Numerical investigation of ternary particle separation in a microchannel with a wall-mounted obstacle using...

In recent years, microfluidic-based particle/cell manipulation techniques have catalyzed significant advances in several fields of science. As an efficient, precise, and label-free particle/cell manipulation technique, dielectrophoresis (DEP) has recently attracted widespread attention. This paper presents the design and investigation of a straight sheathless 3D microchannel with a wall-mounted trapezoidal obstacle for continuous-flow separation of three different populations of polystyrene (PS) particles (5, 10 and 20 µm) using DEP. An OpenFOAM code is developed to simulate and investigate the movement of particles in the microchannel. Then, the code is validated by performing various experimental tests using a microdevice previously fabricated in our lab. By comparing the numerical simulation results with the experimental tests, it can be claimed that the newly developed solver is highly accurate, and its results agree well with experimental tests. Next, the effect of various operational and geometrical parameters such as obstacle height, applied voltage, electrode pairs angle, and flow rate on the efficient focusing and separation of particles are numerically investigated. The results showed that efficient particle separation could only be achieved for obstacle heights of more than 350 µm. Furthermore, the appropriate voltage range for efficient particle separation is increased by decreasing the electrode angle as well as increasing the flow rate. Moreover, the results showed that by employing the appropriate channel design and operational conditions, at a maximum applied voltage of 10V, a sample flow rate of 2.5μL/min could be processed. The proposed design can be beneficial for integrating with lab-on-a-chip and clinical diagnosis applications due to advantages, such as simple design, no need for sheath flow, the simultaneous ternary separation of particles, and providing precise particle separation.