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

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.

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.

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.

Study on Bonding Properties of Copper and Aluminum in Nano Scale Using Molecular Dynamics Simulation

2012 ◽  
Vol 152-154 ◽  
pp. 183-187 ◽  
Author(s):  
Quang Cherng Hsu ◽  
Yen Yu Cheng ◽  
Bao Hsin Liu
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Bonding Strength ◽  
High Speed ◽  
Tensile Force ◽  
Pure Aluminum ◽  
Pure Copper ◽  
Dynamics Simulation ◽  
Low Speed ◽  
Speed Condition

According to MD simulation results, pressing depth between two bonding materials will affect bonding strength. Alloy material (Al0.9Cu0.1) had void defect phenomenon in low bonding speed condition because the increasing chance of atom migration which will result in low bonding strength. High tensile speed causes material fracture phenomena happen earlier than low speed. Material stress in low speed is smaller than in high speed. Fracture morphology of material is different in different tensile speed. In low speed condition, material can be stretched thinner than in high speed condition. Material in high temperature has greater kinetic energy than low temperature; therefore, material in high temperature has better formability and behaves larger tensile strain than low temperature. For pure aluminum, when temperature raises to 900K which is close to melting point (933K), its crystal structure is no longer belongs to F.C.C. structure, so bonding strength is weaker than low temperature. Large size material has larger contact area than small size material; therefore, the tensile force and tensile strength of the former are larger than the latter. The order of bonding strength for these three materials is: binary alloy > pure copper > pure aluminum.

scholarly journals The Effect of Boattail Angles on the Near-Wake Structure of Axisymmetric Afterbody Models at Low-Speed Condition

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
The Hung Tran
Keyword(s):  
Strouhal Number ◽  
Reynolds Shear Stress ◽  
Flow Behavior ◽  
Flow Characteristics ◽  
Wake Flow ◽  
Turbulent Intensity ◽  
Near Wake ◽  
Wake Structure ◽  
Low Speed ◽  
Speed Condition

The effect of a boattail angle on the structure of the wake of an axisymmetric model was investigated at low-speed condition. Four conical boattail models with angles of 0° (blunt-based body), 10°, 16°, and 22° were selected for this study. The Reynolds number based on the diameter of the model was around 1.97×104. Particle image velocimetry (PIV) was used to measure the velocity of the wake flow. The time-averaged flow characteristics including the length of recirculation of the afterbody, turbulent intensity, and Reynolds shear stress were analyzed and compared among those boattail models. The experimental results showed that the length of recirculation decreases with increasing boattail angle to 16°. At a boattail angle above 16°, the flow was fully separated near the shoulder and near-wake structure was highly changed. The turbulent intensity at a boattail angle of 22° showed a similar level to that in the case of the blunt-based body. Flow behavior on boattail surface should be accounted as an important parameter affecting the wake width and drag of the model. Power spectral density and proper orthogonal decomposition (POD) analyses showed that a Strouhal number of StD=0.2 dominated for the boattail model up to 16°. The fully separated flow was dominated by a Strouhal number of StD=0.03−0.06, which was firstly presented in this study.

Nonlinear Modeling of Mechanical Gas Face Seal Systems Using Proper Orthogonal Decomposition

2005 ◽  
Author(s):  
Haojiong Zhang ◽  
Brad A. Miller ◽  
Robert G. Landers
Keyword(s):  
Proper Orthogonal Decomposition ◽  
Initial Conditions ◽  
Nonlinear Modeling ◽  
Orthogonal Decomposition ◽  
Simulation Studies ◽  
Face Seal ◽  
Model Order ◽  
Reduced Order ◽  
Gas Face Seal ◽  
Proper Orthogonal

A nonlinear reduced-order modeling approach based on Proper Orthogonal Decomposition (POD) is utilized to develop an efficient low order model, based on ordinary differential equations, for mechanical gas face seal systems. An example of a coned mechanical gas face seal in a flexibly mounted stator configuration is presented. The axial mode is modeled, and simulation studies are conducted using different initial conditions and forcing inputs. The results agree well with a fully meshed finite difference model, while the resulting model order is significantly decreased.

A Bi-Directional Gas Face Seal

1992 ◽  
Vol 35 (1) ◽  
pp. 53-58 ◽  
Author(s):  
R. A. Shellef ◽  
R. P. Johnson
Keyword(s):  
Face Seal ◽  
Gas Face Seal
Sign in / Sign up

Export Citation Format

Share Document