Abstract
Ultrasonic cavitation treatment of melt significantly improves the downstream properties and quality of conventional and advanced metallic materials. However, the transfer of this technology has been hindered by difficulties in treating large volumes of liquid metal. To improve the understanding of cavitation processing efficiency, the Full Cavitation Model, which is derived from a reduced form of the Rayleigh-Plesset equation, is modified and applied to the two-phase problem of bubble propagation in liquid melt. Numerical simulations of the sound propagation are performed in the microsecond time scale to predict the maximum and minimum acoustic pressure amplitude fields in the domain. This field is applied to the source term of the bubble transport equation to predict the generation and destruction of cavitation bubbles in a time scale relevant to the fluid flow. The use of baffles to limit flow speed in a launder conduit is studied numerically, to determine the optimum configuration that maximizes the residence time of the liquid in high cavitation activity regions. With this configuration, it is then possible to convert the batch processing of liquid metal into a continuous process. The numerical simulations will be validated against water and aluminium alloy experiments, carried out at Brunel University.
Highlights
Significant improvement of quality and properties in metallic materials is observed when melt is treated with ultrasound [1][2]
This technology has not been successfully transferred to the industry due to the difficulty in treating large volumes of liquid metal, as is required by processes such as continuous casting
The authors derived source terms for the bubble mass fraction transport equation from the Rayleigh-Plesset equation [6], which governs the evolution of a spherical bubble [7], to predict the formation and collapse of bubbles in cavitating flows
Summary
Significant improvement of quality and properties in metallic materials is observed when melt is treated with ultrasound [1][2] These improvements are primarily due to ultrasonic cavitation, with the creation, growth, pulsation, and collapse of bubbles in the liquid. The full cavitation model was developed by Athavale et al [3][4] to provide the capability for multidimensional simulation of cavitating flows, the modelling of which is crucial to the design of many engineering devices [5] In their approach, the authors derived source terms for the bubble mass fraction transport equation from the Rayleigh-Plesset equation [6], which governs the evolution of a spherical bubble [7], to predict the formation and collapse of bubbles in cavitating flows.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
