Sensitivity of Contactless Ultrasound Processing to Variations of the Free Surface of the Melt with Induction Heating
Contactless ultrasound treatment can be useful for high-temperature or reactive alloys in the liquid state, where contact with an immersed vibrating probe is undesirable. The alternating component of the Lorentz force can generate sound pressure levels leading to cavitation of gas bubbles in the melt, through acoustic resonance . Resonance is a function of the speed of sound in the liquid, the shape of the volume containing it and surrounding boundary conditions. Induction forces applied to a crucible lead to bulk stirring and in general deform the free surface, whose precise shape may influence the resonance conditions. This effect is investigated here by multi-physics computer modelling. Calculated results for aluminium melts are compared with experimental data and conclusions are drawn as to the sensitivity to process parameters and the reliability of this type of ultrasound metal processing.
KeywordsUltrasound treatment Liquid metal Electromagnetic induction heating Acoustic resonance Cavitation
The authors acknowledge financial support from the ExoMet Project (co-funded by the European Commission, contract FP7-NMP3-LA-2012-280421, by the European Space Agency and by the individual partner organizations).
- 3.G.I. Eskin, D.G. Eskin, Ultrasonic treatment of light alloy melts (CRC Press, Boca Raton, FL, 2015), pp. 1–346Google Scholar
- 10.D.J. Jarvis, K. Pericleous, V. Bojarevics, C. Lehnert, Manufacturing of a metal component or a metal matrix composite component involving contactless induction of high-frequency vibrations. Patent EP3038771A1. www.google.com/patents/WO2015028065A1 (2013)
- 11.G. Djambazov, V. Bojarevics, B. Lebon, K. Pericleous, Contactless acoustic wave generation in a melt by electromagnetic induction. in Light Metals, ed. by J. Grandfield (Wiley, Hoboken, NJ, USA, 2014), pp. 1379–1382Google Scholar