A Kinematic Model for Mechanical Seals With Antirotation Locks or Positive Drive Devices

1986 ◽  
Vol 108 (1) ◽  
pp. 42-45 ◽  
Author(s):  
I. Green ◽  
I. Etsion
Keyword(s):  
Simple Form ◽  
Kinematic Model ◽  
Mechanical Seals ◽  
Kinematic Constraint ◽  
Face Seals

A kinematic model of mechanical face seals is presented. Two basic seal arrangements are considered: a flexibly mounted stator with antirotation locks, and a flexibly mounted rotor with positive drive devices. The equation of kinematic constraint is derived and presented in a simple form for all the possible types of antirotation or positive drive mechanisms found in practical seals. This simple form is then used to derive the dynamic moments acting on the flexibly mounted element of the seal.

Numerical modeling and analysis of the noncontacting impulse gas face seals

2018 ◽  
Vol 233 (8) ◽  
pp. 1139-1153
Author(s):  
Slawomir Blasiak
Keyword(s):  
Computer Software ◽  
Surface Modifications ◽  
Mechanical Seals ◽  
Face Surface ◽  
Modeling And Analysis ◽  
C Language ◽  
Model Studies ◽  
Face Seals ◽  
Radial Gap ◽  
The Impact

Noncontacting mechanical seals with various kinds of face surface modifications have established their position in the sealing technique. Over the last few years, a lot of works dedicated to the impact of various surface modifications on the dynamics of working rings have been created. This paper presents model studies regarding relatively unknown noncontacting impulse gas face seals. Here, a mathematical model of impulse gas face seals is developed including the nonlinear Reynolds equation and stator dynamics equations, which were solved simultaneously using numerical methods. An original computer software written in C + + language was developed. A number of numerical tests were conducted and the phenomena occurring in the radial gap during seal operation were analyzed. Final conclusions were drawn and several features were indicated characterizing impulse face seals. It should be emphasized that numerical research on this type of seals has not been published yet. The literature usually presents simplified models for the noncompressible medium, which can be solved with the use of analytical methods.

A Deterministic Mixed Lubrication Model for Mechanical Seals

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Christophe Minet ◽  
Noël Brunetière ◽  
Bernard Tournerie
Keyword(s):  
Flow Model ◽  
Hydrodynamic Lubrication ◽  
Industrial Applications ◽  
Mixed Lubrication ◽  
Asperity Contact ◽  
Mechanical Seals ◽  
Optimal Point ◽  
Lubrication Regimes ◽  
Face Seals ◽  
Stribeck Curves

Mechanical seals are commonly used in industrial applications. The main purpose of these components is to ensure the sealing of rotating shafts. Their optimal point of operation is obtained at the boundary between the mixed and hydrodynamic lubrication regimes. However, papers focused on this particular aspect in face seals are rather scarce compared with those dealing with other popular sealing devices. The present study thus proposes a numerical flow model of mixed lubrication in mechanical face seals. It achieves this by evaluating the influence of roughness on the performance of the seal. The choice of a deterministic approach has been made, this being justified by a review of the literature. A numerical model for the generation of random rough surfaces has been used prior to the flow model in order to give an accurate description of the surface roughness. The model takes cavitation effects into account and considers Hertzian asperity contact. Results for the model, including Stribeck curves, are presented as a function of the duty parameter.

Pumping Action of Aligned Smooth Face Seals Due to Axial Vibrations-Experiment

1986 ◽  
Vol 108 (1) ◽  
pp. 46-52
Author(s):  
M. Kaneta ◽  
M. Fukahori
Keyword(s):  
Film Thickness ◽  
Previous Investigation ◽  
Design Principles ◽  
Mechanical Seals ◽  
Face Seals ◽  
Axial Vibrations ◽  
Fundamental Design

The mechanism of pumping action caused by axially vibrating one of the seal faces with continuous parallel film thickness is clarified experimentally. The results obtained in the experiment confirm the theory developed in a previous investigation [11]. The fundamental design principles of mechanical seals are also described from the viewpoint of this pumping phenomenon.

