ABSTRACT:

An experimental investigation is carried out to study two-phase vertically upward hydraulic transport of solid particles by water and non-Newtonian fluids in a slim hole concentric annulus with rotation of the inner cylinder. Studying the rheology of particulate suspensions in viscoelastic fluids is essential in many applications such as particle removal from surfaces, transport of proppants in fractured reservoir and cleaning of drilling holes, etc. In this study a clear acrylic pipe was used in order to observe the movement of solid particles. Annular fluid velocities varied from 0.2 to 3.0 m/s. Pressure drop, average flow rate, and particle rising velocity are measured. The higher the concentration of the solid particles is, the larger the pressure gradient becomes in both water and 0.2% Carbomethyl Cellulose(CMC) solutions.

INTRODUCTION

Among various industrial unit operations involved with multi-phase systems, agitation of solid-liquid systems is quite commonly encountered such as catalytic reactions, drilling operation of oil well, etc. Although there are many industrial applications of solid-liquid flows in technology, available knowledge about particle flows is not complete due to the difficulties encountered in analyzing these complex systems. Rotating flows in annular passages are important, since they have many engineering applications in bearings, rotating-tube heat exchangers and, especially, annulus flows of mud in case of slim hole drilling of oil well. This phenomenon can be very dangerous when the rotating rods are not supported anymore by the wall and can break. It strongly depends on the velocity gradients. Delwiche et al. (1992) found that a laminar flow regime induces lower velocity gradients than a turbulent flow and thus lower shear stresses. Wall shear stress is of great importance in fluid mechanics research, as it represents local tangential force by the fluid on a surface in contact with it.

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