Measurement of the film thickness, film velocity and entrainment fraction in a liquid-air annular flow using a conductance flowmeter

Abstract

In certain older oil wells in the Middle East, the produced fluid is predominantly natural gas which flows at very high rates (e.g. 50,000). Smaller quantities of crude oil (e.g. 50) and water (950) are also produced. Given the relatively much higher flow rate of the gas the flow regime is annular with most of the liquid flowing in a thin film on the pipe wall. The annular flow regime makes measurement of the total liquid flow rate difficult. It is even more difficult to measure the individual flow rate of either the oil or the water. In a vertical Perspex pipe (i.d. = 50 mm) using a newly-designed flow loop in the University of Huddersfield, annular flow was established and different measurements were carried out. At the first stage, only water-air annular flow was being used to investigate the possible measurement techniques to achieve the aim of this study. The techniques in this study include the use of conductivity probes to measure the liquid film thickness and to obtain the film velocity using the cross-correlation technique. The obtained results were compared to previous work by Zabaras and Dukler [1] for the same pipe diameter. The results of the present work have shown a good agreement with Zabaras and Dukler’s work which indicates the success of the new measurement techniques