scholarly journals Experimental Verification on Friction Factor Fractal Model of the End Faces for Mechanical Seals

Author(s):  
Xingzhong Chang ◽  
Wenrui Teng ◽  
Penggao Zhang ◽  
Long Wei
2014 ◽  
Vol 687-691 ◽  
pp. 142-147 ◽  
Author(s):  
Long Wei ◽  
Peng Gao Zhang ◽  
Gui Fang Fang

In order to study the effects of operating parameters and surface topography on friction factors between the end faces for mechanical seals, a friction factor fractal model between end faces for contact mechanical seals was established based on the contact fractal model and the average film thickness fractal model, adopting fractal parameters to represent surface topography, separating friction into viscous shear friction of liquid film and contact friction of asperities, and representing the effect of actual rough surface on viscous shear stress of liquid film by introducing the contact factor. The influencing factors of friction factor for B104a-70 mechanical seal were analyzed by simulating. Results showed that the friction factor between the surfaces increases with the increases of spring pressure when the end faces are coarser, while the friction factor decreases slightly with the increases of spring pressure when the end faces are smoother. The friction factor between the faces decreases with the increases of the sealed fluid pressure, which increases approximate linearly with the increases of rotating speed, and it increases with the increases of fractal dimension of end faces and the decreases of the characteristic scale factor.


Fractals ◽  
2020 ◽  
Vol 28 (06) ◽  
pp. 2050097
Author(s):  
BOQI XIAO ◽  
YONGHUI LIU ◽  
HANXIN CHEN ◽  
XUBING CHEN ◽  
GONGBO LONG

In this work, a novel fractal model for the laminar flow in roughened cylindrical microchannels is proposed. The average height of rough elements is derived using the fractal theory. The effects of relative roughness on the friction factor and the Poiseuille number are discussed. It is found that the Darcy friction factor and the Poiseuille number increase with the increase in the relative roughness in the cylindrical microchannel. Besides, it is observed that the Darcy friction factor decreases with the increase in the Reynolds number. Each parameter of the proposed model has a clear physical meaning. The present model can properly reveal some mechanisms that affect the laminar flow in roughened cylindrical microchannels. The present model improves the understanding of the physical mechanisms of fluid flows through roughened cylindrical microchannels. Our model predictions are compared with the existing experimental data, and good agreement can be found.


2014 ◽  
Vol 670-671 ◽  
pp. 860-865
Author(s):  
Long Wei ◽  
Peng Gao Zhang ◽  
Gui Fang Fang

In order to research and master the effect of surface topography on average film thickness between the end faces for mechanical seals, average film thickness fractal model between the end faces for mechanical seal was established using fractal parameters charactering surface topography characteristics, based on contact fractal model of the end face for mechanical seal, and solving micro-void volume. Effect of surface topography fractal parameters on average film thickness between the end faces for B104a-70 mechanical seal was analyzed by theoretical calculation. The results showed that fractal dimension D and characteristic length scale G of the end face had a great influence on the average film thickness h0, and h0 decreased with the increased of D or decreased of G; h0 decreased rapidly with the increased of D or with the decreased of G when the end face was coarser, however, it decreased slowly with the increased of D or with the decreased of G when the end face was smoother. In normal working parameters and surface topography fractal parameters range, average film thickness between end faces was in the range of 0.27~1.7μm. Studying on the effect of the change of surface topography on average film thickness has an important significance on the predicting of operating characteristics of end faces during actual operating and the design of end faces for contact mechanical seal.


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