MEMS ultrasonic resonance separator based on two-dimensional normal mode

Separation of suspended particles with ultrasonic radiation force suggests advantages in MEMS. But there are some difficulties to position the outlets in MEMS ultrasonic separator based on one-dimensional resonance. In this paper, a new type of MEMS ultrasonic resonance separator, where two anti-phase PZT-transducers are employed to generalize two-dimensional normal mode, is analyzed. This new separator is designed to form clean and turbid streams along lateral direction. Then the outlets would be easily located along the flow. A mathematics model of sound field in fluid layer is established and applied to analyze the one-dimensional resonance separator and the new two-dimensional resonance separator. The frequency condition to form (1,1) normal mode is indicated. The structural model of this new separator is also exhibited, and the special design for training wall is introduced. At last, the temporal-average energy densities and the ultrasonic radiation force potential of (1,1) normal mode in the fluid layer are calculated. Then the limitation for the properties of the particles and the fluid in this separator is deduced according to the solution.