Surface Roughness Effects in Hydrodynamic Lubrication Involving the Mixture of Two Fluids

1998 ◽  
Vol 120 (4) ◽  
pp. 772-780 ◽  
Author(s):  
Wang-Long Li
Keyword(s):  
Surface Roughness ◽  
Newtonian Fluid ◽  
Power Law ◽  
Volume Fraction ◽  
Hydrodynamic Lubrication ◽  
Stress Factors ◽  
Function Technique ◽  
Perturbation Approach ◽  
Power Law Fluid ◽  
Special Cases

In this paper, the relations expressing the effects of surface roughness and homogeneous mixture (the mixture of power-law fluid inserted into a Newtonian fluid) on the roughness-induced flow factors are derived. A coordinate transformation is utilized to simplify the derivation. By using the perturbation approach incorporated with Green function technique, the flow factors and shear stress factors are derived and expressed as functions of the volume fraction of the power-law fluid in the mixture (υ p), the viscosity ratio of the power-law fluid to that of the Newtonian fluid (N or μp*), the flow behavior index of the power-law fluid (η), the Peklenik numbers (γi) and the standard deviations (σl) of each surface. A form of the average Reynolds equation is then obtained. It is shown that a number of currently available models are special cases of the theory presented here. Finally, the performance of a journal bearing is discussed.

A Theory of Hydrodynamic Lubrication Involving the Mixture of Two Fluids

1994 ◽  
Vol 61 (3) ◽  
pp. 634-641 ◽  
Author(s):  
F. Dai ◽  
M. M. Khonsari
Keyword(s):  
Continuum Mechanics ◽  
Newtonian Fluid ◽  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Incompressible Fluids ◽  
Theoretical Development ◽  
Governing Equations ◽  
Power Law Fluid ◽  
Two Fluids ◽  
Special Cases

Based on the principles of continuum mechanics, we drive the governing equations for the hydrodynamic lubrication involving the mixture of two incompressible fluids. The governing equations are general in the sense that they can be applied to the mixture of any simple non-Newtonian fluid with a Newtonian fluid. A mixture thus formed is considered to be nonhomogeneous and non-Newtonian. In the theoretical development, the interaction between the constituents is taken into consideration. It is shown that a number of currently available models are special cases of the theory presented in this paper. As an example, results are presented for journal bearing performance lubricated with a mixture of a power-law fluid mixed with Newtonian oil.

A Non-Newtonian Fluid Flow Model for the Slip Condition on Blood Flow through a Stenosed Artery using Power-law Fluid

2018 ◽  
Vol 9 (7) ◽  
pp. 871-879
Author(s):  
Rajesh Shrivastava ◽  
R. S. Chandel ◽  
Ajay Kumar ◽  
Keerty Shrivastava and Sanjeet Kumar
Keyword(s):  
Blood Flow ◽  
Fluid Flow ◽  
Newtonian Fluid ◽  
Power Law ◽  
Flow Model ◽  
Slip Condition ◽  
Power Law Fluid ◽  
Stenosed Artery ◽  
Flow Through

Group invariant solution for a pre-existing fracture driven by a power-law fluid in permeable rock

2016 ◽  
Vol 30 (28n29) ◽  
pp. 1640010 ◽  
Author(s):  
A. G. Fareo ◽  
D. P. Mason
Keyword(s):  
Newtonian Fluid ◽  
Power Law ◽  
Numerical Solutions ◽  
Invariant Solution ◽  
Two Dimensional ◽  
Initial Length ◽  
Power Law Fluid ◽  
Group Invariant ◽  
Permeable Rock ◽  
Fluid Leak

Group invariant analytical and numerical solutions for the evolution of a two-dimensional fracture with nonzero initial length in permeable rock and driven by an incompressible non-Newtonian fluid of power-law rheology are obtained. The effect of fluid leak-off on the evolution of the power-law fluid fracture is investigated.

Reduced Order Model for a Power-Law Fluid

2014 ◽  
Vol 136 (7) ◽  
Author(s):  
M. Ocana ◽  
D. Alonso ◽  
A. Velazquez
Keyword(s):  
Newtonian Fluid ◽  
Power Law ◽  
Reduced Order Model ◽  
Processing Unit ◽  
Order Model ◽  
Power Law Fluid ◽  
Reduced Order ◽  
Polymeric Fluid ◽  
Central Processing ◽  
Highly Nonlinear

This article describes the development of a reduced order model (ROM) based on residual minimization for a generic power-law fluid. The objective of the work is to generate a methodology that allows for the fast and accurate computation of polymeric flow fields in a multiparameter space. It is shown that the ROM allows for the computation of the flow field in a few seconds, as compared with the use of computational fluid dynamics (CFD) methods in which the central processing unit (CPU) time is on the order of hours. The model fluid used in the study is a polymeric fluid characterized by both its power-law consistency index m and its power-law index n. Regarding the ROM development, the main difference between this case and the case of a Newtonian fluid is the order of the nonlinear terms in the viscous stress tensor: In the case of the polymeric fluid these terms are highly nonlinear while they are linear when a Newtonian fluid is considered. After the method is validated and its robustness studied with regard to several parameters, an application case is presented that could be representative of some industrial situations.

