Design of acoustophoretic printing device with acoustic subwavelength focusing of fan resonant cavity

For the focusing problem of acoustic standing wave of subwavelength, an improved fan resonant cavity structure with multiple channels used for the acoustophoretic printing device is proposed, which consists of a three-layer fan structure with the fan radius being an integral multiple of the subwavelength length, and all the fan channels converge to produce Fabry-Perot resonance for subwavelength focusing. In this paper, Comsol software is used to simulate and analyze the effects of groove size, number of grooves, channel width and aperture size of hole on sound pressure amplitude. The results show that the structure achieves acoustic subwavelength focusing at a frequency of 20 kHz, and the sound pressure amplitude at the of focusing can reach about 18 000 Pa. On the basis of this sound pressure amplitude, it is expected that the acoustic printing device can eject droplets with higher viscosity and smaller diameters.