Investigation of flow-induced re-organization in dense micro-particle by computational model and experiments on blood

Yeng-Long Chen^1*

¹Institute of Physics, Academia Sinica, Taipei, Taiwan

* Presenter:Yeng-Long Chen, email:yenglong@phys.sinica.edu.tw

Hydrodynamic lift away from a wall of droplets, cells and other soft particles under flow has been well-noted and exploited for fractionation of healthy and diseased cells. In this study, we employed a coarse-grained Langevin dynamics method to model the particle dynamics and deformation corresponding to oil-in-water emulsions with volume fractions ranging from 0.45 to 0.65. Starting with amorphous structure at rest, we applied simple shear flow and examined the resulting microstructure in real space and the scattering intensities. We also characterized the change in the emulsion viscosity corresponds to the changes in microstructure. Unlike hard colloidal suspensions, we found no dynamic arrest in the soft particle system. Instead, the viscosity increases by a factor of two to five as the volume fraction increases from 0.45 to 0.65, depending on the shear rate. For comparison, we investigated blood rheology and blood microstructure following cardiac surgery with cardio-pulmonary bypass (CPB). We found significant flow-induced microstructural reorganization of blood aggregates and blood viscoelasticity.

Keywords: shear-induced ordering, blood rheology, soft particles, microstructure, rheology