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.

An Approach to Improve on Stiffness for Aerostatics Bearing

2019 ◽  
Vol 889 ◽  
pp. 448-454
Author(s):  
Anh Van Ha Nguyen ◽  
Thien Ngon Dang
Keyword(s):  
High Pressure ◽  
Experimental Results ◽  
Horizontal Force ◽  
Aerostatic Bearing ◽  
Working Process ◽  
High Stiffness

The pocketed orifice structure for the air-nozzles of an aerostatic bearing is usually a particular pocketed orifice. This structure can not help the shaft to reach high stiffness in working process, so the applicability of the aerostatic bearing in machines with large centrifugal or horizontal force is not focused. A common pocketed orifice structure for the air-nozzles of the aerostatic bearing to meet the demand of high stiffness of the journal shaft has been developed.. Experimental results show that the stiffness of the aerostatic bearing increases, the eccentricity is only about 0.03 mm at a pressure of 2 to 2.5 bar compared to the structure of particular pocketed orifice. Besides operating at high pressure, a common pocketed orifice structure does not suffer from air congestion (blockage) as in a particular pocketed orifice structure. This results in reducing vibration and avoiding damage inside the aerostatic bearing.

Analytical study of the extrusion of rectangular elastomeric seals for linear hydraulic actuators

2003 ◽  
Vol 217 (5) ◽  
pp. 365-373 ◽  
Author(s):  
G. K. Nikas
Keyword(s):  
High Pressure ◽  
Analytical Study ◽  
Operating Parameters ◽  
Pressure Side ◽  
Algebraic Equations ◽  
Permanent Damage ◽  
Hydraulic Actuators ◽  
Sealing Performance ◽  
Extrusion Mechanism ◽  
Elastomeric Seals

Rectangular elastomeric seals used on reciprocating piston rods in high-pressure hydraulic actuators often suffer from extrusion damage at the low-pressure side of the actuators. The extrusion takes place at the narrow clearance between the rod and the actuator, where the seal develops a ‘nip’ under conditions of high sealed pressure and/or high friction with the rod, which is amplified in the absence of a back-up ring. This form of strain can lead to permanent damage of the seal and impair the sealing performance of the system. This paper deals with the modelling of this kind of seal extrusion. Algebraic equations were developed to describe the shape and contact pressure of the extruded part of the seal with the rod. A study is presented about the effects of various operating parameters on the extent of seal extrusion in order to minimize the risks of damage. It was found that only the use of a back-up ring can adequately cancel the seal extrusion mechanism.

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.

scholarly journals Quantitative Experimental and Theoretical Investigations on the Interaction of Shock Waves with Magnetic Fields

1969 ◽  
Vol 24 (10) ◽  
pp. 1449-1457
Author(s):  
H. Klingenberg ◽  
F. Sardei ◽  
W. Zimmermann
Keyword(s):  
Magnetic Fields ◽  
Shock Waves ◽  
Physical Model ◽  
Spectroscopic Method ◽  
Experimental Results ◽  
Dimensional Theory ◽  
One Dimensional ◽  
Theoretical Investigations ◽  
Theoretical Predictions ◽  
Interaction Of Shock Waves

Abstract In continuation of the work on interaction between shock waves and magnetic fields 1,2 the experiments reported here measured the atomic and electron densities in the interaction region by means of an interferometric and a spectroscopic method. The transient atomic density was also calculated using a one-dimensional theory based on the work of Johnson3 , but modified to give an improved physical model. The experimental results were compared with the theoretical predictions.

scholarly journals Comparison of Experimental and Numerical Transient Drop Deformation during Transition through Orifices in High-Pressure Homogenizers

2021 ◽  
Vol 5 (3) ◽  
pp. 32
Author(s):  
Benedikt Mutsch ◽  
Peter Walzel ◽  
Christian J. Kähler
Keyword(s):  
High Pressure ◽  
Visual Analysis ◽  
Imaging Technique ◽  
Extensional Flow ◽  
Droplet Breakup ◽  
Experimental Results ◽  
Drop Deformation ◽  
Droplet Deformation ◽  
Shadow Imaging ◽  
Good Agreement