FULL NUMERICAL SIMULATION TO THE PERFORMANCE OF MICRO-TEXTURED MECHANICAL FACE SEALS

2008 ◽  
Vol 07 (02) ◽  
pp. 267-270 ◽  
Author(s):  
XIAO WANG ◽  
HUIXIA LIU ◽  
WEI CHEN ◽  
CHANGJING LIU ◽  
YONGHONG FU ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Friction Coefficient ◽  
Reynolds Equation ◽  
Grid Method ◽  
Numerical Approach ◽  
Polar Coordinates ◽  
Mechanical Seal ◽  
Mechanical Seals ◽  
Face Seals

A mathematical model is established based on a modified Reynolds equation in polar coordinates, and solved by the multi-grid method to demonstrate the performance of micro-texturing mechanical seal surface. Sample cases of cylinder-shaped, square-shaped and diamond-shaped micro-asperity are studied to show the performance of micro-texturing mechanical seals. The results show that geometry has a vital influence on the friction coefficient and leakage. Diamond-shaped micro-texturing asperities have better performance than the others. And the performance is sensitive to the area density than the micro-texturing depth. The numerical approach can be a useful engineering tool, analyzing and optimizing the performance of micro-texturing mechanical face seals.

scholarly journals The Rotor Dynamic Coefficients of Coned-Face Mechanical Seals With Inward or Outward Flow

1987 ◽  
Vol 109 (1) ◽  
pp. 129-135 ◽  
Author(s):  
I. Green
Keyword(s):  
Fluid Film ◽  
Mechanical Seals ◽  
Dynamic Coefficients ◽  
Face Seals ◽  
Stiffness And Damping ◽  
Rotor Dynamic

The linearized fluid film dynamic coefficients, i.e., stiffness and damping, of flexibly-mounted rotor noncontacting mechanical face seals are found. The coefficients are derived from a previous study where the flexibly mounted element was the stator. The two cases of inward and outward flows, both having converging gaps in the direction of flow, are analyzed for the two mounting configurations, and it is found that the later case possesses higher angular stiffness.

Background Fitting in the Low-Loss Region of Electron Energy Loss Spectra

1990 ◽  
Vol 48 (2) ◽  
pp. 56-57
Author(s):  
C P Scott ◽  
A J Craven ◽  
C J Gilmore ◽  
A W Bowen
Keyword(s):  
Energy Loss ◽  
Multiple Scattering ◽  
Simple Form ◽  
Single Scattering ◽  
Low Loss ◽  
Characteristic Energy ◽  
Normal Method ◽  
Fitting In ◽  
Electron Energy Loss ◽  
Electron Energy Loss Spectra

The normal method of background subtraction in quantitative EELS analysis involves fitting an expression of the form I=AE-r to an energy window preceding the edge of interest; E is energy loss, A and r are fitting parameters. The calculated fit is then extrapolated under the edge, allowing the required signal to be extracted. In the case where the characteristic energy loss is small (E < 100eV), the background does not approximate to this simple form. One cause of this is multiple scattering. Even if the effects of multiple scattering are removed by deconvolution, it is not clear that the background from the recovered single scattering distribution follows this simple form, and, in any case, deconvolution can introduce artefacts.The above difficulties are particularly severe in the case of Al-Li alloys, where the Li K edge at ~52eV overlaps the Al L2,3 edge at ~72eV, and sharp plasmon peaks occur at intervals of ~15eV in the low loss region. An alternative background fitting technique, based on the work of Zanchi et al, has been tested on spectra taken from pure Al films, with a view to extending the analysis to Al-Li alloys.

Methods and Means of Reducing Friction Moment in Face Seals

1980 ◽  
Vol 41 (5) ◽  
pp. 604-611
Author(s):  
V. B Balyakin ◽  
◽  
S. V Falaleev ◽  
Keyword(s):  
Friction Moment ◽  
Face Seals

SCREW KINEMATIC MODEL FOR ROBOT CALIBRATION WITH PC-ROBOT COMMUNICATION OVERVIEW

2017 ◽  
Author(s):  
Lucas Kato ◽  
Tiago Pinto ◽  
Henrique Simas ◽  
Daniel Martins
Keyword(s):  
Kinematic Model ◽  
Robot Calibration ◽  
Robot Communication

Multi-criteria optimization of the four-finger gripper mechanism

2020 ◽  
Vol 8 (4) ◽  
pp. 276-286
Author(s):  
Vu Duc Quyen ◽  
Andrey Ronzhin
Keyword(s):  
Multicriteria Optimization ◽  
Kinematic Model ◽  
Objective Functions ◽  
Nsga Ii ◽  
Suction Nozzle

Three posterior algorithms NSGA-II, MOGWO and MOPSO to solve the problem of multicriteria optimization of the robotic gripper design are considered. The description of the kinematic model of the developed prototype of the four-fingered gripper for picking tomatoes, its limitations and objective functions used in the optimization of the design are given. The main advantage of the developed prototype is the use of one actuator for the control of the fingers and the suction nozzle. The results of optimization of the kinematic model and the dimensions of the elements of robotic gripper using the considered posterior algorithms are presented.

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