Phase-isolation of upward oil–water flow using centrifugal method

• A phase-isolation process was presented.
• An optimized style of centrifugal device was chosen.
• The phase-isolation process was well predicted by CFD model which was validated with experiments.
• The ideal oil–water two-phase phase-isolation area was drawn.
• The phase-isolation method is eminently practical when λo≤10%.

Phase-isolation is a process of isolating each phase to a respective space within the transmission pipe by applying various kinds of lateral forces to the two-phase mixture. Once the phase-isolation is completed, two phases will flow concurrently and have a substantially clear interface between them which will greatly benefit for the measurement of two-phase flow parameters and for the separation of two-phase flow. In this study, a simple and optimized style of centrifugal device was employed for producing a swirling motion to the oil–water flow in a vertical upward pipe. The phase-isolation characteristics which influenced by various flow parameters (density, viscosity, oil diameter, inlet oil cut (λo) and velocity etc.) was simulated. Experiments were carried out in an oil–water two-phase flow loop to verify the simulation results and the encouraging agreement is obtained. It is showed that oil–water two-phase flow can be effectively isolated in the vertical upward pipe as predicted in the ranges of oil superficial velocity below 0.2 m/s and water superficial velocity between 0.4 and 1.5 m/s and the D O/W flow pattern performs the best phase-isolation effect. When λo≤10%, the cross section oil holdup after phase-isolation (Po) measured by visual observation is approximately equal to λo and the relative error is within the accepted error range of 0.25–8.5%.