The droplet deformation in dispersing units of high-pressure homogenizers (HPH) is examined experimentally and numerically. Due to the small size of common homogenizer nozzles, the visual analysis of the transient droplet generation is usually not possible. Therefore, a scaled setup was used. The droplet deformation was determined quantitatively by using a shadow imaging technique. It is shown that the influence of transient stresses on the droplets caused by laminar extensional flow upstream the orifice is highly relevant for the droplet breakup behind the nozzle. Classical approaches based on an equilibrium assumption on the other side are not adequate to explain the observed droplet distributions. Based on the experimental results, a relationship from the literature with numerical simulations adopting different models are used to determine the transient droplet deformation during transition through orifices. It is shown that numerical and experimental results are in fairly good agreement at limited settings. It can be concluded that a scaled apparatus is well suited to estimate the transient droplet formation up to the outlet of the orifice.

scholarly journals Experimental study of the $ \gamma p \rightarrow K^{0}\Sigma^{+}$, $ \gamma n \rightarrow K^{0} \Lambda$, and $ \gamma n \rightarrow K^{0} \Sigma^{0}$ reactions at the Mainz Microtron

2019 ◽  
Vol 55 (11) ◽  
Author(s):  
C. S. Akondi ◽  
K. Bantawa ◽  
D. M. Manley ◽  
S. Abt ◽  
P. Achenbach ◽  
...  
Keyword(s):  
Experimental Study ◽  
Cross Sections ◽  
Differential Cross ◽  
Legendre Polynomials ◽  
Neutral Kaon ◽  
Experimental Results ◽  
Differential Cross Sections ◽  
Theoretical Predictions ◽  
Photoproduction Reactions ◽  
Insight Into

Abstract.This work measured $ \mathrm{d}\sigma/\mathrm{d}\Omega$dσ/dΩ for neutral kaon photoproduction reactions from threshold up to a c.m. energy of 1855MeV, focussing specifically on the $ \gamma p\rightarrow K^0\Sigma^+$γp→K0Σ+, $ \gamma n\rightarrow K^0\Lambda$γn→K0Λ, and $ \gamma n\rightarrow K^0 \Sigma^0$γn→K0Σ0 reactions. Our results for $ \gamma n\rightarrow K^0 \Sigma^0$γn→K0Σ0 are the first-ever measurements for that reaction. These data will provide insight into the properties of $ N^{\ast}$N* resonances and, in particular, will lead to an improved knowledge about those states that couple only weakly to the $ \pi N$πN channel. Integrated cross sections were extracted by fitting the differential cross sections for each reaction as a series of Legendre polynomials and our results are compared with prior experimental results and theoretical predictions.

A Technique for the Laboratory Determination of Recirculation in Single Needle Dialysis

1993 ◽  
Vol 16 (2) ◽  
pp. 63-70 ◽  
Author(s):  
N.A. Hoenich ◽  
P.T. Smirthwaite ◽  
C. Woffindin ◽  
P. Lancaster ◽  
T.H. Frost ◽  
...  
Keyword(s):  
Experimental Data ◽  
Flow Rate ◽  
Experimental Results ◽  
New Technique ◽  
Treatment Efficiency ◽  
Single Lumen ◽  
Theoretical Predictions ◽  
Lumen Catheter ◽  
A New Technique

Recirculation is an important factor in single needle dialysis and, if high, can compromise treatment efficiency. To provide information regarding recirculation characteristics of access devices used in single needle dialysis, we have developed a new technique to characterise recirculation and have used this to measure the recirculation of a Terumo 15G fistula needle and a VasCath SC2300 single lumen catheter. The experimentally obtained results agreed well with those established clinically (8.5 ± 2.4% and 18.4 ± 3.4%). The experimental results have also demonstrated a dependence on access type, pump speeds and fistula flow rate. A comparison of experimental data with theoretical predictions showed that the latter exceeded those measured with the largest contribution being due to the experimental fistula.

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