Simulative Investigation of Different DLD Microsystem Designs with Increased Reynolds Numbers Using a Two-Way Coupled IBM-CFD/6-DOF Approach

Abstract

Deterministic lateral displacement (DLD) microsystems are suitable for the size fractionation of particle suspensions in the size range of 0.1 to 10 µm. To be able to fractionate real particles beyond a laboratory scale, these systems have to be designed for higher throughputs. High flow resistances and increasing the clogging of the systems impose substantial challenges for industrial operation. Simulative parameter studies are suitable for improving the design of the systems; for example, the position and shape of the posts. A high-resolution, two-way coupled 6-DOF CFD-DEM approach was used to study the flow and particle behavior of different post shapes (circular and triangular) and post sizes at different Reynolds numbers. The results were compared with the classical first streamline width theory. It was shown that the streamline theory does not account for all effects responsible for the separation. Furthermore, a shift in the critical particle diameter to smaller values could be obtained when increasing the Reynolds number and also when using triangular posts with reduced post sizes compared to the post spacing. These findings can help to improve the efficiency of the systems as the post spacing could be extended, thus reducing the flow resistance and the probability of clogging.

Blood Cell Separation Using Polypropylene-Based Microfluidic Devices Based on Deterministic Lateral Displacement

“…Fluid mechanical insights are important for high-speed imaging that is faster than the video rate [ 4 , 6 ]. These imaging experiments allow us to evaluate the blood cell collision effects on RBC and WBC separation [ 22 ], variances in D c values based on the Reynolds number (Re) of the fluid [ 9 ], and the effects of the wall surface on fluid mechanical environments. In the immunobead separation, D c calculated using Equation (1) and the observed D c values were the same, as shown in Figure 7 .…”

“…The Re of this fluid flow is less than 10, and the effective critical diameter (D c ) in the experiments is similar to the calculated values (at most a 10% decrease) according to the correlation between Re and D c [ 23 ]. Additionally, computational fluid dynamics simulation results suggest that the D c /Gap decrease is approximately 3%, from Re = 1 to Re = 10 [ 9 ]. Throughout this study, the experimental D c was similar to the calculated D c .…”

“…Deterministic lateral displacement (DLD) devices have been used for the size-based separation of microspheres and mammalian cells, such as blood cells and bacteria [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ]. Microfluidic DLD devices contain microfluidic channels with micropillar obstacles.…”

Investigation of Multidimensional Fractionation in Microchannels Combining a Numerical DEM-LBM Approach with Optical Measurements

“…Deterministic Lateral Displacement (DLD) is a microfluidic fractionation method where particles and fluid are led though a periodic array of obstacles [2] (in the following referred to as pillars, as mostly cylinders (see e.g., [7,[47][48][49]) or uniform prisms (see e.g., [50,51]) are used). Each pillar row is laterally shifted from the previous one by a certain distance.…”

Numerical analysis of flow anisotropy in rotated-square deterministic lateral displacement devices at moderate Reynolds number

“…Operating DLD devices with higher flow rates requires larger flow speed, which leads to the onset of inertial effects. DLD devices operating in the inertial regime show a reduction of the critical size [10–12], which is useful to prevent clogging. However, inertia also leads to additional effects, such as breakdown of the separation efficiency [13], loss of symmetry in the flow field [12, 14], and increased influence of the particle-fluid density difference [15].…”