Sampling probe studies of the gas core in annular two-phase flow—II: Studies of the effect of phase flow rates on phase and velocity distribution

Abstract

Data are presented for the distribution of liquid droplet mass velocity and local linear velocity for the gas core in air/water annular flow. The data were obtained using a sampling/impact probe which was maintained in a position far from the water injector. The flow rates of air and water were varied over a wide range. The liquid mass velocity profiles exhibit maxima at the axis of the tube and the droplet volume concentration remains constant across the tube. The gas velocity profiles undergo a marked transformation as the liquid rate is changed. They obey a logarithmic law in all cases, but for higher liquid rates the constant in this law diminishes from its classical value. In the low liquid rate region a promising correlation is obtained between the liquid film thickness and the equivalent roughness height calculated from pressure gradient. The concentration of droplets appeared to be almost independent of gas rate at any given liquid rate and this fact facilitates interpolation of the experimental data for entrainment mass flow.