Effect of inclination on the air-water flow in 4-inch pipe

Air-water two-phase flow in a pipeline often occurs in petroleum industry. It is important to study behavior of such flows in order to characterize two-phase flow in upstream production pipelines. This paper presents pressure drop measurements of air-water two-phase flow in a horizontal and inclined 4 inch diameter stainless steel pipe at different flow conditions. Experiments were carried out for different inclination angles including; 0°, 15°, 30° (upward and downward flows) and for different water-to-air volume fractions. Inlet superficial water velocities were varied from 0.3 to 3 m/s and reference pressure was set at 1 and 2 bars. For a given superficial air velocity, pressure drop has been found to increase with increase in superficial water velocity. Pressure drop was also affected by the inclination of pipe. Upward flows were associated with high pressure drops as compared to downward flows. Measured pressure drops were compared with existing empirical relations and good agreement was found.