Abstract:
The pressure drop for two-phase liquid-liquid flow is theoretically
predicted for each flow regime. Empirical correlations, which
are applicable in all flow regimes, are also presented for holdup as
well as pressure drop.
The experimental study covered bubble and drop flow regimes.
The discontinuous phase was injected by nozzle into the vertical,
0.745 inch ID, 40 foot test section. The drop sizes were varied by
inserting wire screens downstream of the nozzle and also by varying
the nozzle size between .1875 inches and .375 inches OD. Photographs
of the dispersions were taken in order to determine average
drop diameter. The slip velocity between phases was determined by
holding the dispersion in the test section after a run and then draining
the sample and measuring the in situ concentration. The average
fluid velocity ranged from 5 to 15 feet/second and injection concentrations
were as high as 35% by volume. The dispersed phase fluids had
Redacted for Privacy
viscosities of 1, 9 and 200 centipoise.
The pressure drop at a given concentration and size distribution
was found to vary inversely with the average drop diameter; also a
polydisperse (widely spread distribution) dispersion had a lower pressure
drop than the monodisperse one with the same average drop size.
An inverse relationship exists between the pressure drop and
relative slip velocity. This effect appears to increase directly with
the discontinuous phase concentration.
The theoretically derived equations predict the pressure drop of
bubble flow within a 16% relative standard deviation.
Published data were used in evaluating the proposed equations
in other regimes. Annular flow pressure drops were predicted within
8. 5% standard deviation and stratified flow within 13%.
The empirical correlations for holdup and pressure drop had a
standard deviation of approximately 25% when used with data from all
flow regimes.
