Particle Separation in a Viscoelastic Medium Flowing Through a Grooved Microchannel Using Contactless Dielectrophoresis

In this work, we present a numerical study involving the separation of two particles, namely red blood cells (RBCs) and platelets using Contactless Dielectrophoresis. We have demonstrated the movement of RBCs and platelets and their subsequent separation in a viscoelastic flow in a grooved microchannel using dielectrophoresis (DEP). Contactless Dielectrophoresis (cDEP) is the method where the electrodes do not come in direct contact with the working fluid and hence are free from electrode contamination. This method utilises the action of DEP force on suspended particles on the basis of their difference in radii. The working fluid, having properties similar to human blood, is described by the Oldroyd-B model, and the cells (particles) are provided motion by dielectrophoretic (DEP) forces induced by the applied electric field. We have applied voltage to the microchannel using contactless electrodes with alternating potentials. These contactless electrodes are housed in the grooves of the microchannel. We have used a finite element model solver for computation. After numerical analysis, we have achieved and finally demonstrated clean separation of RBCs and platelets flowing in the viscoelastic working fluid and the changes in separation caused by changing the electric potential. Along with the separation, we have also studied the variation of electric potential and the distribution of electric field norm along the length of the microchannel. We have discussed the electric field nature and its application in the separation of the aforementioned particles.