Deformation of a compound drop through a contraction in a pressure-driven pipe flow

Chunfeng Zhou, Pengtao Yue & James J. Feng

Int. J. Multiphase Flow 34, 102-109 (2008)

Summary - We simulate the morphological evolution of a compound drop as it moves along the centerline of a circular tube with a 2:1 gradual contraction. The flow is driven by a fixed pressure difference imposed on the matrix fluid. The deformation of the two interfaces is captured by a phase-field representation, with the interfacial tension determined by the mixing energy in the thin but diffuse interfaces. Results show that the inner core generally hinders deformation of a compound drop and prolongs its transit time. However, the effect is non-monotonic in the core size; it is greatest for an intermediate core radius. The underlying mechanism is the core hampering the inner circulation and subjecting the compound drop to stronger shear inside the shell.