Boundary layer of non-Newtonian fluids obeying a rheological power law for arbitrary pressure gradients

1971 ◽  
Vol 20 (3) ◽  
pp. 280-285
Author(s):  
A. Sh. Dorfman ◽  
V. K. Vishnevskii
Keyword(s):  
Boundary Layer ◽  
Power Law ◽  
Newtonian Fluids ◽  
Pressure Gradients

A Numerical Study of the Laminar Flow of Non-Newtonian Fluids Along a Vertical Wall

1973 ◽  
Vol 40 (1) ◽  
pp. 290-292 ◽  
Author(s):  
T. M. T. Yang ◽  
D. W. Yarbrough
Keyword(s):  
Boundary Layer ◽  
Steady State ◽  
Laminar Flow ◽  
Power Law ◽  
Analytical Solutions ◽  
Numerical Study ◽  
Vertical Wall ◽  
Newtonian Fluids ◽  
Momentum Integral ◽  
Accelerating Flow

The momentum integral technique is used to describe the steady-state, laminar, accelerating flow of a power-law liquid film along a vertical wall. Values for film thicknesses and boundary-layer thicknesses are obtained numerically and compared with existing analytical solutions for Newtonian fluids.

Theoretical Analysis of Turbulent Flow of Power-Law Fluids in Coiled Tubing

SPE Journal ◽  
2007 ◽  
Vol 12 (04) ◽  
pp. 447-457 ◽  
Author(s):  
Yunxu Zhou ◽  
Subhash Nandlal Shah
Keyword(s):  
Boundary Layer ◽  
Theoretical Analysis ◽  
Turbulent Flow ◽  
Friction Factor ◽  
Power Law ◽  
Newtonian Fluids ◽  
Power Law Fluid ◽  
Boundary Layer Approximation ◽  
Coiled Tubing ◽  
Friction Factor Correlation

Summary A comprehensive theoretical analysis of turbulent flow of a power-law fluid in coiled tubing was conducted with the approach of boundary layer approximation. Equations of momentum integrals for the boundary layer flow were derived and solved numerically. Based on the results of the numerical analysis, a new friction-factor correlation was developed which is applicable to a wide range of flow behavior index of power-law fluid model. The new correlation was verified by comparing it with the published Ito correlation for the special case of Newtonian fluid. For non-Newtonian fluids, there is also a close agreement between the new correlation and the experimental data from recent full-scale coiled tubing flow experiments. Introduction Many fluids that are pumped through coiled tubing are typically non-Newtonian fluids, such as polymer gels or drilling muds. Understanding their flow behavior and being able to accurately predict frictional pressure through coiled tubing are essential for better operations design. A recent literature review (Zhou and Shah 2004) indicates that though there are numerous studies on the flow of Newtonian fluids in coiled pipes, there is, however, very little information with regard to the corresponding flow of non-Newtonian fluids. Among the various approaches of investigating fluid flow in coiled pipes, there is one important method called boundary layer approximation analysis. It is especially useful for high-Dean (1927, 1928) number flows where the effect of secondary flow is largely confined in a thin boundary layer adjacent to the pipe wall (Dean number is commonly defined as: (equation). According to this approach, the tubing cross-section can be divided into two regions: the central in viscid core, and the thin viscous boundary layer. This leads to much simplified flow equations for high-Dean number flows in curved geometry. This approach has been used by a number of researchers, for example, by Adler (1934), Barua (1963), Mori and Nakayama (1965), and Ito (1959, 1969) for Newtonian fluids, and by Mashelkar and Devarajan (1976, 1977) for non-Newtonian fluids. In a previous attempt, Zhou and Shah (2007) applied the method of boundary layer approximation to solve the laminar flow problem of a power-law fluid in coiled tubing and obtained an empirical friction-factor correlation based on the theoretical analysis and numerical solutions. In the present study, we take the same analysis approach but consider the turbulent flow of a power-law fluid in coiled tubing. A friction-factor correlation for turbulent flow in coiled tubing is developed, and its validity is evaluated with a published correlation (Ito 1959) and recent full-scale experimental data.

Frictional resistance of spheres rotating in power-law non-Newtonian fluids

1987 ◽  
Vol 52 (5) ◽  
pp. 1172-1177
Author(s):  
Pavel Mitschka
Keyword(s):  
Experimental Data ◽  
Boundary Layer ◽  
Approximate Method ◽  
Laminar Boundary Layer ◽  
Power Law ◽  
Frictional Resistance ◽  
Newtonian Fluids ◽  
Theoretical Solution ◽  
Power Law Fluids ◽  
Resistance Coefficients

Frictional resistance coefficients have been calculated for the rotation of spheres in non-Newtonian power-law fluids under laminar boundary-layer conditions using the approximate method of integral momentum balances. The values obtained agree satisfactorily with the available experimental data and the published theoretical solution.

The Flow of Non-Newtonian Fluids on a Flat Plate With a Uniform Heat Flux

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
M. M. Molla ◽  
L. S. Yao
Keyword(s):  
Boundary Layer ◽  
Heat Flux ◽  
Flat Plate ◽  
Power Law ◽  
Shear Thickening ◽  
Leading Edge ◽  
Newtonian Fluids ◽  
Uniform Heat Flux ◽  
Shear Stresses ◽  
Boundary Layer Equations

Forced convective heat transfer of non-Newtonian fluids on a flat plate with the heating condition of uniform surface heat flux has been investigated using a modified power-law viscosity model. This model does not restrain physically unrealistic limits; consequently, no irremovable singularities are introduced into a boundary-layer formulation for power-law non-Newtonian fluids. Therefore, the boundary-layer equations can be solved by marching from leading edge to downstream as any Newtonian fluids. For shear-thinning and shear-thickening fluids, non-Newtonian effects are illustrated via velocity and temperature distributions, shear stresses, and local temperature distribution. Most significant effects occur near the leading edge, gradually tailing off far downstream where the variation in shear stresses becomes smaller.

Sign in / Sign up

Export Citation Format

Share Document