Herschel–Bulkley fluid

About: Herschel–Bulkley fluid is a research topic. Over the lifetime, 1946 publications have been published within this topic receiving 49318 citations.

Power-law fluid flow on a moving wall

Abstract: The steady boundary-layer flow of a non-Newtonian fluid, represented by a power-law model, over a moving flat plate in a moving fluid is studied. The transformed boundary-layer equation is solved numerically for some values of the power-law index n and velocity ratio parameter e. The effects of these parameters on the skin friction coefficient are analyzed and discussed. It is found that dual solutions exist when the plate and the fluid move in the opposite directions, near the region of separation. It is also found that the drag force is reduced for dilatant fluids compared to pseudo-plastic fluids.

Entropy Generation Due to the Flow of a Non-Newtonian Fluid with Variable Viscosity in a Circular Pipe

Abstract: The non-Newtonian fluid can be considered as a third-grade fluid with variable viscosity. In this case, the rate of fluid strain can be formulated using the third-grade fluid analogy. In the present study, entropy generation due to non-Newtonian fluid flow in a pipe is investigated. A third-grade fluid with variable viscosity is accommodated in the analysis. Analytical solutions for velocity and temperature distributions are presented, and an entropy generation number is computed for different non-Newtonian parameters, viscosity parameters, and Brinkman numbers. It is found that increasing the non-Newtonian parameter lowers the entropy generation number. This is more pronounced in the region close to the pipe wall. Increasing the viscosity parameter and Brinkman number enhances the entropy generation number, particularly in the vicinity of the pipe wall.

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

Abstract: 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 factor 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 (v p ), the viscosity ratio of the power-law fluid to that of the Newtonian fluid (N or μ p * ), the flow behavior index of the power-law fluid (n), the Peklenik numbers (γ i ) and the standard deviations (σ i ) 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.

Non-Newtonian rheology property for two-phase flow on fingering phenomenon in porous media using the lattice Boltzmann method

Abstract: Fingering phenomenon takes place when a less viscous fluid displaces a more viscous fluid and it has been extensively studied due to the importance in industrial fields. In this paper, a lattice Boltzmann method for immiscible non-Newtonian two-phase flow is proposed. The fundamental physical mechanisms of Newtonian fluid displacing non-Newtonian fluid in porous media are investigated in terms of power-law exponent, capillary number, viscosity ratio, surface wettability, Bond number and geometry. The numerical results provide a good understanding of the mechanism for Newtonian fluid displacing non-Newtonian fluid from a mesoscopic point of view, and it also demonstrates that the lattice Boltzmann method is a useful tool for simulating non-Newtonian two-phase flow in porous media.