Design and Simulation of Silicon-Based Ultrasonic Nozzles for Production of Monodispersed Droplets

This paper reports the design and simulation of Si-based ultrasonic nozzles (or atomizers) that consist of multiple Fourier horns at ultrasonic frequency ranging from 0.57 to 2.75 MHz. Such high frequency ultrasonic nozzles should produce monodispersed droplets (or drops) 2 to 6 μm in diameter, which are ideal to efficiently target medications to different locations within the respiratory system depending on the site of disease. 3-D simulations on vibration mode shape and impedance of the nozzles using a commercial finite element method (FEM) program, ANSYS, yield resonant frequencies of pure longitudinal vibration in good agreement with the measured values. The mode shape simulation also shows that at the resonant frequency the longitudinal vibration amplitude gain at the nozzle tip for 3-horn nozzle is 8, four times that for a single-horn nozzle.