Estudo numérico de dispositivo acustofluídico com microcavidade cilíndrica

Abstract

The precision manipulation of microparticles in microfluidic devices has been the subject of numerous researches, due to its application in areas such as medicine and biology. Acustofluidics, an area that uses ultrasound as an external force for this manipulation, has gained strength in recent decades for being a compact, non-contact and versatile technique, in addition to its easy implementation in devices. This work has as main objective the numerical study of an acustofluidics device formed by a cylindrical microcavity, manufactured in polymer (resin), by 3D printing, the advantages of this device are its low production cost compared to chips made of silicon and its portability. Our model consists of a cylindrical cavity filled with water, where levitation and trapping is promoted, the cavity structure modeled in resin, with the exception of the cavity top, which is sealed by a glass slide, in addition to a piezoelectric ceramic coupled below the resin base which provides acoustic excitation of the device. We model the device using the finite element method using the commercial software COMSOL Multiphysicsr, in which we impute the boundary conditions for the solution of the differential equations of fluid dynamics, viscoelastic solid and piezoelectric material. We explore the symmetry of the problem using the software’s 2D Axisymmetric module. After the parametric studies, we obtained the best device configuration, for a cavity with an acoustic energy density of 1000 J m−3, with a levitation plane at the height of 130 µm in relation to the base of the cavity.