Study on the laminar flow in MEMS separator based on two-dimensional normal mode

Particles in fluid suffer the acoustic radiation force from the different physical characteristic between suspended particle and host liquid, so particles would move to predetermined positions in certain sound field. The separation technique utilizing acoustic radiation force is a promising alternative method to conventional technologies, especially in Micro Electro Mechanical Systems (MEMS). This paper describes an MEMS ultrasonic separator´s model operating on two-dimensional normal mode. The particles suspending in fluid are driven to bands in two-dimensional normal mode excited by two anti-phase PZT transducers, so that the outlets are easily placed at the end of cavity in order to provide perfect laminar to dividually carry clean and turbid liquid out. This cavity is suitably fabricated in silicon and Pyrex with common MEMS processing. The laminar flow in the chamber, including development near inlet and partition near outlets, is simulated to optimize the channel. At last, a MEMS separator with transient channels is designed in this paper.