An appraisal of viscous oil-water two-phase flow through an undulated pipeline in peak configuration

Experimental results on flow patterns and pressure drop characteristics of viscous oil-water flow through undulated pipeline in peak configuration have been studied in this work. Undulated pipeline consists of two inclined sections (uphill and downhill) connected between two horizontal pipes (upstream and downstream) at peak configuration. Experiments have been conducted over a wide range of superficial velocities of oil (USO = 0.015-1.3 m/s) and water (USW = 0.1-1.2 m/s). Seven different flow patterns (viz., plug, slug, wavy stratified, stratified mixed, wispy annular, dispersion of oil in water and dispersion of water in oil) are identified by visual, imaging and electrical conductance probe techniques at all the four sections. Our results shows that present undulation (5°) has a marginal effect on the flow behavior of viscous oil-water mixture and the range of fluid velocity differs for a particular flow pattern. The pressure gradient characteristics across the peak experiences relatively more pressure gradient as compared to upstream and downstream at USW ⩾ 0.6 m/s, which is attributed to the combined effect of undulation (viz., peak configuration) along the pipeline, flow pattern, and effective viscosity and density of the fluid mixture.