The Modeling of Form Drag in a Porous Medium Saturated by a Power-Law Fluid

2009 ◽  
Vol 131 (10) ◽  
Author(s):  
D. A. Nield
Keyword(s):  
Porous Medium ◽  
Newtonian Fluid ◽  
Power Law ◽  
Power Law Fluid ◽  
Form Drag ◽  
Current Usage

The alternative ways of modeling form drag in a porous medium saturated by a power-law fluid in current usage are discussed. It is argued that the best alternative is to use the same expression as that used in the case of a Newtonian fluid, but with a modified Forchheimer coefficient.

Simultaneous Wicking-Convection Heat Transfer Process with Non-Newtonian Power-Law Fluid

2010 ◽  
Vol 297-301 ◽  
pp. 117-125
Author(s):  
Oscar Bautista ◽  
Federico Méndez ◽  
Eric Bautista
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Newtonian Fluid ◽  
Power Law ◽  
Transfer Process ◽  
Numerical Solutions ◽  
Heat Transfer Process ◽  
Dimensionless Temperature ◽  
Power Law Fluid ◽  
Temperature And Pressure

In this work, we have theoretically analyzed the heat convection process in a porous medium under the influence of spontaneous wicking of a non-Newtonian power-law fluid, trapped in a capillary element, considering the presence of a temperature gradient. The capillary element is represented by a porous medium which is initially found at temperature and pressure . Suddenly the lower part of the porous medium touches a reservoir with a non-Newtonian fluid with temperature and pressure . This contact between both phases, in turn causes spontaneously the wicking process. Using a one-dimensional formulation of the average conservation laws, we derive the corresponding nondimensional momentum and energy equations. The numerical solutions permit us to evaluate the position and velocity of the imbibitions front as well as the dimensionless temperature profiles and Nusselt number. The above results are shown by considering the physical influence of two nondimensional parameters: the ratio of the characteristic thermal time to the characteristic wicking time, , the ratio of the hydrostatic head of the imbibed fluid to the characteristic pressure difference between the wicking front and the dry zone of the porous medium, , and the power-law index, n, for the non-Newtonian fluid. The predictions show that the wicking and heat transfer process are strongly dependent on the above nondimensional parameters, indicating a clear deviation in comparison with and n = 1, that represents the classical Lucas-Washburn solution.

Study on the Effects of Different Water-Cement Ratios on the Flow Pattern Properties of Cement Grouts

2011 ◽  
Vol 71-78 ◽  
pp. 1264-1267 ◽  
Author(s):  
Zhi Quan Yang ◽  
Ke Peng Hou ◽  
Ting Ting Guo
Keyword(s):  
Flow Pattern ◽  
Newtonian Fluid ◽  
Power Law ◽  
Inflection Point ◽  
Bingham Fluid ◽  
Power Law Fluid ◽  
Conversion Point ◽  
Cement Grouts ◽  
Engineering Practices ◽  
Negative Factors

The article presents an study on the rheological properties of cement grouts with different water-cement ratios of 0.5,0.55,0.6,0.65,0.7,0.75,0.8,0.9,1.0,1.1,1.25,1.0,2.0,5.0 and10.0.It was to investigate different water-cement ratios of cement grouts effecting its flow pattern properties, and thus determinate the conversion point of them among Newtonian fluid, Bingham fluid and Power-law fluid. It confirmed that,when take into accounts of all negative factors possibly affecting the experiment, including asynchronous loading steps, water temperature, apparatus deflection and so on, W/C(water-cement ratio) = 0.75 is a inflection point,which Power-law fluid converted into Bingham fluid, while at W/C =1.25 the cement grouts suffered a conversion from Newtonian fluid to Bingham fluid. This research results supplied, improved and expanded the knowledge of the flow pattern properties of cement grouts and conversion condition with different water-cement ratios, and so it has important theory meaning and realistic value and may contributes to the engineering practices.

Non-Newtonian Lubrication Theory for Rough Surfaces: Application to Rigid and Elastic Rollers

1982 ◽  
Vol 24 (3) ◽  
pp. 147-154 ◽  
Author(s):  
P. Sinha ◽  
J. B. Shukla ◽  
C. Singh ◽  
K. R. Prasad
Keyword(s):  
Surface Roughness ◽  
Elastic Deformation ◽  
Newtonian Fluid ◽  
Power Law ◽  
Reynolds Equation ◽  
Stochastic Theory ◽  
Power Law Model ◽  
Pure Rolling ◽  
Lubrication Characteristics ◽  
Rigid Surfaces

To predict the consequences of the interaction of the lubricant rheology with surface roughness, the stochastic theory of lubrication for Newtonian fluid is modified to take into account the non-Newtonian behaviour of the lubricant, by considering the power law model. Generalized forms of the Reynolds equation for two types of roughness arrangements, viz., longitudinal and transverse, are derived. These equations are subsequently used to study the lubrication characteristics of infinitely long rough roller bearings, and two particular cases, namely pure rolling (rigid surfaces) and rolling with elastic deformation, are discussed.

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