Abstract: | The problem of pressure loss by friction in pipelines, especially in the case of viscous fluids, has a great influence of the efficiency of the technologic process. The paper discuss two main methods for reducing the frictional pressure loss, and therefore the pump discharge pressure requirement, when transporting viscous, often non-Newtonian, slurries and pastes in pipelines. The first method makes use of boundary liquid (such as water, oil, or polymer solution) which is injected at comparatively small flow rates into the pipe downstream from the pump to form a lubricating annulus adjacent to the pipe wall. The second method involves gas injection into the pipe downstream from the pump to form a slug flow pattern which results in substantial frictional pressure loss reductions for shear-thinning, non-Newtonian slurry, initially flowing in the laminar flow regime prior to gas injection. |