Abstract:
Pressure drop through sudden expansions and contractions have been numerically
investigated for two-phase flow of oil-water emulsions. Two-phase computational
fluid dynamics calculations, using Eulerian–Eulerian model are employed to calculate
the velocity profiles and pressure drops across sudden expansion and contraction. The
oil concentration is varied over a wide range of 0-97.3 % by volume. From the
pressure loss and velocity data, the loss coefficients are obtained. The loss coefficients
for the emulsions are found to be independent of the concentration and type of
emulsions. In the single phase flow of water and two-phase flow of oil-water
emulsions vena contracta is always established at a distance of about 0.5D after the
contraction section and depends only slightly on the concentration and inlet velocity
of flow. Pressure drop across sudden contractions in pipes are also numerically
investigated for two-phase air-water mixtures. Eight area ratios ranging from 0.0568
to 0.619 have been considered for the present computation. The mass flow qualities
are varied from 0 to 97% and mass fluxes are varied from 500 to 4000 kg/m2/s. The
effect of various parameters such as mass flux, mass flow quality, area ratios, flow
directions (horizontal/vertical), system pressures etc on the two-phase pressure drops
have been studied.
