Helical flow in an annular space occurs during oil drilling operations. The correct prediction of flow of drilling fluid in an annular space between the wellbore wall and the drill pipe is essential to determine the variation in fluid pressure within the wellbore. This paper presents experimental and CFD simulation results of the pressure drop in the flow of non-Newtonian fluids through a concentric annular section and another section with fixed eccentricity (E = 0.75), using aqueous solutions of two distinct polymers (Xanthan Gum and Carboxymethylcellulose). The hydrodynamic behavior in this annular system was analyzed based on the experimental and CFD results, providing important information such as the formation of zones with preferential flows and stagnation regions.

The purpose of this work was to analyze the hydrodynamic and drying aspects of a rotary dryer used in a fertilizer industry. A set of equations to predict the solids holdup in the flights, the length of fall, the residence time of particles and the drying variables was evaluated by comparison to experimental measurements performed in an industrial rotary dryer of the Copebras Fertilizer Company, located in Catalão, state of Goias, Center-west of Brazil. Because of precise estimations, these equations may be used to design and predict the solids cascading behavior in industrial rotary dryers. Despite larger deviations, reaching 20%, the drying model can also be used for design calculations and process simulations.

Fluid flow in annular spaces has received a lot of attention from oil industries, both in drilling operations and in petroleum artificial rising. In this work, through numerical simulation using the computational fluid dynamics (CFD) technique, the flow of non-Newtonian fluids through the annuli formed by two tubes in concentric and eccentric arrangements of a horizontal system has been investigated. The study analyzes the effects of viscosity, eccentricity, flow and shaft rotation on the tangential and axial velocity profiles and on the hydrodynamic losses. It evaluates the performance of the numerical method used, comparing the results obtained with those in other reported works, aiming to validate the simulation strategy by the interpolation routines as well as the couplings algorithms adopted.

The objective of this work is to study the effect of confining walls on the free settling of spherical particles along the axes of five vertical cylindrical tubes in Newtonian and non-Newtonian liquids. Experimental results were predominantly obtained in the particle flow region between the Stokes and the Newton regimes (intermediate region) and displayed Reynolds numbers in the ranges 0.7<Re<311 for aqueous glycerine solutions and 0.2<Re<340 for aqueous carboximethilcellulose solution considering the range of 0<<FONT FACE="Symbol">b</font><0.55. These results allowed to analyze the procedure for estimating vt<FONT FACE="Symbol">¥ </font>as a function of b based on vt data and present correlations for estimating the wall effects on the fall of spheres in Newtonian liquids as well as for the characteristic shear rate of spheres in non-Newtonian fluids.