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.