Inertial particle separation in helical channels: A calibrated numerical analysis

Abstract

Inertial microfluidics has been used in recent years to separate particles by size, with most efforts focusing on spiral channels with rectangular cross sections. Typically, particles of different sizes have been separated by ensuring that they occupy different equilibrium positions near the inner wall. Trapezoidal cross sections have been shown to improve separation efficiency by entraining one size of particles in Dean vortices near the outer wall and inertially focusing larger particles near the inner wall. Recently, this principle was applied to a helical channel to develop a small-footprint microfluidic device for size-based particle separation and sorting. Despite the promise of these helical devices, the effects of channel geometry and other process parameters on separation efficiency remain unexplored. In this paper, a simplified numerical model was used to estimate the effect of various geometric parameters such as channel pitch, diameter, taper angle, depth, and width on the propensity for particle separation. This study can be used to aid in the design of microfluidic devices for optimal size-based inertial particle separation.

Geometric structure design of passive label-free microfluidic systems for biological micro-object separation

“…The serpentine channel is also modeled in a 2D model 138 . Palumbo et al carried out a numerical study of a 3D helical IMF channel 134 . Other 3D simulations, such as the V-shaped groove structure, have been shown to be effective and helpful in assisting geometry optimization 189 .…”

“…Palumbo et al carried out a numerical study of another 3D inertial microfluidic channel with a helical structure (Fig. 6c ) 134 . Geometric parameters such as the channel pitch, diameter, and taper angle were studied.…”

“…b Obstacle-based spiral channel for CTC separation 128 . c A numerical study of a 3D inertial microfluidic channel with a helical structure 134 . d Asymmetric serpentine structure to reduce the number of equilibrium points 139 .…”

Inertial Separation of Particles Escaped from Electrostatic Precipitators

“…Inertial separators are characterized by simple designs, low investment and operating costs, and a high reliability. The inertial particle separator is widely used as an important gas–solid separation device to protect the core engine in a severely polluted environment. − The separation efficiency of the IPS is not only affected by the single geometrical or aerodynamic parameter but also apparently influenced by the interaction effects between different parameters. In the inertial separator, the trajectories of particles with small size are dominated by the flow direction while the paths of particles with larger size are dominated by the individual particle inertia and bounce characteristics from the walls.…”

Lab on a rod: Size-based particle separation and sorting in a helical channel

“…A numerical analysis will investigate this effect in an upcoming paper by our group. 27 To date, the only successful application of helical channels for size-based particle separation and sorting was in a channel with an outer radius of 15.5 mm made using stereolithography which was reported by Lee et al 28 In that study, free magnetic nanoparticle clusters (MNCs) and MNCs bound with Escherichia coli with diameters of 200 nm and 1 μm, respectively, were separated using an inlet flow rate of 5 ml/min and a sheath flow rate of 5 ml/min. The sheath flow was required to move the 200 nm particles to the wall furthest from the helical axis so that they became entrained in the Dean vortices, while the 1 μm particles migrated toward the channel wall closest to the helix axis.…”