In this paper, we have considered the blood flow in a curved channel with abnormal development of stenosis in an axis-symmetric manner. The constitutive equations for incompressible and steady non-Newtonian tangent hyperbolic fluid have been modeled under the mild stenosis case. A perturbation technique and homotopy perturbation technique have been used to obtain analytical solutions for the wall Shear stress, resistance impedance to flow, wall Shear stress at the stenosis throat and velocity profile. The obtained results have been discussed for different tapered arteries i.e., diverging tapering, converging tapering, non-tapered arteries with the help of different parameters of interest and found that tapering dominant the curvature of the curved channel.

The shape deformation of three bubbles with equilateral triangle arrangement continuously rising in Shear-thinning non-Newtonian fluids was numerically investigated using the three-dimensional volume of fluid method (3D-VOF). The shape deformation of three continuously rising bubbles was compared with that of a single bubble under consistent operations to analyze the effect of interaction between bubbles. The influences of bubble diameter, initial bubble distance, bubble formation frequency, and liquid rheological property on the aspect ratio of the bubble were investigated. The results indicate that the aspect ratio of the bubble for multi-bubble systems with greater bubble diameter, initial bubble distance, and more intense Shear-thinning effect of the liquid decreases and the shape of the bubble deforms flatter. However, as the bubble formation frequency increases, the deformation of the bubble weakens, and the bubble aspect ratio increases. In comparison with the single bubble rising freely, the aspect ratio of the bubble for the multi-bubble systems is larger. Moreover, a modified model of the aspect ratio of the bubble was proposed by considering the interaction between bubbles for the multi-bubble system.

Laminar flow of non-Newtonian fluid (Shear-thinning) through a 1: 3 planar gradual expansion is numerically investigated, for various Power-Law index (0. 6, 0. 8 and 1. 0) and expansion angles (15, 30, 45, 60 and 90° ) at different generalized Reynolds number (1 ≤ Reg ≤ 400). The study of these parameters effect on the flow pattern allowed the determination of the two critical generalized Reynolds numbers (Regcr1 and Regcr2), which correspond to the transition from the symmetric to the asymmetric flow and the appearance of the third recirculation zone respectively. The results showed that decreasing the Power-Law index or the expansion angle stabilizes the flow by increasing significantly the two critical generalized Reynolds numbers. In order to predict the two critical generalized Reynolds numbers, two correlations have been proposed.

The laminar flow of non-Newtonian fluids through a Kenics static mixer is investigated by using the CFD (Computational fluid Dynamics) tool. The working fluids have a Shear thinning behavior modeled by the Ostwald De Waele law. We focus on the effect of Reynolds number, fluid properties, twist angle and blade pitch on the flow characteristics and energy cost. The pressure drop information obtained from the simulations was compared to several experimental correlations and data available in the literature. The numerical results were found in good agreement with the experimental values. From the obtained results, the twist technique is confirmed to be very useful to enhance the mixing with less power consumption and at low Reynolds numbers. A faster axial mixing has been achieved with increased blade length and decreased twist angle. However, the good mixing near the tube walls was obtained with increased twist angle. The power consumption expressed in power drop was found to be increase with increased CMC concentrations, Reynolds number, twist angle and decreased blade length.

Flow bifurcation transitions of Shear-thinning fluid and Newtonian fluid, flow through a two-dimensional rectangular channel in presence of intermediate steps have been considered in this manuscript. Employing SIMPLE algorithm, the governing equations have been solved numerically and using FLUENT software to visualize the simulation results for convenience. The Rheological properties of Shear-thinning and Newtonian fluids are described in the light of Carreau-Yasuda model. The result of this formulation has been validated with those of an earlier work. The motivation of this work is to study the bifurcation characteristics for different values of Reynolds numbers in presence of multiple steps in a rectangular channel. Pressure drop characteristic has also been studied for different values of expansion ratio and intermediate steps. For some particular value of expansion ratio (ER), a linear relation between 〖Re〗_crit and the value of n of Carreau-Yasuda model has been shown.

Taylor bubbles are commonly utilized in a wide range of industrial applications involving non-Newtonian fluids, and a thorough understanding of the relevant knowledge is helpful to the design optimization of related industrial processes. This study investigated the behavior of Taylor bubbles in Shear-thinning fluid using OpenFOAM. The numerical method is verified by comparing the results with experimental data, additionally, the effects of flow index n, surface tension σ, and zero Shear rate viscosity μ0 on the motion behavior of Taylor bubbles were investigated. The results show that as the flow index n and zero Shear viscosity μ0 increase, the terminal velocity of the Taylor bubbles decreases. The impact of various operating parameters on the bubble nose's form is insignificant. Regarding the liquid film surrounding the bubble, when n is small, the bubble rear is broken seriously, resulting in a shorter bubble and thinner liquid film. As the flow index n increases, the bubble elongates, and the liquid film becomes thicker, the length of the wake behind the Taylor bubble decreases. The surface tension mainly affects the bubble rear but has little impact on the bubble nose and rising velocity. For high μ0, the bubble rear does not break, and the Shear thinning area is small.