Air coupled power ultrasound is an emerging green technology particularly promising for food, chemical, medical and environmental applications. This technology is based on the proper exploitation of the nonlinear effects produced in the propagation through air or gas of high amplitude ultrasonic waves. These effects, occurring as a consequence of compressions and rarefactions above specific intensity thresholds, mainly include radiation pressure and acoustic streaming. This work deals with several examples of innovative processes assisted by air- and gasborne power ultrasound. Specifically the application of air coupled power ultrasound in the extraction of substances by means of fluids under supercritical conditions, convective drying at high and low temperature, and agglomeration of aerosol particles, will be described and discussed.
Acknowledgements
This project has been partially funded by the Spanish Ministry of Economy and Competitiveness (Project DPI2012-37466-C03-01) and the European project FP7-Fission-2012 PASSAM 323217.
