Effect of ultrasonic intensification on synthesis of nano-sized particles with an impinging jet reactor

The preparation of nanoparticles can be conducted in a fast way by intensifying the micromixing due to the enhanced turbulence in an impinging jet Reactor (IJR) where the two linear liquid jets collide with high velocity to diminish the segregation. However, the micromixing is significantly affected by the occurrence of the stagnant region which may partially choke the reaction chamber. By imposing the ultrasound to the IJR, micro-scale turbulent eddies generated as the result of collapse of ultrasonically generated micro cavitation bubbles may generate a strong local shear. Such micro-scale turbulent vortices exert shear on the interface between the particles and surrounding fluid, resulting in uniform particle morphology and high surface area for chemical reaction. The paper aims to optimize the ultrasonic intensification effect on synthesis of nano-sized particles with desired homogeneity, reveal the governing mechanisms and present a kinetic model to describe the multiphase flow dynamics in the IJR. Except for the experimental method, numerical method was also used to demonstrate the impact of fluid dynamics on particle synthesis.