Industrial & Engineering Chemistry Research, Vol.41, No.3, 357-366, 2002
Spontaneous interaction of drops, bubbles and particles in viscous fluid driven by capillary inhomogeneities
Spontaneous interaction of drops, bubbles, or particles in a suspension occurs when the continuous and dispersed phases are not in thermodynamic equilibrium. Interfacial mass or heat transfer between a bulk fluid and a drop in the presence of an adjacent particle leads to a spatially inhomogeneous concentration or temperature distribution. This nonuniformity causes surface tension gradients along the interface that induce Marangoni type flows in the vicinity of the interface and an eventual migration of droplets or bubbles relative to each other. We review the various cases of interaction of small inclusions at small and large Peclet numbers and a range of nonlinear unsteady effects implied by convective transport and deformation of surfaces. The interaction of solid spheres with nonisothermal free interfaces and the effect of gravity are also presented.