Sonochemistry is the use of cavitation for achieving a chemical conversion. Implosion of microbubbles (5-20 μm in size) can generate localized extreme temperatures of 10000 K and pressures up to 1000 bar, the conditions of the surrounding liquid remaining ambient. Therefore high temperature chemical conversions can occur at ambient conditions. Reaction products can be used for synthesis of fine chemicals, food ingredients or pharmaceuticals, or for break-down of recalcitrant components in water. However, industrial application of sonochemistry is limited by the energy inefficiency of large scale sonochemical reactors caused by energy losses due to insufficient focus of energy tranfer to the microbubble, as well as wall and bubble interference effects and equipment size. The challenge is therefore to gain full control over the cavitation process and to improve the energy efficiency of the process, by miniaturizing sonochemical reactors. Design, development and energy testing of efficient sonochemical microreactors are studied both experimentally and numerically. Considering its crucial role in chemical conversions, special attention in analytical modeling is given to the temperature field description.
Figure 1: Principle of sonochemistry: a gas bubble in a liquid is subjected to an ultrasonic signal (image 1), shrinks and collapses (image 2 & 3). Temperature and pressure of the gas increase tremendously, thereby producing radicals (image 4), which react with nearby molecules of any suitable type, e.g. contaminants.
Info: Detlef Lohse
Researchers: Laura Stricker, Andrea Prosperetti, Detlef Lohse.
Collaborators: David Fernandez Rivas (PhD-student) and Han Gardeniers from Mesoscale Chemical Systems at U Twente; Joost Rooze (PhD-student) and Jos Keurentjes from Chemical Reactor Engineering at TU Eindhoven.
Embedding: MESA+, JMBC
|Phase diagrams for sonoluminescing bubbles: A comparison between experiment and theory|
R. Tögel and D. Lohse
J. Chem. Phys. 118, 1863–1875 (2003)BibTeΧ