Investigation of Corner Radius Effect in a Piezoelectric Ultrasonic Microcontainer to Improve Nanoemulsion Stability

Utilizing ultrasonic waves for nanoemulsion preparation is one of the most important research topics related to the pharmaceutical, food, mechanical and chemical engineering industries. The number and arrangement of the piezoelectric ceramics (PZTs), the frequency of their excitation and the fillet radius of container’s internal edges are effective parameters in the design and optimization of an ultrasonic bath which cause either resonance or cancelation of the waves. In this paper, using COMSOL Multiphysics software, the simulations of the edge fillet radius effect in four different PZTs layouts of an ultrasonic microcontainer were performed in 36 possible configurations. In this way, the edge fillet radii and excitation frequencies of PZTs are simulated in zero, 2.5 and 5 mm, and 20, 200 and 300 kHz respectively. It has been shown that although sharp edges elimination leads to improve acoustic energy density at all frequencies, however, arrangements which have more PZTs or lower frequencies are affected more. Experimental works were performed to prepare nanoemulsions in two modes of ultrasonic bath: with and without filleted edges. While approving the simulation outputs, the experimental results showed that the use of ultrasonic bath with filleted edges increased the stability of the nanoemulsion.