Particle size in confined channels greatly affects pressure buildup

Though the movement of particles through vessels, arteries and other confining channels in both biological and industrial systems has been studied in depth, continued research is required to make predictive decisions in realistic applications. Li et al. describe the dynamics of pressure buildup when particles temporarily block confined channels.

Injected microgels block pores in reservoirs, which significantly alters its permeability, forcing the subsequent brine to flow to other areas.

“Since this built up pressure is often difficult to measure in the real systems, we conducted this study to find the quantitative correlation between this built-up pressure and other measurable or controllable parameters,” said author Jing Fan.

After experimentally injecting microgels into a confined channel, the authors developed a model that predicted the highest transient pressure during the movement of a soft spherical particle through a channel driven by flow. The model considers the effect of friction and adhesion between the particle and channel wall.

Results indicated pressure buildup depends exponentially on the size of the particle in relation to the channel. A particle with a diameter much larger than that of the channel can result in huge pass-through pressure. In contrast, when a particle is close in size to the channel, its stiffness, adhesion and friction coefficients play an important role in determining the pressure buildup.

“These results can determine this pressure in a variety of biological and engineering processes involving the passage of elastic particles through narrow channels or pores, no matter for small deformation or large deformation,” said Fan. “We are working on extending our research to interconnected pore networks, or porous mediums, to understand the permeability variation of the medium.”

Source: “Understanding transport of an elastic, spherical particle through a confining channel,” by Shuaijun Li, Honghui Yu, Tai-De Li, Zi Chen, Wen Deng, Alimohammad Anbari, and Jing Fan, Applied Physics Letters (2020). The article can be accessed at https://doi.org/10.1063/1.5139887 .