Air-water two-phase annular flow in near-horizontal tubes. (Effect of pipe inclination on the fundamental parameters).

Abstract

An experimental investigation was made into hold up, frictional pressure drop and circumferential distribution of film thickness of an air water two phase annular flow in horizontal and near horizontal tubes of 26.0 mm ID. Superficial velocities of both phases ranged from 10 m/s to 50 m/s for air and from 0.002 m/s to 0.40 m/s for water. The measured values of those physical quantities and the highest circumferential location from which liquid film starts to form toward the tube bottom are presented, and the effects of the inclination angle on them are examined. As a result, it was made clear that the effect of the inclination on these parameters, even if it is within a small angle, could not be neglected and that the mean film thickness averaged over the circumference of the tube was approximately equal to the local film thickness at PHI=120DEGREES independent of the inclination.