Experimental study on the hydrodynamic lubrication characteristics of magnetofluid film in a spiral groove mechanical seal

2016 ◽  
Vol 95 ◽  
pp. 192-198 ◽  
Author(s):  
Jianfeng Zhou ◽  
Haoliang Fan ◽  
Chunlei Shao
Keyword(s):  
Experimental Study ◽  
Hydrodynamic Lubrication ◽  
Mechanical Seal ◽  
Spiral Groove ◽  
Lubrication Characteristics

On hydrodynamic lubrication characteristics of ferrofluid film in a spiral groove mechanical seal

2018 ◽  
Vol 70 (9) ◽  
pp. 1783-1797 ◽  
Author(s):  
Penggao Zhang ◽  
Boqin Gu ◽  
Jianfeng Zhou ◽  
Long Wei
Keyword(s):  
Electromagnetic Field ◽  
Volume Fraction ◽  
Hydrodynamic Lubrication ◽  
Groove Width ◽  
Mechanical Seal ◽  
Spiral Groove ◽  
Content Type ◽  
Rotating Speed ◽  
Lubrication Characteristics ◽  
Spiral Angle

Purpose The purpose of this study is to investigate the hydrodynamic lubrication characteristics of ferrofluid film for spiral groove mechanical seal in external electromagnetic field and to analyze the effects of the volume fraction of ferrofluid, parameters of the electromagnetic field, operating parameters and geometrical parameters of mechanical seal on the characteristics of ferrofluid film. Design/methodology/approach The relationship between the ferrofluid viscosity and the intensity of external electromagnetic field was established. Based on the Muijderman narrow groove theory, the pressure distribution was calculated with the trial method by trapezoid formula. Findings It was found that pressure, average viscosity, average density and opening force of ferrofluid between end faces increase with the increase in intensity of current, volume fraction of ferrofluid, rotating speed, pressure differential and spiral angle; decrease with the increase in temperature; and increase at first and then decrease with the increase in the ratio of groove width to weir and the groove length. All of them reach the maximum value when the ratio of width of groove to weir is 0.7 and the ratio of groove length is 0.6. Leakage of ferrofluid increases with an increase in intensity of current, volume fraction of ferrofluid, rotating speed, pressure differential, spiral angle and ratio of groove length; decreases with an increase in temperature; and increases at first and then decreases with the increase in the ratio of groove width to weir. The tendencies of characteristics of silicone oil are consistent with those of ferrofluid, and the characteristics of silicone oil are smaller than those of ferrofluid under the same condition. Originality/value The volume fraction of ferrofluid, rotating speed, spiral angle, ratio of groove width to weir, groove length and temperature have a significant influence on the characteristics of ferrofluid film; however, intensity of current and the pressure differential have slight influence on the characteristics of ferrofluid film. An analytical method for analyzing hydrodynamic lubrication characteristics of ferrofluid film in a spiral groove mechanical seal was proposed based on the Muijderman narrow groove theory.

scholarly journals Two-scale homogenization of hydrodynamic lubrication in a mechanical seal with isotropic roughness based on the Elrod cavitation algorithm

2021 ◽  
pp. 135065012110176
Author(s):  
Yanxiang Han ◽  
Qingen Meng ◽  
Gregory de Boer
Keyword(s):  
Surface Topography ◽  
Carrying Capacity ◽  
Hydrodynamic Lubrication ◽  
Tribological Performance ◽  
Stribeck Curve ◽  
Polar Coordinate System ◽  
Load Carrying Capacity ◽  
Mechanical Seal ◽  
Macro Scale ◽  
Load Carrying

A two-scale homogenization method for modelling the hydrodynamic lubrication of mechanical seals with isotropic roughness was developed and presented the influence of surface topography coupled into the lubricating domain. A linearization approach was derived to link the effects of surface topography across disparate scales. Solutions were calculated in a polar coordinate system derived based on the Elrod cavitation algorithm and were determined using homogenization of periodic simulations describing the lubrication of a series of surface topographical features. Solutions obtained for the hydrodynamic lubrication regime showed that the two-scale homogenization approach agreed well with lubrication theory in the case without topography. Varying topography amplitude demonstrated that the presence of surface topography improved tribological performance for a mechanical seal in terms of increasing load-carrying capacity and reducing friction coefficient in the radial direction. A Stribeck curve analysis was conducted, which indicated that including surface topography led to an increase in load-carrying capacity and a reduction in friction. A study of macro-scale surface waviness showed that the micro-scale variations observed were smaller in magnitude but cannot be obtained without the two-scale method and cause significant changes in the tribological performance.

Friction Properties of Lubricated Laser-MicroTextured-Surfaces: An Experimental Study from Boundary- to Hydrodynamic-Lubrication

2012 ◽  
Vol 49 (1) ◽  
pp. 117-125 ◽  
Author(s):  
Michele Scaraggi ◽  
Francesco P. Mezzapesa ◽  
Giuseppe Carbone ◽  
Antonio Ancona ◽  
Luigi Tricarico
Keyword(s):  
Experimental Study ◽  
Hydrodynamic Lubrication ◽  
Microtextured Surfaces

Hydrodynamic Performance Produced by Nanotexturing in Submicrometer Clearance With Surface Roughness

2014 ◽  
Vol 137 (1) ◽  
Author(s):  
Tomoko Hirayama ◽  
Heinosuke Shiotani ◽  
Kazuki Yamada ◽  
Naoki Yamashita ◽  
Takashi Matsuoka ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Hydrodynamic Lubrication ◽  
Surface Texturing ◽  
Wave Model ◽  
Physical Models ◽  
Hydrodynamic Performance ◽  
Stribeck Curve ◽  
Spiral Groove ◽  
Transition Speed ◽  
Lubrication Regime

Surface texturing is a promising way to expand the hydrodynamic lubrication regime and thereby modify the tribological properties of sliding surfaces. Spiral-groove textures in particular have attracted much attention over the past several decades because they produce a thicker lubrication film in the gap. However, no research has been reported on the effect of periodic texturing with a several 100 nm depth on hydrodynamic performance in submicrometer clearance with surface roughness. The purpose of the study reported here was to investigate the effect of such nanotexturing on hydrodynamic performance. This was done by conducting ring-on-disk friction tests, focusing on the existence of surface roughness in the narrow clearance. The samples were rings with various degrees of surface roughness and disks with spiral-groove textures produced by femtosecond laser processing. The friction coefficients experimentally obtained were plotted as a Stribeck curve and compared with a theoretical one calculated using a Reynolds equation formulated from two physical models, the Patir–Cheng average flow model and a sinusoidal wave model. The results showed that surface roughness did not affect the friction coefficient in the hydrodynamic lubrication regime. However, the hydrodynamic lubrication regime gradually shrank with an increase in surface roughness, and mild transitions to the mixed lubrication regime were observed at higher rotational speeds. The minimum clearances reached at the transition speed were almost the same, about 200–300 nm, for all experiments regardless of surface roughness.

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