title: CFD study of the flow pattern in an ultrasonic horn reactor: Introducing a realistic vibrating boundary condition.
abstract: Recently, great attention has been paid to predict the acoustic streaming field distribution inside the sonoreactors, induced by high-power ultrasonic wave generator. The focus of this paper is to model an ultrasonic vibrating horn and study the induced flow pattern with a newly developed moving boundary condition. The numerical simulation utilizes the modified cavitation model along with the "mixture" model for turbulent flow (RNG, k-ε), and a moving boundary condition with an oscillating parabolic-logarithmic profile, applied to the horn tip. This moving-boundary provides the situation in which the center of the horn tip vibrates stronger than that of the peripheral regions. The velocity field obtained by computational fluid dynamic was in a reasonably good agreement with the PIV results. The moving boundary model is more accurate since it better approximates the movement of the horn tip in the ultrasonic assisted process. From an optimizing point of view, the model with the new moving boundary is more suitable than the conventional models for design purposes because the displacement magnitude of the horn tip is the only fitting parameter. After developing and validating the numerical model, the model was utilized to predict various quantities such as cavitation zone, pressure field and stream function that are not experimentally feasible to measure.
authors: Process Simulation and Control Research Laboratory, School of Chemical Engineering, Iran University of Science and Technology, 16846 Tehran, Iran.
authors: Masoud
authors: M
authors: Rahimi
authors: School of Chemical Engineering, Iran University of Science and Technology, P.O. Box 16765-163, Tehran, Iran. Electronic address: movahedirad@iust.ac.ir.
authors: Salman
authors: S
authors: Movahedirad
authors: Process Simulation and Control Research Laboratory, School of Chemical Engineering, Iran University of Science and Technology, 16846 Tehran, Iran.
authors: Shahrokh
authors: S
authors: Shahhosseini
keywords: CFD; Moving boundary condition; PIV; Ultrasonic horn reactor