Design and Optimization of a Multi-Purpose, High-Power Ultrasonic Reactor
Many industrial applications require special treatments for fluid products, such as: deagglomeration, dispersion, homogenization, emulsion, special mixing or even catalysis of chemical reactions. Such effects can be obtained through cavitation in a closed ultrasonic reactor, in which it is possible to reach very high sonication intensity. Speaking of a 'flow-cell' type reactor, the ultrasonic power must be enough to process the product in the time available, so very high power ratings of the order of kW or even tens of kW may be necessary.
COMSOL Multiphysics® was used to design the special reactor, consisting in: a high-power piezoelectric converter, a cylindrical flow cell, and a special sonotrode, with 'tuned rings'. A 'tuned ring' sonotrode is very complicated to design because the geometry of the rings must be determined in order to have both high-pressure field levels in the surrounding fluid, both limitation of spurious resonances modes. Moreover, the flow cell and the piezo-transducer must be optimized with great care, in order to have maximum efficiency and minimum thermal losses.
Therefore the system was designed with a parametrized piezo/structural/acoustic COMSOL Multiphysics® model and a complete optimization process was performed.
The simulation results were up to the required level of efficiency and very high ultrasonic pressure values can be obtained in the reactor. Finally, a reactor prototype was built and used for a sonochemical application project.
