◽  
Wei-gang Zhao ◽  
Yan Xiu Tian
Keyword(s):  
Experimental Study ◽  
High Speed ◽  
Rocket Engine ◽  
Groove Depth ◽  
Liquid Oxygen ◽  
Liquid Rocket Engine ◽  
Face Seal ◽  
Content Type ◽  
Face Seals ◽  
Liquid Rocket

Purpose – A new type of hydrostatic and hydrodynamic non-contacting face seals has been designed to meet the requirements of lower leakage, longer life and more repeatedly start and stop on shaft seals raised by liquid rocket engine turbopumps. And an experimental study on the performance of the face seal in the actual liquid oxygen turbopump was completed where low-viscosity water was selected as the seal fluid for the sake of safety. The paper aims to discuss these issues. Design/methodology/approach – Different performances of face seals under preset conditions were obtained by repeatedly running tests, and the main performance parameters encompass leakage, fluid film pressure between the faces, operating power, face temperature, and so on. Findings – The results indicate that the designed face seal has a smaller amount of leakage, with a minimum value of 3 ml/s. Furthermore, the designed face seal has been proved to demand lower operating power. Since its operating power changes slightly with different sealed fluid pressures, the new seal can be deployed in the harsh working condition with high pressure or with high speed (greater than 20,000 rpm). However, one proviso is that when liquid is employed as the seal fluid, the groove depth should be relatively deeper (greater than 10 μm). Research limitations/implications – In response to future engineering requirements, study on the controllable spiral-groove face seals to improve the current design is being conducted. Originality/value – The advancement of such non-contacting face seals proffers important insights to the design of turbo-pump shaft seal in a new generation of liquid rocket engine with regard to the requirement of frequent start and stop as well as long life on it.

Effects of Surface Roughness and Slip Flow on the Performance of a Spiral Groove Gas Face Seal

2007 ◽  
Author(s):  
Xu-Dong Peng ◽  
Song-En Sheng ◽  
Xiao-Ni Yin ◽  
Ji-Yun Li
Keyword(s):  
Surface Roughness ◽  
Standard Deviation ◽  
Slip Flow ◽  
Element Model ◽  
Face Seal ◽  
Spiral Groove ◽  
Sealing Performance ◽  
Set Up ◽  
Gas Face Seal ◽  
Effect Of Surface

Considering the effects of surface roughness and slip flow, the extended Reynolds equation presented by Makino et al [1] is used to set up the finite element model for a non-contact spiral groove dry gas face seal (S-DGS). The analyses for a typical S-DGS at low speed (≤ 500 rpm) and low pressure (≤ 0.606 MPa) showed that the effect of slip flow on the sealing performance is significant for 0.05≤ Kn < 1.0, where Kn refers to the Knudsen number, but the effect of surface roughness on the sealing performance varies with the different areas of both the two faces. When the standard deviation of composite roughness is less than 1.0 micron and in the range of 0.5≤ Kn≤ 1.0, the effects of surface roughness and slip flow diminished on gas film stiffness and frictional work but are still significant on the leakage rate. The effect of surface roughness of the spiral groove bottom is significant and should be considered, but the effects of the other surface roughness, i.e. the soft ring surface roughness and the un-grooved hard ring surface roughness, are negligible only when the value of the standard deviation of composite roughness meets with API standards.

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