Estimation of ultrasound induced cavitation bubble temperatures in aqueous solutions

Abstract

Mean acoustic cavitation bubble temperatures have been measured in a series of aqueous solutions containing C(1)-C(5) aliphatic alcohols, at 355 kHz. The method relies on the distribution of hydrocarbon product yields produced from the recombination of methyl radicals generated on the thermal decomposition of the alcohols. The mean bubble temperature was found to decrease with increasing concentration of alcohol with the effect being more pronounced the higher the molecular weight (the lower the vapour pressure) of the alcohol. It is shown that the decrease in the temperatures measured correlates very well with an increase in the surface excess of the alcohol, similar to that previously reported for the quenching of sonoluminescence in aqueous solutions containing alcohols [J. Phys. Chem. B 101 (1997) 10845; J. Phys. Chem. B 103 (1999) 9231]. The measured temperatures ranged from 4600+/-200 K at zero alcohol concentration to 2300+/-200 K at 0.5 M t-butanol. The validity of the method is discussed and it is concluded that even though a number of assumptions need to be applied the results appear to indicate that the method gives an accurate measure of the mean bubble temperature.

Variable-Frequency Ultrasonic Treatment on Microstructure and Mechanical Properties of ZK60 Alloy during Large Diameter Semi-Continuous Casting

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Degradation of pharmaceuticals by ultrasound-based advanced oxidation process

“…Three main reaction zones are reported in a cavitating bubble (Chowdhury and Viraraghavan 2009 The most reactive zone is the interior of the cavitating bubble. The water molecules undergo pyrolysis inside the cavity to produce Á OH and H Á (Petrier et al 1996(Petrier et al , 1998Rae et al 2005). The target pollutants either undergo pyrolysis or react with the free radicals.…”

SiO2@TiO2 Coating: Synthesis, Physical Characterization and Photocatalytic Evaluation

“…A method that uses sonochemistry has smaller reaction times, is more likely to undergo a complete chemical reaction and more ordered crystallization. Sonochemistry is a process of cavitation that refers to the rapid growth and collapse of implosion bubbles in a liquid in an unusual reaction environment [13,14]. Therefore, this article reports the development of a SiO 2 @TiO 2 coating applicable to cement based materials, such as mortars and glass.…”