Modeling of Small-Sized Acoustic Particle Velocity Horn for MEMS Thermal Acoustic Particle Velocity Sensor

In this paper, a simplified and more accurate model for prediction of the amplification factor of millimeter-sized acoustic particle velocity horns has been proposed and experimentally verified. With scaling down of the horn, the conventional horn model gradually becomes less accurate, claiming for improved model. Compared with the previous horn model, the novelty of this work is that the effect of a viscous boundary layer is considered, resulting in performance aligning better with miniaturized sensors. A MEMS-based three-wire particle velocity sensor packaged in a small 3D-printed double-cone horn is tested in a standing wave tube. Experimental results agree well with theoretical expectations, with an error less than 5% within the experimental frequency range, which demonstrates the potential of the proposed model to offer possible resolutions in engineering applications.