Influence of surfactant on two-phase flow regime and pressure drop in upward inclined pipes

Abstract

The influence of a surfactant on the two-phase flow regime and the pressure drop in upward inclined pipes is investigated for various gas/liquid flow rates. The air/water and air/100 ppm sodium dodecyl sulphate aqueous solution are used as the working fluids. The influence of the surfactant on the two-phase flow regime in upward inclined pipes is investigated using the electrical tomographic technique. For 0°, 2.5° and 5° pipe inclinations, the surfactant has obvious effect on the transition from the stratified wavy flow to the annular flow, and the range of the stratified smooth flow regime is also extended to higher gas velocities. For 10° pipe inclination, no stratified flow regime is observed in the air/water flow. In the air/surfactant solution system, however, the stratified flow regime can be found in the range of USH = 10m/s−28m/s and USL = 0.07m/s−0.2m/s. For all inclination angles, the changes of the pressure gradient characteristics are accompanied with the flow pattern transitions. Adding surfactant in a two-phase flow would reduce the pressure gradient significantly in the slug flow and annular flow regimes. In the annular flow regime, the pressure gradient gradually becomes free of the influence of the upward inclined angle, and is only dependent on the property of the two-phase flow.