Numerical study of liquid-liquid two-phase flow through coiled flow inverters: Effect of volume fraction, dean number and orientation.

[Display omitted] • Two-phase liquid–liquid flow and interaction mechanism in coiled flow invertor (CFI) over a wide range of parameters. • Effect of oil-phase fraction, inlet velocity and CFI orientation on liquid–liquid two-phase flow in CFI. • Oil-fraction have little influence on overall vorticity spectrum of the mixture, however a significant effect on the individual phases vorticity. • The change in CFI orientation (horizontal and vertical) enhanced surface area-to-volume ratio by ≈32%. The present study deals with the numerical investigation of void fraction and flow patterns for liquid–liquid (oil–water) two-phase flow through a coiled flow inverter (CFI) with different flow conditions and geometrical orientations (horizontal and vertical). A CFI comprising 90° bends between two consecutive helical coils, and works on complete flow inversion due to directional change in centrifugal force. The velocity and phase distribution profiles for liquid–liquid two-phase flow in CFI are analysed by varying Reynolds and Dean numbers from 637−5033 and 202–1592, respectively. The orientation significantly influences overall friction factor based on mixture at low inlet velocities, while at higher inlet velocity it is nearly similar despite of CFI orientation. The inherent mechanism of vorticity distribution, to predict fluid rotational motion, is also reported for each phase in CFI. The change in CFI orientation resulted into an increase in the surface area(interface)-to-volume ratio of oil by ≈32%. [ABSTRACT FROM AUTHOR]