Injection of Deformable Capsules in a Reservoir: A Systematic Analysis

Abstract

A computational study of capsule ejection from a narrow channel into a reservoir is undertaken for a combination of varying deformable capsule sizes and channel dimensions. A mass-spring membrane model is coupled to an Immersed Boundary-Lattice Boltzmann model solver. The aim of the present work is the description of the capsules motion, deformation and the response of the fluid due to the complex particles' dynamics. The interactions between the capsules affect the local velocity field significantly and are responsible for the dynamics observed. Capsule membrane deformability is also seen to affect inter-capsule interaction, and we observe that the train of three particles locally homogenizes the velocity field and the leading capsule travels faster than the other two trailing capsules. On the contrary, variations in size of the reservoir do not seem to be relevant, while the ratio of capsule diameter with respect to channel diameter plays a major role as well as the ratio of capsule diameter to inter-capsule spacing. This flow set-up has not been covered in the literature, and consequently we focus on describing capsule motion, membrane deformation and fluid dynamics, as a preliminary investigation in this field.

Rheology and structure of elastic capsule suspensions within rectangular channels

“…Here, for the largest lateral channel dimension (2h = 121) and largest Re = 400, the channel length needed for focusing is L f = 1609Dx. The channel length associated with the equilibration period is (N eq step Dt)u max , and the value of N eq step is varied according to the channel size: N eq step = [7 Â 10 5 , 5 Â 10 5 , 3 Â 10 5 , 3 Â 10 5 , 3 Â 10 5 , 3 Â 10 5 ] for 2h = [121,91,61,41,31,21]. For 2h = 121, this corresponds to a channel length of 21 000 Dx, or roughly 13 times longer than Hur et al 52 approximate.…”

“…Other studies have focused on the hydrodynamic interaction between capsule pairs in channel flow, 32,33 channel flowinduced segregation in binary capsule suspensions, [34][35][36] and capsule dynamics in other channel features including channel corners, 37 channel branches, 38,39 channel constrictions, [40][41][42] and curved channels. 43,44 In this paper, the viscosity and structure of soft, spherical capsule suspensions in planar (slit) and rectangular Poiseuille flow conditions are investigated using 3D computer simulations.…”

Characterization of micro-capsules deformation in branching channels

“…On the other side, the transport of soft particles in branching ducts is also considered for the rational design of biomedical devices able to enrich the concentration of micro-objects with specific characteristics as a result of the sorting induced by the established flow [7][8][9][10][11].…”

A Lattice Boltzmann dynamic-Immersed Boundary scheme for the transport of deformable inertial capsules in low-Re flows

“…In this work, a dynamic-Immersed-Boundary method is combined with a BGK-Lattice-Boltzmann (BGK-LB) technique for describing the evolution of rigid and soft inertial capsules transportded in incompressible flows. This method was extensively studied and validated by the authors for two-dimensional problems [9,[33][34][35]. Here, the authors propose an extension of such scheme to three-dimensional manifolds.…”