Modelling and Measurements of Film Characteristics and Gas Core of Annular Flows

Annular flow is one of the most common flow patterns encountered in natural gas well-bores
and pipelines. It occurs at high gas and low to medium liquid flow rates and at all pipe
orientations. Using a newly-designed flow loop in the University of Huddersfield, annular
flow was established and different measurements were carried in a vertical Perspex pipe (i.d.
= 50mm). An ultrasonic flow meter, USFM, was designed to serve the purpose of measuring
the velocity of the gas in the core. The USFM successfully measured the gas velocity over a
wide range of gas and water flow rates. In this study, another device that was used was a
novel Conductance Flow Meter, CFM, for measuring the liquid film flow rate by measuring
the film thickness and the film velocity (using the cross-correlation technique). An empirical
relationship between the entrainment fraction and the gas superficial velocity has also been
established. The liquid film was mathematically modeled and the film velocity profile was
characterized. The overall results of the present work have shown a good agreement with
Zabaras and Dukler’s work (1986) which indicates the success of the new combination of the
measurement techniques