Acoustofluidic separation of microparticles: a numerical study

In this paper, two-dimensional simulations are performed to separate polystyrene (PS) and polymethyl methacrylate (PMMA) particles suspended in water using an acoustic field. The acoustic waves are generated by two aluminum interdigitated transducers (IDTs) over a piezoelectric substrate. The effect of input power, inlet flow rate, acoustic frequency, and distance between IDTs and channel on separation efficiency is evaluated by considering channel thickness. It is observed that the separation efficiency is enhanced by increasing acoustic frequency and input power. Also, as the inlet flow rate and distance between IDTs and channel decrease, the separation efficiency increases. The optimum values for input power, flow rate, frequency, and distance are 1.4 W, 0.2 ml/min, 5 MHz, and 75 µm, respectively, and a maximum separation of 88% is achieved.