Inertial migration of a deformable particle in pipe flow

TL;DR

This study uses numerical simulations to analyze how deformable hyperelastic particles migrate and deform in pipe flow, revealing that elasticity significantly influences migration speed and final position, largely independent of flow inertia.

Contribution

It provides a detailed numerical analysis of particle migration considering elasticity and inertia, highlighting the dominant role of elasticity in migration dynamics and final focusing position.

Findings

Migration speed increases with particle deformability.

Final equilibrium position is at the pipe centerline.

Migration dynamics are largely unaffected by Reynolds number.

Abstract

We perform fully Eulerian numerical simulations of an initially spherical hyperelastic particle suspended in a Newtonian pressure-driven flow in a cylindrical straight pipe. We study the full particle migration and deformation for different Reynolds numbers and for various levels of particle elasticity, to disentangle the interplay of inertia and elasticity on the particle focusing. We observe that the particle deforms and undergoes a lateral displacement while traveling downstream through the pipe, finally focusing at the pipe centerline. We note that the migration dynamics and the final equilibrium position are almost independent of the Reynolds number, while they strongly depend on the particle elasticity; in particular, the migration is faster as the elasticity increases (i.e. the particle is more deformable), with the particle reaching the final equilibrium position at the centerline in shorter times. Our simulations show that the results are not affected by the particle initial conditions, position and velocity. Finally, we explain the particle migration by computing the total force acting on the particle and its different components, viscous and elastic.