Numerical simulation of ultrasonic field within the large-scale Al alloy melts treated by scalable sonotrodes

摘要

The single sonotrode-generated ultrasonic field cannot fully spread the whole volume of large-scale Al alloy melt. Then, the effective volume of Al alloy melt processed by ultrasound is very limited. Thus, single sonotrode does not completely satisfy the casting of large-scale Al alloys. Scalable power ultrasounds provide an alternative way for this dilemma. However, only the optimal configuration of scalable power ultrasounds lead to a high efficiency during casting. In the present work, numerical simulation of ultrasonic field within the large-scale Al alloy melts was carried out for three cases, i.e. single sonotrode, three parallel sonotrodes, and three non-parallel sonotrodes that were configured in various ways. Simulation work mainly focused on investigating (a) the three dimensional (3D) distribution of acoustic pressure under different configurations, (b) the 2D distribution of acoustic pressure along each sonotrode’s axis, (c) the 1D distribution of acoustic pressure along the central axis of large-scale Al alloy melts, and (d) the mean acoustic energy density and the cavitation zones as well. Meanwhile, the 3D dynamic evolution of acoustic pressure fields for different configurations was also analyzed in one cyclic vibration time. Compared with single sonotrode, three scalable sonotrodes (when configured in an appropriate way) enable to generate larger high-pressure zones, increase the mean acoustic energy density, and enlarge the volume fraction of potential cavitation zones. The present work raises insights for the configuration and optimization of scalable sonotrodes for casting the large-scale metallic materials, like Al alloy.