2014 Volume 54 Issue 8 Pages 1830-1835
The main objectives of this study is to determine the fluid flow characteristics and cavitation phenomena during molten A356 alloys processed via high power ultrasonic treatment (UST) as well as the resulting solidification microstructure of the ultrasonically processed A356 alloys. A previously developed UST modeling approach is applied to obtain the simulation results in this study. The modeling approach consists of two main models: (1) A CFD UST cavitation model is applied to simulate acoustic streaming, cavitation and bubble dynamics during molten alloy processing and (2) A stochastic mesoscopic modeling to predict microstructure evolution during alloy solidification. The first model can predict the amount of the cavitated phase that is used to determine the number of potential nuclei formed due to the UST processing. The second model uses the predicted number of nuclei from the first model as an input to predict the microstructure evolution during the solidification of cast alloys. In addition, the UST model predicts the fluid flow characteristics that include flow profile, velocity vectors and magnitude, pressure contours, and streamlines under two different gravity conditions. The fluid flow characteristics are analyzed to ensure that proper ultrasonic stirring and cavitation of the melt are achieved.